* [PATCH 3/4] dt-bindings: net: dsa: remove obsolete dsa.txt
From: Akash Sukhavasi @ 2026-05-29 5:22 UTC (permalink / raw)
To: devicetree
Cc: Andrew Lunn, Vladimir Oltean, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, Simon Horman, Jonathan Corbet, Shuah Khan, netdev,
linux-kernel, linux-doc
In-Reply-To: <20260529052246.4934-1-akash.sukhavasi@gmail.com>
dsa.txt has been a redirect to dsa.yaml since commit bce58590d1bd
("dt-bindings: net: dsa: Add DSA yaml binding") introduced the .yaml
schema. The .yaml has the same filename in the same directory, making
this redirect unnecessary for discoverability.
Two files still reference dsa.txt, forcing readers through an extra
hop to reach the .yaml. The stub has not been touched since August
2020. Update references in lan9303.txt and
Documentation/networking/dsa/dsa.rst to point directly to dsa.yaml
and remove the stub.
Signed-off-by: Akash Sukhavasi <akash.sukhavasi@gmail.com>
---
Documentation/devicetree/bindings/net/dsa/dsa.txt | 4 ----
Documentation/devicetree/bindings/net/dsa/lan9303.txt | 2 +-
Documentation/networking/dsa/dsa.rst | 2 +-
3 files changed, 2 insertions(+), 6 deletions(-)
delete mode 100644 Documentation/devicetree/bindings/net/dsa/dsa.txt
diff --git a/Documentation/devicetree/bindings/net/dsa/dsa.txt b/Documentation/devicetree/bindings/net/dsa/dsa.txt
deleted file mode 100644
index dab208b5c7c7..000000000000
--- a/Documentation/devicetree/bindings/net/dsa/dsa.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-Distributed Switch Architecture Device Tree Bindings
-----------------------------------------------------
-
-See Documentation/devicetree/bindings/net/dsa/dsa.yaml for the documentation.
diff --git a/Documentation/devicetree/bindings/net/dsa/lan9303.txt b/Documentation/devicetree/bindings/net/dsa/lan9303.txt
index 46a732087f5c..0337c2ccfa9a 100644
--- a/Documentation/devicetree/bindings/net/dsa/lan9303.txt
+++ b/Documentation/devicetree/bindings/net/dsa/lan9303.txt
@@ -16,7 +16,7 @@ Optional properties:
Subnodes:
The integrated switch subnode should be specified according to the binding
-described in dsa/dsa.txt. The CPU port of this switch is always port 0.
+described in dsa/dsa.yaml. The CPU port of this switch is always port 0.
Note: always use 'reg = <0/1/2>;' for the three DSA ports, even if the device is
configured to use 1/2/3 instead. This hardware configuration will be
diff --git a/Documentation/networking/dsa/dsa.rst b/Documentation/networking/dsa/dsa.rst
index fd3c254ced1d..42a99f5dfa2e 100644
--- a/Documentation/networking/dsa/dsa.rst
+++ b/Documentation/networking/dsa/dsa.rst
@@ -509,7 +509,7 @@ Device Tree
-----------
DSA features a standardized binding which is documented in
-``Documentation/devicetree/bindings/net/dsa/dsa.txt``. PHY/MDIO library helper
+``Documentation/devicetree/bindings/net/dsa/dsa.yaml``. PHY/MDIO library helper
functions such as ``of_get_phy_mode()``, ``of_phy_connect()`` are also used to query
per-port PHY specific details: interface connection, MDIO bus location, etc.
--
2.54.0
^ permalink raw reply related
* Re: [PATCH linux next] tools headers UAPI: sync linux/taskstats.h for procacct.c
From: wang.yaxin @ 2026-05-29 4:44 UTC (permalink / raw)
To: akpm, linux
Cc: fan.yu9, yang.yang29, corbet, linux-kernel, linux-doc, xu.xin16,
linux
In-Reply-To: <20260527125034.ba695164344d2645dd055af0@linux-foundation.org>
>> From: Wang Yaxin <wang.yaxin@zte.com.cn>
>>
>> Background
>> ==========
>> After commit 9b93f7e32774 ("tools/getdelays: use the static UAPI
>> headers from tools/include/uapi"), the Makefile was changed to use
>> -I../include/uapi/ instead of -I../../usr/include to ensure tools
>> always use the up-to-date UAPI headers.
>>
>> However, only linux/taskstats.h was added to tools/include/uapi/ in
>> commit e5bbb35a07b3 ("tools headers UAPI: sync linux/taskstats.h"),
>> but linux/acct.h was missing.
>
>Please let's Cc the author of both of these commits!
Ok
>> Problem
>> =======
>> This causes procacct.c to fail to compile with:
>>
>> procacct.c:234:37: error: 'AGROUP' undeclared (first use in this function)
>>
>> gcc -I../include/uapi/ getdelays.c -o getdelays
>> gcc -I../include/uapi/ procacct.c -o procacct
>> procacct.c: In function ‘print_procacct’:
>> procacct.c:234:37: error: ‘AGROUP’ undeclared (first use in this function)
>> did you mean ‘NOGROUP’?
>> 234 | , t->version >= 12 ? (t->ac_flag & AGROUP ? 'P' : 'T') : '?'
>> | ^~~~~~
>> | NOGROUP
>> procacct.c:234:37: note: each undeclared ident
>>
>> because procacct.c uses the AGROUP macro defined in linux/acct.h.
>>
>> Solution
>> ========
>> Add the missing linux/acct.h to complete the static UAPI header set.
>
>It has always annoyed me that we do this by copying the file. I'm
>surprised that there isn't a way of using the original file directly.
Using -I../../usr/include avoids duplicate headers and relies on a
single original copy, but requires make headers_install. This aligns
with commit 9b93f7e32774 ("tools/getdelays: use the static UAPI headers
from tools/include/uapi").
Using -I../include/uapi/ keeps two separate header copies, which may
cause inconsistencies when one copy is updated. Can we optimize it
with symbolic links, or revert to the first solution?
Thanks
Yaxin
^ permalink raw reply
* Re: [PATCH] docs: zh_TW: process: localize terminologies and improve fluency in 8.Conclusion
From: Dongliang Mu @ 2026-05-29 4:33 UTC (permalink / raw)
To: CHEN-YOU-0331
Cc: Hu Haowen, Jonathan Corbet, Shuah Khan, linux-doc, linux-kernel
In-Reply-To: <20260528041330.23247-1-chenyou910331@gmail.com>
On Thu, May 28, 2026 at 12:14 PM CHEN-YOU-0331 <chenyou910331@gmail.com> wrote:
>
> Translate PRC tech terms into Taiwanese tech terms (e.g.,
> 內核 -> 核心, 代碼 -> 程式碼, 軟件 -> 軟體) to improve
> readability for local developers. Also, rephrase several
> awkward sentences to make the document more fluent.
I am not very familiar with Taiwanese tech terms. After checking with
LLMs, I am almost fine with these term changes, except one place.
>
> Signed-off-by: CHEN-YOU-0331 <chenyou910331@gmail.com>
> ---
> .../zh_TW/process/8.Conclusion.rst | 45 +++++++++----------
> 1 file changed, 22 insertions(+), 23 deletions(-)
>
> diff --git a/Documentation/translations/zh_TW/process/8.Conclusion.rst b/Documentation/translations/zh_TW/process/8.Conclusion.rst
> index d1634421b62c..823969cf793d 100644
> --- a/Documentation/translations/zh_TW/process/8.Conclusion.rst
> +++ b/Documentation/translations/zh_TW/process/8.Conclusion.rst
> @@ -14,42 +14,41 @@
>
> .. _tw_development_conclusion:
>
> -更多信息
> +更多資訊
> ========
>
> -關於Linux內核開發和相關主題的信息來源很多。首先是在內核源代碼分發中找到的
> -文檔目錄。頂級
> +關於Linux核心開發和相關主題的資訊來源很多。首先是在核心原始碼分發中找到的
> +文件目錄。頂級
> :ref:`Documentation/translations/zh_CN/process/howto.rst <tw_process_howto>`
> 文件是一個重要的起點；
> :ref:`Documentation/translations/zh_CN/process/submitting-patches.rst <tw_submittingpatches>`
> -也是所有內核開發人員都應該閱讀的內容。許多內部內核API都是使用kerneldoc機制
> -記錄的；“make htmldocs”或“make pdfdocs”可用於以HTML或PDF格式生成這些文檔
> -（儘管某些發行版提供的tex版本會遇到內部限制，無法正確處理文檔）。
> -
> -不同的網站在各個細節層次上討論內核開發。本文作者想謙虛地建議用 https://lwn.net/
> -作爲來源；有關許多特定內核主題的信息可以通過以下網址的 LWN 內核索引找到：
> +也是所有核心開發人員都應該閱讀的內容。許多內部核心API都是使用kerneldoc機制
"核心API" may cause confusion to me, which means "core API" other than
"kernel API".
Dongliang Mu
> +記錄的；“make htmldocs”或“make pdfdocs”可用於以HTML或PDF格式生成這些文件
> +（儘管某些發行版提供的tex版本會遇到內部限制，無法正確處理文件）。
>
> +不同的網站在各個細節層次上討論核心開發。本文作者想謙虛地建議用 https://lwn.net/
> +作爲來源；有關許多特定核心主題的資訊可以通過以下網址的 LWN 核心索引找到:
> http://lwn.net/kernel/index/
>
> -除此之外，內核開發人員的一個寶貴資源是：
> +除此之外，核心開發人員的一個寶貴資源是：
>
> https://kernelnewbies.org/
>
> -當然，也不應該忘記 https://kernel.org/ ，這是內核發佈信息的最終位置。
> +當然，也不應該忘記 https://kernel.org/ ，這是核心發佈資訊的最終位置。
>
> -關於內核開發有很多書：
> +關於核心開發有很多書：
>
> 《Linux設備驅動程序》第三版（Jonathan Corbet、Alessandro Rubini和Greg Kroah Hartman）
> 線上版本在 http://lwn.net/kernel/ldd3/
>
> - 《Linux內核設計與實現》（Robert Love）
> + 《Linux核心設計與實現》（Robert Love）
>
> - 《深入理解Linux內核》(Daniel Bovet和Marco Cesati）
> + 《深入理解Linux核心》(Daniel Bovet和Marco Cesati）
>
> 然而，所有這些書都有一個共同的缺點：它們上架時就往往有些過時，而且已經上架
> -一段時間了。不過，在那裏還是可以找到相當多的好信息。
> +一段時間了。不過，在那裏還是可以找到相當多的好資訊。
>
> -有關git的文檔，請訪問：
> +有關git的文件，請訪問：
>
> https://www.kernel.org/pub/software/scm/git/docs/
>
> @@ -58,16 +57,16 @@
> 結論
> ====
>
> -祝賀所有通過這篇冗長的文檔的人。希望它能夠幫助您理解Linux內核是如何開發的，
> +祝賀所有通過這篇冗長的文件的人。希望它能夠幫助您理解Linux核心是如何開發的，
> 以及您如何參與這個過程。
>
> -最後，重要的是參與。任何開源軟件項目都不會超過其貢獻者投入其中的總和。Linux
> -內核的發展速度和以前一樣快，因爲它得到了大量開發人員的幫助，他們都在努力使它
> -變得更好。內核是一個最成功的例子，說明了當成千上萬的人爲了一個共同的目標一起
> +最後，重要的是參與。任何開源軟體專案都不會超過其貢獻者投入其中的總和。Linux
> +核心的發展速度和以前一樣快，因爲它得到了大量開發人員的幫助，他們都在努力使它
> +變得更好。核心是一個最成功的例子，說明了當成千上萬的人爲了一個共同的目標一起
> 工作時，可以做出什麼。
>
> -不過，內核總是可以從更大的開發人員基礎中獲益。總有更多的工作要做。但是同樣
> -重要的是，Linux生態系統中的大多數其他參與者可以通過爲內核做出貢獻而受益。使
> -代碼進入主線是提高代碼質量、降低維護和分發成本、提高對內核開發方向的影響程度
> +不過，核心總是可以從更大的開發人員基礎中獲益。總有更多的工作要做。但是同樣
> +重要的是，Linux生態系統中的大多數其他參與者可以通過爲核心做出貢獻而受益。使
> +程式碼進入主線是提高程式碼品質、降低維護和分發成本、提高對核心開發方向的影響程度
> 等的關鍵。這是一種共贏的局面。啓動你的編輯器，來加入我們吧；你會非常受歡迎的。
>
> --
> 2.43.0
>
>
^ permalink raw reply
* Re: [PATCH] docs: zh_TW: process: localize terminologies and improve fluency in 8.Conclusion
From: Alex Shi @ 2026-05-29 4:04 UTC (permalink / raw)
To: Jonathan Corbet, CHEN-YOU-0331, Hu Haowen
Cc: Shuah Khan, linux-doc, linux-kernel, alexs, Dongliang Mu,
Yanteng Si
In-Reply-To: <87cxyfllhr.fsf@trenco.lwn.net>
On 2026/5/28 21:19, Jonathan Corbet wrote:
> CHEN-YOU-0331<chenyou910331@gmail.com> writes:
>
>> Translate PRC tech terms into Taiwanese tech terms (e.g.,
>> 內核 -> 核心, 代碼 -> 程式碼, 軟件 -> 軟體) to improve
>> readability for local developers. Also, rephrase several
>> awkward sentences to make the document more fluent.
>>
>> Signed-off-by: CHEN-YOU-0331<chenyou910331@gmail.com>
>> ---
>> .../zh_TW/process/8.Conclusion.rst | 45 +++++++++----------
>> 1 file changed, 22 insertions(+), 23 deletions(-)
> I, of course, am in no position to judge these changes, and I worry
> about getting into some sort of turf war over differences in
> terminology. Alex, are you able to give me a recommendation on this
> change?
>
CC to Dongliang and Yanteng,
Yes, we could take care of tradition Chinese translation in Haowen's
absence.
thanks!
Alex
> Meanwhile, the signoff should have your proper name, please.
>
> Thanks,
>
> jon
>
^ permalink raw reply
* [PATCH v3 11/11] selftests/liveupdate: Add stress-files kexec test
From: Pasha Tatashin @ 2026-05-29 3:21 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
Add a new luo_stress_files kexec test that verifies preserving and
retrieving 500 files across a kexec reboot.
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
tools/testing/selftests/liveupdate/Makefile | 1 +
.../selftests/liveupdate/luo_stress_files.c | 101 ++++++++++++++++++
2 files changed, 102 insertions(+)
create mode 100644 tools/testing/selftests/liveupdate/luo_stress_files.c
diff --git a/tools/testing/selftests/liveupdate/Makefile b/tools/testing/selftests/liveupdate/Makefile
index ed7534468386..30689d22cb02 100644
--- a/tools/testing/selftests/liveupdate/Makefile
+++ b/tools/testing/selftests/liveupdate/Makefile
@@ -7,6 +7,7 @@ TEST_GEN_PROGS += liveupdate
TEST_GEN_PROGS_EXTENDED += luo_kexec_simple
TEST_GEN_PROGS_EXTENDED += luo_multi_session
TEST_GEN_PROGS_EXTENDED += luo_stress_sessions
+TEST_GEN_PROGS_EXTENDED += luo_stress_files
TEST_FILES += do_kexec.sh
diff --git a/tools/testing/selftests/liveupdate/luo_stress_files.c b/tools/testing/selftests/liveupdate/luo_stress_files.c
new file mode 100644
index 000000000000..b6a0c3899890
--- /dev/null
+++ b/tools/testing/selftests/liveupdate/luo_stress_files.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright (c) 2026, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ *
+ * Validate that LUO can handle a large number of files per session across
+ * a kexec reboot.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include "luo_test_utils.h"
+
+#define NUM_FILES 500
+#define STATE_SESSION_NAME "kexec_many_files_state"
+#define STATE_MEMFD_TOKEN 9999
+#define TEST_SESSION_NAME "many_files_session"
+
+/* Stage 1: Executed before the kexec reboot. */
+static void run_stage_1(int luo_fd)
+{
+ int session_fd, ret, i;
+
+ ksft_print_msg("[STAGE 1] Increasing ulimit for open files...\n");
+ ret = luo_ensure_nofile_limit(NUM_FILES);
+ if (ret == -EPERM)
+ ksft_exit_skip("Insufficient privileges to set RLIMIT_NOFILE\n");
+ if (ret < 0)
+ ksft_exit_fail_msg("luo_ensure_nofile_limit failed: %s\n", strerror(-ret));
+
+ ksft_print_msg("[STAGE 1] Creating state file for next stage (2)...\n");
+ create_state_file(luo_fd, STATE_SESSION_NAME, STATE_MEMFD_TOKEN, 2);
+
+ ksft_print_msg("[STAGE 1] Creating test session '%s'...\n", TEST_SESSION_NAME);
+ session_fd = luo_create_session(luo_fd, TEST_SESSION_NAME);
+ if (session_fd < 0)
+ fail_exit("luo_create_session");
+
+ ksft_print_msg("[STAGE 1] Preserving %d files...\n", NUM_FILES);
+ for (i = 0; i < NUM_FILES; i++) {
+ char data[64];
+
+ snprintf(data, sizeof(data), "file-data-%d", i);
+ if (create_and_preserve_memfd(session_fd, i, data) < 0)
+ fail_exit("create_and_preserve_memfd for index %d", i);
+ }
+
+ ksft_print_msg("[STAGE 1] Successfully preserved %d files.\n", NUM_FILES);
+
+ close(luo_fd);
+ daemonize_and_wait();
+}
+
+/* Stage 2: Executed after the kexec reboot. */
+static void run_stage_2(int luo_fd, int state_session_fd)
+{
+ int session_fd;
+ int i, stage;
+
+ ksft_print_msg("[STAGE 2] Starting post-kexec verification...\n");
+
+ restore_and_read_stage(state_session_fd, STATE_MEMFD_TOKEN, &stage);
+ if (stage != 2) {
+ fail_exit("Expected stage 2, but state file contains %d",
+ stage);
+ }
+
+ ksft_print_msg("[STAGE 2] Retrieving test session '%s'...\n", TEST_SESSION_NAME);
+ session_fd = luo_retrieve_session(luo_fd, TEST_SESSION_NAME);
+ if (session_fd < 0)
+ fail_exit("luo_retrieve_session");
+
+ ksft_print_msg("[STAGE 2] Verifying %d files...\n", NUM_FILES);
+ for (i = 0; i < NUM_FILES; i++) {
+ char data[64];
+
+ snprintf(data, sizeof(data), "file-data-%d", i);
+ if (restore_and_verify_memfd(session_fd, i, data) < 0)
+ fail_exit("restore_and_verify_memfd for index %d", i);
+ }
+
+ ksft_print_msg("[STAGE 2] Finishing test session...\n");
+ if (luo_session_finish(session_fd) < 0)
+ fail_exit("luo_session_finish for test session");
+ close(session_fd);
+
+ ksft_print_msg("[STAGE 2] Finalizing state session...\n");
+ if (luo_session_finish(state_session_fd) < 0)
+ fail_exit("luo_session_finish for state session");
+ close(state_session_fd);
+
+ ksft_print_msg("\n--- MANY-FILES KEXEC TEST PASSED (%d files) ---\n",
+ NUM_FILES);
+}
+
+int main(int argc, char *argv[])
+{
+ return luo_test(argc, argv, STATE_SESSION_NAME,
+ run_stage_1, run_stage_2);
+}
--
2.53.0
^ permalink raw reply related
* [PATCH v3 10/11] selftests/liveupdate: Add stress-sessions kexec test
From: Pasha Tatashin @ 2026-05-29 3:21 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
Add a new test that creates 2000 LUO sessions before a kexec
reboot and verifies their presence after the reboot. This ensures
that the linked-block serialization mechanism works correctly for
a large number of sessions.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
tools/testing/selftests/liveupdate/Makefile | 1 +
.../liveupdate/luo_stress_sessions.c | 102 ++++++++++++++++++
2 files changed, 103 insertions(+)
create mode 100644 tools/testing/selftests/liveupdate/luo_stress_sessions.c
diff --git a/tools/testing/selftests/liveupdate/Makefile b/tools/testing/selftests/liveupdate/Makefile
index 080754787ede..ed7534468386 100644
--- a/tools/testing/selftests/liveupdate/Makefile
+++ b/tools/testing/selftests/liveupdate/Makefile
@@ -6,6 +6,7 @@ TEST_GEN_PROGS += liveupdate
TEST_GEN_PROGS_EXTENDED += luo_kexec_simple
TEST_GEN_PROGS_EXTENDED += luo_multi_session
+TEST_GEN_PROGS_EXTENDED += luo_stress_sessions
TEST_FILES += do_kexec.sh
diff --git a/tools/testing/selftests/liveupdate/luo_stress_sessions.c b/tools/testing/selftests/liveupdate/luo_stress_sessions.c
new file mode 100644
index 000000000000..f201b1839d1d
--- /dev/null
+++ b/tools/testing/selftests/liveupdate/luo_stress_sessions.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright (c) 2026, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ *
+ * Validate that LUO can handle a large number of sessions across a kexec
+ * reboot.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include "luo_test_utils.h"
+
+#define NUM_SESSIONS 2000
+#define STATE_SESSION_NAME "kexec_many_state"
+#define STATE_MEMFD_TOKEN 999
+
+/* Stage 1: Executed before the kexec reboot. */
+static void run_stage_1(int luo_fd)
+{
+ int ret, i;
+
+ ksft_print_msg("[STAGE 1] Increasing ulimit for open files...\n");
+ ret = luo_ensure_nofile_limit(NUM_SESSIONS);
+ if (ret == -EPERM)
+ ksft_exit_skip("Insufficient privileges to set RLIMIT_NOFILE\n");
+ if (ret < 0)
+ ksft_exit_fail_msg("luo_ensure_nofile_limit failed: %s\n", strerror(-ret));
+
+ ksft_print_msg("[STAGE 1] Creating state file for next stage (2)...\n");
+ create_state_file(luo_fd, STATE_SESSION_NAME, STATE_MEMFD_TOKEN, 2);
+
+ ksft_print_msg("[STAGE 1] Creating %d sessions...\n", NUM_SESSIONS);
+
+ for (i = 0; i < NUM_SESSIONS; i++) {
+ char name[LIVEUPDATE_SESSION_NAME_LENGTH];
+ int s_fd;
+
+ snprintf(name, sizeof(name), "many-test-%d", i);
+ s_fd = luo_create_session(luo_fd, name);
+ if (s_fd < 0) {
+ fail_exit("luo_create_session for '%s' at index %d",
+ name, i);
+ }
+ }
+
+ ksft_print_msg("[STAGE 1] Successfully created %d sessions.\n",
+ NUM_SESSIONS);
+
+ close(luo_fd);
+ daemonize_and_wait();
+}
+
+/* Stage 2: Executed after the kexec reboot. */
+static void run_stage_2(int luo_fd, int state_session_fd)
+{
+ int i, stage;
+
+ ksft_print_msg("[STAGE 2] Starting post-kexec verification...\n");
+
+ restore_and_read_stage(state_session_fd, STATE_MEMFD_TOKEN, &stage);
+ if (stage != 2) {
+ fail_exit("Expected stage 2, but state file contains %d",
+ stage);
+ }
+
+ ksft_print_msg("[STAGE 2] Retrieving and finishing %d sessions...\n",
+ NUM_SESSIONS);
+
+ for (i = 0; i < NUM_SESSIONS; i++) {
+ char name[LIVEUPDATE_SESSION_NAME_LENGTH];
+ int s_fd;
+
+ snprintf(name, sizeof(name), "many-test-%d", i);
+ s_fd = luo_retrieve_session(luo_fd, name);
+ if (s_fd < 0) {
+ fail_exit("luo_retrieve_session for '%s' at index %d",
+ name, i);
+ }
+
+ if (luo_session_finish(s_fd) < 0) {
+ fail_exit("luo_session_finish for '%s' at index %d",
+ name, i);
+ }
+ close(s_fd);
+ }
+
+ ksft_print_msg("[STAGE 2] Finalizing state session...\n");
+ if (luo_session_finish(state_session_fd) < 0)
+ fail_exit("luo_session_finish for state session");
+ close(state_session_fd);
+
+ ksft_print_msg("\n--- MANY-SESSIONS KEXEC TEST PASSED (%d sessions) ---\n",
+ NUM_SESSIONS);
+}
+
+int main(int argc, char *argv[])
+{
+ return luo_test(argc, argv, STATE_SESSION_NAME,
+ run_stage_1, run_stage_2);
+}
--
2.53.0
^ permalink raw reply related
* [PATCH v3 09/11] selftests/liveupdate: Test session and file limit removal
From: Pasha Tatashin @ 2026-05-29 3:21 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
With the removal of static limits on the number of sessions and files per
session, the orchestrator now uses dynamic allocation.
Add new test cases to verify that the system can handle a large number of
sessions and files. These tests ensure that the dynamic block allocation
and reuse logic for session metadata and outgoing files work correctly
beyond the previous static limits.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
.../testing/selftests/liveupdate/liveupdate.c | 75 +++++++++++++++++++
.../selftests/liveupdate/luo_test_utils.c | 24 ++++++
.../selftests/liveupdate/luo_test_utils.h | 2 +
3 files changed, 101 insertions(+)
diff --git a/tools/testing/selftests/liveupdate/liveupdate.c b/tools/testing/selftests/liveupdate/liveupdate.c
index c7d94b9181e1..502fb3567e38 100644
--- a/tools/testing/selftests/liveupdate/liveupdate.c
+++ b/tools/testing/selftests/liveupdate/liveupdate.c
@@ -26,6 +26,7 @@
#include <linux/liveupdate.h>
+#include "luo_test_utils.h"
#include "../kselftest.h"
#include "../kselftest_harness.h"
@@ -499,4 +500,78 @@ TEST_F(liveupdate_device, get_session_name_max_length)
ASSERT_EQ(close(session_fd), 0);
}
+/*
+ * Test Case: Manage Many Sessions
+ *
+ * Verifies that a large number of sessions can be created and then
+ * destroyed during normal system operation. This specifically tests the
+ * dynamic block allocation and reuse logic for session metadata management
+ * without preserving any files.
+ */
+TEST_F(liveupdate_device, preserve_many_sessions)
+{
+#define MANY_SESSIONS 2000
+ int session_fds[MANY_SESSIONS];
+ int ret, i;
+
+ self->fd1 = open(LIVEUPDATE_DEV, O_RDWR);
+ if (self->fd1 < 0 && errno == ENOENT)
+ SKIP(return, "%s does not exist", LIVEUPDATE_DEV);
+ ASSERT_GE(self->fd1, 0);
+
+ ret = luo_ensure_nofile_limit(MANY_SESSIONS);
+ if (ret == -EPERM)
+ SKIP(return, "Insufficient privileges to set RLIMIT_NOFILE");
+ ASSERT_EQ(ret, 0);
+
+ for (i = 0; i < MANY_SESSIONS; i++) {
+ char name[64];
+
+ snprintf(name, sizeof(name), "many-session-%d", i);
+ session_fds[i] = create_session(self->fd1, name);
+ ASSERT_GE(session_fds[i], 0);
+ }
+
+ for (i = 0; i < MANY_SESSIONS; i++)
+ ASSERT_EQ(close(session_fds[i]), 0);
+}
+
+/*
+ * Test Case: Preserve Many Files
+ *
+ * Verifies that a large number of files can be preserved in a single session
+ * and then destroyed during normal system operation. This tests the dynamic
+ * block allocation and management for outgoing files.
+ */
+TEST_F(liveupdate_device, preserve_many_files)
+{
+#define MANY_FILES 500
+ int mem_fds[MANY_FILES];
+ int session_fd, ret, i;
+
+ self->fd1 = open(LIVEUPDATE_DEV, O_RDWR);
+ if (self->fd1 < 0 && errno == ENOENT)
+ SKIP(return, "%s does not exist", LIVEUPDATE_DEV);
+ ASSERT_GE(self->fd1, 0);
+
+ session_fd = create_session(self->fd1, "many-files-test");
+ ASSERT_GE(session_fd, 0);
+
+ ret = luo_ensure_nofile_limit(MANY_FILES + 10);
+ if (ret == -EPERM)
+ SKIP(return, "Insufficient privileges to set RLIMIT_NOFILE");
+ ASSERT_EQ(ret, 0);
+
+ for (i = 0; i < MANY_FILES; i++) {
+ mem_fds[i] = memfd_create("test-memfd", 0);
+ ASSERT_GE(mem_fds[i], 0);
+ ASSERT_EQ(preserve_fd(session_fd, mem_fds[i], i), 0);
+ }
+
+ for (i = 0; i < MANY_FILES; i++)
+ ASSERT_EQ(close(mem_fds[i]), 0);
+
+ ASSERT_EQ(close(session_fd), 0);
+}
+
TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/liveupdate/luo_test_utils.c b/tools/testing/selftests/liveupdate/luo_test_utils.c
index 3c8721c505df..333a3530051b 100644
--- a/tools/testing/selftests/liveupdate/luo_test_utils.c
+++ b/tools/testing/selftests/liveupdate/luo_test_utils.c
@@ -17,6 +17,7 @@
#include <sys/syscall.h>
#include <sys/mman.h>
#include <sys/types.h>
+#include <sys/resource.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdarg.h>
@@ -28,6 +29,29 @@ int luo_open_device(void)
return open(LUO_DEVICE, O_RDWR);
}
+int luo_ensure_nofile_limit(long min_limit)
+{
+ struct rlimit hl;
+
+ /* Allow to extra files to be used by test itself */
+ min_limit += 32;
+
+ if (getrlimit(RLIMIT_NOFILE, &hl) < 0)
+ return -errno;
+
+ if (hl.rlim_cur >= min_limit)
+ return 0;
+
+ hl.rlim_cur = min_limit;
+ if (hl.rlim_cur > hl.rlim_max)
+ hl.rlim_max = hl.rlim_cur;
+
+ if (setrlimit(RLIMIT_NOFILE, &hl) < 0)
+ return -errno;
+
+ return 0;
+}
+
int luo_create_session(int luo_fd, const char *name)
{
struct liveupdate_ioctl_create_session arg = { .size = sizeof(arg) };
diff --git a/tools/testing/selftests/liveupdate/luo_test_utils.h b/tools/testing/selftests/liveupdate/luo_test_utils.h
index 90099bf49577..6a0d85386613 100644
--- a/tools/testing/selftests/liveupdate/luo_test_utils.h
+++ b/tools/testing/selftests/liveupdate/luo_test_utils.h
@@ -26,6 +26,8 @@ int luo_create_session(int luo_fd, const char *name);
int luo_retrieve_session(int luo_fd, const char *name);
int luo_session_finish(int session_fd);
+int luo_ensure_nofile_limit(long min_limit);
+
int create_and_preserve_memfd(int session_fd, int token, const char *data);
int restore_and_verify_memfd(int session_fd, int token, const char *expected_data);
--
2.53.0
^ permalink raw reply related
* [PATCH v3 08/11] liveupdate: Remove limit on the number of files per session
From: Pasha Tatashin @ 2026-05-29 3:21 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
To remove the fixed limit on the number of preserved files per session,
transition the file metadata serialization from a single contiguous
memory block to a chain of linked blocks.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
include/linux/kho/abi/luo.h | 13 +--
kernel/liveupdate/luo_file.c | 142 +++++++++++++++----------------
kernel/liveupdate/luo_internal.h | 6 +-
3 files changed, 78 insertions(+), 83 deletions(-)
diff --git a/include/linux/kho/abi/luo.h b/include/linux/kho/abi/luo.h
index 79758d92ed5f..16df550ef143 100644
--- a/include/linux/kho/abi/luo.h
+++ b/include/linux/kho/abi/luo.h
@@ -35,8 +35,8 @@
*
* - struct luo_session_ser:
* Metadata for a single session, including its name and a physical pointer
- * to another preserved memory block containing an array of
- * `struct luo_file_ser` for all files in that session.
+ * to the first `struct kho_block_header_ser` for all files in that session.
+ * Multiple blocks are linked via the `next` field in the header.
*
* - struct luo_file_ser:
* Metadata for a single preserved file. Contains the `compatible` string to
@@ -65,7 +65,7 @@
* The LUO state is registered under this KHO entry name.
*/
#define LUO_KHO_ENTRY_NAME "LUO"
-#define LUO_COMPAT_BASE "luo-v3"
+#define LUO_COMPAT_BASE "luo-v4"
#define LUO_ABI_COMPATIBLE LUO_COMPAT_BASE "-" KHO_BLOCK_ABI_COMPATIBLE
#define LUO_ABI_COMPAT_LEN ALIGN(sizeof(LUO_ABI_COMPATIBLE), 8)
@@ -103,9 +103,10 @@ struct luo_file_ser {
/**
* struct luo_file_set_ser - Represents the serialized metadata for file set
- * @files: The physical address of a contiguous memory block that holds
- * the serialized state of files (array of luo_file_ser) in this file
- * set.
+ * @files: The physical address of the first `struct kho_block_header_ser`.
+ * This structure is the header for a block of memory containing
+ * an array of `struct luo_file_ser` entries. Multiple blocks are
+ * linked via the `next` field in the header.
* @count: The total number of files that were part of this session during
* serialization. Used for iteration and validation during
* restoration.
diff --git a/kernel/liveupdate/luo_file.c b/kernel/liveupdate/luo_file.c
index 9eec07a9e9fc..06eb083cc759 100644
--- a/kernel/liveupdate/luo_file.c
+++ b/kernel/liveupdate/luo_file.c
@@ -118,11 +118,6 @@ static LIST_HEAD(luo_file_handler_list);
/* Keep track of files being preserved by LUO */
static DEFINE_XARRAY(luo_preserved_files);
-/* 2 4K pages, give space for 128 files per file_set */
-#define LUO_FILE_PGCNT 2ul
-#define LUO_FILE_MAX \
- ((LUO_FILE_PGCNT << PAGE_SHIFT) / sizeof(struct luo_file_ser))
-
/**
* struct luo_file - Represents a single preserved file instance.
* @fh: Pointer to the &struct liveupdate_file_handler that manages
@@ -174,39 +169,6 @@ struct luo_file {
u64 token;
};
-static int luo_alloc_files_mem(struct luo_file_set *file_set)
-{
- size_t size;
- void *mem;
-
- if (file_set->files)
- return 0;
-
- WARN_ON_ONCE(file_set->count);
-
- size = LUO_FILE_PGCNT << PAGE_SHIFT;
- mem = kho_alloc_preserve(size);
- if (IS_ERR(mem))
- return PTR_ERR(mem);
-
- file_set->files = mem;
-
- return 0;
-}
-
-static void luo_free_files_mem(struct luo_file_set *file_set)
-{
- /* If file_set has files, no need to free preservation memory */
- if (file_set->count)
- return;
-
- if (!file_set->files)
- return;
-
- kho_unpreserve_free(file_set->files);
- file_set->files = NULL;
-}
-
static unsigned long luo_get_id(struct liveupdate_file_handler *fh,
struct file *file)
{
@@ -276,16 +238,15 @@ int luo_preserve_file(struct luo_file_set *file_set, u64 token, int fd)
if (luo_token_is_used(file_set, token))
return -EEXIST;
- if (file_set->count == LUO_FILE_MAX)
- return -ENOSPC;
+ err = kho_block_grow(&file_set->block_set, file_set->count);
+ if (err)
+ return err;
file = fget(fd);
- if (!file)
- return -EBADF;
-
- err = luo_alloc_files_mem(file_set);
- if (err)
- goto err_fput;
+ if (!file) {
+ err = -EBADF;
+ goto err_shrink;
+ }
err = -ENOENT;
down_read(&luo_register_rwlock);
@@ -300,7 +261,7 @@ int luo_preserve_file(struct luo_file_set *file_set, u64 token, int fd)
/* err is still -ENOENT if no handler was found */
if (err)
- goto err_free_files_mem;
+ goto err_fput;
err = xa_insert(&luo_preserved_files, luo_get_id(fh, file),
file, GFP_KERNEL);
@@ -343,10 +304,10 @@ int luo_preserve_file(struct luo_file_set *file_set, u64 token, int fd)
xa_erase(&luo_preserved_files, luo_get_id(fh, file));
err_module_put:
module_put(fh->ops->owner);
-err_free_files_mem:
- luo_free_files_mem(file_set);
err_fput:
fput(file);
+err_shrink:
+ kho_block_shrink(&file_set->block_set, file_set->count);
return err;
}
@@ -392,13 +353,14 @@ void luo_file_unpreserve_files(struct luo_file_set *file_set)
list_del(&luo_file->list);
file_set->count--;
+ kho_block_shrink(&file_set->block_set, file_set->count);
fput(luo_file->file);
mutex_destroy(&luo_file->mutex);
kfree(luo_file);
}
- luo_free_files_mem(file_set);
+ kho_block_destroy(&file_set->block_set);
}
static int luo_file_freeze_one(struct luo_file_set *file_set,
@@ -454,7 +416,7 @@ static void __luo_file_unfreeze(struct luo_file_set *file_set,
luo_file_unfreeze_one(file_set, luo_file);
}
- memset(file_set->files, 0, LUO_FILE_PGCNT << PAGE_SHIFT);
+ kho_block_set_clear(&file_set->block_set);
}
/**
@@ -493,19 +455,23 @@ static void __luo_file_unfreeze(struct luo_file_set *file_set,
int luo_file_freeze(struct luo_file_set *file_set,
struct luo_file_set_ser *file_set_ser)
{
- struct luo_file_ser *file_ser = file_set->files;
struct luo_file *luo_file;
+ struct kho_block_it it;
int err;
- int i;
if (!file_set->count)
return 0;
- if (WARN_ON(!file_ser))
- return -EINVAL;
+ kho_block_it_init(&it, &file_set->block_set);
- i = 0;
list_for_each_entry(luo_file, &file_set->files_list, list) {
+ struct luo_file_ser *file_ser = kho_block_it_next(&it);
+
+ if (!file_ser) {
+ err = -ENOSPC;
+ goto err_unfreeze;
+ }
+
err = luo_file_freeze_one(file_set, luo_file);
if (err < 0) {
pr_warn("Freeze failed for token[%#0llx] handler[%s] err[%pe]\n",
@@ -514,16 +480,21 @@ int luo_file_freeze(struct luo_file_set *file_set,
goto err_unfreeze;
}
- strscpy(file_ser[i].compatible, luo_file->fh->compatible,
- sizeof(file_ser[i].compatible));
- file_ser[i].data = luo_file->serialized_data;
- file_ser[i].token = luo_file->token;
- i++;
+ strscpy(file_ser->compatible, luo_file->fh->compatible,
+ sizeof(file_ser->compatible));
+ file_ser->data = luo_file->serialized_data;
+ file_ser->token = luo_file->token;
}
+ kho_block_it_finalize(&it);
file_set_ser->count = file_set->count;
- if (file_set->files)
- file_set_ser->files = virt_to_phys(file_set->files);
+ if (!list_empty(&file_set->block_set.blocks)) {
+ struct kho_block *block;
+
+ block = list_first_entry(&file_set->block_set.blocks,
+ struct kho_block, list);
+ file_set_ser->files = virt_to_phys(block->ser);
+ }
return 0;
@@ -741,14 +712,12 @@ int luo_file_finish(struct luo_file_set *file_set)
module_put(luo_file->fh->ops->owner);
list_del(&luo_file->list);
file_set->count--;
+ kho_block_shrink(&file_set->block_set, file_set->count);
mutex_destroy(&luo_file->mutex);
kfree(luo_file);
}
- if (file_set->files) {
- kho_restore_free(file_set->files);
- file_set->files = NULL;
- }
+ kho_block_destroy(&file_set->block_set);
return 0;
}
@@ -822,16 +791,18 @@ int luo_file_deserialize(struct luo_file_set *file_set,
struct luo_file_set_ser *file_set_ser)
{
struct luo_file_ser *file_ser;
+ struct kho_block_it it;
int err;
- u64 i;
if (!file_set_ser->files) {
WARN_ON(file_set_ser->count);
return 0;
}
- file_set->count = file_set_ser->count;
- file_set->files = phys_to_virt(file_set_ser->files);
+ file_set->count = 0;
+ err = kho_block_restore(&file_set->block_set, file_set_ser->files);
+ if (err)
+ return err;
/*
* Note on error handling:
@@ -848,25 +819,48 @@ int luo_file_deserialize(struct luo_file_set *file_set,
* userspace to detect the failure and trigger a reboot, which will
* reliably reset devices and reclaim memory.
*/
- file_ser = file_set->files;
- for (i = 0; i < file_set->count; i++) {
- err = luo_file_deserialize_one(file_set, &file_ser[i]);
+ kho_block_it_init(&it, &file_set->block_set);
+ while ((file_ser = kho_block_it_read(&it))) {
+ err = luo_file_deserialize_one(file_set, file_ser);
if (err)
- return err;
+ goto err_destroy_blocks;
+ file_set->count++;
+ }
+
+ if (file_set->count != file_set_ser->count) {
+ pr_warn("File count mismatch: expected %llu, found %ld\n",
+ file_set_ser->count, file_set->count);
}
return 0;
+
+err_destroy_blocks:
+ while (!list_empty(&file_set->files_list)) {
+ struct luo_file *luo_file;
+
+ luo_file = list_first_entry(&file_set->files_list,
+ struct luo_file, list);
+ list_del(&luo_file->list);
+ module_put(luo_file->fh->ops->owner);
+ mutex_destroy(&luo_file->mutex);
+ kfree(luo_file);
+ }
+ file_set->count = 0;
+ kho_block_destroy(&file_set->block_set);
+ return err;
}
void luo_file_set_init(struct luo_file_set *file_set)
{
INIT_LIST_HEAD(&file_set->files_list);
+ kho_block_set_init(&file_set->block_set, sizeof(struct luo_file_ser));
}
void luo_file_set_destroy(struct luo_file_set *file_set)
{
WARN_ON(file_set->count);
WARN_ON(!list_empty(&file_set->files_list));
+ WARN_ON(!list_empty(&file_set->block_set.blocks));
}
/**
diff --git a/kernel/liveupdate/luo_internal.h b/kernel/liveupdate/luo_internal.h
index 28ebb4f3000b..2c5e8bcb219c 100644
--- a/kernel/liveupdate/luo_internal.h
+++ b/kernel/liveupdate/luo_internal.h
@@ -10,6 +10,7 @@
#include <linux/liveupdate.h>
#include <linux/uaccess.h>
+#include <linux/kho_block.h>
struct luo_ucmd {
void __user *ubuffer;
@@ -44,14 +45,13 @@ static inline int luo_ucmd_respond(struct luo_ucmd *ucmd,
* struct luo_file_set - A set of files that belong to the same sessions.
* @files_list: An ordered list of files associated with this session, it is
* ordered by preservation time.
- * @files: The physically contiguous memory block that holds the serialized
- * state of files.
+ * @block_set: The set of serialization blocks.
* @count: A counter tracking the number of files currently stored in the
* @files_list for this session.
*/
struct luo_file_set {
struct list_head files_list;
- struct luo_file_ser *files;
+ struct kho_block_set block_set;
long count;
};
--
2.53.0
^ permalink raw reply related
* [PATCH v3 07/11] liveupdate: Remove limit on the number of sessions
From: Pasha Tatashin @ 2026-05-29 3:21 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
Currently, the number of LUO sessions is limited by a fixed number of
pre-allocated pages for serialization (16 pages, allowing for ~819
sessions).
This limitation is problematic if LUO is used to support things such as
systemd file descriptor store, and would be used not just as VM memory
but to save other states on the machine.
Remove this limit by transitioning to a linked-block approach for
session metadata serialization. Instead of a single contiguous block,
session metadata is now stored in a chain of 16-page blocks. Each block
starts with a header containing the physical address of the next block
and the number of session entries in the current block.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
include/linux/kho/abi/luo.h | 24 +------
kernel/liveupdate/luo_session.c | 114 +++++++++++++++-----------------
2 files changed, 56 insertions(+), 82 deletions(-)
diff --git a/include/linux/kho/abi/luo.h b/include/linux/kho/abi/luo.h
index 9a4fe491812b..79758d92ed5f 100644
--- a/include/linux/kho/abi/luo.h
+++ b/include/linux/kho/abi/luo.h
@@ -33,11 +33,6 @@
* It includes the compatibility string, the liveupdate-number, and pointers
* to sessions and FLBs.
*
- * - struct luo_session_header_ser:
- * Header for the session array. Contains the total page count of the
- * preserved memory block and the number of `struct luo_session_ser`
- * entries that follow.
- *
* - struct luo_session_ser:
* Metadata for a single session, including its name and a physical pointer
* to another preserved memory block containing an array of
@@ -63,13 +58,15 @@
#define _LINUX_KHO_ABI_LUO_H
#include <linux/align.h>
+#include <linux/kho/abi/block.h>
#include <uapi/linux/liveupdate.h>
/*
* The LUO state is registered under this KHO entry name.
*/
#define LUO_KHO_ENTRY_NAME "LUO"
-#define LUO_ABI_COMPATIBLE "luo-v3"
+#define LUO_COMPAT_BASE "luo-v3"
+#define LUO_ABI_COMPATIBLE LUO_COMPAT_BASE "-" KHO_BLOCK_ABI_COMPATIBLE
#define LUO_ABI_COMPAT_LEN ALIGN(sizeof(LUO_ABI_COMPATIBLE), 8)
/**
@@ -118,21 +115,6 @@ struct luo_file_set_ser {
u64 count;
} __packed;
-/**
- * struct luo_session_header_ser - Header for the serialized session data block.
- * @count: The number of `struct luo_session_ser` entries that immediately
- * follow this header in the memory block.
- *
- * This structure is located at the beginning of a contiguous block of
- * physical memory preserved across the kexec. It provides the necessary
- * metadata to interpret the array of session entries that follow.
- *
- * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated.
- */
-struct luo_session_header_ser {
- u64 count;
-} __packed;
-
/**
* struct luo_session_ser - Represents the serialized metadata for a LUO session.
* @name: The unique name of the session, provided by the userspace at
diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c
index ec72f16185f3..c340ae4bf743 100644
--- a/kernel/liveupdate/luo_session.c
+++ b/kernel/liveupdate/luo_session.c
@@ -24,9 +24,10 @@
* ioctls on /dev/liveupdate.
*
* - Serialization: Session metadata is preserved using the KHO framework. When
- * a live update is triggered via kexec, an array of `struct luo_session_ser`
- * is populated and placed in a preserved memory region. The physical address
- * of this array is stored in the centralized `struct luo_ser` structure.
+ * a live update is triggered via kexec, session metadata is serialized into
+ * a chain of linked-blocks and placed in a preserved memory region. The
+ * physical address of the first block header is stored in the centralized
+ * `struct luo_ser` structure.
*
* Session Lifecycle:
*
@@ -89,6 +90,7 @@
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/kexec_handover.h>
+#include <linux/kho_block.h>
#include <linux/kho/abi/luo.h>
#include <linux/list.h>
#include <linux/liveupdate.h>
@@ -98,23 +100,14 @@
#include <uapi/linux/liveupdate.h>
#include "luo_internal.h"
-/* 16 4K pages, give space for 744 sessions */
-#define LUO_SESSION_PGCNT 16ul
-#define LUO_SESSION_MAX (((LUO_SESSION_PGCNT << PAGE_SHIFT) - \
- sizeof(struct luo_session_header_ser)) / \
- sizeof(struct luo_session_ser))
-
static DECLARE_RWSEM(luo_session_serialize_rwsem);
-
/**
* struct luo_session_header - Header struct for managing LUO sessions.
* @count: The number of sessions currently tracked in the @list.
* @list: The head of the linked list of `struct luo_session` instances.
* @rwsem: A read-write semaphore providing synchronized access to the
* session list and other fields in this structure.
- * @header_ser: The header data of serialization array.
- * @ser: The serialized session data (an array of
- * `struct luo_session_ser`).
+ * @block_set: The set of serialization blocks.
* @sessions_pa: Points to the location of sessions_pa within struct luo_ser.
* @active: Set to true when first initialized. If previous kernel did not
* send session data, active stays false for incoming.
@@ -123,8 +116,7 @@ struct luo_session_header {
long count;
struct list_head list;
struct rw_semaphore rwsem;
- struct luo_session_header_ser *header_ser;
- struct luo_session_ser *ser;
+ struct kho_block_set block_set;
u64 *sessions_pa;
bool active;
};
@@ -143,10 +135,14 @@ static struct luo_session_global luo_session_global = {
.incoming = {
.list = LIST_HEAD_INIT(luo_session_global.incoming.list),
.rwsem = __RWSEM_INITIALIZER(luo_session_global.incoming.rwsem),
+ .block_set = KHO_BLOCK_SET_INIT(luo_session_global.incoming.block_set,
+ sizeof(struct luo_session_ser)),
},
.outgoing = {
.list = LIST_HEAD_INIT(luo_session_global.outgoing.list),
.rwsem = __RWSEM_INITIALIZER(luo_session_global.outgoing.rwsem),
+ .block_set = KHO_BLOCK_SET_INIT(luo_session_global.outgoing.block_set,
+ sizeof(struct luo_session_ser)),
},
};
@@ -173,25 +169,6 @@ static void luo_session_free(struct luo_session *session)
kfree(session);
}
-static int luo_session_grow_ser(struct luo_session_header *sh)
-{
- struct luo_session_header_ser *header_ser;
-
- if (sh->count == LUO_SESSION_MAX)
- return -ENOMEM;
-
- if (sh->header_ser)
- return 0;
-
- header_ser = kho_alloc_preserve(LUO_SESSION_PGCNT << PAGE_SHIFT);
- if (IS_ERR(header_ser))
- return PTR_ERR(header_ser);
-
- sh->header_ser = header_ser;
- sh->ser = (void *)(header_ser + 1);
- return 0;
-}
-
static int luo_session_insert(struct luo_session_header *sh,
struct luo_session *session)
{
@@ -205,7 +182,7 @@ static int luo_session_insert(struct luo_session_header *sh,
* for new session.
*/
if (sh == &luo_session_global.outgoing) {
- err = luo_session_grow_ser(sh);
+ err = kho_block_grow(&sh->block_set, sh->count);
if (err)
return err;
}
@@ -232,6 +209,8 @@ static void luo_session_remove(struct luo_session_header *sh,
guard(rwsem_write)(&sh->rwsem);
list_del(&session->list);
sh->count--;
+ if (sh == &luo_session_global.outgoing)
+ kho_block_shrink(&sh->block_set, sh->count);
}
static int luo_session_finish_one(struct luo_session *session)
@@ -526,15 +505,17 @@ void __init luo_session_setup_outgoing(u64 *sessions_pa)
int __init luo_session_setup_incoming(u64 sessions_pa)
{
- struct luo_session_header_ser *header_ser;
+ struct luo_session_header *sh = &luo_session_global.incoming;
+ int err;
- if (sessions_pa) {
- header_ser = phys_to_virt(sessions_pa);
- luo_session_global.incoming.header_ser = header_ser;
- luo_session_global.incoming.ser = (void *)(header_ser + 1);
- luo_session_global.incoming.active = true;
- }
+ if (!sessions_pa)
+ return 0;
+ err = kho_block_restore(&sh->block_set, sessions_pa);
+ if (err)
+ return err;
+
+ sh->active = true;
return 0;
}
@@ -576,6 +557,8 @@ int luo_session_deserialize(void)
{
struct luo_session_header *sh = &luo_session_global.incoming;
static bool is_deserialized;
+ struct luo_session_ser *ser;
+ struct kho_block_it it;
static int err;
/* If has been deserialized, always return the same error code */
@@ -601,53 +584,62 @@ int luo_session_deserialize(void)
* userspace to detect the failure and trigger a reboot, which will
* reliably reset devices and reclaim memory.
*/
- for (int i = 0; i < sh->header_ser->count; i++) {
- err = luo_session_deserialize_one(sh, &sh->ser[i]);
+ kho_block_it_init(&it, &sh->block_set);
+ while ((ser = kho_block_it_read(&it))) {
+ err = luo_session_deserialize_one(sh, ser);
if (err)
- return err;
+ goto err_destroy_blocks;
}
- kho_restore_free(sh->header_ser);
- sh->header_ser = NULL;
- sh->ser = NULL;
+err_destroy_blocks:
+ kho_block_destroy(&sh->block_set);
- return 0;
+ return err;
}
int luo_session_serialize(void)
{
struct luo_session_header *sh = &luo_session_global.outgoing;
struct luo_session *session;
- int i = 0;
+ struct kho_block_it it;
int err;
down_write(&luo_session_serialize_rwsem);
down_write(&sh->rwsem);
*sh->sessions_pa = 0;
+ kho_block_it_init(&it, &sh->block_set);
+
list_for_each_entry(session, &sh->list, list) {
- err = luo_session_freeze_one(session, &sh->ser[i]);
+ struct luo_session_ser *ser = kho_block_it_next(&it);
+
+ if (!ser) {
+ err = -ENOSPC;
+ goto err_undo;
+ }
+
+ err = luo_session_freeze_one(session, ser);
if (err)
goto err_undo;
- strscpy(sh->ser[i].name, session->name,
- sizeof(sh->ser[i].name));
- i++;
+ strscpy(ser->name, session->name, sizeof(ser->name));
}
- if (sh->header_ser && sh->count > 0) {
- sh->header_ser->count = sh->count;
- *sh->sessions_pa = virt_to_phys(sh->header_ser);
- }
+ kho_block_it_finalize(&it);
+
+ if (sh->sessions_pa && sh->count > 0)
+ *sh->sessions_pa = sh->block_set.head_pa;
up_write(&sh->rwsem);
return 0;
err_undo:
+ kho_block_it_prev(&it);
list_for_each_entry_continue_reverse(session, &sh->list, list) {
- i--;
- luo_session_unfreeze_one(session, &sh->ser[i]);
- memset(sh->ser[i].name, 0, sizeof(sh->ser[i].name));
+ struct luo_session_ser *ser = kho_block_it_prev(&it);
+
+ luo_session_unfreeze_one(session, ser);
+ memset(ser->name, 0, sizeof(ser->name));
}
up_write(&sh->rwsem);
up_write(&luo_session_serialize_rwsem);
--
2.53.0
^ permalink raw reply related
* [PATCH v3 06/11] liveupdate: defer session block allocation and PA setting
From: Pasha Tatashin @ 2026-05-29 3:21 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
Currently, luo_session_setup_outgoing() allocates the session block and
sets its physical address in the header immediately. With upcoming
dynamic block-based session management, this makes the first block
different from the rest. Move the allocation to where it is first needed.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
kernel/liveupdate/luo_core.c | 4 +-
kernel/liveupdate/luo_internal.h | 2 +-
kernel/liveupdate/luo_session.c | 68 ++++++++++++++++++++------------
3 files changed, 45 insertions(+), 29 deletions(-)
diff --git a/kernel/liveupdate/luo_core.c b/kernel/liveupdate/luo_core.c
index 5e12c8f8669b..92f8c53c7a73 100644
--- a/kernel/liveupdate/luo_core.c
+++ b/kernel/liveupdate/luo_core.c
@@ -157,9 +157,7 @@ static int __init luo_state_setup(void)
strscpy(luo_ser->compatible, LUO_ABI_COMPATIBLE, sizeof(luo_ser->compatible));
luo_ser->liveupdate_num = luo_global.liveupdate_num + 1;
- err = luo_session_setup_outgoing(&luo_ser->sessions_pa);
- if (err)
- goto exit_free_luo_ser;
+ luo_session_setup_outgoing(&luo_ser->sessions_pa);
err = luo_flb_setup_outgoing(&luo_ser->flbs_pa);
if (err)
diff --git a/kernel/liveupdate/luo_internal.h b/kernel/liveupdate/luo_internal.h
index 9bf26c5b1495..28ebb4f3000b 100644
--- a/kernel/liveupdate/luo_internal.h
+++ b/kernel/liveupdate/luo_internal.h
@@ -79,7 +79,7 @@ extern struct rw_semaphore luo_register_rwlock;
int luo_session_create(const char *name, struct file **filep);
int luo_session_retrieve(const char *name, struct file **filep);
-int __init luo_session_setup_outgoing(u64 *sessions_pa);
+void __init luo_session_setup_outgoing(u64 *sessions_pa);
int __init luo_session_setup_incoming(u64 sessions_pa);
int luo_session_serialize(void);
int luo_session_deserialize(void);
diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c
index 5c092c71797e..ec72f16185f3 100644
--- a/kernel/liveupdate/luo_session.c
+++ b/kernel/liveupdate/luo_session.c
@@ -108,15 +108,16 @@ static DECLARE_RWSEM(luo_session_serialize_rwsem);
/**
* struct luo_session_header - Header struct for managing LUO sessions.
- * @count: The number of sessions currently tracked in the @list.
- * @list: The head of the linked list of `struct luo_session` instances.
- * @rwsem: A read-write semaphore providing synchronized access to the
- * session list and other fields in this structure.
- * @header_ser: The header data of serialization array.
- * @ser: The serialized session data (an array of
- * `struct luo_session_ser`).
- * @active: Set to true when first initialized. If previous kernel did not
- * send session data, active stays false for incoming.
+ * @count: The number of sessions currently tracked in the @list.
+ * @list: The head of the linked list of `struct luo_session` instances.
+ * @rwsem: A read-write semaphore providing synchronized access to the
+ * session list and other fields in this structure.
+ * @header_ser: The header data of serialization array.
+ * @ser: The serialized session data (an array of
+ * `struct luo_session_ser`).
+ * @sessions_pa: Points to the location of sessions_pa within struct luo_ser.
+ * @active: Set to true when first initialized. If previous kernel did not
+ * send session data, active stays false for incoming.
*/
struct luo_session_header {
long count;
@@ -124,6 +125,7 @@ struct luo_session_header {
struct rw_semaphore rwsem;
struct luo_session_header_ser *header_ser;
struct luo_session_ser *ser;
+ u64 *sessions_pa;
bool active;
};
@@ -171,10 +173,30 @@ static void luo_session_free(struct luo_session *session)
kfree(session);
}
+static int luo_session_grow_ser(struct luo_session_header *sh)
+{
+ struct luo_session_header_ser *header_ser;
+
+ if (sh->count == LUO_SESSION_MAX)
+ return -ENOMEM;
+
+ if (sh->header_ser)
+ return 0;
+
+ header_ser = kho_alloc_preserve(LUO_SESSION_PGCNT << PAGE_SHIFT);
+ if (IS_ERR(header_ser))
+ return PTR_ERR(header_ser);
+
+ sh->header_ser = header_ser;
+ sh->ser = (void *)(header_ser + 1);
+ return 0;
+}
+
static int luo_session_insert(struct luo_session_header *sh,
struct luo_session *session)
{
struct luo_session *it;
+ int err;
guard(rwsem_write)(&sh->rwsem);
@@ -183,8 +205,9 @@ static int luo_session_insert(struct luo_session_header *sh,
* for new session.
*/
if (sh == &luo_session_global.outgoing) {
- if (sh->count == LUO_SESSION_MAX)
- return -ENOMEM;
+ err = luo_session_grow_ser(sh);
+ if (err)
+ return err;
}
/*
@@ -495,21 +518,10 @@ int luo_session_retrieve(const char *name, struct file **filep)
return err;
}
-int __init luo_session_setup_outgoing(u64 *sessions_pa)
+void __init luo_session_setup_outgoing(u64 *sessions_pa)
{
- struct luo_session_header_ser *header_ser;
-
- header_ser = kho_alloc_preserve(LUO_SESSION_PGCNT << PAGE_SHIFT);
- if (IS_ERR(header_ser))
- return PTR_ERR(header_ser);
-
- *sessions_pa = virt_to_phys(header_ser);
-
- luo_session_global.outgoing.header_ser = header_ser;
- luo_session_global.outgoing.ser = (void *)(header_ser + 1);
+ luo_session_global.outgoing.sessions_pa = sessions_pa;
luo_session_global.outgoing.active = true;
-
- return 0;
}
int __init luo_session_setup_incoming(u64 sessions_pa)
@@ -611,6 +623,8 @@ int luo_session_serialize(void)
down_write(&luo_session_serialize_rwsem);
down_write(&sh->rwsem);
+ *sh->sessions_pa = 0;
+
list_for_each_entry(session, &sh->list, list) {
err = luo_session_freeze_one(session, &sh->ser[i]);
if (err)
@@ -620,7 +634,11 @@ int luo_session_serialize(void)
sizeof(sh->ser[i].name));
i++;
}
- sh->header_ser->count = sh->count;
+
+ if (sh->header_ser && sh->count > 0) {
+ sh->header_ser->count = sh->count;
+ *sh->sessions_pa = virt_to_phys(sh->header_ser);
+ }
up_write(&sh->rwsem);
return 0;
--
2.53.0
^ permalink raw reply related
* [PATCH v3 05/11] kho: add support for linked-block serialization
From: Pasha Tatashin @ 2026-05-29 3:21 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
Introduce a linked-block serialization mechanism for state handover.
Previously, LUO used contiguous memory blocks for serializing sessions
and files, which imposed limits on the total number of items that could
be preserved across a live update.
This commit adds the infrastructure for a more flexible, block-based
approach where serialized data is stored in a chain of linked blocks.
This is a generic KHO serialization block infrastructure that can be
used by multiple subsystems.
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
Documentation/core-api/kho/abi.rst | 5 +
Documentation/core-api/kho/index.rst | 11 +
MAINTAINERS | 1 +
include/linux/kho/abi/block.h | 56 ++++
include/linux/kho_block.h | 79 ++++++
kernel/liveupdate/Makefile | 1 +
kernel/liveupdate/kho_block.c | 382 +++++++++++++++++++++++++++
7 files changed, 535 insertions(+)
create mode 100644 include/linux/kho/abi/block.h
create mode 100644 include/linux/kho_block.h
create mode 100644 kernel/liveupdate/kho_block.c
diff --git a/Documentation/core-api/kho/abi.rst b/Documentation/core-api/kho/abi.rst
index 799d743105a6..edeb5b311963 100644
--- a/Documentation/core-api/kho/abi.rst
+++ b/Documentation/core-api/kho/abi.rst
@@ -28,6 +28,11 @@ KHO persistent memory tracker ABI
.. kernel-doc:: include/linux/kho/abi/kexec_handover.h
:doc: KHO persistent memory tracker
+KHO serialization block ABI
+===========================
+
+.. kernel-doc:: include/linux/kho/abi/block.h
+
See Also
========
diff --git a/Documentation/core-api/kho/index.rst b/Documentation/core-api/kho/index.rst
index 0a2dee4f8e7d..320914a42178 100644
--- a/Documentation/core-api/kho/index.rst
+++ b/Documentation/core-api/kho/index.rst
@@ -83,6 +83,17 @@ Public API
.. kernel-doc:: kernel/liveupdate/kexec_handover.c
:export:
+KHO Serialization Blocks API
+============================
+
+.. kernel-doc:: kernel/liveupdate/kho_block.c
+ :doc: KHO Serialization Blocks
+
+.. kernel-doc:: include/linux/kho_block.h
+
+.. kernel-doc:: kernel/liveupdate/kho_block.c
+ :internal:
+
See Also
========
diff --git a/MAINTAINERS b/MAINTAINERS
index 2fb1c75afd16..fd119b343e99 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14194,6 +14194,7 @@ F: Documentation/admin-guide/mm/kho.rst
F: Documentation/core-api/kho/*
F: include/linux/kexec_handover.h
F: include/linux/kho/
+F: include/linux/kho_block.h
F: kernel/liveupdate/kexec_handover*
F: lib/test_kho.c
F: tools/testing/selftests/kho/
diff --git a/include/linux/kho/abi/block.h b/include/linux/kho/abi/block.h
new file mode 100644
index 000000000000..8641c20b379b
--- /dev/null
+++ b/include/linux/kho/abi/block.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2026, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ */
+
+/**
+ * DOC: KHO Serialization Blocks ABI
+ *
+ * Subsystems using the KHO Serialization Blocks framework rely on the stable
+ * Application Binary Interface defined below to pass serialized state from a
+ * pre-update kernel to a post-update kernel.
+ *
+ * This interface is a contract. Any modification to the structure fields,
+ * compatible strings, or the layout of the `__packed` serialization
+ * structures defined here constitutes a breaking change. Such changes require
+ * incrementing the version number in the `KHO_BLOCK_ABI_COMPATIBLE` string to
+ * prevent a new kernel from misinterpreting data from an old kernel.
+ *
+ * Changes are allowed provided the compatibility version is incremented;
+ * however, backward/forward compatibility is only guaranteed for kernels
+ * supporting the same ABI version.
+ */
+
+#ifndef _LINUX_KHO_ABI_BLOCK_H
+#define _LINUX_KHO_ABI_BLOCK_H
+
+#include <asm/page.h>
+#include <linux/types.h>
+
+#define KHO_BLOCK_ABI_COMPATIBLE "kho-block-v1"
+
+/**
+ * KHO_BLOCK_SIZE - The size of each serialization block.
+ *
+ * This is defined as PAGE_SIZE. PAGE_SIZE is ABI compliant because live
+ * update between kernels with different page sizes is not supported by KHO.
+ */
+#define KHO_BLOCK_SIZE PAGE_SIZE
+
+/**
+ * struct kho_block_header_ser - Header for the serialized data block.
+ * @next: Physical address of the next struct kho_block_header_ser.
+ * @count: The number of entries that immediately follow this header in the
+ * memory block.
+ *
+ * This structure is located at the beginning of a block of physical memory
+ * preserved across a kexec. It provides the necessary metadata to interpret
+ * the array of entries that follow.
+ */
+struct kho_block_header_ser {
+ u64 next;
+ u64 count;
+} __packed;
+
+#endif /* _LINUX_KHO_ABI_BLOCK_H */
diff --git a/include/linux/kho_block.h b/include/linux/kho_block.h
new file mode 100644
index 000000000000..5e6b87b1befa
--- /dev/null
+++ b/include/linux/kho_block.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2026, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ */
+
+#ifndef _LINUX_KHO_BLOCK_H
+#define _LINUX_KHO_BLOCK_H
+
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/kho/abi/block.h>
+
+/**
+ * struct kho_block - Internal representation of a serialization block.
+ * @list: List head for linking blocks in memory.
+ * @ser: Pointer to the serialized header in preserved memory.
+ */
+struct kho_block {
+ struct list_head list;
+ struct kho_block_header_ser *ser;
+};
+
+/**
+ * struct kho_block_set - A set of blocks that belong to the same object.
+ * @blocks: The list of serialization blocks (struct kho_block).
+ * @nblocks: The number of allocated serialization blocks.
+ * @head_pa: Physical address of the first block header.
+ * @entry_size: The size of each entry in the blocks.
+ * @count_per_block: The maximum number of entries each block can hold.
+ * @incoming: True if this block set was restored from the previous kernel.
+ */
+struct kho_block_set {
+ struct list_head blocks;
+ long nblocks;
+ u64 head_pa;
+ size_t entry_size;
+ u64 count_per_block;
+ bool incoming;
+};
+
+/**
+ * struct kho_block_it - Iterator for serializing entries into blocks.
+ * @bs: The block set being iterated.
+ * @block: The current block.
+ * @i: The current entry index within @block.
+ */
+struct kho_block_it {
+ struct kho_block_set *bs;
+ struct kho_block *block;
+ u64 i;
+};
+
+/**
+ * KHO_BLOCK_SET_INIT - Initialize a static kho_block_set.
+ * @_name: Name of the kho_block_set variable.
+ * @_entry_size: The size of each entry in the block set.
+ */
+#define KHO_BLOCK_SET_INIT(_name, _entry_size) { \
+ .blocks = LIST_HEAD_INIT((_name).blocks), \
+ .entry_size = _entry_size, \
+}
+
+void kho_block_set_init(struct kho_block_set *bs, size_t entry_size);
+
+int kho_block_grow(struct kho_block_set *bs, u64 count);
+void kho_block_shrink(struct kho_block_set *bs, u64 count);
+
+int kho_block_restore(struct kho_block_set *bs, u64 head_pa);
+void kho_block_destroy(struct kho_block_set *bs);
+void kho_block_set_clear(struct kho_block_set *bs);
+
+void kho_block_it_init(struct kho_block_it *it, struct kho_block_set *bs);
+void *kho_block_it_next(struct kho_block_it *it);
+void *kho_block_it_read(struct kho_block_it *it);
+void *kho_block_it_prev(struct kho_block_it *it);
+void kho_block_it_finalize(struct kho_block_it *it);
+
+#endif /* _LINUX_KHO_BLOCK_H */
diff --git a/kernel/liveupdate/Makefile b/kernel/liveupdate/Makefile
index d2f779cbe279..eec9d3ae07eb 100644
--- a/kernel/liveupdate/Makefile
+++ b/kernel/liveupdate/Makefile
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
luo-y := \
+ kho_block.o \
luo_core.o \
luo_file.o \
luo_flb.o \
diff --git a/kernel/liveupdate/kho_block.c b/kernel/liveupdate/kho_block.c
new file mode 100644
index 000000000000..c781c1e36056
--- /dev/null
+++ b/kernel/liveupdate/kho_block.c
@@ -0,0 +1,382 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (c) 2026, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ */
+
+/**
+ * DOC: KHO Serialization Blocks
+ *
+ * KHO provides a mechanism to preserve stateful data across a kexec handover
+ * by serializing it into memory blocks. This file provides the common
+ * infrastructure for managing these blocks.
+ *
+ * Each block consists of a header (struct kho_block_header_ser) followed by an
+ * array of serialized entries. Multiple blocks are linked together via a
+ * physical pointer in the header, forming a linked list that can be easily
+ * traversed in both the current and the next kernel.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/io.h>
+#include <linux/kexec_handover.h>
+#include <linux/kho/abi/block.h>
+#include <linux/kho_block.h>
+#include <linux/slab.h>
+
+/*
+ * Safeguard limit for the number of serialization blocks. This is used to
+ * prevent infinite loops and excessive memory allocation in case of memory
+ * corruption in the preserved state.
+ */
+#define KHO_MAX_BLOCKS 10000
+
+/**
+ * kho_block_set_init - Initialize a block set.
+ * @bs: The block set to initialize.
+ * @entry_size: The size of each entry in the blocks.
+ */
+void kho_block_set_init(struct kho_block_set *bs, size_t entry_size)
+{
+ *bs = (struct kho_block_set)KHO_BLOCK_SET_INIT(*bs, entry_size);
+}
+
+static inline u64 kho_block_count_per_block(struct kho_block_set *bs)
+{
+ if (unlikely(!bs->count_per_block)) {
+ bs->count_per_block = (KHO_BLOCK_SIZE -
+ sizeof(struct kho_block_header_ser)) /
+ bs->entry_size;
+ WARN_ON(!bs->count_per_block);
+ }
+ return bs->count_per_block;
+}
+
+/* Free serialized data */
+static void kho_block_free_ser(struct kho_block_set *bs,
+ struct kho_block_header_ser *ser)
+{
+ if (bs->incoming)
+ kho_restore_free(ser);
+ else
+ kho_unpreserve_free(ser);
+}
+
+static struct kho_block_header_ser *kho_block_alloc_ser(struct kho_block_set *bs)
+{
+ WARN_ON(bs->incoming);
+ return kho_alloc_preserve(KHO_BLOCK_SIZE);
+}
+
+static int kho_block_add(struct kho_block_set *bs,
+ struct kho_block_header_ser *ser)
+{
+ struct kho_block *block, *last;
+
+ if (bs->nblocks >= KHO_MAX_BLOCKS)
+ return -ENOSPC;
+
+ block = kzalloc_obj(*block);
+ if (!block)
+ return -ENOMEM;
+
+ block->ser = ser;
+ last = list_last_entry_or_null(&bs->blocks, struct kho_block, list);
+ list_add_tail(&block->list, &bs->blocks);
+ bs->nblocks++;
+
+ if (last)
+ last->ser->next = virt_to_phys(ser);
+ else
+ bs->head_pa = virt_to_phys(ser);
+
+ return 0;
+}
+
+/**
+ * kho_block_grow - Create a new block if the current capacity is reached.
+ * @bs: The block set.
+ * @count: The current number of entries.
+ *
+ * This function handles the dynamic expansion of a block set. It allocates
+ * and links a new serialization block if the provided entry count matches
+ * the current total capacity of the set.
+ *
+ * Return: 0 on success, or a negative errno on failure.
+ */
+int kho_block_grow(struct kho_block_set *bs, u64 count)
+{
+ struct kho_block_header_ser *ser;
+ int err;
+
+ if (WARN_ON(bs->incoming))
+ return -EINVAL;
+
+ if (count != bs->nblocks * kho_block_count_per_block(bs))
+ return 0;
+
+ ser = kho_block_alloc_ser(bs);
+ if (IS_ERR(ser))
+ return PTR_ERR(ser);
+
+ err = kho_block_add(bs, ser);
+ if (err) {
+ kho_block_free_ser(bs, ser);
+ return err;
+ }
+
+ return 0;
+}
+
+/**
+ * kho_block_shrink - Conditionally destroy the last block in a block set.
+ * @bs: The block set.
+ * @count: The current number of entries across all blocks.
+ *
+ * This function checks if the last block in the set is redundant based on the
+ * total entry count and the capacity of the preceding blocks. If the entry
+ * count can be accommodated by the blocks that come before the last one, the
+ * last block is destroyed and removed from the set.
+ */
+void kho_block_shrink(struct kho_block_set *bs, u64 count)
+{
+ struct kho_block *last, *new_last;
+
+ if (count > (bs->nblocks - 1) * kho_block_count_per_block(bs))
+ return;
+
+ if (list_empty(&bs->blocks))
+ return;
+
+ last = list_last_entry(&bs->blocks, struct kho_block, list);
+ list_del(&last->list);
+ bs->nblocks--;
+ kho_block_free_ser(bs, last->ser);
+ kfree(last);
+
+ new_last = list_last_entry_or_null(&bs->blocks, struct kho_block, list);
+ if (new_last)
+ new_last->ser->next = 0;
+ else
+ bs->head_pa = 0;
+}
+
+/*
+ * kho_cyclic_blocks_check - Check for cycles in a linked list of blocks.
+ * Uses Floyd's cycle-finding algorithm to ensure sanity of the incoming list.
+ */
+static bool kho_cyclic_blocks_check(struct kho_block_set *bs)
+{
+ struct kho_block_header_ser *fast;
+ struct kho_block_header_ser *slow;
+ int count = 0;
+
+ fast = phys_to_virt(bs->head_pa);
+ slow = fast;
+
+ while (fast) {
+ if (count++ >= KHO_MAX_BLOCKS) {
+ pr_err("Linked list too long\n");
+ return false;
+ }
+
+ if (!fast->next)
+ break;
+
+ fast = phys_to_virt(fast->next);
+ if (!fast->next)
+ break;
+
+ fast = phys_to_virt(fast->next);
+ slow = phys_to_virt(slow->next);
+
+ if (slow == fast) {
+ pr_err("Cyclic list detected\n");
+ return false;
+ }
+ }
+
+ return true;
+}
+
+/**
+ * kho_block_restore - Restore a block set from a physical address.
+ * @bs: The block set to restore.
+ * @head_pa: Physical address of the first block header.
+ *
+ * Return: 0 on success, or a negative errno on failure.
+ */
+int kho_block_restore(struct kho_block_set *bs, u64 head_pa)
+{
+ struct kho_block_header_ser *ser;
+ u64 next_pa = head_pa;
+ int err;
+
+ /* Restored block sets use size from the previous kernel */
+ bs->incoming = true;
+ if (!head_pa)
+ return 0;
+
+ bs->head_pa = head_pa;
+ if (!kho_cyclic_blocks_check(bs))
+ return -EINVAL;
+
+ while (next_pa) {
+ ser = phys_to_virt(next_pa);
+ if (ser->count > kho_block_count_per_block(bs)) {
+ pr_warn("Block contains too many entries: %llu\n",
+ ser->count);
+ err = -EINVAL;
+ goto err_destroy;
+ }
+ err = kho_block_add(bs, ser);
+ if (err)
+ goto err_destroy;
+ next_pa = ser->next;
+ }
+
+ return 0;
+
+err_destroy:
+ kho_block_destroy(bs);
+ return err;
+}
+
+/**
+ * kho_block_destroy - Destroy all blocks in a block set.
+ * @bs: The block set.
+ */
+void kho_block_destroy(struct kho_block_set *bs)
+{
+ u64 head_pa = bs->head_pa;
+ struct kho_block *block;
+
+ while (!list_empty(&bs->blocks)) {
+ block = list_first_entry(&bs->blocks, struct kho_block, list);
+ list_del(&block->list);
+ kfree(block);
+ }
+ bs->nblocks = 0;
+ bs->head_pa = 0;
+
+ while (head_pa) {
+ struct kho_block_header_ser *ser = phys_to_virt(head_pa);
+
+ head_pa = ser->next;
+ kho_block_free_ser(bs, ser);
+ }
+}
+
+/**
+ * kho_block_set_clear - Clear all serialized data in a block set.
+ * @bs: The block set to clear.
+ */
+void kho_block_set_clear(struct kho_block_set *bs)
+{
+ struct kho_block *block;
+
+ list_for_each_entry(block, &bs->blocks, list) {
+ block->ser->count = 0;
+ memset(block->ser + 1, 0, KHO_BLOCK_SIZE - sizeof(*block->ser));
+ }
+}
+
+/**
+ * kho_block_it_init - Initialize a block set iterator.
+ * @it: The iterator to initialize.
+ * @bs: The block set to iterate over.
+ */
+void kho_block_it_init(struct kho_block_it *it, struct kho_block_set *bs)
+{
+ it->bs = bs;
+ it->block = list_first_entry_or_null(&bs->blocks, struct kho_block, list);
+ it->i = 0;
+}
+
+/**
+ * kho_block_it_next - Return the next entry slot in the block set.
+ * @it: The block iterator.
+ *
+ * If the current block is full, it automatically advances to the next block
+ * in the set.
+ *
+ * Return: A pointer to the next entry slot, or NULL if no more slots are
+ * available.
+ */
+void *kho_block_it_next(struct kho_block_it *it)
+{
+ if (!it->block)
+ return NULL;
+
+ if (it->i == kho_block_count_per_block(it->bs)) {
+ it->block->ser->count = it->i;
+ if (list_is_last(&it->block->list, &it->bs->blocks))
+ return NULL;
+ it->block = list_next_entry(it->block, list);
+ it->i = 0;
+ }
+
+ return (void *)(it->block->ser + 1) + (it->i++ * it->bs->entry_size);
+}
+
+/**
+ * kho_block_it_read - Return the next entry slot for reading.
+ * @it: The block iterator.
+ *
+ * This function iterates through entries that were previously serialized,
+ * respecting the count stored in each block's header.
+ *
+ * Return: A pointer to the next entry slot, or NULL if no more entries are
+ * available.
+ */
+void *kho_block_it_read(struct kho_block_it *it)
+{
+ if (!it->block)
+ return NULL;
+
+ while (it->i == it->block->ser->count) {
+ if (list_is_last(&it->block->list, &it->bs->blocks))
+ return NULL;
+ it->block = list_next_entry(it->block, list);
+ it->i = 0;
+ }
+
+ return (void *)(it->block->ser + 1) + (it->i++ * it->bs->entry_size);
+}
+
+/**
+ * kho_block_it_prev - Return the previous entry slot in the block set.
+ * @it: The block iterator.
+ *
+ * If the current index is at the start of a block, it automatically moves to
+ * the end of the previous block.
+ *
+ * Return: A pointer to the previous entry slot, or NULL if at the very
+ * beginning of the block set.
+ */
+void *kho_block_it_prev(struct kho_block_it *it)
+{
+ if (!it->block)
+ return NULL;
+
+ if (it->i == 0) {
+ if (list_is_first(&it->block->list, &it->bs->blocks))
+ return NULL;
+ it->block = list_prev_entry(it->block, list);
+ it->i = kho_block_count_per_block(it->bs);
+ }
+
+ return (void *)(it->block->ser + 1) + (--it->i * it->bs->entry_size);
+}
+
+/**
+ * kho_block_it_finalize - Finalize the current block by setting its entry count.
+ * @it: The block iterator.
+ */
+void kho_block_it_finalize(struct kho_block_it *it)
+{
+ if (it->block)
+ it->block->ser->count = it->i;
+}
--
2.53.0
^ permalink raw reply related
* [PATCH v3 04/11] liveupdate: Extract luo_session_deserialize_one helper
From: Pasha Tatashin @ 2026-05-29 3:20 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
Extract the logic for deserializing single entries for sessions into
separate helper functions. In preparation to a linked-block
serialization for sessions.
This is a pure code movement, no other changes intended.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
kernel/liveupdate/luo_session.c | 62 +++++++++++++++++++--------------
1 file changed, 36 insertions(+), 26 deletions(-)
diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c
index 1cad54ea8209..5c092c71797e 100644
--- a/kernel/liveupdate/luo_session.c
+++ b/kernel/liveupdate/luo_session.c
@@ -526,6 +526,40 @@ int __init luo_session_setup_incoming(u64 sessions_pa)
return 0;
}
+static int luo_session_deserialize_one(struct luo_session_header *sh,
+ struct luo_session_ser *ser)
+{
+ struct luo_session *session;
+ int err;
+
+ session = luo_session_alloc(ser->name);
+ if (IS_ERR(session)) {
+ pr_warn("Failed to allocate session [%.*s] during deserialization %pe\n",
+ (int)sizeof(ser->name), ser->name, session);
+ return PTR_ERR(session);
+ }
+
+ err = luo_session_insert(sh, session);
+ if (err) {
+ pr_warn("Failed to insert session [%s] %pe\n",
+ session->name, ERR_PTR(err));
+ luo_session_free(session);
+ return err;
+ }
+
+ scoped_guard(mutex, &session->mutex) {
+ err = luo_file_deserialize(&session->file_set,
+ &ser->file_set_ser);
+ }
+ if (err) {
+ pr_warn("Failed to deserialize files for session [%s] %pe\n",
+ session->name, ERR_PTR(err));
+ return err;
+ }
+
+ return 0;
+}
+
int luo_session_deserialize(void)
{
struct luo_session_header *sh = &luo_session_global.incoming;
@@ -556,33 +590,9 @@ int luo_session_deserialize(void)
* reliably reset devices and reclaim memory.
*/
for (int i = 0; i < sh->header_ser->count; i++) {
- struct luo_session *session;
-
- session = luo_session_alloc(sh->ser[i].name);
- if (IS_ERR(session)) {
- pr_warn("Failed to allocate session [%.*s] during deserialization %pe\n",
- (int)sizeof(sh->ser[i].name),
- sh->ser[i].name, session);
- return PTR_ERR(session);
- }
-
- err = luo_session_insert(sh, session);
- if (err) {
- pr_warn("Failed to insert session [%s] %pe\n",
- session->name, ERR_PTR(err));
- luo_session_free(session);
- return err;
- }
-
- scoped_guard(mutex, &session->mutex) {
- err = luo_file_deserialize(&session->file_set,
- &sh->ser[i].file_set_ser);
- }
- if (err) {
- pr_warn("Failed to deserialize files for session [%s] %pe\n",
- session->name, ERR_PTR(err));
+ err = luo_session_deserialize_one(sh, &sh->ser[i]);
+ if (err)
return err;
- }
}
kho_restore_free(sh->header_ser);
--
2.53.0
^ permalink raw reply related
* [PATCH v3 03/11] liveupdate: Extract luo_file_deserialize_one helper
From: Pasha Tatashin @ 2026-05-29 3:20 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
Extract the logic for deserializing single entries for files into
separate helper functions. In preparation to a linked-block
serialization for files.
This is a pure code movement, no other changes intended.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
kernel/liveupdate/luo_file.c | 77 ++++++++++++++++++++----------------
1 file changed, 44 insertions(+), 33 deletions(-)
diff --git a/kernel/liveupdate/luo_file.c b/kernel/liveupdate/luo_file.c
index 208987502f73..9eec07a9e9fc 100644
--- a/kernel/liveupdate/luo_file.c
+++ b/kernel/liveupdate/luo_file.c
@@ -753,6 +753,46 @@ int luo_file_finish(struct luo_file_set *file_set)
return 0;
}
+static int luo_file_deserialize_one(struct luo_file_set *file_set,
+ struct luo_file_ser *ser)
+{
+ struct liveupdate_file_handler *fh;
+ bool handler_found = false;
+ struct luo_file *luo_file;
+
+ down_read(&luo_register_rwlock);
+ list_private_for_each_entry(fh, &luo_file_handler_list, list) {
+ if (!strcmp(fh->compatible, ser->compatible)) {
+ if (try_module_get(fh->ops->owner))
+ handler_found = true;
+ break;
+ }
+ }
+ up_read(&luo_register_rwlock);
+
+ if (!handler_found) {
+ pr_warn("No registered handler for compatible '%.*s'\n",
+ (int)sizeof(ser->compatible),
+ ser->compatible);
+ return -ENOENT;
+ }
+
+ luo_file = kzalloc_obj(*luo_file);
+ if (!luo_file) {
+ module_put(fh->ops->owner);
+ return -ENOMEM;
+ }
+
+ luo_file->fh = fh;
+ luo_file->file = NULL;
+ luo_file->serialized_data = ser->data;
+ luo_file->token = ser->token;
+ mutex_init(&luo_file->mutex);
+ list_add_tail(&luo_file->list, &file_set->files_list);
+
+ return 0;
+}
+
/**
* luo_file_deserialize - Reconstructs the list of preserved files in the new kernel.
* @file_set: The incoming file_set to fill with deserialized data.
@@ -782,6 +822,7 @@ int luo_file_deserialize(struct luo_file_set *file_set,
struct luo_file_set_ser *file_set_ser)
{
struct luo_file_ser *file_ser;
+ int err;
u64 i;
if (!file_set_ser->files) {
@@ -809,39 +850,9 @@ int luo_file_deserialize(struct luo_file_set *file_set,
*/
file_ser = file_set->files;
for (i = 0; i < file_set->count; i++) {
- struct liveupdate_file_handler *fh;
- bool handler_found = false;
- struct luo_file *luo_file;
-
- down_read(&luo_register_rwlock);
- list_private_for_each_entry(fh, &luo_file_handler_list, list) {
- if (!strcmp(fh->compatible, file_ser[i].compatible)) {
- if (try_module_get(fh->ops->owner))
- handler_found = true;
- break;
- }
- }
- up_read(&luo_register_rwlock);
-
- if (!handler_found) {
- pr_warn("No registered handler for compatible '%.*s'\n",
- (int)sizeof(file_ser[i].compatible),
- file_ser[i].compatible);
- return -ENOENT;
- }
-
- luo_file = kzalloc_obj(*luo_file);
- if (!luo_file) {
- module_put(fh->ops->owner);
- return -ENOMEM;
- }
-
- luo_file->fh = fh;
- luo_file->file = NULL;
- luo_file->serialized_data = file_ser[i].data;
- luo_file->token = file_ser[i].token;
- mutex_init(&luo_file->mutex);
- list_add_tail(&luo_file->list, &file_set->files_list);
+ err = luo_file_deserialize_one(file_set, &file_ser[i]);
+ if (err)
+ return err;
}
return 0;
--
2.53.0
^ permalink raw reply related
* [PATCH v3 02/11] liveupdate: register luo_ser as KHO subtree
From: Pasha Tatashin @ 2026-05-29 3:20 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
Entirely remove the LUO FDT wrapper since the FDT only carries the
compatible string and the pointer to the centralized struct luo_ser.
Instead, register the struct luo_ser via the KHO raw subtree
API, placing the compatibility string inside the structure itself.
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
include/linux/kho/abi/luo.h | 57 +++++++++---------------
kernel/liveupdate/luo_core.c | 85 +++++++++++-------------------------
2 files changed, 46 insertions(+), 96 deletions(-)
diff --git a/include/linux/kho/abi/luo.h b/include/linux/kho/abi/luo.h
index 1b2f865a771a..9a4fe491812b 100644
--- a/include/linux/kho/abi/luo.h
+++ b/include/linux/kho/abi/luo.h
@@ -10,11 +10,11 @@
*
* Live Update Orchestrator uses the stable Application Binary Interface
* defined below to pass state from a pre-update kernel to a post-update
- * kernel. The ABI is built upon the Kexec HandOver framework and uses a
- * Flattened Device Tree to describe the preserved data.
+ * kernel. The ABI is built upon the Kexec HandOver framework and registers
+ * the central `struct luo_ser` via the KHO raw subtree API.
*
- * This interface is a contract. Any modification to the FDT structure, node
- * properties, compatible strings, or the layout of the `__packed` serialization
+ * This interface is a contract. Any modification to the structure fields,
+ * compatible strings, or the layout of the `__packed` serialization
* structures defined here constitutes a breaking change. Such changes require
* incrementing the version number in the relevant `_COMPATIBLE` string to
* prevent a new kernel from misinterpreting data from an old kernel.
@@ -23,31 +23,15 @@
* however, backward/forward compatibility is only guaranteed for kernels
* supporting the same ABI version.
*
- * FDT Structure Overview:
+ * KHO Structure Overview:
* The entire LUO state is encapsulated within a single KHO entry named "LUO".
- * This entry contains an FDT with the following layout:
- *
- * .. code-block:: none
- *
- * / {
- * compatible = "luo-v2";
- * luo-abi-header = <phys_addr_of_luo_ser>;
- * };
- *
- * Main LUO Node (/):
- *
- * - compatible: "luo-v2"
- * Identifies the overall LUO ABI version.
- * - luo-abi-header: u64
- * The physical address of `struct luo_ser`.
+ * This entry contains the `struct luo_ser` structure.
*
* Serialization Structures:
- * The FDT properties point to memory regions containing arrays of simple,
- * `__packed` structures. These structures contain the actual preserved state.
- *
* - struct luo_ser:
* The central ABI structure that contains the overall state of the LUO.
- * It includes the liveupdate-number and pointers to sessions and FLBs.
+ * It includes the compatibility string, the liveupdate-number, and pointers
+ * to sessions and FLBs.
*
* - struct luo_session_header_ser:
* Header for the session array. Contains the total page count of the
@@ -78,26 +62,27 @@
#ifndef _LINUX_KHO_ABI_LUO_H
#define _LINUX_KHO_ABI_LUO_H
+#include <linux/align.h>
#include <uapi/linux/liveupdate.h>
/*
- * The LUO FDT hooks all LUO state for sessions, fds, etc.
+ * The LUO state is registered under this KHO entry name.
*/
-#define LUO_FDT_SIZE PAGE_SIZE
-#define LUO_FDT_KHO_ENTRY_NAME "LUO"
-#define LUO_FDT_COMPATIBLE "luo-v2"
-#define LUO_FDT_ABI_HEADER "luo-abi-header"
+#define LUO_KHO_ENTRY_NAME "LUO"
+#define LUO_ABI_COMPATIBLE "luo-v3"
+#define LUO_ABI_COMPAT_LEN ALIGN(sizeof(LUO_ABI_COMPATIBLE), 8)
/**
* struct luo_ser - Centralized LUO ABI header.
+ * @compatible: Compatibility string identifying the LUO ABI version.
* @liveupdate_num: A counter tracking the number of successful live updates.
* @sessions_pa: Physical address of the first session block header.
* @flbs_pa: Physical address of the FLB header.
*
- * This structure is the root of all preserved LUO state. It is pointed to by
- * the "luo-abi-header" property in the LUO FDT.
+ * This structure is the root of all preserved LUO state.
*/
struct luo_ser {
+ char compatible[LUO_ABI_COMPAT_LEN];
u64 liveupdate_num;
u64 sessions_pa;
u64 flbs_pa;
@@ -111,7 +96,7 @@ struct luo_ser {
* @data: Private data
* @token: User provided token for this file
*
- * If this structure is modified, LUO_SESSION_COMPATIBLE must be updated.
+ * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated.
*/
struct luo_file_ser {
char compatible[LIVEUPDATE_HNDL_COMPAT_LENGTH];
@@ -142,7 +127,7 @@ struct luo_file_set_ser {
* physical memory preserved across the kexec. It provides the necessary
* metadata to interpret the array of session entries that follow.
*
- * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated.
+ * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated.
*/
struct luo_session_header_ser {
u64 count;
@@ -159,7 +144,7 @@ struct luo_session_header_ser {
* session) is created and passed to the new kernel, allowing it to reconstruct
* the session context.
*
- * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated.
+ * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated.
*/
struct luo_session_ser {
char name[LIVEUPDATE_SESSION_NAME_LENGTH];
@@ -180,7 +165,7 @@ struct luo_session_ser {
* This structure is located at the physical address specified by the
* flbs_pa in luo_ser.
*
- * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated.
+ * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated.
*/
struct luo_flb_header_ser {
u64 pgcnt;
@@ -202,7 +187,7 @@ struct luo_flb_header_ser {
* passed to the new kernel. Each entry allows the LUO core to restore one
* global, shared object.
*
- * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated.
+ * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated.
*/
struct luo_flb_ser {
char name[LIVEUPDATE_FLB_COMPAT_LENGTH];
diff --git a/kernel/liveupdate/luo_core.c b/kernel/liveupdate/luo_core.c
index c1c290aefc76..5e12c8f8669b 100644
--- a/kernel/liveupdate/luo_core.c
+++ b/kernel/liveupdate/luo_core.c
@@ -50,7 +50,6 @@
#include <linux/kexec_handover.h>
#include <linux/kho/abi/luo.h>
#include <linux/kobject.h>
-#include <linux/libfdt.h>
#include <linux/liveupdate.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
@@ -63,8 +62,7 @@
static struct {
bool enabled;
- void *fdt_out;
- void *fdt_in;
+ struct luo_ser *luo_ser_out;
u64 liveupdate_num;
} luo_global;
@@ -81,11 +79,10 @@ early_param("liveupdate", early_liveupdate_param);
static int __init luo_early_startup(void)
{
+ phys_addr_t luo_ser_phys;
struct luo_ser *luo_ser;
- int err, header_size;
- phys_addr_t fdt_phys;
- const void *ptr;
- u64 luo_ser_pa;
+ size_t len;
+ int err;
if (!kho_is_enabled()) {
if (liveupdate_enabled())
@@ -94,40 +91,29 @@ static int __init luo_early_startup(void)
return 0;
}
- /* Retrieve LUO subtree, and verify its format. */
- err = kho_retrieve_subtree(LUO_FDT_KHO_ENTRY_NAME, &fdt_phys, NULL);
+ /* Retrieve LUO state from KHO. */
+ err = kho_retrieve_subtree(LUO_KHO_ENTRY_NAME, &luo_ser_phys, &len);
if (err) {
if (err != -ENOENT) {
- pr_err("failed to retrieve FDT '%s' from KHO: %pe\n",
- LUO_FDT_KHO_ENTRY_NAME, ERR_PTR(err));
+ pr_err("failed to retrieve LUO state '%s' from KHO: %pe\n",
+ LUO_KHO_ENTRY_NAME, ERR_PTR(err));
return err;
}
return 0;
}
- luo_global.fdt_in = phys_to_virt(fdt_phys);
- err = fdt_node_check_compatible(luo_global.fdt_in, 0,
- LUO_FDT_COMPATIBLE);
- if (err) {
- pr_err("FDT '%s' is incompatible with '%s' [%d]\n",
- LUO_FDT_KHO_ENTRY_NAME, LUO_FDT_COMPATIBLE, err);
-
+ if (len < sizeof(*luo_ser)) {
+ pr_err("LUO state is too small (%zu < %zu)\n", len, sizeof(*luo_ser));
return -EINVAL;
}
- header_size = 0;
- ptr = fdt_getprop(luo_global.fdt_in, 0, LUO_FDT_ABI_HEADER, &header_size);
- if (!ptr || header_size != sizeof(u64)) {
- pr_err("Unable to get ABI header '%s' [%d]\n",
- LUO_FDT_ABI_HEADER, header_size);
-
+ luo_ser = phys_to_virt(luo_ser_phys);
+ if (strncmp(luo_ser->compatible, LUO_ABI_COMPATIBLE, LUO_ABI_COMPAT_LEN)) {
+ pr_err("LUO state is incompatible with '%s'\n", LUO_ABI_COMPATIBLE);
return -EINVAL;
}
- luo_ser_pa = get_unaligned((u64 *)ptr);
- luo_ser = phys_to_virt(luo_ser_pa);
-
luo_global.liveupdate_num = luo_ser->liveupdate_num;
pr_info("Retrieved live update data, liveupdate number: %lld\n",
luo_global.liveupdate_num);
@@ -156,37 +142,20 @@ static int __init liveupdate_early_init(void)
}
early_initcall(liveupdate_early_init);
-/* Called during boot to create outgoing LUO fdt tree */
-static int __init luo_fdt_setup(void)
+/* Called during boot to create outgoing LUO state */
+static int __init luo_state_setup(void)
{
struct luo_ser *luo_ser;
- u64 luo_ser_pa;
- void *fdt_out;
int err;
- fdt_out = kho_alloc_preserve(LUO_FDT_SIZE);
- if (IS_ERR(fdt_out)) {
- pr_err("failed to allocate/preserve FDT memory\n");
- return PTR_ERR(fdt_out);
- }
-
luo_ser = kho_alloc_preserve(sizeof(*luo_ser));
if (IS_ERR(luo_ser)) {
- err = PTR_ERR(luo_ser);
- goto exit_free_fdt;
+ pr_err("failed to allocate/preserve LUO state memory\n");
+ return PTR_ERR(luo_ser);
}
- luo_ser_pa = virt_to_phys(luo_ser);
-
- err = fdt_create(fdt_out, LUO_FDT_SIZE);
- err |= fdt_finish_reservemap(fdt_out);
- err |= fdt_begin_node(fdt_out, "");
- err |= fdt_property_string(fdt_out, "compatible", LUO_FDT_COMPATIBLE);
- err |= fdt_property(fdt_out, LUO_FDT_ABI_HEADER, &luo_ser_pa,
- sizeof(luo_ser_pa));
- err |= fdt_end_node(fdt_out);
- err |= fdt_finish(fdt_out);
- if (err)
- goto exit_free_luo_ser;
+
+ strscpy(luo_ser->compatible, LUO_ABI_COMPATIBLE, sizeof(luo_ser->compatible));
+ luo_ser->liveupdate_num = luo_global.liveupdate_num + 1;
err = luo_session_setup_outgoing(&luo_ser->sessions_pa);
if (err)
@@ -196,21 +165,17 @@ static int __init luo_fdt_setup(void)
if (err)
goto exit_free_luo_ser;
- luo_ser->liveupdate_num = luo_global.liveupdate_num + 1;
-
- err = kho_add_subtree(LUO_FDT_KHO_ENTRY_NAME, fdt_out,
- fdt_totalsize(fdt_out));
+ err = kho_add_subtree(LUO_KHO_ENTRY_NAME, luo_ser, sizeof(*luo_ser));
if (err)
goto exit_free_luo_ser;
- luo_global.fdt_out = fdt_out;
+
+ luo_global.luo_ser_out = luo_ser;
return 0;
exit_free_luo_ser:
kho_unpreserve_free(luo_ser);
-exit_free_fdt:
- kho_unpreserve_free(fdt_out);
- pr_err("failed to prepare LUO FDT: %d\n", err);
+ pr_err("failed to prepare LUO state: %d\n", err);
return err;
}
@@ -226,7 +191,7 @@ static int __init luo_late_startup(void)
if (!liveupdate_enabled())
return 0;
- err = luo_fdt_setup();
+ err = luo_state_setup();
if (err)
luo_global.enabled = false;
--
2.53.0
^ permalink raw reply related
* [PATCH v3 01/11] liveupdate: centralize state management into struct luo_ser
From: Pasha Tatashin @ 2026-05-29 3:20 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
In-Reply-To: <20260529032106.1505796-1-pasha.tatashin@soleen.com>
Transition the LUO to ABI v2, which centralizes state management into a
single struct luo_ser header.
Previously, LUO state was spread across multiple FDT properties and
subnodes. ABI v2 simplifies this by placing all core state, including
the liveupdate number and physical addresses for sessions and FLB
headers into a centralized struct luo_ser.
Note that this change introduces a semantic difference: the sessions
and FLB serialization formats are no longer completely independent of
the core LUO. Their metadata (such as physical addresses for sessions
and FLB headers) is now coupled to and managed via the centralized
struct luo_ser.
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
include/linux/kho/abi/luo.h | 91 +++++++++++---------------------
kernel/liveupdate/luo_core.c | 60 ++++++++++++++-------
kernel/liveupdate/luo_flb.c | 65 +++--------------------
kernel/liveupdate/luo_internal.h | 8 +--
kernel/liveupdate/luo_session.c | 64 ++++------------------
5 files changed, 94 insertions(+), 194 deletions(-)
diff --git a/include/linux/kho/abi/luo.h b/include/linux/kho/abi/luo.h
index 46750a0ddf88..1b2f865a771a 100644
--- a/include/linux/kho/abi/luo.h
+++ b/include/linux/kho/abi/luo.h
@@ -30,52 +30,25 @@
* .. code-block:: none
*
* / {
- * compatible = "luo-v1";
- * liveupdate-number = <...>;
- *
- * luo-session {
- * compatible = "luo-session-v1";
- * luo-session-header = <phys_addr_of_session_header_ser>;
- * };
- *
- * luo-flb {
- * compatible = "luo-flb-v1";
- * luo-flb-header = <phys_addr_of_flb_header_ser>;
- * };
+ * compatible = "luo-v2";
+ * luo-abi-header = <phys_addr_of_luo_ser>;
* };
*
* Main LUO Node (/):
*
- * - compatible: "luo-v1"
+ * - compatible: "luo-v2"
* Identifies the overall LUO ABI version.
- * - liveupdate-number: u64
- * A counter tracking the number of successful live updates performed.
- *
- * Session Node (luo-session):
- * This node describes all preserved user-space sessions.
- *
- * - compatible: "luo-session-v1"
- * Identifies the session ABI version.
- * - luo-session-header: u64
- * The physical address of a `struct luo_session_header_ser`. This structure
- * is the header for a contiguous block of memory containing an array of
- * `struct luo_session_ser`, one for each preserved session.
- *
- * File-Lifecycle-Bound Node (luo-flb):
- * This node describes all preserved global objects whose lifecycle is bound
- * to that of the preserved files (e.g., shared IOMMU state).
- *
- * - compatible: "luo-flb-v1"
- * Identifies the FLB ABI version.
- * - luo-flb-header: u64
- * The physical address of a `struct luo_flb_header_ser`. This structure is
- * the header for a contiguous block of memory containing an array of
- * `struct luo_flb_ser`, one for each preserved global object.
+ * - luo-abi-header: u64
+ * The physical address of `struct luo_ser`.
*
* Serialization Structures:
* The FDT properties point to memory regions containing arrays of simple,
* `__packed` structures. These structures contain the actual preserved state.
*
+ * - struct luo_ser:
+ * The central ABI structure that contains the overall state of the LUO.
+ * It includes the liveupdate-number and pointers to sessions and FLBs.
+ *
* - struct luo_session_header_ser:
* Header for the session array. Contains the total page count of the
* preserved memory block and the number of `struct luo_session_ser`
@@ -109,13 +82,26 @@
/*
* The LUO FDT hooks all LUO state for sessions, fds, etc.
- * In the root it also carries "liveupdate-number" 64-bit property that
- * corresponds to the number of live-updates performed on this machine.
*/
#define LUO_FDT_SIZE PAGE_SIZE
#define LUO_FDT_KHO_ENTRY_NAME "LUO"
-#define LUO_FDT_COMPATIBLE "luo-v1"
-#define LUO_FDT_LIVEUPDATE_NUM "liveupdate-number"
+#define LUO_FDT_COMPATIBLE "luo-v2"
+#define LUO_FDT_ABI_HEADER "luo-abi-header"
+
+/**
+ * struct luo_ser - Centralized LUO ABI header.
+ * @liveupdate_num: A counter tracking the number of successful live updates.
+ * @sessions_pa: Physical address of the first session block header.
+ * @flbs_pa: Physical address of the FLB header.
+ *
+ * This structure is the root of all preserved LUO state. It is pointed to by
+ * the "luo-abi-header" property in the LUO FDT.
+ */
+struct luo_ser {
+ u64 liveupdate_num;
+ u64 sessions_pa;
+ u64 flbs_pa;
+} __packed;
#define LIVEUPDATE_HNDL_COMPAT_LENGTH 48
@@ -147,15 +133,6 @@ struct luo_file_set_ser {
u64 count;
} __packed;
-/*
- * LUO FDT session node
- * LUO_FDT_SESSION_HEADER: is a u64 physical address of struct
- * luo_session_header_ser
- */
-#define LUO_FDT_SESSION_NODE_NAME "luo-session"
-#define LUO_FDT_SESSION_COMPATIBLE "luo-session-v2"
-#define LUO_FDT_SESSION_HEADER "luo-session-header"
-
/**
* struct luo_session_header_ser - Header for the serialized session data block.
* @count: The number of `struct luo_session_ser` entries that immediately
@@ -165,7 +142,7 @@ struct luo_file_set_ser {
* physical memory preserved across the kexec. It provides the necessary
* metadata to interpret the array of session entries that follow.
*
- * If this structure is modified, `LUO_FDT_SESSION_COMPATIBLE` must be updated.
+ * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated.
*/
struct luo_session_header_ser {
u64 count;
@@ -182,7 +159,7 @@ struct luo_session_header_ser {
* session) is created and passed to the new kernel, allowing it to reconstruct
* the session context.
*
- * If this structure is modified, `LUO_FDT_SESSION_COMPATIBLE` must be updated.
+ * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated.
*/
struct luo_session_ser {
char name[LIVEUPDATE_SESSION_NAME_LENGTH];
@@ -192,10 +169,6 @@ struct luo_session_ser {
/* The max size is set so it can be reliably used during in serialization */
#define LIVEUPDATE_FLB_COMPAT_LENGTH 48
-#define LUO_FDT_FLB_NODE_NAME "luo-flb"
-#define LUO_FDT_FLB_COMPATIBLE "luo-flb-v1"
-#define LUO_FDT_FLB_HEADER "luo-flb-header"
-
/**
* struct luo_flb_header_ser - Header for the serialized FLB data block.
* @pgcnt: The total number of pages occupied by the entire preserved memory
@@ -205,11 +178,9 @@ struct luo_session_ser {
* in the memory block.
*
* This structure is located at the physical address specified by the
- * `LUO_FDT_FLB_HEADER` FDT property. It provides the new kernel with the
- * necessary information to find and iterate over the array of preserved
- * File-Lifecycle-Bound objects and to manage the underlying memory.
+ * flbs_pa in luo_ser.
*
- * If this structure is modified, LUO_FDT_FLB_COMPATIBLE must be updated.
+ * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated.
*/
struct luo_flb_header_ser {
u64 pgcnt;
@@ -231,7 +202,7 @@ struct luo_flb_header_ser {
* passed to the new kernel. Each entry allows the LUO core to restore one
* global, shared object.
*
- * If this structure is modified, LUO_FDT_FLB_COMPATIBLE must be updated.
+ * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated.
*/
struct luo_flb_ser {
char name[LIVEUPDATE_FLB_COMPAT_LENGTH];
diff --git a/kernel/liveupdate/luo_core.c b/kernel/liveupdate/luo_core.c
index 803f51c84275..c1c290aefc76 100644
--- a/kernel/liveupdate/luo_core.c
+++ b/kernel/liveupdate/luo_core.c
@@ -57,7 +57,6 @@
#include <linux/rwsem.h>
#include <linux/sizes.h>
#include <linux/string.h>
-#include <linux/unaligned.h>
#include "kexec_handover_internal.h"
#include "luo_internal.h"
@@ -82,9 +81,11 @@ early_param("liveupdate", early_liveupdate_param);
static int __init luo_early_startup(void)
{
+ struct luo_ser *luo_ser;
+ int err, header_size;
phys_addr_t fdt_phys;
- int err, ln_size;
const void *ptr;
+ u64 luo_ser_pa;
if (!kho_is_enabled()) {
if (liveupdate_enabled())
@@ -115,27 +116,29 @@ static int __init luo_early_startup(void)
return -EINVAL;
}
- ln_size = 0;
- ptr = fdt_getprop(luo_global.fdt_in, 0, LUO_FDT_LIVEUPDATE_NUM,
- &ln_size);
- if (!ptr || ln_size != sizeof(luo_global.liveupdate_num)) {
- pr_err("Unable to get live update number '%s' [%d]\n",
- LUO_FDT_LIVEUPDATE_NUM, ln_size);
+ header_size = 0;
+ ptr = fdt_getprop(luo_global.fdt_in, 0, LUO_FDT_ABI_HEADER, &header_size);
+ if (!ptr || header_size != sizeof(u64)) {
+ pr_err("Unable to get ABI header '%s' [%d]\n",
+ LUO_FDT_ABI_HEADER, header_size);
return -EINVAL;
}
- luo_global.liveupdate_num = get_unaligned((u64 *)ptr);
+ luo_ser_pa = get_unaligned((u64 *)ptr);
+ luo_ser = phys_to_virt(luo_ser_pa);
+
+ luo_global.liveupdate_num = luo_ser->liveupdate_num;
pr_info("Retrieved live update data, liveupdate number: %lld\n",
luo_global.liveupdate_num);
- err = luo_session_setup_incoming(luo_global.fdt_in);
+ err = luo_session_setup_incoming(luo_ser->sessions_pa);
if (err)
return err;
- err = luo_flb_setup_incoming(luo_global.fdt_in);
+ luo_flb_setup_incoming(luo_ser->flbs_pa);
- return err;
+ return 0;
}
static int __init liveupdate_early_init(void)
@@ -156,7 +159,8 @@ early_initcall(liveupdate_early_init);
/* Called during boot to create outgoing LUO fdt tree */
static int __init luo_fdt_setup(void)
{
- const u64 ln = luo_global.liveupdate_num + 1;
+ struct luo_ser *luo_ser;
+ u64 luo_ser_pa;
void *fdt_out;
int err;
@@ -166,27 +170,45 @@ static int __init luo_fdt_setup(void)
return PTR_ERR(fdt_out);
}
+ luo_ser = kho_alloc_preserve(sizeof(*luo_ser));
+ if (IS_ERR(luo_ser)) {
+ err = PTR_ERR(luo_ser);
+ goto exit_free_fdt;
+ }
+ luo_ser_pa = virt_to_phys(luo_ser);
+
err = fdt_create(fdt_out, LUO_FDT_SIZE);
err |= fdt_finish_reservemap(fdt_out);
err |= fdt_begin_node(fdt_out, "");
err |= fdt_property_string(fdt_out, "compatible", LUO_FDT_COMPATIBLE);
- err |= fdt_property(fdt_out, LUO_FDT_LIVEUPDATE_NUM, &ln, sizeof(ln));
- err |= luo_session_setup_outgoing(fdt_out);
- err |= luo_flb_setup_outgoing(fdt_out);
+ err |= fdt_property(fdt_out, LUO_FDT_ABI_HEADER, &luo_ser_pa,
+ sizeof(luo_ser_pa));
err |= fdt_end_node(fdt_out);
err |= fdt_finish(fdt_out);
if (err)
- goto exit_free;
+ goto exit_free_luo_ser;
+
+ err = luo_session_setup_outgoing(&luo_ser->sessions_pa);
+ if (err)
+ goto exit_free_luo_ser;
+
+ err = luo_flb_setup_outgoing(&luo_ser->flbs_pa);
+ if (err)
+ goto exit_free_luo_ser;
+
+ luo_ser->liveupdate_num = luo_global.liveupdate_num + 1;
err = kho_add_subtree(LUO_FDT_KHO_ENTRY_NAME, fdt_out,
fdt_totalsize(fdt_out));
if (err)
- goto exit_free;
+ goto exit_free_luo_ser;
luo_global.fdt_out = fdt_out;
return 0;
-exit_free:
+exit_free_luo_ser:
+ kho_unpreserve_free(luo_ser);
+exit_free_fdt:
kho_unpreserve_free(fdt_out);
pr_err("failed to prepare LUO FDT: %d\n", err);
diff --git a/kernel/liveupdate/luo_flb.c b/kernel/liveupdate/luo_flb.c
index 8f5c5dd01cd0..c8dd30b41238 100644
--- a/kernel/liveupdate/luo_flb.c
+++ b/kernel/liveupdate/luo_flb.c
@@ -44,13 +44,11 @@
#include <linux/io.h>
#include <linux/kexec_handover.h>
#include <linux/kho/abi/luo.h>
-#include <linux/libfdt.h>
#include <linux/list_private.h>
#include <linux/liveupdate.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
-#include <linux/unaligned.h>
#include "luo_internal.h"
#define LUO_FLB_PGCNT 1ul
@@ -551,27 +549,15 @@ int liveupdate_flb_get_outgoing(struct liveupdate_flb *flb, void **objp)
return 0;
}
-int __init luo_flb_setup_outgoing(void *fdt_out)
+int __init luo_flb_setup_outgoing(u64 *flbs_pa)
{
struct luo_flb_header_ser *header_ser;
- u64 header_ser_pa;
- int err;
header_ser = kho_alloc_preserve(LUO_FLB_PGCNT << PAGE_SHIFT);
if (IS_ERR(header_ser))
return PTR_ERR(header_ser);
- header_ser_pa = virt_to_phys(header_ser);
-
- err = fdt_begin_node(fdt_out, LUO_FDT_FLB_NODE_NAME);
- err |= fdt_property_string(fdt_out, "compatible",
- LUO_FDT_FLB_COMPATIBLE);
- err |= fdt_property(fdt_out, LUO_FDT_FLB_HEADER, &header_ser_pa,
- sizeof(header_ser_pa));
- err |= fdt_end_node(fdt_out);
-
- if (err)
- goto err_unpreserve;
+ *flbs_pa = virt_to_phys(header_ser);
header_ser->pgcnt = LUO_FLB_PGCNT;
luo_flb_global.outgoing.header_ser = header_ser;
@@ -579,53 +565,18 @@ int __init luo_flb_setup_outgoing(void *fdt_out)
luo_flb_global.outgoing.active = true;
return 0;
-
-err_unpreserve:
- kho_unpreserve_free(header_ser);
-
- return err;
}
-int __init luo_flb_setup_incoming(void *fdt_in)
+void __init luo_flb_setup_incoming(u64 flbs_pa)
{
struct luo_flb_header_ser *header_ser;
- int err, header_size, offset;
- const void *ptr;
- u64 header_ser_pa;
- offset = fdt_subnode_offset(fdt_in, 0, LUO_FDT_FLB_NODE_NAME);
- if (offset < 0) {
- pr_err("Unable to get FLB node [%s]\n", LUO_FDT_FLB_NODE_NAME);
-
- return -ENOENT;
+ if (flbs_pa) {
+ header_ser = phys_to_virt(flbs_pa);
+ luo_flb_global.incoming.header_ser = header_ser;
+ luo_flb_global.incoming.ser = (void *)(header_ser + 1);
+ luo_flb_global.incoming.active = true;
}
-
- err = fdt_node_check_compatible(fdt_in, offset,
- LUO_FDT_FLB_COMPATIBLE);
- if (err) {
- pr_err("FLB node is incompatible with '%s' [%d]\n",
- LUO_FDT_FLB_COMPATIBLE, err);
-
- return -EINVAL;
- }
-
- header_size = 0;
- ptr = fdt_getprop(fdt_in, offset, LUO_FDT_FLB_HEADER, &header_size);
- if (!ptr || header_size != sizeof(u64)) {
- pr_err("Unable to get FLB header property '%s' [%d]\n",
- LUO_FDT_FLB_HEADER, header_size);
-
- return -EINVAL;
- }
-
- header_ser_pa = get_unaligned((u64 *)ptr);
- header_ser = phys_to_virt(header_ser_pa);
-
- luo_flb_global.incoming.header_ser = header_ser;
- luo_flb_global.incoming.ser = (void *)(header_ser + 1);
- luo_flb_global.incoming.active = true;
-
- return 0;
}
/**
diff --git a/kernel/liveupdate/luo_internal.h b/kernel/liveupdate/luo_internal.h
index dd53d4a7277e..9bf26c5b1495 100644
--- a/kernel/liveupdate/luo_internal.h
+++ b/kernel/liveupdate/luo_internal.h
@@ -79,8 +79,8 @@ extern struct rw_semaphore luo_register_rwlock;
int luo_session_create(const char *name, struct file **filep);
int luo_session_retrieve(const char *name, struct file **filep);
-int __init luo_session_setup_outgoing(void *fdt);
-int __init luo_session_setup_incoming(void *fdt);
+int __init luo_session_setup_outgoing(u64 *sessions_pa);
+int __init luo_session_setup_incoming(u64 sessions_pa);
int luo_session_serialize(void);
int luo_session_deserialize(void);
@@ -102,8 +102,8 @@ int luo_flb_file_preserve(struct liveupdate_file_handler *fh);
void luo_flb_file_unpreserve(struct liveupdate_file_handler *fh);
void luo_flb_file_finish(struct liveupdate_file_handler *fh);
void luo_flb_unregister_all(struct liveupdate_file_handler *fh);
-int __init luo_flb_setup_outgoing(void *fdt);
-int __init luo_flb_setup_incoming(void *fdt);
+int __init luo_flb_setup_outgoing(u64 *flbs_pa);
+void __init luo_flb_setup_incoming(u64 flbs_pa);
void luo_flb_serialize(void);
#ifdef CONFIG_LIVEUPDATE_TEST
diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c
index 146414933977..1cad54ea8209 100644
--- a/kernel/liveupdate/luo_session.c
+++ b/kernel/liveupdate/luo_session.c
@@ -25,9 +25,8 @@
*
* - Serialization: Session metadata is preserved using the KHO framework. When
* a live update is triggered via kexec, an array of `struct luo_session_ser`
- * is populated and placed in a preserved memory region. An FDT node is also
- * created, containing the count of sessions and the physical address of this
- * array.
+ * is populated and placed in a preserved memory region. The physical address
+ * of this array is stored in the centralized `struct luo_ser` structure.
*
* Session Lifecycle:
*
@@ -91,13 +90,11 @@
#include <linux/io.h>
#include <linux/kexec_handover.h>
#include <linux/kho/abi/luo.h>
-#include <linux/libfdt.h>
#include <linux/list.h>
#include <linux/liveupdate.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/slab.h>
-#include <linux/unaligned.h>
#include <uapi/linux/liveupdate.h>
#include "luo_internal.h"
@@ -498,75 +495,34 @@ int luo_session_retrieve(const char *name, struct file **filep)
return err;
}
-int __init luo_session_setup_outgoing(void *fdt_out)
+int __init luo_session_setup_outgoing(u64 *sessions_pa)
{
struct luo_session_header_ser *header_ser;
- u64 header_ser_pa;
- int err;
header_ser = kho_alloc_preserve(LUO_SESSION_PGCNT << PAGE_SHIFT);
if (IS_ERR(header_ser))
return PTR_ERR(header_ser);
- header_ser_pa = virt_to_phys(header_ser);
-
- err = fdt_begin_node(fdt_out, LUO_FDT_SESSION_NODE_NAME);
- err |= fdt_property_string(fdt_out, "compatible",
- LUO_FDT_SESSION_COMPATIBLE);
- err |= fdt_property(fdt_out, LUO_FDT_SESSION_HEADER, &header_ser_pa,
- sizeof(header_ser_pa));
- err |= fdt_end_node(fdt_out);
- if (err)
- goto err_unpreserve;
+ *sessions_pa = virt_to_phys(header_ser);
luo_session_global.outgoing.header_ser = header_ser;
luo_session_global.outgoing.ser = (void *)(header_ser + 1);
luo_session_global.outgoing.active = true;
return 0;
-
-err_unpreserve:
- kho_unpreserve_free(header_ser);
- return err;
}
-int __init luo_session_setup_incoming(void *fdt_in)
+int __init luo_session_setup_incoming(u64 sessions_pa)
{
struct luo_session_header_ser *header_ser;
- int err, header_size, offset;
- u64 header_ser_pa;
- const void *ptr;
-
- offset = fdt_subnode_offset(fdt_in, 0, LUO_FDT_SESSION_NODE_NAME);
- if (offset < 0) {
- pr_err("Unable to get session node: [%s]\n",
- LUO_FDT_SESSION_NODE_NAME);
- return -EINVAL;
- }
- err = fdt_node_check_compatible(fdt_in, offset,
- LUO_FDT_SESSION_COMPATIBLE);
- if (err) {
- pr_err("Session node incompatible [%s]\n",
- LUO_FDT_SESSION_COMPATIBLE);
- return -EINVAL;
- }
-
- header_size = 0;
- ptr = fdt_getprop(fdt_in, offset, LUO_FDT_SESSION_HEADER, &header_size);
- if (!ptr || header_size != sizeof(u64)) {
- pr_err("Unable to get session header '%s' [%d]\n",
- LUO_FDT_SESSION_HEADER, header_size);
- return -EINVAL;
+ if (sessions_pa) {
+ header_ser = phys_to_virt(sessions_pa);
+ luo_session_global.incoming.header_ser = header_ser;
+ luo_session_global.incoming.ser = (void *)(header_ser + 1);
+ luo_session_global.incoming.active = true;
}
- header_ser_pa = get_unaligned((u64 *)ptr);
- header_ser = phys_to_virt(header_ser_pa);
-
- luo_session_global.incoming.header_ser = header_ser;
- luo_session_global.incoming.ser = (void *)(header_ser + 1);
- luo_session_global.incoming.active = true;
-
return 0;
}
--
2.53.0
^ permalink raw reply related
* [PATCH v3 00/11] liveupdate: Remove limits on the number of files and sessions
From: Pasha Tatashin @ 2026-05-29 3:20 UTC (permalink / raw)
To: linux-kselftest, rppt, shuah, akpm, linux-mm, skhan, linux-doc,
linux-kernel, corbet, pasha.tatashin, dmatlack, kexec, pratyush,
skhawaja, graf
This series removes the fixed limits on the number of files that can
be preserved within a single session, and the total number of sessions
managed by the Live Update Orchestrator (LUO).
The core of the change is a transition from single contiguous memory
blocks for metadata serialization to a chain of linked blocks. This
allows LUO to scale dynamically.
1. ABI Evolution:
- Introduced linked-block headers for both file and session
serialization.
- Bumped session ABI version to v4.
2. Memory Management & Security:
- Implemented a dynamic block allocation and reuse strategy. Blocks
are allocated only when existing ones are exhausted and are reused
during session/file removal cycles.
- Introduced KHO_MAX_BLOCKS (10000) as a safeguard against stupid
excessive allocations or corrupted cyclic lists during restore.
3. Expanded Selftests:
- Added new kexec-based tests verifying preservation of
2000 sessions and 500 files per session.
- Added self-tests for many sessions and many files management.
Tree: git.kernel.org/pub/scm/linux/kernel/git/tatashin/linux.git
Branch: luo-remove-max-files-sessions-limits/v3
Changes v3:
- Moved the linked-block serialization infrastructure from LUO-specific
(luo_block.c) to generic KHO helper infrastructure (kho_block.c,
include/linux/kho_block.h, include/linux/kho/abi/block.h).
- Registered luo_ser directly as a raw KHO subtree instead of wrapping
it inside FDT.
- Collected Acked-by tags from Mike Rapoport.
Pasha Tatashin (11):
liveupdate: centralize state management into struct luo_ser
liveupdate: register luo_ser as KHO subtree
liveupdate: Extract luo_file_deserialize_one helper
liveupdate: Extract luo_session_deserialize_one helper
kho: add support for linked-block serialization
liveupdate: defer session block allocation and PA setting
liveupdate: Remove limit on the number of sessions
liveupdate: Remove limit on the number of files per session
selftests/liveupdate: Test session and file limit removal
selftests/liveupdate: Add stress-sessions kexec test
selftests/liveupdate: Add stress-files kexec test
Documentation/core-api/kho/abi.rst | 5 +
Documentation/core-api/kho/index.rst | 11 +
MAINTAINERS | 1 +
include/linux/kho/abi/block.h | 56 +++
include/linux/kho/abi/luo.h | 149 ++-----
include/linux/kho_block.h | 79 ++++
kernel/liveupdate/Makefile | 1 +
kernel/liveupdate/kho_block.c | 382 ++++++++++++++++++
kernel/liveupdate/luo_core.c | 95 ++---
kernel/liveupdate/luo_file.c | 209 +++++-----
kernel/liveupdate/luo_flb.c | 65 +--
kernel/liveupdate/luo_internal.h | 14 +-
kernel/liveupdate/luo_session.c | 214 +++++-----
tools/testing/selftests/liveupdate/Makefile | 2 +
.../testing/selftests/liveupdate/liveupdate.c | 75 ++++
.../selftests/liveupdate/luo_stress_files.c | 101 +++++
.../liveupdate/luo_stress_sessions.c | 102 +++++
.../selftests/liveupdate/luo_test_utils.c | 24 ++
.../selftests/liveupdate/luo_test_utils.h | 2 +
19 files changed, 1142 insertions(+), 445 deletions(-)
create mode 100644 include/linux/kho/abi/block.h
create mode 100644 include/linux/kho_block.h
create mode 100644 kernel/liveupdate/kho_block.c
create mode 100644 tools/testing/selftests/liveupdate/luo_stress_files.c
create mode 100644 tools/testing/selftests/liveupdate/luo_stress_sessions.c
base-commit: 5428435567cbe06c19914592fc22ca23c9ca1de5
--
2.53.0
^ permalink raw reply
* Re: [PATCH net-next] Documentation: networking: Add a test plan for ethtool pause validation
From: Andrew Lunn @ 2026-05-29 2:52 UTC (permalink / raw)
To: Xuan Zhuo
Cc: Jakub Kicinski, davem, Eric Dumazet, Paolo Abeni, Simon Horman,
Russell King, Heiner Kallweit, Jonathan Corbet, Shuah Khan,
Oleksij Rempel, Vladimir Oltean, Florian Fainelli,
thomas.petazzoni, netdev, linux-kernel, linux-doc,
Maxime Chevallier
In-Reply-To: <1780018791.8076131-1-xuanzhuo@linux.alibaba.com>
> So I've been thinking lately: should we let AI generate and maintain these tests,
> including kselftest? This would give us a much richer and more comprehensive
> set of tests. Plus, each test could come with a complete explanation of its
> purpose and methodology. In short, much of the work we used to do manually
> can be offloaded to AI. This way, we can build a massive test suite and
> achieve much broader coverage.
A test suite only has value if it is correct. It actually has negative
value if it is wrong, because you are forcing developers to make their
implementations wrong in order to pass the tests.
Do you have the knowledge to validate whatever you generate via IA?
Can you argue it is correct? Do you have a range of hardware to test
it on?
It could be an interesting experiment, but i'm sceptical, until proven
otherwise.
Andrew
^ permalink raw reply
* Re: [PATCH] docs/filesystems/9p: fix broken external links
From: Dominique Martinet @ 2026-05-29 2:40 UTC (permalink / raw)
To: Aayush Patil
Cc: ericvh, lucho, linux_oss, corbet, skhan, v9fs, linux-doc,
linux-kernel
In-Reply-To: <CABc3pKEY8QvQzWPeU9QGBFG1dtGSdseTRdXF_5MUX1MeNBV5QQ@mail.gmail.com>
Aayush Patil wrote on Tue, May 19, 2026 at 07:23:38PM +0530:
> Regarding the replacement links, should I include them in v2 or leave
> those entries removed since you're not sure if they're the same files?
> Happy to go either way.
This is fine as is, if Eric replies or someone wants to add the links
back we can always update again later
(I've also fixed the typo in commit message directly)
Thanks,
--
Dominique Martinet | Asmadeus
^ permalink raw reply
* Re: [PATCH net-next] Documentation: networking: Add a test plan for ethtool pause validation
From: Xuan Zhuo @ 2026-05-29 1:39 UTC (permalink / raw)
To: Andrew Lunn
Cc: Jakub Kicinski, davem, Eric Dumazet, Paolo Abeni, Simon Horman,
Russell King, Heiner Kallweit, Jonathan Corbet, Shuah Khan,
Oleksij Rempel, Vladimir Oltean, Florian Fainelli,
thomas.petazzoni, netdev, linux-kernel, linux-doc,
Maxime Chevallier
In-Reply-To: <81777bc8-b046-4c76-9f53-e33563b6ad62@lunn.ch>
On Wed, 27 May 2026 14:08:30 +0200, Andrew Lunn <andrew@lunn.ch> wrote:
> > As for the kAPI testing, I agree that the end goal is to get driver
> > authors to get their flow control implementation right running this
> > suite.
> >
> > But I don't really see how we can validate kAPI itself, as we're down at
> > the ethnl level.
>
> All we can do is invoke the kAPI in different ways, and test we get
> the expected results. When it fails, it is down to the developer to
> figure out why, which layer. But they have a description of what the
> test is doing, and why? In most reviews, all i need to explain is the
> expected behaviour, and the second version is correct. So a test with
> explanation text should sort cut that process. I don't think we need
> any more.
>
> To some extent, we have an iterative process here. We have never done
> testing of this, we don't know exactly what we need. If we get
> feedback that a test is failing, but they cannot figure out why, we
> might need to help out, and then extend either the text, or add finer
> grain testing to narrow down the problem space. If we get a submission
> which passes all the tests but review turns up problems, we might want
> to ask the developers to extend the tests to catch the failure.
>
So I've been thinking lately: should we let AI generate and maintain these tests,
including kselftest? This would give us a much richer and more comprehensive
set of tests. Plus, each test could come with a complete explanation of its
purpose and methodology. In short, much of the work we used to do manually
can be offloaded to AI. This way, we can build a massive test suite and
achieve much broader coverage.
I'm actually trying this out right now.
Thanks.
> Andrew
>
^ permalink raw reply
* Re: [PATCH net-next 0/4] docs: page_pool: tweaks and updates
From: patchwork-bot+netdevbpf @ 2026-05-29 1:20 UTC (permalink / raw)
To: Jakub Kicinski
Cc: davem, netdev, edumazet, pabeni, andrew+netdev, horms, corbet,
tariqt, dtatulea, linux-doc, hawk, ilias.apalodimas
In-Reply-To: <20260526155722.2790742-1-kuba@kernel.org>
Hello:
This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Tue, 26 May 2026 08:57:18 -0700 you wrote:
> I'm hoping to start feeding our docs into the AI review tools, instead
> of maintaining a separate repo with review prompts. To experiment with
> that we have to refresh the docs a little bit.
>
> This set exclusively focuses on the page pool API. First patch is
> a straightforward fix for information which is now out of date.
> Second one attempts to clarify the NAPI linking requirements.
> Third drops the dedicated section about the stats; the document
> is primarily developer-facing and the stats should require no
> development effort in most cases. Last but not least minor
> API cleanup.
>
> [...]
Here is the summary with links:
- [net-next,1/4] docs: net: page_pool: drop reference to removed PP_FLAG_PAGE_FRAG
https://git.kernel.org/netdev/net-next/c/63c4530050d0
- [net-next,2/4] docs: clarify page pool NAPI consumer requirement
https://git.kernel.org/netdev/net-next/c/bbf2313cbeaf
- [net-next,3/4] docs: page_pool: drop the mention of the legacy stats API
https://git.kernel.org/netdev/net-next/c/ac0056e4f14b
- [net-next,4/4] net: make page_pool_get_stats() void
https://git.kernel.org/netdev/net-next/c/81a4d039537a
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply
* Re: [PATCH v5 09/18] mm: add MM_CP_UFFD_RWP change_protection() flag
From: SeongJae Park @ 2026-05-29 1:19 UTC (permalink / raw)
To: Kiryl Shutsemau
Cc: SeongJae Park, akpm, rppt, peterx, david, ljs, surenb, vbabka,
Liam.Howlett, ziy, corbet, skhan, seanjc, pbonzini, jthoughton,
aarcange, usama.arif, linux-mm, linux-kernel, linux-doc,
linux-kselftest, kvm, kernel-team, Kiryl Shutsemau (Meta)
In-Reply-To: <20260526130509.2748441-10-kirill@shutemov.name>
On Tue, 26 May 2026 14:04:57 +0100 Kiryl Shutsemau <kirill@shutemov.name> wrote:
> From: "Kiryl Shutsemau (Meta)" <kas@kernel.org>
>
> Preparatory patch. Add the change_protection() primitive that
> userfaultfd RWP will use.
>
> An RWP-protected PTE is PAGE_NONE with the uffd PTE bit set. The
> PROT_NONE half makes the CPU fault on any access; the uffd bit
> distinguishes an RWP fault from a plain mprotect(PROT_NONE) or NUMA
> hinting fault. MM_CP_UFFD_WP and MM_CP_UFFD_RWP share the same PTE
> bit, so the two cannot be used together on the same range.
>
> Two new change_protection() flags:
>
> MM_CP_UFFD_RWP install PAGE_NONE and set the uffd bit
> MM_CP_UFFD_RWP_RESOLVE restore vma->vm_page_prot, clear the uffd bit
>
> Both are wired through change_pte_range(), change_huge_pmd(), and
> hugetlb_change_protection() so anon, shmem, THP, and hugetlb all
> share the same semantics.
>
> Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
> Assisted-by: Claude:claude-opus-4-6
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
> ---
> include/linux/mm.h | 5 ++++
> include/linux/userfaultfd_k.h | 1 -
> mm/huge_memory.c | 30 +++++++++++++----------
> mm/hugetlb.c | 25 ++++++++++++++-----
> mm/mprotect.c | 46 +++++++++++++++++++++++++++--------
> 5 files changed, 77 insertions(+), 30 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 6499cfb61dc4..f79801816f32 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3297,6 +3297,11 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen);
> #define MM_CP_UFFD_WP_RESOLVE (1UL << 3) /* Resolve wp */
> #define MM_CP_UFFD_WP_ALL (MM_CP_UFFD_WP | \
> MM_CP_UFFD_WP_RESOLVE)
> +/* Whether this change is for uffd RWP */
> +#define MM_CP_UFFD_RWP (1UL << 4) /* do rwp */
> +#define MM_CP_UFFD_RWP_RESOLVE (1UL << 5) /* resolve rwp */
> +#define MM_CP_UFFD_RWP_ALL (MM_CP_UFFD_RWP | \
> + MM_CP_UFFD_RWP_RESOLVE)
>
> bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
> pte_t pte);
> diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
> index 0aef628514df..564eb2aac321 100644
> --- a/include/linux/userfaultfd_k.h
> +++ b/include/linux/userfaultfd_k.h
> @@ -361,7 +361,6 @@ static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
> return false;
> }
>
> -
Nice cleanup.
Thanks,
SJ
[...]
^ permalink raw reply
* [PATCH v3 1/2] dt-bindings: hwmon: pmbus: Add Analog Devices MAX20860A
From: Pradhan, Sanman @ 2026-05-29 0:19 UTC (permalink / raw)
To: linux-hwmon@vger.kernel.org
Cc: linux@roeck-us.net, robh@kernel.org, krzk+dt@kernel.org,
conor+dt@kernel.org, corbet@lwn.net, skhan@linuxfoundation.org,
devicetree@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, Syed, Arif, Sanman Pradhan
In-Reply-To: <20260529001903.625737-1-sanman.pradhan@hpe.com>
From: Sanman Pradhan <psanman@juniper.net>
Add devicetree binding documentation for the Analog Devices MAX20860A
step-down DC-DC switching regulator with PMBus interface.
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
---
v3:
- Drop "maxim,max20860a" and keep only "adi,max20860a"
v2:
- Added allOf regulator.yaml reference and unevaluatedProperties
.../bindings/hwmon/pmbus/adi,max20860a.yaml | 45 +++++++++++++++++++
1 file changed, 45 insertions(+)
create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml
diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml
new file mode 100644
index 000000000000..dd238265d462
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/pmbus/adi,max20860a.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices MAX20860A Step-Down Converter
+
+maintainers:
+ - Sanman Pradhan <psanman@juniper.net>
+
+description: |
+ The MAX20860A is a fully integrated step-down DC-DC switching regulator
+ with PMBus interface for monitoring input/output voltage, output current
+ and temperature.
+
+ Datasheet: https://www.analog.com/en/products/max20860a.html
+
+allOf:
+ - $ref: /schemas/regulator/regulator.yaml#
+
+properties:
+ compatible:
+ const: adi,max20860a
+
+ reg:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ regulator@40 {
+ compatible = "adi,max20860a";
+ reg = <0x40>;
+ };
+ };
--
2.34.1
^ permalink raw reply related
* [PATCH v3 0/2] hwmon: (pmbus/max20860a) Add driver for Analog Devices MAX20860A
From: Pradhan, Sanman @ 2026-05-29 0:19 UTC (permalink / raw)
To: linux-hwmon@vger.kernel.org
Cc: linux@roeck-us.net, robh@kernel.org, krzk+dt@kernel.org,
conor+dt@kernel.org, corbet@lwn.net, skhan@linuxfoundation.org,
devicetree@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, Syed, Arif, Sanman Pradhan
From: Sanman Pradhan <psanman@juniper.net>
Add PMBus hwmon driver and DT binding for the Analog Devices MAX20860A
step-down DC-DC switching regulator. The driver provides monitoring of
input/output voltage, output current, and temperature using linear data
format.
The driver does not modify device write-protection state during probe and
relies on the PMBus core to handle write-protect detection and sysfs
attribute permissions.
Tested on PTX platform with MAX20860A at i2c-195/0x23:
- All sensors (vin, vout, iout, temp1, temp2) read correctly
- Limit attributes correctly read-only (HW write-protect honored)
- Clean dmesg (no probe errors)
Changes since v2:
- DT binding: Drop "maxim,max20860a" and keep only "adi,max20860a"
- Driver: Drop matching "maxim,max20860a" OF match entry
Changes since v1:
- DT binding: Added allOf regulator.yaml reference and unevaluatedProperties
- Driver: Removed WRITE_PROTECT write from probe
Sanman Pradhan (1):
dt-bindings: hwmon: pmbus: Add Analog Devices MAX20860A
Syed Arif (1):
hwmon: (pmbus/max20860a) Add driver for Analog Devices MAX20860A
.../bindings/hwmon/pmbus/adi,max20860a.yaml | 45 +++++++++++++++
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/max20860a.rst | 57 +++++++++++++++++++
MAINTAINERS | 8 +++
drivers/hwmon/pmbus/Kconfig | 9 +++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/max20860a.c | 57 +++++++++++++++++++
7 files changed, 178 insertions(+)
create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml
create mode 100644 Documentation/hwmon/max20860a.rst
create mode 100644 drivers/hwmon/pmbus/max20860a.c
--
2.34.1
^ permalink raw reply
* [PATCH v3 2/2] hwmon: (pmbus/max20860a) Add driver for Analog Devices MAX20860A
From: Pradhan, Sanman @ 2026-05-29 0:19 UTC (permalink / raw)
To: linux-hwmon@vger.kernel.org
Cc: linux@roeck-us.net, robh@kernel.org, krzk+dt@kernel.org,
conor+dt@kernel.org, corbet@lwn.net, skhan@linuxfoundation.org,
devicetree@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, Syed, Arif, Sanman Pradhan
In-Reply-To: <20260529001903.625737-1-sanman.pradhan@hpe.com>
From: Syed Arif <arif.syed@hpe.com>
Add a PMBus driver for the Analog Devices MAX20860A step-down DC-DC
switching regulator. The MAX20860A provides monitoring of input/output
voltage, output current, and temperature via the PMBus interface using
linear data format.
Signed-off-by: Syed Arif <arif.syed@hpe.com>
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
---
v3:
- Removed "maxim,max20860a" from of_device_id
v2:
- Removed WRITE_PROTECT write from probe
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/max20860a.rst | 57 +++++++++++++++++++++++++++++++
MAINTAINERS | 8 +++++
drivers/hwmon/pmbus/Kconfig | 9 +++++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/max20860a.c | 57 +++++++++++++++++++++++++++++++
6 files changed, 133 insertions(+)
create mode 100644 Documentation/hwmon/max20860a.rst
create mode 100644 drivers/hwmon/pmbus/max20860a.c
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index e880c6ca84f0..ffaacda416e7 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -163,6 +163,7 @@ Hardware Monitoring Kernel Drivers
max20730
max20751
max20830
+ max20860a
max31722
max31730
max31760
diff --git a/Documentation/hwmon/max20860a.rst b/Documentation/hwmon/max20860a.rst
new file mode 100644
index 000000000000..ea6d2228fafc
--- /dev/null
+++ b/Documentation/hwmon/max20860a.rst
@@ -0,0 +1,57 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver max20860a
+=======================
+
+Supported chips:
+
+ * Analog Devices MAX20860A
+
+ Prefix: 'max20860a'
+
+ Addresses scanned: -
+
+ Datasheet: https://www.analog.com/en/products/max20860a.html
+
+Author:
+
+ - Syed Arif <arif.syed@hpe.com>
+ - Sanman Pradhan <psanman@juniper.net>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Analog Devices MAX20860A
+Step-Down Switching Regulator with PMBus Interface.
+
+The MAX20860A is a fully integrated step-down DC-DC switching regulator.
+Through the PMBus interface, the device can monitor input/output voltages,
+output current and temperature.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate
+the devices explicitly.
+
+Sysfs entries
+-------------
+
+================= ========================================
+in1_label "vin"
+in1_input Measured input voltage
+in1_alarm Input voltage alarm
+in2_label "vout1"
+in2_input Measured output voltage
+in2_alarm Output voltage alarm
+curr1_label "iout1"
+curr1_input Measured output current
+curr1_alarm Output current alarm
+temp1_input Measured temperature
+temp1_alarm Chip temperature alarm
+temp2_input Measured temperature (secondary)
+================= ========================================
diff --git a/MAINTAINERS b/MAINTAINERS
index b71acb130395..1d9651947ee3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15688,6 +15688,14 @@ F: Documentation/devicetree/bindings/hwmon/pmbus/adi,max20830.yaml
F: Documentation/hwmon/max20830.rst
F: drivers/hwmon/pmbus/max20830.c
+MAX20860A HARDWARE MONITOR DRIVER
+M: Sanman Pradhan <psanman@juniper.net>
+L: linux-hwmon@vger.kernel.org
+S: Maintained
+F: Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml
+F: Documentation/hwmon/max20860a.rst
+F: drivers/hwmon/pmbus/max20860a.c
+
MAX2175 SDR TUNER DRIVER
M: Ramesh Shanmugasundaram <rashanmu@gmail.com>
L: linux-media@vger.kernel.org
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 64f38654f4e7..5825dda75f2c 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -402,6 +402,15 @@ config SENSORS_MAX20830
This driver can also be built as a module. If so, the module will
be called max20830.
+config SENSORS_MAX20860A
+ tristate "Analog Devices MAX20860A"
+ help
+ If you say yes here you get hardware monitoring support for Analog
+ Devices MAX20860A step-down converter.
+
+ This driver can also be built as a module. If so, the module will
+ be called max20860a.
+
config SENSORS_MAX31785
tristate "Maxim MAX31785 and compatibles"
help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 1f2c73b71953..ffc05f493213 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_SENSORS_MAX17616) += max17616.o
obj-$(CONFIG_SENSORS_MAX20730) += max20730.o
obj-$(CONFIG_SENSORS_MAX20751) += max20751.o
obj-$(CONFIG_SENSORS_MAX20830) += max20830.o
+obj-$(CONFIG_SENSORS_MAX20860A) += max20860a.o
obj-$(CONFIG_SENSORS_MAX31785) += max31785.o
obj-$(CONFIG_SENSORS_MAX34440) += max34440.o
obj-$(CONFIG_SENSORS_MAX8688) += max8688.o
diff --git a/drivers/hwmon/pmbus/max20860a.c b/drivers/hwmon/pmbus/max20860a.c
new file mode 100644
index 000000000000..f5feefcbe407
--- /dev/null
+++ b/drivers/hwmon/pmbus/max20860a.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for Analog Devices MAX20860A
+ *
+ * SPDX-FileCopyrightText: Copyright Hewlett Packard Enterprise Development LP
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+static struct pmbus_driver_info max20860a_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = linear,
+ .format[PSC_VOLTAGE_OUT] = linear,
+ .format[PSC_CURRENT_OUT] = linear,
+ .format[PSC_TEMPERATURE] = linear,
+ .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT |
+ PMBUS_HAVE_STATUS_VOUT |
+ PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+ PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 |
+ PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_STATUS_INPUT,
+};
+
+static int max20860a_probe(struct i2c_client *client)
+{
+ return pmbus_do_probe(client, &max20860a_info);
+}
+
+static const struct i2c_device_id max20860a_id[] = {
+ {"max20860a"},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, max20860a_id);
+
+static const struct of_device_id max20860a_of_match[] = {
+ { .compatible = "adi,max20860a" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, max20860a_of_match);
+
+static struct i2c_driver max20860a_driver = {
+ .driver = {
+ .name = "max20860a",
+ .of_match_table = max20860a_of_match,
+ },
+ .probe = max20860a_probe,
+ .id_table = max20860a_id,
+};
+
+module_i2c_driver(max20860a_driver);
+
+MODULE_AUTHOR("Syed Arif <arif.syed@hpe.com>");
+MODULE_AUTHOR("Sanman Pradhan <psanman@juniper.net>");
+MODULE_DESCRIPTION("PMBus driver for Analog Devices MAX20860A");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");
--
2.34.1
^ permalink raw reply related
* [PATCH v2] docs: gpu: todo: fix spelling of "fucntion"
From: Godswill Onwusilike @ 2026-05-28 22:37 UTC (permalink / raw)
To: Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie,
Simona Vetter, Jonathan Corbet
Cc: Shuah Khan, dri-devel, linux-doc, linux-kernel,
Godswill Onwusilike
Correct the spelling of "fucntion" to "function" in
Documentation/gpu/todo.rst.
v2:
Fix the actual typo instead of newline-only change
Signed-off-by: Godswill Onwusilike <onwusilikegodswill@gmail.com>
---
Documentation/gpu/todo.rst | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index bc9f14c8a2ec..841e4e986c48 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -55,7 +55,7 @@ There are still drivers that use drm_simple_display_pipe. The task here is to
convert them to use regular atomic helpers. Search for a driver that calls
drm_simple_display_pipe_init() and inline all helpers from drm_simple_kms_helper.c
into the driver, such that no simple-KMS interfaces are required. Please also
-rename all inlined fucntions according to driver conventions.
+rename all inlined functions according to driver conventions.
Contact: Thomas Zimmermann, respective driver maintainer
--
2.53.0
^ permalink raw reply related
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