From: Andrew Donnellan <ajd@linux.ibm.com>
To: stable@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 4.14] powerpc/powernv/idle: Restore AMR/UAMOR/AMOR after idle
Date: Wed, 15 Apr 2020 22:39:24 +1000 [thread overview]
Message-ID: <20200415123924.26799-1-ajd@linux.ibm.com> (raw)
From: Michael Ellerman <mpe@ellerman.id.au>
commit 53a712bae5dd919521a58d7bad773b949358add0 upstream.
In order to implement KUAP (Kernel Userspace Access Protection) on
Power9 we will be using the AMR, and therefore indirectly the
UAMOR/AMOR.
So save/restore these regs in the idle code.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[ajd: Backport to 4.14 tree, CVE-2020-11669]
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
---
arch/powerpc/kernel/idle_book3s.S | 27 +++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 74fc20431082..01b823bdb49c 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -163,8 +163,11 @@ core_idle_lock_held:
bne- core_idle_lock_held
blr
-/* Reuse an unused pt_regs slot for IAMR */
+/* Reuse some unused pt_regs slots for AMR/IAMR/UAMOR/UAMOR */
+#define PNV_POWERSAVE_AMR _TRAP
#define PNV_POWERSAVE_IAMR _DAR
+#define PNV_POWERSAVE_UAMOR _DSISR
+#define PNV_POWERSAVE_AMOR RESULT
/*
* Pass requested state in r3:
@@ -198,8 +201,16 @@ pnv_powersave_common:
SAVE_NVGPRS(r1)
BEGIN_FTR_SECTION
+ mfspr r4, SPRN_AMR
mfspr r5, SPRN_IAMR
+ mfspr r6, SPRN_UAMOR
+ std r4, PNV_POWERSAVE_AMR(r1)
std r5, PNV_POWERSAVE_IAMR(r1)
+ std r6, PNV_POWERSAVE_UAMOR(r1)
+BEGIN_FTR_SECTION_NESTED(42)
+ mfspr r7, SPRN_AMOR
+ std r7, PNV_POWERSAVE_AMOR(r1)
+END_FTR_SECTION_NESTED_IFSET(CPU_FTR_HVMODE, 42)
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
mfcr r5
@@ -951,12 +962,20 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
REST_GPR(2, r1)
BEGIN_FTR_SECTION
- /* IAMR was saved in pnv_powersave_common() */
+ /* These regs were saved in pnv_powersave_common() */
+ ld r4, PNV_POWERSAVE_AMR(r1)
ld r5, PNV_POWERSAVE_IAMR(r1)
+ ld r6, PNV_POWERSAVE_UAMOR(r1)
+ mtspr SPRN_AMR, r4
mtspr SPRN_IAMR, r5
+ mtspr SPRN_UAMOR, r6
+BEGIN_FTR_SECTION_NESTED(42)
+ ld r7, PNV_POWERSAVE_AMOR(r1)
+ mtspr SPRN_AMOR, r7
+END_FTR_SECTION_NESTED_IFSET(CPU_FTR_HVMODE, 42)
/*
- * We don't need an isync here because the upcoming mtmsrd is
- * execution synchronizing.
+ * We don't need an isync here after restoring IAMR because the upcoming
+ * mtmsrd is execution synchronizing.
*/
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
--
2.20.1
reply other threads:[~2020-04-15 13:18 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200415123924.26799-1-ajd@linux.ibm.com \
--to=ajd@linux.ibm.com \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).