+ crash_core-change-parse_crashkernel-to-support-crashkernel=highlow-parsing.patch added to mm-nonmm-unstable branch

+ crash_core-change-parse_crashkernel-to-support-crashkernel=highlow-parsing.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: crash_core: change parse_crashkernel() to support crashkernel=,high|low parsing
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     crash_core-change-parse_crashkernel-to-support-crashkernel=highlow-parsing.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/crash_core-change-parse_crashkernel-to-support-crashkernel=highlow-parsing.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Baoquan He <bhe@redhat.com>
Subject: crash_core: change parse_crashkernel() to support crashkernel=,high|low parsing
Date: Thu, 14 Sep 2023 11:31:36 +0800

Now parse_crashkernel() is a real entry point for all kinds of crahskernel
parsing on any architecture.

And wrap the crahskernel=,high|low handling inside
CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION ifdeffery scope.

Link: https://lkml.kernel.org/r/20230914033142.676708-4-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Jiahao <chenjiahao16@huawei.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/crash_core.h |    6 +++++
 kernel/crash_core.c        |   36 ++++++++++++++++++++++++++++++++---
 2 files changed, 39 insertions(+), 3 deletions(-)

--- a/include/linux/crash_core.h~crash_core-change-parse_crashkernel-to-support-crashkernel=highlow-parsing
+++ a/include/linux/crash_core.h
@@ -79,6 +79,12 @@ Elf_Word *append_elf_note(Elf_Word *buf,
 			  void *data, size_t data_len);
 void final_note(Elf_Word *buf);
 
+#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
+#ifndef DEFAULT_CRASH_KERNEL_LOW_SIZE
+#define DEFAULT_CRASH_KERNEL_LOW_SIZE  (128UL << 20)
+#endif
+#endif
+
 int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
 		unsigned long long *crash_size, unsigned long long *crash_base,
 		unsigned long long *low_size, bool *high);
--- a/kernel/crash_core.c~crash_core-change-parse_crashkernel-to-support-crashkernel=highlow-parsing
+++ a/kernel/crash_core.c
@@ -283,6 +283,9 @@ static int __init __parse_crashkernel(ch
 /*
  * That function is the entry point for command line parsing and should be
  * called from the arch-specific code.
+ *
+ * If crashkernel=,high|low is supported on architecture, non-NULL values
+ * should be passed to parameters 'low_size' and 'high'.
  */
 int __init parse_crashkernel(char *cmdline,
 			     unsigned long long system_ram,
@@ -296,10 +299,37 @@ int __init parse_crashkernel(char *cmdli
 	/* crashkernel=X[@offset] */
 	ret = __parse_crashkernel(cmdline, system_ram, crash_size,
 				crash_base, NULL);
-	if (!high)
-		return ret;
+#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
+	/*
+	 * If non-NULL 'high' passed in and no normal crashkernel
+	 * setting detected, try parsing crashkernel=,high|low.
+	 */
+	if (high && ret == -ENOENT) {
+		ret = __parse_crashkernel(cmdline, 0, crash_size,
+				crash_base, suffix_tbl[SUFFIX_HIGH]);
+		if (ret || !*crash_size)
+			return -EINVAL;
 
-	return 0;
+		/*
+		 * crashkernel=Y,low can be specified or not, but invalid value
+		 * is not allowed.
+		 */
+		ret = __parse_crashkernel(cmdline, 0, low_size,
+				crash_base, suffix_tbl[SUFFIX_LOW]);
+		if (ret == -ENOENT) {
+			*low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
+			ret = 0;
+		} else if (ret) {
+			return ret;
+		}
+
+		*high = true;
+	}
+#endif
+	if (!*crash_size)
+		ret = -EINVAL;
+
+	return ret;
 }
 
 int __init parse_crashkernel_high(char *cmdline,
_

Patches currently in -mm which might be from bhe@redhat.com are

crash_corec-remove-unnecessary-parameter-of-function.patch
crash_core-change-the-prototype-of-function-parse_crashkernel.patch
crash_core-change-parse_crashkernel-to-support-crashkernel=highlow-parsing.patch
crash_core-add-generic-function-to-do-reservation.patch
crash_core-move-crashk_res-definition-into-crash_corec.patch
x86-kdump-use-generic-interface-to-simplify-crashkernel-reservation-code.patch
arm64-kdump-use-generic-interface-to-simplify-crashkernel-reservation.patch
riscv-kdump-use-generic-interface-to-simplify-crashkernel-reservation.patch
crash_corec-remove-unneeded-functions.patch