[PATCH v4 0/3] crash: Fix x86_32 memory reserve dead loop bug

[PATCH v4 0/3] crash: Fix x86_32 memory reserve dead loop bug

[Jinjie Ruan]

Fix two bugs for x86_32 crash memory reserve, and prepare to apply generic
crashkernel reservation to 32bit system. Then use generic interface to
simplify crashkernel reservation for ARM32.

changes in v4:
- Add the missing macro for loongarch.
- Only define the macro for 64bit RISCV.
- Signed-off-by -> Suggested-by as suggested.
- Remove the Tested-by as suggested.
- Update the commit message.
- Add acked-by.

changes in v3:
- Fix it as Baoquan suggested.
- Update the commit message.

changes in v2:
- Peel off the other two patches.
- Update the commit message and fix tag.

Jinjie Ruan (3):
  crash: Fix x86_32 crash memory reserve dead loop bug
  crash: Fix x86_32 crash memory reserve dead loop
  ARM: Use generic interface to simplify crashkernel reservation

 arch/arm/Kconfig                           |  3 ++
 arch/arm/include/asm/crash_reserve.h       | 24 +++++++++
 arch/arm/kernel/setup.c                    | 63 ++++------------------
 arch/arm64/include/asm/crash_reserve.h     |  2 +
 arch/loongarch/include/asm/crash_reserve.h |  2 +
 arch/riscv/include/asm/crash_reserve.h     |  4 ++
 arch/x86/include/asm/crash_reserve.h       |  1 +
 kernel/crash_reserve.c                     |  5 +-
 8 files changed, 48 insertions(+), 56 deletions(-)
 create mode 100644 arch/arm/include/asm/crash_reserve.h

-- 
2.34.1

[PATCH v4 1/3] crash: Fix x86_32 crash memory reserve dead loop bug

[Jinjie Ruan]

On x86_32 Qemu machine with 1GB memory, the cmdline "crashkernel=1G,high"
will cause system stall as below:

	ACPI: Reserving FACP table memory at [mem 0x3ffe18b8-0x3ffe192b]
	ACPI: Reserving DSDT table memory at [mem 0x3ffe0040-0x3ffe18b7]
	ACPI: Reserving FACS table memory at [mem 0x3ffe0000-0x3ffe003f]
	ACPI: Reserving APIC table memory at [mem 0x3ffe192c-0x3ffe19bb]
	ACPI: Reserving HPET table memory at [mem 0x3ffe19bc-0x3ffe19f3]
	ACPI: Reserving WAET table memory at [mem 0x3ffe19f4-0x3ffe1a1b]
	143MB HIGHMEM available.
	879MB LOWMEM available.
	  mapped low ram: 0 - 36ffe000
	  low ram: 0 - 36ffe000
	 (stall here)

The reason is that the CRASH_ADDR_LOW_MAX is equal to CRASH_ADDR_HIGH_MAX
on x86_32, the first high crash kernel memory reservation will fail, then
go into the "retry" loop and never came out as below.

-> reserve_crashkernel_generic() and high is true
 -> alloc at [CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX] fail
    -> alloc at [0, CRASH_ADDR_LOW_MAX] fail and repeatedly
       (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX).

Fix it by prevent crashkernel=,high from being parsed successfully on 32bit
system with a architecture-defined macro.

After this patch, the 'crashkernel=,high' for 32bit system can't succeed,
and it has no chance to call reserve_crashkernel_generic(), therefore this
issue on x86_32 is solved.

Fixes: 9c08a2a139fe ("x86: kdump: use generic interface to simplify crashkernel reservation code")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Suggested-by: Baoquan He <bhe@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
---
v4:
- Add the missing macro for loongarch.
- Only define the macro for 64bit RISCV.
- Signed-off-by -> Suggested-by as suggested.
- Remove the Tested-by as suggested.
- Add acked-by.
v3:
- Fix it as Baoquan suggested.
- Update the commit message.
v2:
- Peel off the other two patches.
- Update the commit message and fix tag.
---
 arch/arm64/include/asm/crash_reserve.h     | 2 ++
 arch/loongarch/include/asm/crash_reserve.h | 2 ++
 arch/riscv/include/asm/crash_reserve.h     | 4 ++++
 arch/x86/include/asm/crash_reserve.h       | 1 +
 kernel/crash_reserve.c                     | 2 +-
 5 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/crash_reserve.h b/arch/arm64/include/asm/crash_reserve.h
index 4afe027a4e7b..bf362c1a612f 100644
--- a/arch/arm64/include/asm/crash_reserve.h
+++ b/arch/arm64/include/asm/crash_reserve.h
@@ -7,4 +7,6 @@
 
 #define CRASH_ADDR_LOW_MAX              arm64_dma_phys_limit
 #define CRASH_ADDR_HIGH_MAX             (PHYS_MASK + 1)
+
+#define HAVE_ARCH_CRASHKERNEL_RESERVATION_HIGH
 #endif
diff --git a/arch/loongarch/include/asm/crash_reserve.h b/arch/loongarch/include/asm/crash_reserve.h
index a1d9b84b1c7d..2d02517c2127 100644
--- a/arch/loongarch/include/asm/crash_reserve.h
+++ b/arch/loongarch/include/asm/crash_reserve.h
@@ -7,6 +7,8 @@
 #define CRASH_ADDR_LOW_MAX		SZ_4G
 #define CRASH_ADDR_HIGH_MAX		memblock_end_of_DRAM()
 
+#define HAVE_ARCH_CRASHKERNEL_RESERVATION_HIGH
+
 extern phys_addr_t memblock_end_of_DRAM(void);
 
 #endif
diff --git a/arch/riscv/include/asm/crash_reserve.h b/arch/riscv/include/asm/crash_reserve.h
index 013962e63587..216402ea5b7c 100644
--- a/arch/riscv/include/asm/crash_reserve.h
+++ b/arch/riscv/include/asm/crash_reserve.h
@@ -7,5 +7,9 @@
 #define CRASH_ADDR_LOW_MAX		dma32_phys_limit
 #define CRASH_ADDR_HIGH_MAX		memblock_end_of_DRAM()
 
+#ifdef CONFIG_64BIT
+#define HAVE_ARCH_CRASHKERNEL_RESERVATION_HIGH
+#endif
+
 extern phys_addr_t memblock_end_of_DRAM(void);
 #endif
diff --git a/arch/x86/include/asm/crash_reserve.h b/arch/x86/include/asm/crash_reserve.h
index 7835b2cdff04..24c2327f9a16 100644
--- a/arch/x86/include/asm/crash_reserve.h
+++ b/arch/x86/include/asm/crash_reserve.h
@@ -26,6 +26,7 @@ extern unsigned long swiotlb_size_or_default(void);
 #else
 # define CRASH_ADDR_LOW_MAX     SZ_4G
 # define CRASH_ADDR_HIGH_MAX    SZ_64T
+#define HAVE_ARCH_CRASHKERNEL_RESERVATION_HIGH
 #endif
 
 # define DEFAULT_CRASH_KERNEL_LOW_SIZE crash_low_size_default()
diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c
index 5b2722a93a48..c5213f123e19 100644
--- a/kernel/crash_reserve.c
+++ b/kernel/crash_reserve.c
@@ -306,7 +306,7 @@ int __init parse_crashkernel(char *cmdline,
 	/* crashkernel=X[@offset] */
 	ret = __parse_crashkernel(cmdline, system_ram, crash_size,
 				crash_base, NULL);
-#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
+#ifdef HAVE_ARCH_CRASHKERNEL_RESERVATION_HIGH
 	/*
 	 * If non-NULL 'high' passed in and no normal crashkernel
 	 * setting detected, try parsing crashkernel=,high|low.
-- 
2.34.1

[PATCH v4 2/3] crash: Fix x86_32 crash memory reserve dead loop

[Jinjie Ruan]

On x86_32 Qemu machine with 1GB memory, the cmdline "crashkernel=512M" will
also cause system stall as below:

	ACPI: Reserving FACP table memory at [mem 0x3ffe18b8-0x3ffe192b]
	ACPI: Reserving DSDT table memory at [mem 0x3ffe0040-0x3ffe18b7]
	ACPI: Reserving FACS table memory at [mem 0x3ffe0000-0x3ffe003f]
	ACPI: Reserving APIC table memory at [mem 0x3ffe192c-0x3ffe19bb]
	ACPI: Reserving HPET table memory at [mem 0x3ffe19bc-0x3ffe19f3]
	ACPI: Reserving WAET table memory at [mem 0x3ffe19f4-0x3ffe1a1b]
	143MB HIGHMEM available.
	879MB LOWMEM available.
	  mapped low ram: 0 - 36ffe000
	  low ram: 0 - 36ffe000
	  (stall here)

The reason is that the CRASH_ADDR_LOW_MAX is equal to CRASH_ADDR_HIGH_MAX
on x86_32, the first "low" crash kernel memory reservation for 512M fails,
then it go into the "retry" loop and never came out as below (consider
CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX = 512M):

-> reserve_crashkernel_generic() and high is false
   -> alloc at [0, 0x20000000] fail
      -> alloc at [0x20000000, 0x20000000] fail and repeatedly
      (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX).

Fix it by skipping meaningless calls of memblock_phys_alloc_range() with
`start = end`

After this patch, the retry dead loop is avoided and print below info:
	cannot allocate crashkernel (size:0x20000000)

And apply generic crashkernel reservation to 32bit system will be ready.

Fixes: 9c08a2a139fe ("x86: kdump: use generic interface to simplify crashkernel reservation code")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Suggested-by: Baoquan He <bhe@redhat.com>
---
v4:
- Signed-off-by -> Suggested-by as suggested.
- Remove the Tested-by as suggested.
- Update the commit subject
v3:
- Fix it as Baoquan suggested.
- Update the commit message.
---
 kernel/crash_reserve.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c
index c5213f123e19..dacc268429e2 100644
--- a/kernel/crash_reserve.c
+++ b/kernel/crash_reserve.c
@@ -414,7 +414,8 @@ void __init reserve_crashkernel_generic(char *cmdline,
 			search_end = CRASH_ADDR_HIGH_MAX;
 			search_base = CRASH_ADDR_LOW_MAX;
 			crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
-			goto retry;
+			if (search_base != search_end)
+				goto retry;
 		}
 
 		/*
-- 
2.34.1

Re: [PATCH v4 2/3] crash: Fix x86_32 crash memory reserve dead loop

[Baoquan He]

On 07/19/24 at 05:57pm, Jinjie Ruan wrote:
> On x86_32 Qemu machine with 1GB memory, the cmdline "crashkernel=512M" will
> also cause system stall as below:
> 
> 	ACPI: Reserving FACP table memory at [mem 0x3ffe18b8-0x3ffe192b]
> 	ACPI: Reserving DSDT table memory at [mem 0x3ffe0040-0x3ffe18b7]
> 	ACPI: Reserving FACS table memory at [mem 0x3ffe0000-0x3ffe003f]
> 	ACPI: Reserving APIC table memory at [mem 0x3ffe192c-0x3ffe19bb]
> 	ACPI: Reserving HPET table memory at [mem 0x3ffe19bc-0x3ffe19f3]
> 	ACPI: Reserving WAET table memory at [mem 0x3ffe19f4-0x3ffe1a1b]
> 	143MB HIGHMEM available.
> 	879MB LOWMEM available.
> 	  mapped low ram: 0 - 36ffe000
> 	  low ram: 0 - 36ffe000
> 	  (stall here)
> 
> The reason is that the CRASH_ADDR_LOW_MAX is equal to CRASH_ADDR_HIGH_MAX
> on x86_32, the first "low" crash kernel memory reservation for 512M fails,
> then it go into the "retry" loop and never came out as below (consider
> CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX = 512M):
> 
> -> reserve_crashkernel_generic() and high is false
>    -> alloc at [0, 0x20000000] fail
>       -> alloc at [0x20000000, 0x20000000] fail and repeatedly
>       (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX).
> 
> Fix it by skipping meaningless calls of memblock_phys_alloc_range() with
> `start = end`
> 
> After this patch, the retry dead loop is avoided and print below info:
> 	cannot allocate crashkernel (size:0x20000000)
> 
> And apply generic crashkernel reservation to 32bit system will be ready.
      ~~~ applying

Other than this nit, it looks good to me.

Acked-by: Baoquan He <bhe@redhat.com>

> 
> Fixes: 9c08a2a139fe ("x86: kdump: use generic interface to simplify crashkernel reservation code")
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> Suggested-by: Baoquan He <bhe@redhat.com>
> ---
> v4:
> - Signed-off-by -> Suggested-by as suggested.
> - Remove the Tested-by as suggested.
> - Update the commit subject
> v3:
> - Fix it as Baoquan suggested.
> - Update the commit message.
> ---
>  kernel/crash_reserve.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c
> index c5213f123e19..dacc268429e2 100644
> --- a/kernel/crash_reserve.c
> +++ b/kernel/crash_reserve.c
> @@ -414,7 +414,8 @@ void __init reserve_crashkernel_generic(char *cmdline,
>  			search_end = CRASH_ADDR_HIGH_MAX;
>  			search_base = CRASH_ADDR_LOW_MAX;
>  			crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
> -			goto retry;
> +			if (search_base != search_end)
> +				goto retry;
>  		}
>  
>  		/*
> -- 
> 2.34.1
> 

[PATCH v4 3/3] ARM: Use generic interface to simplify crashkernel reservation

[Jinjie Ruan]

Currently, x86, arm64, riscv and loongarch has been switched to generic
crashkernel reservation, which is also ready for 32bit system.
So with the help of function parse_crashkernel() and generic
reserve_crashkernel_generic(), arm32 crashkernel reservation can also
be simplified by steps:

1) Add a new header file <asm/crash_reserve.h>, and define CRASH_ALIGN,
   CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX in it;

2) Add arch_reserve_crashkernel() to call parse_crashkernel() and
   reserve_crashkernel_generic();

3) Add ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION Kconfig in
   arch/arm/Kconfig.

The old reserve_crashkernel() can be removed.

Following test cases have been performed as expected on QEMU vexpress-a9
(1GB system memory):

1) crashkernel=4G,high				// invalid
2) crashkernel=1G,high				// invalid
3) crashkernel=1G,high crashkernel=0M,low	// invalid
4) crashkernel=256M,high			// invalid
5) crashkernel=256M,low				// invalid
6) crashkernel=256M crashkernel=256M,high	// high is ignored, ok
7) crashkernel=256M crashkernel=256M,low	// low is ignored, ok
8) crashkernel=256M,high crashkernel=256M,low	// invalid
9) crashkernel=256M,high crashkernel=4G,low	// invalid
10) crashkernel=256M				// ok
11) crashkernel=512M				// ok
12) crashkernel=256M@0x88000000			// ok
13) crashkernel=256M@0x78000000			// ok
14) crashkernel=512M@0x78000000			// ok

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
v4:
- Remove the Tested-by as suggested.
v3:
- Update the commit message.
---
 arch/arm/Kconfig                     |  3 ++
 arch/arm/include/asm/crash_reserve.h | 24 +++++++++++
 arch/arm/kernel/setup.c              | 63 ++++------------------------
 3 files changed, 36 insertions(+), 54 deletions(-)
 create mode 100644 arch/arm/include/asm/crash_reserve.h

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index f434afff4a2c..3f198ae63950 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1597,6 +1597,9 @@ config ATAGS_PROC
 config ARCH_SUPPORTS_CRASH_DUMP
 	def_bool y
 
+config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
+	def_bool CRASH_RESERVE
+
 config AUTO_ZRELADDR
 	bool "Auto calculation of the decompressed kernel image address" if !ARCH_MULTIPLATFORM
 	default !(ARCH_FOOTBRIDGE || ARCH_RPC || ARCH_SA1100)
diff --git a/arch/arm/include/asm/crash_reserve.h b/arch/arm/include/asm/crash_reserve.h
new file mode 100644
index 000000000000..85c9298bd3b7
--- /dev/null
+++ b/arch/arm/include/asm/crash_reserve.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ARM_CRASH_RESERVE_H
+#define _ARM_CRASH_RESERVE_H
+
+/*
+ * The crash region must be aligned to 128MB to avoid
+ * zImage relocating below the reserved region.
+ */
+#define CRASH_ALIGN			(128 << 20)
+
+#define CRASH_ADDR_LOW_MAX		crash_addr_low_max()
+#define CRASH_ADDR_HIGH_MAX		memblock_end_of_DRAM()
+
+static inline unsigned long crash_addr_low_max(void)
+{
+	unsigned long long crash_max = idmap_to_phys((u32)~0);
+	unsigned long long lowmem_max = __pa(high_memory - 1) + 1;
+
+	return (crash_max > lowmem_max) ? lowmem_max : crash_max;
+}
+
+
+#define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
+#endif
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index e6a857bf0ce6..fc0ada003f6d 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -979,13 +979,6 @@ static int __init init_machine_late(void)
 }
 late_initcall(init_machine_late);
 
-#ifdef CONFIG_CRASH_RESERVE
-/*
- * The crash region must be aligned to 128MB to avoid
- * zImage relocating below the reserved region.
- */
-#define CRASH_ALIGN	(128 << 20)
-
 static inline unsigned long long get_total_mem(void)
 {
 	unsigned long total;
@@ -994,60 +987,25 @@ static inline unsigned long long get_total_mem(void)
 	return total << PAGE_SHIFT;
 }
 
-/**
- * reserve_crashkernel() - reserves memory are for crash kernel
- *
- * This function reserves memory area given in "crashkernel=" kernel command
- * line parameter. The memory reserved is used by a dump capture kernel when
- * primary kernel is crashing.
- */
-static void __init reserve_crashkernel(void)
+static void __init arch_reserve_crashkernel(void)
 {
-	unsigned long long crash_size, crash_base;
+	unsigned long long crash_size, crash_base, low_size = 0;
 	unsigned long long total_mem;
+	bool high = false;
 	int ret;
 
+	if (!IS_ENABLED(CONFIG_CRASH_RESERVE))
+		return;
+
 	total_mem = get_total_mem();
 	ret = parse_crashkernel(boot_command_line, total_mem,
 				&crash_size, &crash_base,
-				NULL, NULL);
+				&low_size, &high);
 	/* invalid value specified or crashkernel=0 */
 	if (ret || !crash_size)
 		return;
 
-	if (crash_base <= 0) {
-		unsigned long long crash_max = idmap_to_phys((u32)~0);
-		unsigned long long lowmem_max = __pa(high_memory - 1) + 1;
-		if (crash_max > lowmem_max)
-			crash_max = lowmem_max;
-
-		crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
-						       CRASH_ALIGN, crash_max);
-		if (!crash_base) {
-			pr_err("crashkernel reservation failed - No suitable area found.\n");
-			return;
-		}
-	} else {
-		unsigned long long crash_max = crash_base + crash_size;
-		unsigned long long start;
-
-		start = memblock_phys_alloc_range(crash_size, SECTION_SIZE,
-						  crash_base, crash_max);
-		if (!start) {
-			pr_err("crashkernel reservation failed - memory is in use.\n");
-			return;
-		}
-	}
-
-	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
-		(unsigned long)(crash_size >> 20),
-		(unsigned long)(crash_base >> 20),
-		(unsigned long)(total_mem >> 20));
-
-	/* The crashk resource must always be located in normal mem */
-	crashk_res.start = crash_base;
-	crashk_res.end = crash_base + crash_size - 1;
-	insert_resource(&iomem_resource, &crashk_res);
+	reserve_crashkernel_generic(boot_command_line, crash_size, crash_base, low_size, high);
 
 	if (arm_has_idmap_alias()) {
 		/*
@@ -1064,9 +1022,6 @@ static void __init reserve_crashkernel(void)
 		insert_resource(&iomem_resource, &crashk_boot_res);
 	}
 }
-#else
-static inline void reserve_crashkernel(void) {}
-#endif /* CONFIG_CRASH_RESERVE*/
 
 void __init hyp_mode_check(void)
 {
@@ -1189,7 +1144,7 @@ void __init setup_arch(char **cmdline_p)
 	if (!is_smp())
 		hyp_mode_check();
 
-	reserve_crashkernel();
+	arch_reserve_crashkernel();
 
 #ifdef CONFIG_VT
 #if defined(CONFIG_VGA_CONSOLE)
-- 
2.34.1

Re: [PATCH v4 3/3] ARM: Use generic interface to simplify crashkernel reservation

[Baoquan He]

On 07/19/24 at 05:57pm, Jinjie Ruan wrote:
> Currently, x86, arm64, riscv and loongarch has been switched to generic
> crashkernel reservation, which is also ready for 32bit system.
> So with the help of function parse_crashkernel() and generic
> reserve_crashkernel_generic(), arm32 crashkernel reservation can also
> be simplified by steps:
> 
> 1) Add a new header file <asm/crash_reserve.h>, and define CRASH_ALIGN,
>    CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX in it;
> 
> 2) Add arch_reserve_crashkernel() to call parse_crashkernel() and
>    reserve_crashkernel_generic();
> 
> 3) Add ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION Kconfig in
>    arch/arm/Kconfig.
> 
> The old reserve_crashkernel() can be removed.
> 
> Following test cases have been performed as expected on QEMU vexpress-a9
> (1GB system memory):
> 
> 1) crashkernel=4G,high				// invalid
> 2) crashkernel=1G,high				// invalid
> 3) crashkernel=1G,high crashkernel=0M,low	// invalid
> 4) crashkernel=256M,high			// invalid
> 5) crashkernel=256M,low				// invalid
> 6) crashkernel=256M crashkernel=256M,high	// high is ignored, ok
> 7) crashkernel=256M crashkernel=256M,low	// low is ignored, ok
> 8) crashkernel=256M,high crashkernel=256M,low	// invalid
> 9) crashkernel=256M,high crashkernel=4G,low	// invalid
> 10) crashkernel=256M				// ok
> 11) crashkernel=512M				// ok
> 12) crashkernel=256M@0x88000000			// ok
> 13) crashkernel=256M@0x78000000			// ok
> 14) crashkernel=512M@0x78000000			// ok
> 
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> ---
> v4:
> - Remove the Tested-by as suggested.
> v3:
> - Update the commit message.
> ---
>  arch/arm/Kconfig                     |  3 ++
>  arch/arm/include/asm/crash_reserve.h | 24 +++++++++++
>  arch/arm/kernel/setup.c              | 63 ++++------------------------
>  3 files changed, 36 insertions(+), 54 deletions(-)
>  create mode 100644 arch/arm/include/asm/crash_reserve.h

LGTM,

Acked-by: Baoquan He <bhe@redhat.com>

By the way, you may need respost the parsed crashkernel value limitation
checking patch for arm32 and i386.

Re: [PATCH v4 3/3] ARM: Use generic interface to simplify crashkernel reservation

[Jinjie Ruan]

On 2024/7/22 9:38, Baoquan He wrote:
> On 07/19/24 at 05:57pm, Jinjie Ruan wrote:
>> Currently, x86, arm64, riscv and loongarch has been switched to generic
>> crashkernel reservation, which is also ready for 32bit system.
>> So with the help of function parse_crashkernel() and generic
>> reserve_crashkernel_generic(), arm32 crashkernel reservation can also
>> be simplified by steps:
>>
>> 1) Add a new header file <asm/crash_reserve.h>, and define CRASH_ALIGN,
>>    CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX in it;
>>
>> 2) Add arch_reserve_crashkernel() to call parse_crashkernel() and
>>    reserve_crashkernel_generic();
>>
>> 3) Add ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION Kconfig in
>>    arch/arm/Kconfig.
>>
>> The old reserve_crashkernel() can be removed.
>>
>> Following test cases have been performed as expected on QEMU vexpress-a9
>> (1GB system memory):
>>
>> 1) crashkernel=4G,high				// invalid
>> 2) crashkernel=1G,high				// invalid
>> 3) crashkernel=1G,high crashkernel=0M,low	// invalid
>> 4) crashkernel=256M,high			// invalid
>> 5) crashkernel=256M,low				// invalid
>> 6) crashkernel=256M crashkernel=256M,high	// high is ignored, ok
>> 7) crashkernel=256M crashkernel=256M,low	// low is ignored, ok
>> 8) crashkernel=256M,high crashkernel=256M,low	// invalid
>> 9) crashkernel=256M,high crashkernel=4G,low	// invalid
>> 10) crashkernel=256M				// ok
>> 11) crashkernel=512M				// ok
>> 12) crashkernel=256M@0x88000000			// ok
>> 13) crashkernel=256M@0x78000000			// ok
>> 14) crashkernel=512M@0x78000000			// ok
>>
>> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
>> ---
>> v4:
>> - Remove the Tested-by as suggested.
>> v3:
>> - Update the commit message.
>> ---
>>  arch/arm/Kconfig                     |  3 ++
>>  arch/arm/include/asm/crash_reserve.h | 24 +++++++++++
>>  arch/arm/kernel/setup.c              | 63 ++++------------------------
>>  3 files changed, 36 insertions(+), 54 deletions(-)
>>  create mode 100644 arch/arm/include/asm/crash_reserve.h
> 
> LGTM,
> 
> Acked-by: Baoquan He <bhe@redhat.com>
> 
> By the way, you may need respost the parsed crashkernel value limitation
> checking patch for arm32 and i386.

Thank you for the kind reminder. I'll rebase and resend it later.

> 
>