[PATCH] arm64/crashdump-arm64: align 'Kernel code' with '_stext'

[PATCH] arm64/crashdump-arm64: align 'Kernel code' with '_stext'

[Pingfan Liu]

Since kernel commit e2a073dde921 ("arm64: omit [_text, _stext) from
permanent kernel mapping"), the physical address of 'Kernel code' in
/proc/iomem is mapped from _text, instead, from _stext.

Change the code to cope with this kernel change.

Signed-off-by: Pingfan Liu <piliu@redhat.com>
---
 kexec/arch/arm64/crashdump-arm64.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kexec/arch/arm64/crashdump-arm64.c b/kexec/arch/arm64/crashdump-arm64.c
index 38d1a0f..1da663e 100644
--- a/kexec/arch/arm64/crashdump-arm64.c
+++ b/kexec/arch/arm64/crashdump-arm64.c
@@ -148,7 +148,11 @@ static int crash_get_memory_ranges(void)
 	 * For additional kernel code/data segment.
 	 * kern_paddr_start/kern_size are determined in iomem_range_callback
 	 */
-	elf_info.kern_vaddr_start = get_kernel_sym("_text");
+	/* Refer to kernel:
+	 *     kernel_code.start   = __pa_symbol(_stext);
+	 * which is exported through /proc/iomem as "Kernel code"
+	 */
+	elf_info.kern_vaddr_start = get_kernel_sym("_stext");
 	if (!elf_info.kern_vaddr_start)
 		elf_info.kern_vaddr_start = UINT64_MAX;
 
-- 
2.29.2


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Re: [PATCH] arm64/crashdump-arm64: align 'Kernel code' with '_stext'

[Simon Horman]

On Wed, May 19, 2021 at 11:16:21AM +0800, Pingfan Liu wrote:
> Since kernel commit e2a073dde921 ("arm64: omit [_text, _stext) from
> permanent kernel mapping"), the physical address of 'Kernel code' in
> /proc/iomem is mapped from _text, instead, from _stext.
> 
> Change the code to cope with this kernel change.
> 
> Signed-off-by: Pingfan Liu <piliu@redhat.com>

Thanks, will kexec still work with older kernels with this change in place?

> ---
>  kexec/arch/arm64/crashdump-arm64.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/kexec/arch/arm64/crashdump-arm64.c b/kexec/arch/arm64/crashdump-arm64.c
> index 38d1a0f..1da663e 100644
> --- a/kexec/arch/arm64/crashdump-arm64.c
> +++ b/kexec/arch/arm64/crashdump-arm64.c
> @@ -148,7 +148,11 @@ static int crash_get_memory_ranges(void)
>  	 * For additional kernel code/data segment.
>  	 * kern_paddr_start/kern_size are determined in iomem_range_callback
>  	 */
> -	elf_info.kern_vaddr_start = get_kernel_sym("_text");
> +	/* Refer to kernel:
> +	 *     kernel_code.start   = __pa_symbol(_stext);
> +	 * which is exported through /proc/iomem as "Kernel code"
> +	 */
> +	elf_info.kern_vaddr_start = get_kernel_sym("_stext");
>  	if (!elf_info.kern_vaddr_start)
>  		elf_info.kern_vaddr_start = UINT64_MAX;
>  
> -- 
> 2.29.2
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
> 

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Re: [PATCH] arm64/crashdump-arm64: align 'Kernel code' with '_stext'

[piliu]

On 5/23/21 3:56 PM, Simon Horman wrote:
> On Wed, May 19, 2021 at 11:16:21AM +0800, Pingfan Liu wrote:
>> Since kernel commit e2a073dde921 ("arm64: omit [_text, _stext) from
>> permanent kernel mapping"), the physical address of 'Kernel code' in
>> /proc/iomem is mapped from _text, instead, from _stext.
>>
>> Change the code to cope with this kernel change.
>>
>> Signed-off-by: Pingfan Liu <piliu@redhat.com>
> 
> Thanks, will kexec still work with older kernels with this change in place?
> 
Oops, it will. Let me try to bring up another idea to tackle it.

Thanks,
Pingfan
>> ---
>>   kexec/arch/arm64/crashdump-arm64.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/kexec/arch/arm64/crashdump-arm64.c b/kexec/arch/arm64/crashdump-arm64.c
>> index 38d1a0f..1da663e 100644
>> --- a/kexec/arch/arm64/crashdump-arm64.c
>> +++ b/kexec/arch/arm64/crashdump-arm64.c
>> @@ -148,7 +148,11 @@ static int crash_get_memory_ranges(void)
>>   	 * For additional kernel code/data segment.
>>   	 * kern_paddr_start/kern_size are determined in iomem_range_callback
>>   	 */
>> -	elf_info.kern_vaddr_start = get_kernel_sym("_text");
>> +	/* Refer to kernel:
>> +	 *     kernel_code.start   = __pa_symbol(_stext);
>> +	 * which is exported through /proc/iomem as "Kernel code"
>> +	 */
>> +	elf_info.kern_vaddr_start = get_kernel_sym("_stext");
>>   	if (!elf_info.kern_vaddr_start)
>>   		elf_info.kern_vaddr_start = UINT64_MAX;
>>   
>> -- 
>> 2.29.2
>>
>>
>> _______________________________________________
>> kexec mailing list
>> kexec@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec
>>
> 


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