[kexec-tools PATCH] x86: extend kernel text size up to 1GB

[Dave Young]

On 03/12/14 at 11:13am, WANG Chao wrote:
> Currently kexec hard code X86_64_KERNEL_TEXT_SIZE to 512M. With kASLR
> enabled (CONFIG_RANDOMIZED_BASE=y), kernel image base offset could be
> randomized from 0 to 1GB and kexec-tools fails to get kernel virtual
> address from /proc/kcore when the offset is >512M.
> 
> Now extend X86_64_KERNEL_TEXT_SIZE to 1GB to adapt kASLR.
> 
> Signed-off-by: WANG Chao <chaowang at redhat.com>
> ---
>  kexec/arch/i386/crashdump-x86.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kexec/arch/i386/crashdump-x86.h b/kexec/arch/i386/crashdump-x86.h
> index e68b626..a5b2dfd 100644
> --- a/kexec/arch/i386/crashdump-x86.h
> +++ b/kexec/arch/i386/crashdump-x86.h
> @@ -18,7 +18,7 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline,
>  #define X86_64_MAXMEM        		0x3fffffffffffUL
>  
>  /* Kernel text size */
> -#define X86_64_KERNEL_TEXT_SIZE  (512UL*1024*1024)
> +#define X86_64_KERNEL_TEXT_SIZE  (1UL*1024*1024*1024)

Should define a new macro such as: X86_KERNEL_TEXT_START_LIMIT (1UL*1024*1024*1024)
and then check end addr with X86_64_KERNEL_TEXT_SIZE + X86_64_KERNEL_TEXT_SIZE

Previously I did not find this problem probably because kernel text happen to randomized
to a address < 512M..

BTW since we can get physical start and size from /proc/iomem, why not just get
vaddr by phys_start + PAGE_OFFSET.

>  
>  #define CRASH_MAX_MEMMAP_NR	CRASH_MAX_MEMORY_RANGES
>  #define CRASH_MAX_MEMORY_RANGES	(MAX_MEMORY_RANGES + 2)
> -- 
> 1.8.5.3
> 
> 
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