[PATCH v2 4/5] powerpc/fadump: Make ELF eflags depend on endian

[Mahesh Jagannath Salgaonkar]

On 09/06/2016 11:02 AM, Daniel Axtens wrote:
> Firmware Assisted Dump is a facility to dump kernel core with assistance
> from firmware.  As part of this process the kernel ELF version is
> stored.
> 
> Currently, fadump.h defines this to 0 if it is not already defined. This
> clashes with a define in elf.h which sets it based on the current task -
> not based on the kernel.
> 
> When the kernel is compiled on LE, the kernel will always be version
> 2. Otherwise it will be version 0. So the correct behaviour is to set
> the ELF eflags based on the endianness of the kernel. Do that.
> 
> Remove the definition in fadump.h, which becomes unused.
> 
> Cc: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>
> Cc: Hari Bathini <hbathini at linux.vnet.ibm.com>
> Signed-off-by: Daniel Axtens <dja at axtens.net>
> 
> ---
> 
> Mahesh or Hari: I'm not familiar with this code at all, so if either of
> you could check that this makes sense I would really appreciate that.
> Thanks!
> ---
>  arch/powerpc/include/asm/fadump.h | 4 ----
>  arch/powerpc/kernel/fadump.c      | 6 +++++-
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/fadump.h b/arch/powerpc/include/asm/fadump.h
> index b4407d0add27..0031806475f0 100644
> --- a/arch/powerpc/include/asm/fadump.h
> +++ b/arch/powerpc/include/asm/fadump.h
> @@ -45,10 +45,6 @@
> 
>  #define memblock_num_regions(memblock_type)	(memblock.memblock_type.cnt)
> 
> -#ifndef ELF_CORE_EFLAGS
> -#define ELF_CORE_EFLAGS 0
> -#endif
> -
>  /* Firmware provided dump sections */
>  #define FADUMP_CPU_STATE_DATA	0x0001
>  #define FADUMP_HPTE_REGION	0x0002
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index 0638b82ce294..457f08e544c6 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -779,7 +779,11 @@ static int fadump_init_elfcore_header(char *bufp)
>  	elf->e_entry = 0;
>  	elf->e_phoff = sizeof(struct elfhdr);
>  	elf->e_shoff = 0;
> -	elf->e_flags = ELF_CORE_EFLAGS;
> +#ifdef __LITTLE_ENDIAN__

Wouldn't '#ifdef PPC64_ELF_ABI_v2' be more appropriate here ?

> +	elf->e_flags = 2;
> +#else
> +	elf->e_flags = 0;
> +#endif
>  	elf->e_ehsize = sizeof(struct elfhdr);
>  	elf->e_phentsize = sizeof(struct elf_phdr);
>  	elf->e_phnum = 0;
> 

Reviewed-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>

Thanks,
-Mahesh.