[PATCH v2 1/5] elfcore: Replace CONFIG_{IA64,UML} checks with a new option

[Will Deacon]

On Mon, Jan 31, 2022 at 04:54:52PM +0000, Catalin Marinas wrote:
> As arm64 is about to introduce MTE-specific phdrs in the core dump, add
> a common CONFIG_ARCH_BINFMT_ELF_EXTRA_PHDRS option currently selectable
> by UML_X86 and IA64.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Eric Biederman <ebiederm at xmission.com>
> ---
>  arch/ia64/Kconfig       | 1 +
>  arch/x86/um/Kconfig     | 1 +
>  fs/Kconfig.binfmt       | 3 +++
>  include/linux/elfcore.h | 4 ++--
>  4 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
> index a7e01573abd8..e003b2473c64 100644
> --- a/arch/ia64/Kconfig
> +++ b/arch/ia64/Kconfig
> @@ -8,6 +8,7 @@ menu "Processor type and features"
>  
>  config IA64
>  	bool
> +	select ARCH_BINFMT_ELF_EXTRA_PHDRS
>  	select ARCH_HAS_DMA_MARK_CLEAN
>  	select ARCH_HAS_STRNCPY_FROM_USER
>  	select ARCH_HAS_STRNLEN_USER
> diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
> index 40d6a06e41c8..ead7e5b3a975 100644
> --- a/arch/x86/um/Kconfig
> +++ b/arch/x86/um/Kconfig
> @@ -8,6 +8,7 @@ endmenu
>  
>  config UML_X86
>  	def_bool y
> +	select ARCH_BINFMT_ELF_EXTRA_PHDRS if X86_32
>  
>  config 64BIT
>  	bool "64-bit kernel" if "$(SUBARCH)" = "x86"
> diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
> index 4d5ae61580aa..68e586283764 100644
> --- a/fs/Kconfig.binfmt
> +++ b/fs/Kconfig.binfmt
> @@ -36,6 +36,9 @@ config COMPAT_BINFMT_ELF
>  config ARCH_BINFMT_ELF_STATE
>  	bool
>  
> +config ARCH_BINFMT_ELF_EXTRA_PHDRS
> +	bool
> +
>  config ARCH_HAVE_ELF_PROT
>  	bool
>  
> diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h
> index 746e081879a5..b02d5fc711db 100644
> --- a/include/linux/elfcore.h
> +++ b/include/linux/elfcore.h
> @@ -114,7 +114,7 @@ static inline int elf_core_copy_task_fpregs(struct task_struct *t, struct pt_reg
>  #endif
>  }
>  
> -#if (defined(CONFIG_UML) && defined(CONFIG_X86_32)) || defined(CONFIG_IA64)
> +#ifdef CONFIG_ARCH_BINFMT_ELF_EXTRA_PHDRS
>  /*
>   * These functions parameterize elf_core_dump in fs/binfmt_elf.c to write out
>   * extra segments containing the gate DSO contents.  Dumping its
> @@ -149,6 +149,6 @@ static inline size_t elf_core_extra_data_size(void)
>  {
>  	return 0;
>  }
> -#endif
> +#endif /* CONFIG_ARCH_EXTRA_PHDRS */

nit: closing comment doesn't match the name of the new Kconfig symbol.

I'll fix that and put the series into -next.

Will