Re: [PATCH v2 3/3] elf: Remove has_interp property from arch_adjust_elf_prot()

[Dave Martin <Dave.Martin@arm.com>]

On Fri, Jun 04, 2021 at 12:24:50PM +0100, Mark Brown wrote:
> Since we have added an is_interp flag to arch_parse_elf_property() we can
> drop the has_interp flag from arch_elf_adjust_prot(), the only user was
> the arm64 code which no longer needs it and any future users will be able
> to use arch_parse_elf_properties() to determine if an interpreter is in
> use.

So far so good, but can we also drop the has_interp argument from
arch_parse_elf_properties()?

Cross-check with Yu-Cheng Yu's series, but I don't see this being used
any more (except for passthrough in binfmt_elf.c).

Since we are treating the interpreter and main executable orthogonally
to each other now, I don't think we should need a has_interp argument to
pass knowledge between the interpreter and executable handling phases
here.

> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>  arch/arm64/kernel/process.c | 2 +-
>  fs/binfmt_elf.c             | 2 +-
>  include/linux/elf.h         | 4 ++--
>  3 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index f7fff4a4c99f..e51c4aa7e048 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -742,7 +742,7 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void)
>  
>  #ifdef CONFIG_BINFMT_ELF
>  int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
> -			 bool has_interp, bool is_interp)
> +			 bool is_interp)
>  {
>  	if (prot & PROT_EXEC) {
>  		if (state->flags & ARM64_ELF_INTERP_BTI && is_interp)
> diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
> index 253ca9969345..1aba4e50e651 100644
> --- a/fs/binfmt_elf.c
> +++ b/fs/binfmt_elf.c
> @@ -580,7 +580,7 @@ static inline int make_prot(u32 p_flags, struct arch_elf_state *arch_state,
>  	if (p_flags & PF_X)
>  		prot |= PROT_EXEC;
>  
> -	return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp);
> +	return arch_elf_adjust_prot(prot, arch_state, is_interp);
>  }
>  
>  /* This is much more generalized than the library routine read function,
> diff --git a/include/linux/elf.h b/include/linux/elf.h
> index 1c45ecf29147..d8392531899d 100644
> --- a/include/linux/elf.h
> +++ b/include/linux/elf.h
> @@ -101,11 +101,11 @@ extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
>  
>  #ifdef CONFIG_ARCH_HAVE_ELF_PROT
>  int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
> -			 bool has_interp, bool is_interp);
> +			 bool is_interp);
>  #else
>  static inline int arch_elf_adjust_prot(int prot,
>  				       const struct arch_elf_state *state,
> -				       bool has_interp, bool is_interp)
> +				       bool is_interp)

[...]

Otherwise, looks reasonable.

Cheers
---Dave