Re: [PATCH 4/7] uprobes/x86: Kill the "ia32_compat" check in handle_riprel_insn(), remove "mm" arg

[Masami Hiramatsu]

(2014/04/01 4:44), Oleg Nesterov wrote:
> Kill the "mm->context.ia32_compat" check in handle_riprel_insn(), if
> it is true insn_rip_relative() must return false. validate_insn_bits()
> passed "ia32_compat" as !x86_64 to insn_init(), and insn_rip_relative()
> checks insn->x86_64.
> 
> Also, remove the no longer needed "struct mm_struct *mm" argument and
> the unnecessary "return" at the end.
> 
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

This looks good to me.

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>

Thank you,

> ---
>  arch/x86/kernel/uprobes.c |   10 +++-------
>  1 files changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
> index d72dfbf..382a69d 100644
> --- a/arch/x86/kernel/uprobes.c
> +++ b/arch/x86/kernel/uprobes.c
> @@ -253,14 +253,11 @@ static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn)
>   *  - The displacement is always 4 bytes.
>   */
>  static void
> -handle_riprel_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn)
> +handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn)
>  {
>  	u8 *cursor;
>  	u8 reg;
>  
> -	if (mm->context.ia32_compat)
> -		return;
> -
>  	if (!insn_rip_relative(insn))
>  		return;
>  
> @@ -314,7 +311,6 @@ handle_riprel_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, struct ins
>  		cursor++;
>  		memmove(cursor, cursor + insn->displacement.nbytes, insn->immediate.nbytes);
>  	}
> -	return;
>  }
>  
>  static int validate_insn_64bits(struct arch_uprobe *auprobe, struct insn *insn)
> @@ -343,7 +339,7 @@ static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm,
>  	return validate_insn_64bits(auprobe, insn);
>  }
>  #else /* 32-bit: */
> -static void handle_riprel_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn)
> +static void handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn)
>  {
>  	/* No RIP-relative addressing on 32-bit */
>  }
> @@ -406,7 +402,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
>  		}
>  		/* fall through */
>  	default:
> -		handle_riprel_insn(auprobe, mm, &insn);
> +		handle_riprel_insn(auprobe, &insn);
>  	}
>  
>  	if (fix_ip)
> 


-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx


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