linux-kernel - Re: [PATCH] objtool: fix iret's opcode

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Date:   Wed, 18 Jan 2017 10:17:08 -0600
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Jiri Slaby <jslaby@...e.cz>
Cc:     mingo@...nel.org, x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] objtool: fix iret's opcode

On Wed, Jan 18, 2017 at 02:29:21PM +0100, Jiri Slaby wrote:
> iret is 0xcf according to the Intel manual and also to objdump of my
> vmlinux:
>     1ea8:       48 cf                   iretq
> 
> Fix the opcode in arch_decode_instruction.
> 
> The previous value (0xc5) seems to correspond to lds.
> 
> Signed-off-by: Jiri Slaby <jslaby@...e.cz>
> Cc: Josh Poimboeuf <jpoimboe@...hat.com>
> Cc: Ingo Molnar <mingo@...nel.org>

Thanks!

Acked-by: Josh Poimboeuf <jpoimboe@...hat.com>

> ---
>  tools/objtool/arch/x86/decode.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
> index 5e0dea2cdc01..039636ffb6c8 100644
> --- a/tools/objtool/arch/x86/decode.c
> +++ b/tools/objtool/arch/x86/decode.c
> @@ -150,9 +150,9 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
>  		*type = INSN_RETURN;
>  		break;
>  
> -	case 0xc5: /* iret */
>  	case 0xca: /* retf */
>  	case 0xcb: /* retf */
> +	case 0xcf: /* iret */
>  		*type = INSN_CONTEXT_SWITCH;
>  		break;
>  
> -- 
> 2.11.0
> 

-- 
Josh