linux-kernel - Re: [PATCH 2/3] objtool: Add is_static

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Message-ID: <e582e4d4-32b1-260d-96d6-69267455788d@redhat.com>
Date:   Tue, 11 Feb 2020 07:52:41 +0000
From:   Julien Thierry <jthierry@...hat.com>
To:     Josh Poimboeuf <jpoimboe@...hat.com>, x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, Borislav Petkov <bp@...e.de>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 2/3] objtool: Add is_static_jump() helper



On 2/10/20 6:32 PM, Josh Poimboeuf wrote:
> There are several places where objtool tests for a non-dynamic (aka
> direct) jump.  Move the check to a helper function.
> 

Makes sense.

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

Reviewed-by: Julien Thierry <jthierry@...hat.com>

> ---
>   tools/objtool/check.c | 15 +++++++++------
>   1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index 61d2d1877fd2..5ea2ce7ed8a3 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -97,14 +97,19 @@ static struct instruction *next_insn_same_func(struct objtool_file *file,
>   	for (insn = next_insn_same_sec(file, insn); insn;		\
>   	     insn = next_insn_same_sec(file, insn))
>   
> +static bool is_static_jump(struct instruction *insn)
> +{
> +	return insn->type == INSN_JUMP_CONDITIONAL ||
> +	       insn->type == INSN_JUMP_UNCONDITIONAL;
> +}
> +
>   static bool is_sibling_call(struct instruction *insn)
>   {
>   	/* An indirect jump is either a sibling call or a jump to a table. */
>   	if (insn->type == INSN_JUMP_DYNAMIC)
>   		return list_empty(&insn->alts);
>   
> -	if (insn->type != INSN_JUMP_CONDITIONAL &&
> -	    insn->type != INSN_JUMP_UNCONDITIONAL)
> +	if (!is_static_jump(insn))
>   		return false;
>   
>   	/* add_jump_destinations() sets insn->call_dest for sibling calls. */
> @@ -571,8 +576,7 @@ static int add_jump_destinations(struct objtool_file *file)
>   	unsigned long dest_off;
>   
>   	for_each_insn(file, insn) {
> -		if (insn->type != INSN_JUMP_CONDITIONAL &&
> -		    insn->type != INSN_JUMP_UNCONDITIONAL)
> +		if (!is_static_jump(insn))
>   			continue;
>   
>   		if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET)
> @@ -782,8 +786,7 @@ static int handle_group_alt(struct objtool_file *file,
>   		insn->ignore = orig_insn->ignore_alts;
>   		insn->func = orig_insn->func;
>   
> -		if (insn->type != INSN_JUMP_CONDITIONAL &&
> -		    insn->type != INSN_JUMP_UNCONDITIONAL)
> +		if (!is_static_jump(insn))
>   			continue;
>   
>   		if (!insn->immediate)
> 

-- 
Julien Thierry