linux-kernel - Re: [RFC PATCH v2 12/20] objtool: Warn about non __ro_after

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Message-ID: <20230728153557.frzmaayyy3auibx3@treble>
Date:   Fri, 28 Jul 2023 10:35:57 -0500
From:   Josh Poimboeuf <jpoimboe@...nel.org>
To:     Valentin Schneider <vschneid@...hat.com>
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Subject: Re: [RFC PATCH v2 12/20] objtool: Warn about non __ro_after_init
 static key usage in .noinstr

On Thu, Jul 20, 2023 at 05:30:48PM +0100, Valentin Schneider wrote:
> +static int validate_static_key(struct instruction *insn, struct insn_state *state)
> +{
> +	if (state->noinstr && state->instr <= 0) {
> +		if ((strcmp(insn->key_sym->sec->name, ".data..ro_after_init"))) {
> +			WARN_INSN(insn,
> +				  "Non __ro_after_init static key \"%s\" in .noinstr section",

For consistency with other warnings, this should start with a lowercase
"n" and the string literal should be on the same line as the WARN_INSN,
like

			WARN_INSN(insn, "non __ro_after_init static key \"%s\" in .noinstr section",
				  ...

> diff --git a/tools/objtool/special.c b/tools/objtool/special.c
> index 91b1950f5bd8a..1f76cfd815bf3 100644
> --- a/tools/objtool/special.c
> +++ b/tools/objtool/special.c
> @@ -127,6 +127,9 @@ static int get_alt_entry(struct elf *elf, const struct special_entry *entry,
>  			return -1;
>  		}
>  		alt->key_addend = reloc_addend(key_reloc);
> +
> +		reloc_to_sec_off(key_reloc, &sec, &offset);
> +		alt->key_sym = find_symbol_by_offset(sec, offset & ~2);

Bits 0 and 1 can both store data, should be ~3?

-- 
Josh