Re: [PATCH] x86/cfi: add __init_or_module annotations for fineibt

[Calvin Owens <calvin@wbinvd.org>]

On Monday 05/25 at 20:22 -0700, Calvin Owens wrote:
> I'm seeing some benign section mismatch warnings with fineibt when
> building kernels with CONFIG_MODULES=n:
> 
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0x1db (section: .text) -> text_poke_early (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0x473 (section: .text) -> text_poke_early (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0x57c (section: .text) -> text_poke_early (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0x6d9 (section: .text) -> text_poke_early (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xb57 (section: .text) -> text_poke_early (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xb81 (section: .text) -> text_poke_early (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xd00 (section: .text) -> poison_endbr (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xdd3 (section: .text) -> text_poke_early (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xe58 (section: .text) -> text_poke_early (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xe85 (section: .text) -> text_poke_early (section: .init.text)
>     WARNING: modpost: vmlinux: section mismatch in reference: apply_fineibt+0x8 (section: .text.unlikely.) -> __apply_fineibt (section: .init.text)
> 
> Add the missing __init_or_module section annotations to fix the
> warnings, and also free up a tiny bit of memory after boot.
> 
> Signed-off-by: Calvin Owens <calvin@wbinvd.org>

Gentle ping.

> ---
>  arch/x86/kernel/alternative.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index 62936a3bde19..400baffcd609 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -1775,8 +1775,8 @@ static int cfi_rewrite_callers(s32 *start, s32 *end)
>  #define FINEIBT_WARN(_f, _v) \
>  	WARN_ONCE((_f) != (_v), "FineIBT: " #_f " %ld != %d\n", _f, _v)
>  
> -static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
> -			    s32 *start_cfi, s32 *end_cfi, bool builtin)
> +static void __init_or_module __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
> +					     s32 *start_cfi, s32 *end_cfi, bool builtin)
>  {
>  	int ret;
>  
> @@ -2088,8 +2088,8 @@ bool decode_fineibt_insn(struct pt_regs *regs, unsigned long *target, u32 *type)
>  
>  #else /* !CONFIG_FINEIBT: */
>  
> -static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
> -			    s32 *start_cfi, s32 *end_cfi, bool builtin)
> +static void __init_or_module __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
> +					     s32 *start_cfi, s32 *end_cfi, bool builtin)
>  {
>  	if (IS_ENABLED(CONFIG_CFI) && builtin)
>  		pr_info("CFI: Using standard kCFI\n");
> @@ -2101,8 +2101,8 @@ static void poison_cfi(void *addr) { }
>  
>  #endif /* !CONFIG_FINEIBT */
>  
> -void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
> -		   s32 *start_cfi, s32 *end_cfi)
> +void __init_or_module apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
> +				    s32 *start_cfi, s32 *end_cfi)
>  {
>  	return __apply_fineibt(start_retpoline, end_retpoline,
>  			       start_cfi, end_cfi,
> -- 
> 2.47.3
>