Re: [PATCH 05/24] x86/entry: Introduce __entry_text for entry code written in C

[Peter Zijlstra]

On Wed, Sep 01, 2021 at 01:50:06AM +0800, Lai Jiangshan wrote:
> From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
> 
> Some entry code will be implemented in traps.c.  We need __entry_text
> to set them in .entry.text section.
> 
> Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
> ---
>  arch/x86/entry/traps.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/x86/entry/traps.c b/arch/x86/entry/traps.c
> index f71db7934f90..ef07ae5fb3a0 100644
> --- a/arch/x86/entry/traps.c
> +++ b/arch/x86/entry/traps.c
> @@ -69,6 +69,11 @@
>  extern unsigned char native_irq_return_iret[];
>  extern unsigned char asm_load_gs_index_gs_change[];
>  
> +/* Entry code written in C. Must be only used in traps.c */
> +#define __entry_text							\
> +	noinline notrace __attribute((__section__(".entry.text")))	\
> +	__no_kcsan __no_sanitize_address __no_profile __no_sanitize_coverage

Urgh, that's bound to get out of sync with noinstr.. How about you make
noinstr something like:

#define __noinstr_section(section) \
	noinline notrace __attribute((__section__(section)))	\
	__no_kcsan __no_sanitize_address __no_profile __no_sanitize_coverage

#define noinstr __noinstr_section(".noinstr.text")

and then write the above like:

#define __entry_text __noinstr_section(".entry.text")