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Subject: Re: [PATCH v2 29/35] powerpc/perf: remove current_is_64bit()
To:     Michal Suchanek <msuchanek@suse.de>, linuxppc-dev@lists.ozlabs.org
Cc:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
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References: <cover.1574798487.git.msuchanek@suse.de>
 <83795e9690ad8b51a2d991919bc102351a3bbb20.1574798487.git.msuchanek@suse.de>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Message-ID: <ecceebf5-391a-c75d-28a7-44623adc06e8@c-s.fr>
Date:   Wed, 27 Nov 2019 06:41:09 +0100
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Le 26/11/2019 à 21:13, Michal Suchanek a écrit :
> Since commit ed1cd6deb013 ("powerpc: Activate CONFIG_THREAD_INFO_IN_TASK")
> current_is_64bit() is quivalent to !is_32bit_task().
> Remove the redundant function.
> 
> Link: https://github.com/linuxppc/issues/issues/275
> Link: https://lkml.org/lkml/2019/9/12/540
> 
> Fixes: linuxppc#275
> Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
> Signed-off-by: Michal Suchanek <msuchanek@suse.de>

This change is already in powerpc/next, see 
https://github.com/linuxppc/linux/commit/42484d2c0f82b666292faf6668c77b49a3a04bc0

Christophe

> ---
>   arch/powerpc/perf/callchain.c | 17 +----------------
>   1 file changed, 1 insertion(+), 16 deletions(-)
> 
> diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
> index c84bbd4298a0..35d542515faf 100644
> --- a/arch/powerpc/perf/callchain.c
> +++ b/arch/powerpc/perf/callchain.c
> @@ -284,16 +284,6 @@ static void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
>   	}
>   }
>   
> -static inline int current_is_64bit(void)
> -{
> -	/*
> -	 * We can't use test_thread_flag() here because we may be on an
> -	 * interrupt stack, and the thread flags don't get copied over
> -	 * from the thread_info on the main stack to the interrupt stack.
> -	 */
> -	return !test_ti_thread_flag(task_thread_info(current), TIF_32BIT);
> -}
> -
>   #else  /* CONFIG_PPC64 */
>   /*
>    * On 32-bit we just access the address and let hash_page create a
> @@ -321,11 +311,6 @@ static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry
>   {
>   }
>   
> -static inline int current_is_64bit(void)
> -{
> -	return 0;
> -}
> -
>   static inline int valid_user_sp(unsigned long sp, int is_64)
>   {
>   	if (!sp || (sp & 7) || sp > TASK_SIZE - 32)
> @@ -486,7 +471,7 @@ static void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry,
>   void
>   perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
>   {
> -	if (current_is_64bit())
> +	if (!is_32bit_task())
>   		perf_callchain_user_64(entry, regs);
>   	else
>   		perf_callchain_user_32(entry, regs);
>