linux-kernel - Re: [PATCH v2 29/35] powerpc/perf: remove current_is

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Date:   Wed, 27 Nov 2019 06:41:09 +0100
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Michal Suchanek <msuchanek@...e.de>, linuxppc-dev@...ts.ozlabs.org
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Oleg Nesterov <oleg@...hat.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Christian Brauner <christian@...uner.io>,
        Nicholas Piggin <npiggin@...il.com>,
        Allison Randal <allison@...utok.net>,
        "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Breno Leitao <leitao@...ian.org>,
        Claudio Carvalho <cclaudio@...ux.ibm.com>,
        Russell Currey <ruscur@...sell.cc>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
        Arnd Bergmann <arnd@...db.de>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Firoz Khan <firoz.khan@...aro.org>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Hari Bathini <hbathini@...ux.ibm.com>,
        Andrew Donnellan <andrew.donnellan@....ibm.com>,
        Nicolai Stange <nstange@...e.de>,
        Valentin Schneider <valentin.schneider@....com>,
        Diana Craciun <diana.craciun@....com>,
        Daniel Axtens <dja@...ens.net>,
        Michael Neuling <mikey@...ling.org>,
        Gustavo Romero <gromero@...ux.ibm.com>,
        Mathieu Malaterre <malat@...ian.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        David Howells <dhowells@...hat.com>,
        Brajeswar Ghosh <brajeswar.linux@...il.com>,
        Jagadeesh Pagadala <jagdsh.linux@...il.com>,
        David Hildenbrand <david@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Madhavan Srinivasan <maddy@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 29/35] powerpc/perf: remove current_is_64bit()



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@....fr>
> Signed-off-by: Michal Suchanek <msuchanek@...e.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);
>