From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Arnd Bergmann <arnd@kernel.org>, Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Lynch <nathanl@linux.ibm.com>,
Arnd Bergmann <arnd@arndb.de>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
Hugh Dickins <hughd@google.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Maninder Singh <maninder1.s@samsung.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jiri Slaby <jirislaby@kernel.org>
Subject: Re: [PATCH 1/2] powerpc: mark more local variables as volatile
Date: Wed, 9 Aug 2023 13:17:02 +0000 [thread overview]
Message-ID: <66ca8677-6a8d-c2f6-f215-a49ae7248458@csgroup.eu> (raw)
In-Reply-To: <20230809131024.2039647-1-arnd@kernel.org>
Le 09/08/2023 à 15:10, Arnd Bergmann a écrit :
> From: Arnd Bergmann <arnd@arndb.de>
>
> A while ago I created a2305e3de8193 ("powerpc: mark local variables
> around longjmp as volatile") in order to allow building powerpc with
> -Wextra enabled on gcc-11.
Should this be explained in
https://docs.kernel.org/process/volatile-considered-harmful.html ?
Christophe
>
> I tried this again with gcc-13 and found two more of the same issues,
> presumably based on slightly different optimization paths being taken
> here:
>
> arch/powerpc/xmon/xmon.c:3306:27: error: variable 'mm' might be clobbered by 'longjmp' or 'vfork' [-Werror=clobbered]
> arch/powerpc/kexec/crash.c:353:22: error: variable 'i' might be clobbered by 'longjmp' or 'vfork' [-Werror=clobbered]
>
> I checked a bunch of randconfigs and found only these two, so just
> address them the same way as the others.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> arch/powerpc/kexec/crash.c | 2 +-
> arch/powerpc/xmon/xmon.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c
> index 252724ed666a3..ef5c2d25ec397 100644
> --- a/arch/powerpc/kexec/crash.c
> +++ b/arch/powerpc/kexec/crash.c
> @@ -350,7 +350,7 @@ EXPORT_SYMBOL(crash_shutdown_unregister);
>
> void default_machine_crash_shutdown(struct pt_regs *regs)
> {
> - unsigned int i;
> + volatile unsigned int i;
> int (*old_handler)(struct pt_regs *regs);
>
> if (TRAP(regs) == INTERRUPT_SYSTEM_RESET)
> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> index 3b6f524c790e3..9e12b75850d75 100644
> --- a/arch/powerpc/xmon/xmon.c
> +++ b/arch/powerpc/xmon/xmon.c
> @@ -3303,7 +3303,7 @@ static void show_pte(unsigned long addr)
> {
> unsigned long tskv = 0;
> struct task_struct *volatile tsk = NULL;
> - struct mm_struct *mm;
> + struct mm_struct *volatile mm;
> pgd_t *pgdp;
> p4d_t *p4dp;
> pud_t *pudp;
next prev parent reply other threads:[~2023-08-09 13:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-09 13:10 [PATCH 1/2] powerpc: mark more local variables as volatile Arnd Bergmann
2023-08-09 13:10 ` [PATCH 2/2] powerpc: xmon: remove unused variables Arnd Bergmann
2023-08-09 13:17 ` Christophe Leroy [this message]
2023-08-09 13:35 ` [PATCH 1/2] powerpc: mark more local variables as volatile Arnd Bergmann
2023-08-23 11:55 ` Michael Ellerman
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