Messages in this thread | | | From | Christophe Leroy <> | Subject | Re: [PATCH 1/2] powerpc: mark more local variables as volatile | Date | Wed, 9 Aug 2023 13:17:02 +0000 |
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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;
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