Messages in this thread | | | Subject | Re: [PATCH] powerpc/32s: Fix RTAS machine check with VMAP stack | From | Christophe Leroy <> | Date | Wed, 23 Dec 2020 07:48:03 +0100 |
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Le 22/12/2020 à 08:11, Christophe Leroy a écrit : > When we have VMAP stack, exception prolog 1 sets r1, not r11.
But exception prolog 1 uses r1 to setup r1 when machine check happens in kernel. So r1 must be restored when the branch is not taken. See subsequent patch I just sent out.
Christophe
> > Fixes: da7bb43ab9da ("powerpc/32: Fix vmap stack - Properly set r1 before activating MMU") > Fixes: d2e006036082 ("powerpc/32: Use SPRN_SPRG_SCRATCH2 in exception prologs") > Cc: stable@vger.kernel.org > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > --- > arch/powerpc/kernel/head_book3s_32.S | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S > index 349bf3f0c3af..fbc48a500846 100644 > --- a/arch/powerpc/kernel/head_book3s_32.S > +++ b/arch/powerpc/kernel/head_book3s_32.S > @@ -260,9 +260,16 @@ __secondary_hold_acknowledge: > MachineCheck: > EXCEPTION_PROLOG_0 > #ifdef CONFIG_PPC_CHRP > +#ifdef CONFIG_VMAP_STACK > + mtspr SPRN_SPRG_SCRATCH2,r1 > + mfspr r1, SPRN_SPRG_THREAD > + lwz r1, RTAS_SP(r1) > + cmpwi cr1, r1, 0 > +#else > mfspr r11, SPRN_SPRG_THREAD > lwz r11, RTAS_SP(r11) > cmpwi cr1, r11, 0 > +#endif > bne cr1, 7f > #endif /* CONFIG_PPC_CHRP */ > EXCEPTION_PROLOG_1 for_rtas=1 >
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