Nicholas Piggin <npig...@gmail.com> writes: > Excerpts from Geert Uytterhoeven's message of December 10, 2020 7:06 pm: >> Hi Nicholas, >> >> On Fri, Nov 20, 2020 at 4:01 AM Nicholas Piggin <npig...@gmail.com> wrote: >>> >>> When offlining a CPU, powerpc/64s does not flush TLBs, rather it just >>> leaves the CPU set in mm_cpumasks, so it continues to receive TLBIEs >>> to manage its TLBs. >>> >>> However the exit_flush_lazy_tlbs() function expects that after >>> returning, all CPUs (except self) have flushed TLBs for that mm, in >>> which case TLBIEL can be used for this flush. This breaks for offline >>> CPUs because they don't get the IPI to flush their TLB. This can lead >>> to stale translations. >>> >>> Fix this by clearing the CPU from mm_cpumasks, then flushing all TLBs >>> before going offline. >>> >>> These offlined CPU bits stuck in the cpumask also prevents the cpumask >>> from being trimmed back to local mode, which means continual broadcast >>> IPIs or TLBIEs are needed for TLB flushing. This patch prevents that >>> situation too. >>> >>> Signed-off-by: Nicholas Piggin <npig...@gmail.com> >> >> Thanks for your patch! >> >>> --- a/arch/powerpc/platforms/powermac/smp.c >>> +++ b/arch/powerpc/platforms/powermac/smp.c >>> @@ -911,6 +911,8 @@ static int smp_core99_cpu_disable(void) >>> >>> mpic_cpu_set_priority(0xf); >>> >>> + cleanup_cpu_mmu_context(); >>> + >> >> I guess this change broke pmac32_defconfig+SMP in v5.10-rc7? >> >> arch/powerpc/platforms/powermac/smp.c: error: implicit >> declaration of function 'cleanup_cpu_mmu_context' >> [-Werror=implicit-function-declaration]: => 914:2 >> >> http://kisskb.ellerman.id.au/kisskb/buildresult/14423174/ > > Hey, yeah it does thanks for catching it. This patch fixes it for me > > --- > From a9b5ec92ffac975e81c6d7db6ff2b1486b2723f7 Mon Sep 17 00:00:00 2001 > From: Nicholas Piggin <npig...@gmail.com> > Date: Mon, 14 Dec 2020 13:52:39 +1000 > Subject: [PATCH] powerpc/32s: Fix cleanup_cpu_mmu_context() compile bug > > 32s has no tlbiel_all() defined, so just disable the cleanup with a > comment.
Or what about just: diff --git a/arch/powerpc/include/asm/book3s/32/mmu-hash.h b/arch/powerpc/include/asm/book3s/32/mmu-hash.h index 331187661236..685c589e723f 100644 --- a/arch/powerpc/include/asm/book3s/32/mmu-hash.h +++ b/arch/powerpc/include/asm/book3s/32/mmu-hash.h @@ -94,6 +94,7 @@ typedef struct { } mm_context_t; void update_bats(void); +static inline void cleanup_cpu_mmu_context(void) { }; /* patch sites */ extern s32 patch__hash_page_A0, patch__hash_page_A1, patch__hash_page_A2; cheers