diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2020-04-29 16:56:51 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-05-28 23:24:37 +1000 |
| commit | 579940bb451c2dd33396d2d56ce6ef5d92154b3b (patch) | |
| tree | 93b85c1cc80e6e4b572a3a31c6b033142799edee /arch/powerpc/include | |
| parent | cb2b53cbffe3c388cd676b63f34e54ceb2643ae2 (diff) | |
powerpc/64/kuap: Conditionally restore AMR in interrupt exit
The AMR update is made conditional on AMR actually changing, which
should be the less common case on most workloads (though kernel page
faults on uaccess could be frequent, this doesn't significantly slow
down that case).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200429065654.1677541-4-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/book3s/64/kup-radix.h | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h b/arch/powerpc/include/asm/book3s/64/kup-radix.h index 101d60f16d46..820169bac6c4 100644 --- a/arch/powerpc/include/asm/book3s/64/kup-radix.h +++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h @@ -62,9 +62,9 @@ #include <asm/mmu.h> #include <asm/ptrace.h> -static inline void kuap_restore_amr(struct pt_regs *regs) +static inline void kuap_restore_amr(struct pt_regs *regs, unsigned long amr) { - if (mmu_has_feature(MMU_FTR_RADIX_KUAP)) { + if (mmu_has_feature(MMU_FTR_RADIX_KUAP) && unlikely(regs->kuap != amr)) { isync(); mtspr(SPRN_AMR, regs->kuap); /* @@ -75,6 +75,17 @@ static inline void kuap_restore_amr(struct pt_regs *regs) } } +static inline unsigned long kuap_get_and_check_amr(void) +{ + if (mmu_has_feature(MMU_FTR_RADIX_KUAP)) { + unsigned long amr = mfspr(SPRN_AMR); + if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG)) /* kuap_check_amr() */ + WARN_ON_ONCE(amr != AMR_KUAP_BLOCKED); + return amr; + } + return 0; +} + static inline void kuap_check_amr(void) { if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && mmu_has_feature(MMU_FTR_RADIX_KUAP)) @@ -151,13 +162,18 @@ bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read"); } #else /* CONFIG_PPC_KUAP */ -static inline void kuap_restore_amr(struct pt_regs *regs) +static inline void kuap_restore_amr(struct pt_regs *regs, unsigned long amr) { } static inline void kuap_check_amr(void) { } + +static inline unsigned long kuap_get_and_check_amr(void) +{ + return 0; +} #endif /* CONFIG_PPC_KUAP */ #endif /* __ASSEMBLY__ */ |