diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2021-05-03 23:02:41 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-21 21:13:19 +1000 |
| commit | 84ed26fd00c514da57cd46aa3728a48f1f9b35cd (patch) | |
| tree | c57be6639b730d5a84d556460bc92319e1085816 | |
| parent | 65c7d070850e109a8a75a431f5a7f6eb4c007b77 (diff) | |
powerpc/security: Add a security feature for STF barrier
Rather than tying this mitigation to RFI L1D flush requirement, add a
new bit for it.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210503130243.891868-3-npiggin@gmail.com
| -rw-r--r-- | arch/powerpc/include/asm/security_features.h | 4 | ||||
| -rw-r--r-- | arch/powerpc/kernel/security.c | 7 |
2 files changed, 6 insertions, 5 deletions
diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h index b774a4477d5f..792eefaf230b 100644 --- a/arch/powerpc/include/asm/security_features.h +++ b/arch/powerpc/include/asm/security_features.h @@ -92,6 +92,9 @@ static inline bool security_ftr_enabled(u64 feature) // The L1-D cache should be flushed after user accesses from the kernel #define SEC_FTR_L1D_FLUSH_UACCESS 0x0000000000008000ull +// The STF flush should be executed on privilege state switch +#define SEC_FTR_STF_BARRIER 0x0000000000010000ull + // Features enabled by default #define SEC_FTR_DEFAULT \ (SEC_FTR_L1D_FLUSH_HV | \ @@ -99,6 +102,7 @@ static inline bool security_ftr_enabled(u64 feature) SEC_FTR_BNDS_CHK_SPEC_BAR | \ SEC_FTR_L1D_FLUSH_ENTRY | \ SEC_FTR_L1D_FLUSH_UACCESS | \ + SEC_FTR_STF_BARRIER | \ SEC_FTR_FAVOUR_SECURITY) #endif /* _ASM_POWERPC_SECURITY_FEATURES_H */ diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c index 9c2f7b909911..cc51fa52e783 100644 --- a/arch/powerpc/kernel/security.c +++ b/arch/powerpc/kernel/security.c @@ -300,9 +300,7 @@ static void stf_barrier_enable(bool enable) void setup_stf_barrier(void) { enum stf_barrier_type type; - bool enable, hv; - - hv = cpu_has_feature(CPU_FTR_HVMODE); + bool enable; /* Default to fallback in case fw-features are not available */ if (cpu_has_feature(CPU_FTR_ARCH_300)) @@ -315,8 +313,7 @@ void setup_stf_barrier(void) type = STF_BARRIER_NONE; enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) && - (security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR) || - (security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) && hv)); + security_ftr_enabled(SEC_FTR_STF_BARRIER); if (type == STF_BARRIER_FALLBACK) { pr_info("stf-barrier: fallback barrier available\n"); |