diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2019-04-11 21:46:15 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-17 08:36:42 +0200 |
| commit | 98f6dedbcb1fe30ee9e7eeafd220269ae75b8afd (patch) | |
| tree | 19327fd4cb2448d2dbc6fb28d41d4b9b1db47625 /arch/powerpc/include | |
| parent | 2f4fed0185515cc6da36ac718969fa12537a6868 (diff) | |
powerpc/64s: Add support for software count cache flush
commit ee13cb249fabdff8b90aaff61add347749280087 upstream.
Some CPU revisions support a mode where the count cache needs to be
flushed by software on context switch. Additionally some revisions may
have a hardware accelerated flush, in which case the software flush
sequence can be shortened.
If we detect the appropriate flag from firmware we patch a branch
into _switch() which takes us to a count cache flush sequence.
That sequence in turn may be patched to return early if we detect that
the CPU supports accelerating the flush sequence in hardware.
Add debugfs support for reporting the state of the flush, as well as
runtime disabling it.
And modify the spectre_v2 sysfs file to report the state of the
software flush.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/asm-prototypes.h | 6 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/security_features.h | 1 |
2 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h index e0baba1535e6..f3daa175f86c 100644 --- a/arch/powerpc/include/asm/asm-prototypes.h +++ b/arch/powerpc/include/asm/asm-prototypes.h @@ -121,4 +121,10 @@ extern s64 __ashrdi3(s64, int); extern int __cmpdi2(s64, s64); extern int __ucmpdi2(u64, u64); +/* Patch sites */ +extern s32 patch__call_flush_count_cache; +extern s32 patch__flush_count_cache_return; + +extern long flush_count_cache; + #endif /* _ASM_POWERPC_ASM_PROTOTYPES_H */ diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h index a0d47bc18a5c..759597bf0fd8 100644 --- a/arch/powerpc/include/asm/security_features.h +++ b/arch/powerpc/include/asm/security_features.h @@ -22,6 +22,7 @@ enum stf_barrier_type { void setup_stf_barrier(void); void do_stf_barrier_fixups(enum stf_barrier_type types); +void setup_count_cache_flush(void); static inline void security_ftr_set(unsigned long feature) { |