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| author | Nicholas Piggin <npiggin@gmail.com> | 2020-07-16 04:35:22 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-07-23 10:43:23 +0300 |
| commit | 2384b36f9156c3b815a5ce5f694edc5054ab7625 (patch) | |
| tree | 1c899ff71242c1660cdf826f87bd1136898fb1d8 /arch/powerpc/include/asm/exception-64s.h | |
| parent | 147c13413c04bc6a2bd76f2503402905e5e98cff (diff) | |
| download | linux-2384b36f9156c3b815a5ce5f694edc5054ab7625.tar.xz | |
powerpc: Select ARCH_HAS_MEMBARRIER_SYNC_CORE
powerpc return from interrupt and return from system call sequences
are context synchronising.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200716013522.338318-1-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/include/asm/exception-64s.h')
| -rw-r--r-- | arch/powerpc/include/asm/exception-64s.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index 47bd4ea0837d..d7a1a427a690 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -68,6 +68,14 @@ * * The nop instructions allow us to insert one or more instructions to flush the * L1-D cache when returning to userspace or a guest. + * + * powerpc relies on return from interrupt/syscall being context synchronising + * (which hrfid, rfid, and rfscv are) to support ARCH_HAS_MEMBARRIER_SYNC_CORE + * without additional synchronisation instructions. + * + * soft-masked interrupt replay does not include a context-synchronising rfid, + * but those always return to kernel, the sync is only required when returning + * to user. */ #define RFI_FLUSH_SLOT \ RFI_FLUSH_FIXUP_SECTION; \ |