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| author | Nicholas Piggin <npiggin@gmail.com> | 2020-07-16 11:35:22 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-07-23 17:43:23 +1000 |
| commit | 2384b36f9156c3b815a5ce5f694edc5054ab7625 (patch) | |
| tree | 1c899ff71242c1660cdf826f87bd1136898fb1d8 /arch | |
| parent | 147c13413c04bc6a2bd76f2503402905e5e98cff (diff) | |
| download | linux-2384b36f9156c3b815a5ce5f694edc5054ab7625.tar.gz linux-2384b36f9156c3b815a5ce5f694edc5054ab7625.tar.bz2 linux-2384b36f9156c3b815a5ce5f694edc5054ab7625.zip | |
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')
| -rw-r--r-- | arch/powerpc/Kconfig | 1 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/exception-64e.h | 6 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/exception-64s.h | 8 | ||||
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 6 |
4 files changed, 20 insertions, 1 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 70adf69f8b1a..81c0dee1cbff 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -131,6 +131,7 @@ config PPC select ARCH_HAS_PTE_DEVMAP if PPC_BOOK3S_64 select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_MEMBARRIER_CALLBACKS + select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64 select ARCH_HAS_STRICT_KERNEL_RWX if (PPC32 && !HIBERNATION) select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST diff --git a/arch/powerpc/include/asm/exception-64e.h b/arch/powerpc/include/asm/exception-64e.h index 54a98ef7d7fe..72b6657acd2d 100644 --- a/arch/powerpc/include/asm/exception-64e.h +++ b/arch/powerpc/include/asm/exception-64e.h @@ -204,7 +204,11 @@ exc_##label##_book3e: LOAD_REG_ADDR(r3,interrupt_base_book3e);\ ori r3,r3,vector_offset@l; \ mtspr SPRN_IVOR##vector_number,r3; - +/* + * powerpc relies on return from interrupt/syscall being context synchronising + * (which rfi is) to support ARCH_HAS_MEMBARRIER_SYNC_CORE without additional + * synchronisation instructions. + */ #define RFI_TO_KERNEL \ rfi 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; \ diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 217ebdf5b00b..f4d0af8e1136 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -36,6 +36,12 @@ #include "head_32.h" /* + * powerpc relies on return from interrupt/syscall being context synchronising + * (which rfi is) to support ARCH_HAS_MEMBARRIER_SYNC_CORE without additional + * synchronisation instructions. + */ + +/* * Align to 4k in order to ensure that all functions modyfing srr0/srr1 * fit into one page in order to not encounter a TLB miss between the * modification of srr0/srr1 and the associated rfi. |