Re: [PATCH v2 00/36] MIPS: barriers & atomics cleanups

From: Paul Burton
Date: Mon Oct 07 2019 - 13:51:36 EST


Hello,

Paul Burton wrote:
> This series consists of a bunch of cleanups to the way we handle memory
> barriers (though no changes to the sync instructions we use to implement
> them) & atomic memory accesses. One major goal was to ensure the
> Loongson3 LL/SC errata workarounds are applied in a safe manner from
> within inline-asm & that we can automatically verify the resulting
> kernel binary looks reasonable. Many patches are cleanups found along
> the way.
>
> Applies atop v5.4-rc1.
>
> Changes in v2:
> - Keep our fls/ffs implementations. Turns out GCC's builtins call
> intrinsics in some configurations, and if we'd need to go implement
> those then using the generic fls/ffs doesn't seem like such a win.
> - De-string __WEAK_LLSC_MB to allow use with __SYNC_ELSE().
> - Only try to build the loongson3-llsc-check tool from
> arch/mips/Makefile when CONFIG_CPU_LOONGSON3_WORKAROUNDS is enabled.
>
> Paul Burton (36):
> MIPS: Unify sc beqz definition
> MIPS: Use compact branch for LL/SC loops on MIPSr6+
> MIPS: barrier: Add __SYNC() infrastructure
> MIPS: barrier: Clean up rmb() & wmb() definitions
> MIPS: barrier: Clean up __smp_mb() definition
> MIPS: barrier: Remove fast_mb() Octeon #ifdef'ery
> MIPS: barrier: Clean up __sync() definition
> MIPS: barrier: Clean up sync_ginv()
> MIPS: atomic: Fix whitespace in ATOMIC_OP macros
> MIPS: atomic: Handle !kernel_uses_llsc first
> MIPS: atomic: Use one macro to generate 32b & 64b functions
> MIPS: atomic: Emit Loongson3 sync workarounds within asm
> MIPS: atomic: Use _atomic barriers in atomic_sub_if_positive()
> MIPS: atomic: Unify 32b & 64b sub_if_positive
> MIPS: atomic: Deduplicate 32b & 64b read, set, xchg, cmpxchg
> MIPS: bitops: Handle !kernel_uses_llsc first
> MIPS: bitops: Only use ins for bit 16 or higher
> MIPS: bitops: Use MIPS_ISA_REV, not #ifdefs
> MIPS: bitops: ins start position is always an immediate
> MIPS: bitops: Implement test_and_set_bit() in terms of _lock variant
> MIPS: bitops: Allow immediates in test_and_{set,clear,change}_bit
> MIPS: bitops: Use the BIT() macro
> MIPS: bitops: Avoid redundant zero-comparison for non-LLSC
> MIPS: bitops: Abstract LL/SC loops
> MIPS: bitops: Use BIT_WORD() & BITS_PER_LONG
> MIPS: bitops: Emit Loongson3 sync workarounds within asm
> MIPS: bitops: Use smp_mb__before_atomic in test_* ops
> MIPS: cmpxchg: Emit Loongson3 sync workarounds within asm
> MIPS: cmpxchg: Omit redundant barriers for Loongson3
> MIPS: futex: Emit Loongson3 sync workarounds within asm
> MIPS: syscall: Emit Loongson3 sync workarounds within asm
> MIPS: barrier: Remove loongson_llsc_mb()
> MIPS: barrier: Make __smp_mb__before_atomic() a no-op for Loongson3
> MIPS: genex: Add Loongson3 LL/SC workaround to ejtag_debug_handler
> MIPS: genex: Don't reload address unnecessarily
> MIPS: Check Loongson3 LL/SC errata workaround correctness
>
> arch/mips/Makefile | 3 +
> arch/mips/Makefile.postlink | 10 +-

Series applied to mips-next.

> MIPS: Unify sc beqz definition
> commit 878f75c7a253
> https://git.kernel.org/mips/c/878f75c7a253
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: Use compact branch for LL/SC loops on MIPSr6+
> commit ef85d057a605
> https://git.kernel.org/mips/c/ef85d057a605
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: barrier: Add __SYNC() infrastructure
> commit bf92927251b3
> https://git.kernel.org/mips/c/bf92927251b3
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: barrier: Clean up rmb() & wmb() definitions
> commit 21e3134b3ec0
> https://git.kernel.org/mips/c/21e3134b3ec0
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: barrier: Clean up __smp_mb() definition
> commit 05e6da742b5b
> https://git.kernel.org/mips/c/05e6da742b5b
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: barrier: Remove fast_mb() Octeon #ifdef'ery
> commit 5c12a6eff6ae
> https://git.kernel.org/mips/c/5c12a6eff6ae
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: barrier: Clean up __sync() definition
> commit fe0065e56227
> https://git.kernel.org/mips/c/fe0065e56227
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: barrier: Clean up sync_ginv()
> commit 185d7d7a5819
> https://git.kernel.org/mips/c/185d7d7a5819
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: atomic: Fix whitespace in ATOMIC_OP macros
> commit 36d3295c5a0d
> https://git.kernel.org/mips/c/36d3295c5a0d
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: atomic: Handle !kernel_uses_llsc first
> commit 9537db24c65a
> https://git.kernel.org/mips/c/9537db24c65a
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: atomic: Use one macro to generate 32b & 64b functions
> commit a38ee6bb14a4
> https://git.kernel.org/mips/c/a38ee6bb14a4
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: atomic: Emit Loongson3 sync workarounds within asm
> commit 4d1dbfe6cbec
> https://git.kernel.org/mips/c/4d1dbfe6cbec
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: atomic: Use _atomic barriers in atomic_sub_if_positive()
> commit 77d281b7966e
> https://git.kernel.org/mips/c/77d281b7966e
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: atomic: Unify 32b & 64b sub_if_positive
> commit 40e784b4d4bc
> https://git.kernel.org/mips/c/40e784b4d4bc
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: atomic: Deduplicate 32b & 64b read, set, xchg, cmpxchg
> commit 1da7bce8591d
> https://git.kernel.org/mips/c/1da7bce8591d
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Handle !kernel_uses_llsc first
> commit fe7cd97e68fa
> https://git.kernel.org/mips/c/fe7cd97e68fa
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Only use ins for bit 16 or higher
> commit 3d2920cf4fd4
> https://git.kernel.org/mips/c/3d2920cf4fd4
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Use MIPS_ISA_REV, not #ifdefs
> commit 59361e9975fd
> https://git.kernel.org/mips/c/59361e9975fd
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: ins start position is always an immediate
> commit 27aab27259ae
> https://git.kernel.org/mips/c/27aab27259ae
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Implement test_and_set_bit() in terms of _lock variant
> commit 6bbe043bd3f4
> https://git.kernel.org/mips/c/6bbe043bd3f4
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Allow immediates in test_and_{set,clear,change}_bit
> commit a2e66b862cc7
> https://git.kernel.org/mips/c/a2e66b862cc7
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Use the BIT() macro
> commit d6103510e7cc
> https://git.kernel.org/mips/c/d6103510e7cc
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Avoid redundant zero-comparison for non-LLSC
> commit aad028cadb17
> https://git.kernel.org/mips/c/aad028cadb17
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Abstract LL/SC loops
> commit cc99987c375e
> https://git.kernel.org/mips/c/cc99987c375e
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Use BIT_WORD() & BITS_PER_LONG
> commit c042be02d730
> https://git.kernel.org/mips/c/c042be02d730
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Emit Loongson3 sync workarounds within asm
> commit 5bb29275df7a
> https://git.kernel.org/mips/c/5bb29275df7a
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: bitops: Use smp_mb__before_atomic in test_* ops
> commit 9026737703ae
> https://git.kernel.org/mips/c/9026737703ae
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: cmpxchg: Emit Loongson3 sync workarounds within asm
> commit 6a57d2d1e7c3
> https://git.kernel.org/mips/c/6a57d2d1e7c3
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: cmpxchg: Omit redundant barriers for Loongson3
> commit a91f2a1dba44
> https://git.kernel.org/mips/c/a91f2a1dba44
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: futex: Emit Loongson3 sync workarounds within asm
> commit 3c1d3f097972
> https://git.kernel.org/mips/c/3c1d3f097972
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: syscall: Emit Loongson3 sync workarounds within asm
> commit e84957e6ae04
> https://git.kernel.org/mips/c/e84957e6ae04
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: barrier: Remove loongson_llsc_mb()
> commit 7f56b1235481
> https://git.kernel.org/mips/c/7f56b1235481
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: barrier: Make __smp_mb__before_atomic() a no-op for Loongson3
> commit ae4cd0b1a475
> https://git.kernel.org/mips/c/ae4cd0b1a475
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: genex: Add Loongson3 LL/SC workaround to ejtag_debug_handler
> commit 12dbb04f2ac1
> https://git.kernel.org/mips/c/12dbb04f2ac1
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: genex: Don't reload address unnecessarily
> commit 4dee90d7b579
> https://git.kernel.org/mips/c/4dee90d7b579
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
>
> MIPS: Check Loongson3 LL/SC errata workaround correctness
> commit e4acfbc18fc9
> https://git.kernel.org/mips/c/e4acfbc18fc9
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>

Thanks,
Paul

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