Thread (10 messages) read the whole thread 10 messages, 2 authors, 2021-03-28
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Revision v5 of 4 in this series.

Revisions (4)
  1. v3 [diff vs current]
  2. v4 [diff vs current]
  3. v5 current
  4. v6 [diff vs current]

[PATCH v5 4/7] powerpc/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32

From: guoren@kernel.org
Date: 2021-03-28 06:32:28
Also in: linux-arch, linux-riscv, lkml, sparclinux
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Linus Torvalds

From: Guo Ren <redacted>

We don't have native hw xchg16 instruction, so let qspinlock
generic code to deal with it.

Using the full-word atomic xchg instructions implement xchg16 has
the semantic risk for atomic operations.

This patch cancels the dependency of on qspinlock generic code on
architecture's xchg16.

Signed-off-by: Guo Ren <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
---
 arch/powerpc/Kconfig | 1 +
 1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 386ae12d8523..69ec4ade6521 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -151,6 +151,7 @@ config PPC
 	select ARCH_USE_CMPXCHG_LOCKREF		if PPC64
 	select ARCH_USE_QUEUED_RWLOCKS		if PPC_QUEUED_SPINLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS	if PPC_QUEUED_SPINLOCKS
+	select ARCH_USE_QUEUED_SPINLOCKS_XCHG32	if PPC_QUEUED_SPINLOCKS
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
 	select ARCH_WANT_LD_ORPHAN_WARN
-- 
2.17.1
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