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commit 857c34cd094b94a82aceba23fdd9af47296404a2
parent e2f8b472a70827348ce2007e121d67f49047ba62
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Wed, 14 Nov 2018 13:42:41 -0600

Merge branch 'parisc-4.20-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc fix from Helge Deller:
 "Revert one patch which changed how spinlocks get released. It breaks
  the rwlock implementation in glibc"

* 'parisc-4.20-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Revert "Release spinlocks using ordered store"

Diffstat:
March/parisc/include/asm/spinlock.h | 4++--
March/parisc/kernel/syscall.S | 12++++++++----
2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/parisc/include/asm/spinlock.h b/arch/parisc/include/asm/spinlock.h @@ -37,8 +37,8 @@ static inline void arch_spin_unlock(arch_spinlock_t *x) volatile unsigned int *a; a = __ldcw_align(x); - /* Release with ordered store. */ - __asm__ __volatile__("stw,ma %0,0(%1)" : : "r"(1), "r"(a) : "memory"); + mb(); + *a = 1; } static inline int arch_spin_trylock(arch_spinlock_t *x) diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S @@ -640,7 +640,8 @@ cas_action: sub,<> %r28, %r25, %r0 2: stw %r24, 0(%r26) /* Free lock */ - stw,ma %r20, 0(%sr2,%r20) + sync + stw %r20, 0(%sr2,%r20) #if ENABLE_LWS_DEBUG /* Clear thread register indicator */ stw %r0, 4(%sr2,%r20) @@ -654,7 +655,8 @@ cas_action: 3: /* Error occurred on load or store */ /* Free lock */ - stw,ma %r20, 0(%sr2,%r20) + sync + stw %r20, 0(%sr2,%r20) #if ENABLE_LWS_DEBUG stw %r0, 4(%sr2,%r20) #endif @@ -855,7 +857,8 @@ cas2_action: cas2_end: /* Free lock */ - stw,ma %r20, 0(%sr2,%r20) + sync + stw %r20, 0(%sr2,%r20) /* Enable interrupts */ ssm PSW_SM_I, %r0 /* Return to userspace, set no error */ @@ -865,7 +868,8 @@ cas2_end: 22: /* Error occurred on load or store */ /* Free lock */ - stw,ma %r20, 0(%sr2,%r20) + sync + stw %r20, 0(%sr2,%r20) ssm PSW_SM_I, %r0 ldo 1(%r0),%r28 b lws_exit