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76695af20c
Replace ACCESS_ONCE() macro in smp_store_release() and smp_load_acquire() with WRITE_ONCE() and READ_ONCE() on x86, arm, arm64, ia64, metag, mips, powerpc, s390, sparc and asm-generic since ACCESS_ONCE() does not work reliably on non-scalar types. WRITE_ONCE() and READ_ONCE() were introduced in the following commits:230fa253df("kernel: Provide READ_ONCE and ASSIGN_ONCE")43239cbe79("kernel: Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)") Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Alexander Duyck <alexander.h.duyck@redhat.com> Cc: Andre Przywara <andre.przywara@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@suse.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1438528264-714-1-git-send-email-andreyknvl@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
78 lines
2.4 KiB
C
78 lines
2.4 KiB
C
#ifndef __SPARC64_BARRIER_H
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#define __SPARC64_BARRIER_H
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/* These are here in an effort to more fully work around Spitfire Errata
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* #51. Essentially, if a memory barrier occurs soon after a mispredicted
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* branch, the chip can stop executing instructions until a trap occurs.
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* Therefore, if interrupts are disabled, the chip can hang forever.
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*
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* It used to be believed that the memory barrier had to be right in the
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* delay slot, but a case has been traced recently wherein the memory barrier
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* was one instruction after the branch delay slot and the chip still hung.
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* The offending sequence was the following in sym_wakeup_done() of the
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* sym53c8xx_2 driver:
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*
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* call sym_ccb_from_dsa, 0
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* movge %icc, 0, %l0
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* brz,pn %o0, .LL1303
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* mov %o0, %l2
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* membar #LoadLoad
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*
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* The branch has to be mispredicted for the bug to occur. Therefore, we put
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* the memory barrier explicitly into a "branch always, predicted taken"
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* delay slot to avoid the problem case.
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*/
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#define membar_safe(type) \
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do { __asm__ __volatile__("ba,pt %%xcc, 1f\n\t" \
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" membar " type "\n" \
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"1:\n" \
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: : : "memory"); \
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} while (0)
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/* The kernel always executes in TSO memory model these days,
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* and furthermore most sparc64 chips implement more stringent
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* memory ordering than required by the specifications.
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*/
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#define mb() membar_safe("#StoreLoad")
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#define rmb() __asm__ __volatile__("":::"memory")
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#define wmb() __asm__ __volatile__("":::"memory")
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#define dma_rmb() rmb()
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#define dma_wmb() wmb()
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#define smp_store_mb(__var, __value) \
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do { WRITE_ONCE(__var, __value); membar_safe("#StoreLoad"); } while(0)
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#ifdef CONFIG_SMP
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#define smp_mb() mb()
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#define smp_rmb() rmb()
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#define smp_wmb() wmb()
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#else
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#define smp_mb() __asm__ __volatile__("":::"memory")
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#define smp_rmb() __asm__ __volatile__("":::"memory")
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#define smp_wmb() __asm__ __volatile__("":::"memory")
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#endif
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#define read_barrier_depends() do { } while (0)
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#define smp_read_barrier_depends() do { } while (0)
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#define smp_store_release(p, v) \
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do { \
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compiletime_assert_atomic_type(*p); \
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barrier(); \
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WRITE_ONCE(*p, v); \
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} while (0)
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#define smp_load_acquire(p) \
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({ \
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typeof(*p) ___p1 = READ_ONCE(*p); \
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compiletime_assert_atomic_type(*p); \
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barrier(); \
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___p1; \
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})
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#define smp_mb__before_atomic() barrier()
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#define smp_mb__after_atomic() barrier()
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#endif /* !(__SPARC64_BARRIER_H) */
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