linux_dsm_epyc7002/arch/mips/include/asm/barrier.h

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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2006 by Ralf Baechle (ralf@linux-mips.org)
*/
#ifndef __ASM_BARRIER_H
#define __ASM_BARRIER_H
#include <asm/addrspace.h>
#define read_barrier_depends() do { } while(0)
#define smp_read_barrier_depends() do { } while(0)
#ifdef CONFIG_CPU_HAS_SYNC
#define __sync() \
__asm__ __volatile__( \
".set push\n\t" \
".set noreorder\n\t" \
".set mips2\n\t" \
"sync\n\t" \
".set pop" \
: /* no output */ \
: /* no input */ \
: "memory")
#else
#define __sync() do { } while(0)
#endif
#define __fast_iob() \
__asm__ __volatile__( \
".set push\n\t" \
".set noreorder\n\t" \
"lw $0,%0\n\t" \
"nop\n\t" \
".set pop" \
: /* no output */ \
: "m" (*(int *)CKSEG1) \
: "memory")
#ifdef CONFIG_CPU_CAVIUM_OCTEON
# define OCTEON_SYNCW_STR ".set push\n.set arch=octeon\nsyncw\nsyncw\n.set pop\n"
# define __syncw() __asm__ __volatile__(OCTEON_SYNCW_STR : : : "memory")
# define fast_wmb() __syncw()
# define fast_rmb() barrier()
# define fast_mb() __sync()
# define fast_iob() do { } while (0)
#else /* ! CONFIG_CPU_CAVIUM_OCTEON */
# define fast_wmb() __sync()
# define fast_rmb() __sync()
# define fast_mb() __sync()
# ifdef CONFIG_SGI_IP28
# define fast_iob() \
__asm__ __volatile__( \
".set push\n\t" \
".set noreorder\n\t" \
"lw $0,%0\n\t" \
"sync\n\t" \
"lw $0,%0\n\t" \
".set pop" \
: /* no output */ \
: "m" (*(int *)CKSEG1ADDR(0x1fa00004)) \
: "memory")
# else
# define fast_iob() \
do { \
__sync(); \
__fast_iob(); \
} while (0)
# endif
#endif /* CONFIG_CPU_CAVIUM_OCTEON */
#ifdef CONFIG_CPU_HAS_WB
#include <asm/wbflush.h>
#define wmb() fast_wmb()
#define rmb() fast_rmb()
#define mb() wbflush()
#define iob() wbflush()
#else /* !CONFIG_CPU_HAS_WB */
#define wmb() fast_wmb()
#define rmb() fast_rmb()
#define mb() fast_mb()
#define iob() fast_iob()
#endif /* !CONFIG_CPU_HAS_WB */
#if defined(CONFIG_WEAK_ORDERING) && defined(CONFIG_SMP)
# ifdef CONFIG_CPU_CAVIUM_OCTEON
# define smp_mb() __sync()
# define smp_rmb() barrier()
# define smp_wmb() __syncw()
# else
# define smp_mb() __asm__ __volatile__("sync" : : :"memory")
# define smp_rmb() __asm__ __volatile__("sync" : : :"memory")
# define smp_wmb() __asm__ __volatile__("sync" : : :"memory")
# endif
#else
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#endif
#if defined(CONFIG_WEAK_REORDERING_BEYOND_LLSC) && defined(CONFIG_SMP)
#define __WEAK_LLSC_MB " sync \n"
#else
#define __WEAK_LLSC_MB " \n"
#endif
#define set_mb(var, value) \
do { var = value; smp_mb(); } while (0)
#define smp_llsc_mb() __asm__ __volatile__(__WEAK_LLSC_MB : : :"memory")
#ifdef CONFIG_CPU_CAVIUM_OCTEON
#define smp_mb__before_llsc() smp_wmb()
/* Cause previous writes to become visible on all CPUs as soon as possible */
#define nudge_writes() __asm__ __volatile__(".set push\n\t" \
".set arch=octeon\n\t" \
"syncw\n\t" \
".set pop" : : : "memory")
#else
#define smp_mb__before_llsc() smp_llsc_mb()
#define nudge_writes() mb()
#endif
arch: Introduce smp_load_acquire(), smp_store_release() A number of situations currently require the heavyweight smp_mb(), even though there is no need to order prior stores against later loads. Many architectures have much cheaper ways to handle these situations, but the Linux kernel currently has no portable way to make use of them. This commit therefore supplies smp_load_acquire() and smp_store_release() to remedy this situation. The new smp_load_acquire() primitive orders the specified load against any subsequent reads or writes, while the new smp_store_release() primitive orders the specifed store against any prior reads or writes. These primitives allow array-based circular FIFOs to be implemented without an smp_mb(), and also allow a theoretical hole in rcu_assign_pointer() to be closed at no additional expense on most architectures. In addition, the RCU experience transitioning from explicit smp_read_barrier_depends() and smp_wmb() to rcu_dereference() and rcu_assign_pointer(), respectively resulted in substantial improvements in readability. It therefore seems likely that replacing other explicit barriers with smp_load_acquire() and smp_store_release() will provide similar benefits. It appears that roughly half of the explicit barriers in core kernel code might be so replaced. [Changelog by PaulMck] Reviewed-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Michael Neuling <mikey@neuling.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Victor Kaplansky <VICTORK@il.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/20131213150640.908486364@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-06 20:57:36 +07:00
#define smp_store_release(p, v) \
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
ACCESS_ONCE(*p) = (v); \
} while (0)
#define smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = ACCESS_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
})
#define smp_mb__before_atomic() smp_mb__before_llsc()
#define smp_mb__after_atomic() smp_llsc_mb()
#endif /* __ASM_BARRIER_H */