forked from luck/tmp_suning_uos_patched
e4f9bfb3fe
IA64 doesn't actually have acquire/release barriers, its a lie! Add a comment explaining this and fix up the bitop barriers. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/n/tip-akevfh136um9dqvb1ohm55ca@git.kernel.org Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-ia64@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
157 lines
4.1 KiB
C
157 lines
4.1 KiB
C
#ifndef _ASM_IA64_CMPXCHG_H
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#define _ASM_IA64_CMPXCHG_H
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/*
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* Compare/Exchange, forked from asm/intrinsics.h
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* which was:
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*
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* Copyright (C) 2002-2003 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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*/
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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/* include compiler specific intrinsics */
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#include <asm/ia64regs.h>
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#ifdef __INTEL_COMPILER
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# include <asm/intel_intrin.h>
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#else
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# include <asm/gcc_intrin.h>
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#endif
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/*
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* This function doesn't exist, so you'll get a linker error if
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* something tries to do an invalid xchg().
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*/
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extern void ia64_xchg_called_with_bad_pointer(void);
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#define __xchg(x, ptr, size) \
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({ \
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unsigned long __xchg_result; \
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\
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switch (size) { \
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case 1: \
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__xchg_result = ia64_xchg1((__u8 *)ptr, x); \
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break; \
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\
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case 2: \
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__xchg_result = ia64_xchg2((__u16 *)ptr, x); \
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break; \
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\
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case 4: \
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__xchg_result = ia64_xchg4((__u32 *)ptr, x); \
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break; \
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\
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case 8: \
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__xchg_result = ia64_xchg8((__u64 *)ptr, x); \
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break; \
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default: \
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ia64_xchg_called_with_bad_pointer(); \
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} \
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__xchg_result; \
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})
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#define xchg(ptr, x) \
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((__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr))))
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/*
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* Atomic compare and exchange. Compare OLD with MEM, if identical,
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* store NEW in MEM. Return the initial value in MEM. Success is
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* indicated by comparing RETURN with OLD.
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*/
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#define __HAVE_ARCH_CMPXCHG 1
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/*
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* This function doesn't exist, so you'll get a linker error
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* if something tries to do an invalid cmpxchg().
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*/
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extern long ia64_cmpxchg_called_with_bad_pointer(void);
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#define ia64_cmpxchg(sem, ptr, old, new, size) \
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({ \
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__u64 _o_, _r_; \
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\
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switch (size) { \
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case 1: \
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_o_ = (__u8) (long) (old); \
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break; \
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case 2: \
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_o_ = (__u16) (long) (old); \
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break; \
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case 4: \
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_o_ = (__u32) (long) (old); \
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break; \
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case 8: \
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_o_ = (__u64) (long) (old); \
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break; \
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default: \
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break; \
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} \
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switch (size) { \
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case 1: \
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_r_ = ia64_cmpxchg1_##sem((__u8 *) ptr, new, _o_); \
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break; \
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\
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case 2: \
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_r_ = ia64_cmpxchg2_##sem((__u16 *) ptr, new, _o_); \
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break; \
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\
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case 4: \
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_r_ = ia64_cmpxchg4_##sem((__u32 *) ptr, new, _o_); \
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break; \
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\
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case 8: \
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_r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_); \
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break; \
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\
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default: \
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_r_ = ia64_cmpxchg_called_with_bad_pointer(); \
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break; \
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} \
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(__typeof__(old)) _r_; \
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})
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#define cmpxchg_acq(ptr, o, n) \
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ia64_cmpxchg(acq, (ptr), (o), (n), sizeof(*(ptr)))
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#define cmpxchg_rel(ptr, o, n) \
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ia64_cmpxchg(rel, (ptr), (o), (n), sizeof(*(ptr)))
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/*
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* Worse still - early processor implementations actually just ignored
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* the acquire/release and did a full fence all the time. Unfortunately
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* this meant a lot of badly written code that used .acq when they really
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* wanted .rel became legacy out in the wild - so when we made a cpu
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* that strictly did the .acq or .rel ... all that code started breaking - so
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* we had to back-pedal and keep the "legacy" behavior of a full fence :-(
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*/
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/* for compatibility with other platforms: */
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#define cmpxchg(ptr, o, n) cmpxchg_acq((ptr), (o), (n))
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#define cmpxchg64(ptr, o, n) cmpxchg_acq((ptr), (o), (n))
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#define cmpxchg_local cmpxchg
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#define cmpxchg64_local cmpxchg64
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#ifdef CONFIG_IA64_DEBUG_CMPXCHG
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# define CMPXCHG_BUGCHECK_DECL int _cmpxchg_bugcheck_count = 128;
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# define CMPXCHG_BUGCHECK(v) \
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do { \
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if (_cmpxchg_bugcheck_count-- <= 0) { \
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void *ip; \
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extern int printk(const char *fmt, ...); \
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ip = (void *) ia64_getreg(_IA64_REG_IP); \
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printk("CMPXCHG_BUGCHECK: stuck at %p on word %p\n", ip, (v));\
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break; \
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} \
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} while (0)
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#else /* !CONFIG_IA64_DEBUG_CMPXCHG */
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# define CMPXCHG_BUGCHECK_DECL
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# define CMPXCHG_BUGCHECK(v)
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#endif /* !CONFIG_IA64_DEBUG_CMPXCHG */
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_IA64_CMPXCHG_H */
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