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![David Daney](/assets/img/avatar_default.png)
Replace some instances of smp_llsc_mb() with a new macro smp_mb__before_llsc(). It is used before ll/sc sequences that are documented as needing write barrier semantics. The default implementation of smp_mb__before_llsc() is just smp_llsc_mb(), so there are no changes in semantics. Also simplify definition of smp_mb(), smp_rmb(), and smp_wmb() to be just barrier() in the non-SMP case. Signed-off-by: David Daney <ddaney@caviumnetworks.com> To: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/851/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
239 lines
5.9 KiB
C
239 lines
5.9 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1994, 95, 96, 97, 98, 99, 2003, 06 by Ralf Baechle
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* Copyright (C) 1996 by Paul M. Antoine
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* Copyright (C) 1999 Silicon Graphics
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* Kevin D. Kissell, kevink@mips.org and Carsten Langgaard, carstenl@mips.com
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* Copyright (C) 2000 MIPS Technologies, Inc.
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*/
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#ifndef _ASM_SYSTEM_H
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#define _ASM_SYSTEM_H
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/irqflags.h>
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#include <asm/addrspace.h>
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#include <asm/barrier.h>
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#include <asm/cmpxchg.h>
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#include <asm/cpu-features.h>
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#include <asm/dsp.h>
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#include <asm/watch.h>
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#include <asm/war.h>
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/*
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* switch_to(n) should switch tasks to task nr n, first
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* checking that n isn't the current task, in which case it does nothing.
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*/
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extern asmlinkage void *resume(void *last, void *next, void *next_ti);
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struct task_struct;
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extern unsigned int ll_bit;
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extern struct task_struct *ll_task;
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#ifdef CONFIG_MIPS_MT_FPAFF
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/*
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* Handle the scheduler resume end of FPU affinity management. We do this
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* inline to try to keep the overhead down. If we have been forced to run on
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* a "CPU" with an FPU because of a previous high level of FP computation,
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* but did not actually use the FPU during the most recent time-slice (CU1
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* isn't set), we undo the restriction on cpus_allowed.
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*
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* We're not calling set_cpus_allowed() here, because we have no need to
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* force prompt migration - we're already switching the current CPU to a
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* different thread.
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*/
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#define __mips_mt_fpaff_switch_to(prev) \
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do { \
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struct thread_info *__prev_ti = task_thread_info(prev); \
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\
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if (cpu_has_fpu && \
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test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) && \
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(!(KSTK_STATUS(prev) & ST0_CU1))) { \
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clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND); \
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prev->cpus_allowed = prev->thread.user_cpus_allowed; \
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} \
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next->thread.emulated_fp = 0; \
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} while(0)
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#else
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#define __mips_mt_fpaff_switch_to(prev) do { (void) (prev); } while (0)
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#endif
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#define __clear_software_ll_bit() \
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do { \
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if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc) \
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ll_bit = 0; \
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} while (0)
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#define switch_to(prev, next, last) \
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do { \
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__mips_mt_fpaff_switch_to(prev); \
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if (cpu_has_dsp) \
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__save_dsp(prev); \
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__clear_software_ll_bit(); \
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(last) = resume(prev, next, task_thread_info(next)); \
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} while (0)
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#define finish_arch_switch(prev) \
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do { \
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if (cpu_has_dsp) \
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__restore_dsp(current); \
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if (cpu_has_userlocal) \
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write_c0_userlocal(current_thread_info()->tp_value); \
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__restore_watch(); \
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} while (0)
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static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
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{
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__u32 retval;
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smp_mb__before_llsc();
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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unsigned long dummy;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: ll %0, %3 # xchg_u32 \n"
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" .set mips0 \n"
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" move %2, %z4 \n"
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" .set mips3 \n"
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" sc %2, %1 \n"
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" beqzl %2, 1b \n"
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" .set mips0 \n"
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: "=&r" (retval), "=m" (*m), "=&r" (dummy)
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: "R" (*m), "Jr" (val)
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: "memory");
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} else if (kernel_uses_llsc) {
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unsigned long dummy;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: ll %0, %3 # xchg_u32 \n"
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" .set mips0 \n"
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" move %2, %z4 \n"
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" .set mips3 \n"
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" sc %2, %1 \n"
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" beqz %2, 2f \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" .previous \n"
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" .set mips0 \n"
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: "=&r" (retval), "=m" (*m), "=&r" (dummy)
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: "R" (*m), "Jr" (val)
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: "memory");
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} else {
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unsigned long flags;
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raw_local_irq_save(flags);
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retval = *m;
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*m = val;
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raw_local_irq_restore(flags); /* implies memory barrier */
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}
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smp_llsc_mb();
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return retval;
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}
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#ifdef CONFIG_64BIT
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static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
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{
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__u64 retval;
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smp_mb__before_llsc();
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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unsigned long dummy;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: lld %0, %3 # xchg_u64 \n"
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" move %2, %z4 \n"
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" scd %2, %1 \n"
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" beqzl %2, 1b \n"
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" .set mips0 \n"
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: "=&r" (retval), "=m" (*m), "=&r" (dummy)
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: "R" (*m), "Jr" (val)
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: "memory");
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} else if (kernel_uses_llsc) {
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unsigned long dummy;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: lld %0, %3 # xchg_u64 \n"
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" move %2, %z4 \n"
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" scd %2, %1 \n"
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" beqz %2, 2f \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" .previous \n"
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" .set mips0 \n"
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: "=&r" (retval), "=m" (*m), "=&r" (dummy)
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: "R" (*m), "Jr" (val)
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: "memory");
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} else {
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unsigned long flags;
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raw_local_irq_save(flags);
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retval = *m;
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*m = val;
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raw_local_irq_restore(flags); /* implies memory barrier */
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}
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smp_llsc_mb();
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return retval;
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}
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#else
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extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
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#define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
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#endif
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static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
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{
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switch (size) {
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case 4:
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return __xchg_u32(ptr, x);
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case 8:
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return __xchg_u64(ptr, x);
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}
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return x;
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}
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#define xchg(ptr, x) \
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({ \
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BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc); \
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\
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((__typeof__(*(ptr))) \
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__xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
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})
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extern void set_handler(unsigned long offset, void *addr, unsigned long len);
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extern void set_uncached_handler(unsigned long offset, void *addr, unsigned long len);
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typedef void (*vi_handler_t)(void);
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extern void *set_vi_handler(int n, vi_handler_t addr);
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extern void *set_except_vector(int n, void *addr);
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extern unsigned long ebase;
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extern void per_cpu_trap_init(void);
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/*
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* See include/asm-ia64/system.h; prevents deadlock on SMP
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* systems.
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*/
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#define __ARCH_WANT_UNLOCKED_CTXSW
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extern unsigned long arch_align_stack(unsigned long sp);
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#endif /* _ASM_SYSTEM_H */
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