2013-12-31 08:05:35 +01:00
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/* Linux-specific atomic operations for Nios II Linux.
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2022-01-03 10:42:10 +01:00
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Copyright (C) 2008-2022 Free Software Foundation, Inc.
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2013-12-31 08:05:35 +01:00
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This file is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 3, or (at your option) any
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later version.
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This file is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* We implement byte, short and int versions of each atomic operation
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using the kernel helper defined below. There is no support for
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64-bit operations yet. */
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/* Crash a userspace program with SIGSEV. */
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#define ABORT_INSTRUCTION asm ("stw zero, 0(zero)")
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/* Kernel helper for compare-and-exchange a 32-bit value. */
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static inline long
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__kernel_cmpxchg (int oldval, int newval, int *mem)
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{
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register int r2 asm ("r2");
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register int *r4 asm ("r4") = mem;
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register int r5 asm ("r5") = oldval;
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register int r6 asm ("r6") = newval;
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/* Call the kernel provided fixed address cmpxchg helper routine. */
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asm volatile ("movi %0, %4\n\t"
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"callr %0\n"
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: "=r" (r2)
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: "r" (r4), "r" (r5), "r" (r6), "I" (0x00001004)
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: "ra", "memory");
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return r2;
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}
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#define HIDDEN __attribute__ ((visibility ("hidden")))
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#ifdef __nios2_little_endian__
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#define INVERT_MASK_1 0
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#define INVERT_MASK_2 0
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#else
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#define INVERT_MASK_1 24
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#define INVERT_MASK_2 16
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#endif
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#define MASK_1 0xffu
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#define MASK_2 0xffffu
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#define FETCH_AND_OP_WORD(OP, PFX_OP, INF_OP) \
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int HIDDEN \
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__sync_fetch_and_##OP##_4 (int *ptr, int val) \
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{ \
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int failure, tmp; \
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\
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do { \
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tmp = *ptr; \
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failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr); \
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} while (failure != 0); \
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\
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return tmp; \
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}
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FETCH_AND_OP_WORD (add, , +)
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FETCH_AND_OP_WORD (sub, , -)
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FETCH_AND_OP_WORD (or, , |)
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FETCH_AND_OP_WORD (and, , &)
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FETCH_AND_OP_WORD (xor, , ^)
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FETCH_AND_OP_WORD (nand, ~, &)
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#define NAME_oldval(OP, WIDTH) __sync_fetch_and_##OP##_##WIDTH
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#define NAME_newval(OP, WIDTH) __sync_##OP##_and_fetch_##WIDTH
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/* Implement both __sync_<op>_and_fetch and __sync_fetch_and_<op> for
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subword-sized quantities. */
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#define SUBWORD_SYNC_OP(OP, PFX_OP, INF_OP, TYPE, WIDTH, RETURN) \
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TYPE HIDDEN \
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NAME##_##RETURN (OP, WIDTH) (TYPE *ptr, TYPE val) \
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{ \
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int *wordptr = (int *) ((unsigned long) ptr & ~3); \
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unsigned int mask, shift, oldval, newval; \
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int failure; \
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\
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shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \
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mask = MASK_##WIDTH << shift; \
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\
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do { \
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oldval = *wordptr; \
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newval = ((PFX_OP (((oldval & mask) >> shift) \
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INF_OP (unsigned int) val)) << shift) & mask; \
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newval |= oldval & ~mask; \
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failure = __kernel_cmpxchg (oldval, newval, wordptr); \
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} while (failure != 0); \
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\
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return (RETURN & mask) >> shift; \
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}
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SUBWORD_SYNC_OP (add, , +, unsigned short, 2, oldval)
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SUBWORD_SYNC_OP (sub, , -, unsigned short, 2, oldval)
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SUBWORD_SYNC_OP (or, , |, unsigned short, 2, oldval)
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SUBWORD_SYNC_OP (and, , &, unsigned short, 2, oldval)
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SUBWORD_SYNC_OP (xor, , ^, unsigned short, 2, oldval)
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SUBWORD_SYNC_OP (nand, ~, &, unsigned short, 2, oldval)
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SUBWORD_SYNC_OP (add, , +, unsigned char, 1, oldval)
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SUBWORD_SYNC_OP (sub, , -, unsigned char, 1, oldval)
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SUBWORD_SYNC_OP (or, , |, unsigned char, 1, oldval)
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SUBWORD_SYNC_OP (and, , &, unsigned char, 1, oldval)
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SUBWORD_SYNC_OP (xor, , ^, unsigned char, 1, oldval)
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SUBWORD_SYNC_OP (nand, ~, &, unsigned char, 1, oldval)
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#define OP_AND_FETCH_WORD(OP, PFX_OP, INF_OP) \
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int HIDDEN \
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__sync_##OP##_and_fetch_4 (int *ptr, int val) \
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{ \
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int tmp, failure; \
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\
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do { \
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tmp = *ptr; \
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failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr); \
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} while (failure != 0); \
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\
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return PFX_OP (tmp INF_OP val); \
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}
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OP_AND_FETCH_WORD (add, , +)
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OP_AND_FETCH_WORD (sub, , -)
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OP_AND_FETCH_WORD (or, , |)
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OP_AND_FETCH_WORD (and, , &)
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OP_AND_FETCH_WORD (xor, , ^)
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OP_AND_FETCH_WORD (nand, ~, &)
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SUBWORD_SYNC_OP (add, , +, unsigned short, 2, newval)
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SUBWORD_SYNC_OP (sub, , -, unsigned short, 2, newval)
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SUBWORD_SYNC_OP (or, , |, unsigned short, 2, newval)
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SUBWORD_SYNC_OP (and, , &, unsigned short, 2, newval)
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SUBWORD_SYNC_OP (xor, , ^, unsigned short, 2, newval)
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SUBWORD_SYNC_OP (nand, ~, &, unsigned short, 2, newval)
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SUBWORD_SYNC_OP (add, , +, unsigned char, 1, newval)
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SUBWORD_SYNC_OP (sub, , -, unsigned char, 1, newval)
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SUBWORD_SYNC_OP (or, , |, unsigned char, 1, newval)
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SUBWORD_SYNC_OP (and, , &, unsigned char, 1, newval)
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SUBWORD_SYNC_OP (xor, , ^, unsigned char, 1, newval)
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SUBWORD_SYNC_OP (nand, ~, &, unsigned char, 1, newval)
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int HIDDEN
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__sync_val_compare_and_swap_4 (int *ptr, int oldval, int newval)
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{
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int actual_oldval, fail;
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while (1)
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{
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actual_oldval = *ptr;
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if (oldval != actual_oldval)
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return actual_oldval;
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fail = __kernel_cmpxchg (actual_oldval, newval, ptr);
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if (!fail)
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return oldval;
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}
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}
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#define SUBWORD_VAL_CAS(TYPE, WIDTH) \
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TYPE HIDDEN \
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__sync_val_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval, \
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TYPE newval) \
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{ \
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int *wordptr = (int *)((unsigned long) ptr & ~3), fail; \
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unsigned int mask, shift, actual_oldval, actual_newval; \
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\
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shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \
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mask = MASK_##WIDTH << shift; \
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\
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while (1) \
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{ \
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actual_oldval = *wordptr; \
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\
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if (((actual_oldval & mask) >> shift) != (unsigned int) oldval) \
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return (actual_oldval & mask) >> shift; \
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\
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actual_newval = (actual_oldval & ~mask) \
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| (((unsigned int) newval << shift) & mask); \
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\
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fail = __kernel_cmpxchg (actual_oldval, actual_newval, \
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wordptr); \
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\
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if (!fail) \
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return oldval; \
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} \
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}
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SUBWORD_VAL_CAS (unsigned short, 2)
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SUBWORD_VAL_CAS (unsigned char, 1)
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typedef unsigned char bool;
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bool HIDDEN
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__sync_bool_compare_and_swap_4 (int *ptr, int oldval, int newval)
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{
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int failure = __kernel_cmpxchg (oldval, newval, ptr);
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return (failure == 0);
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}
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#define SUBWORD_BOOL_CAS(TYPE, WIDTH) \
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bool HIDDEN \
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__sync_bool_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval, \
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TYPE newval) \
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{ \
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TYPE actual_oldval \
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= __sync_val_compare_and_swap_##WIDTH (ptr, oldval, newval); \
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return (oldval == actual_oldval); \
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}
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SUBWORD_BOOL_CAS (unsigned short, 2)
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SUBWORD_BOOL_CAS (unsigned char, 1)
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int HIDDEN
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__sync_lock_test_and_set_4 (int *ptr, int val)
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{
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int failure, oldval;
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do {
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oldval = *ptr;
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failure = __kernel_cmpxchg (oldval, val, ptr);
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} while (failure != 0);
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return oldval;
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}
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#define SUBWORD_TEST_AND_SET(TYPE, WIDTH) \
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TYPE HIDDEN \
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__sync_lock_test_and_set_##WIDTH (TYPE *ptr, TYPE val) \
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{ \
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int failure; \
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unsigned int oldval, newval, shift, mask; \
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int *wordptr = (int *) ((unsigned long) ptr & ~3); \
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\
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shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \
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mask = MASK_##WIDTH << shift; \
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\
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do { \
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oldval = *wordptr; \
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newval = (oldval & ~mask) \
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| (((unsigned int) val << shift) & mask); \
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failure = __kernel_cmpxchg (oldval, newval, wordptr); \
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} while (failure != 0); \
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\
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return (oldval & mask) >> shift; \
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}
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SUBWORD_TEST_AND_SET (unsigned short, 2)
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SUBWORD_TEST_AND_SET (unsigned char, 1)
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#define SYNC_LOCK_RELEASE(TYPE, WIDTH) \
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void HIDDEN \
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__sync_lock_release_##WIDTH (TYPE *ptr) \
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{ \
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/* All writes before this point must be seen before we release \
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the lock itself. */ \
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__builtin_sync (); \
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*ptr = 0; \
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}
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SYNC_LOCK_RELEASE (int, 4)
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SYNC_LOCK_RELEASE (short, 2)
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SYNC_LOCK_RELEASE (char, 1)
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