/* Linux-specific atomic operations for Nios II Linux. Copyright (C) 2008-2015 Free Software Foundation, Inc. This file is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. This file is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. Under Section 7 of GPL version 3, you are granted additional permissions described in the GCC Runtime Library Exception, version 3.1, as published by the Free Software Foundation. You should have received a copy of the GNU General Public License and a copy of the GCC Runtime Library Exception along with this program; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see . */ #include #define EFAULT 14 #define EBUSY 16 #define ENOSYS 38 /* We implement byte, short and int versions of each atomic operation using the kernel helper defined below. There is no support for 64-bit operations yet. */ /* Crash a userspace program with SIGSEV. */ #define ABORT_INSTRUCTION asm ("stw zero, 0(zero)") /* Kernel helper for compare-and-exchange a 32-bit value. */ static inline long __kernel_cmpxchg (int oldval, int newval, int *mem) { register int r2 asm ("r2"); register int *r4 asm ("r4") = mem; register int r5 asm ("r5") = oldval; register int r6 asm ("r6") = newval; /* Call the kernel provided fixed address cmpxchg helper routine. */ asm volatile ("movi %0, %4\n\t" "callr %0\n" : "=r" (r2) : "r" (r4), "r" (r5), "r" (r6), "I" (0x00001004) : "ra", "memory"); return r2; } #define HIDDEN __attribute__ ((visibility ("hidden"))) #ifdef __nios2_little_endian__ #define INVERT_MASK_1 0 #define INVERT_MASK_2 0 #else #define INVERT_MASK_1 24 #define INVERT_MASK_2 16 #endif #define MASK_1 0xffu #define MASK_2 0xffffu #define FETCH_AND_OP_WORD(OP, PFX_OP, INF_OP) \ int HIDDEN \ __sync_fetch_and_##OP##_4 (int *ptr, int val) \ { \ int failure, tmp; \ \ do { \ tmp = *ptr; \ failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr); \ } while (failure != 0); \ \ return tmp; \ } FETCH_AND_OP_WORD (add, , +) FETCH_AND_OP_WORD (sub, , -) FETCH_AND_OP_WORD (or, , |) FETCH_AND_OP_WORD (and, , &) FETCH_AND_OP_WORD (xor, , ^) FETCH_AND_OP_WORD (nand, ~, &) #define NAME_oldval(OP, WIDTH) __sync_fetch_and_##OP##_##WIDTH #define NAME_newval(OP, WIDTH) __sync_##OP##_and_fetch_##WIDTH /* Implement both __sync__and_fetch and __sync_fetch_and_ for subword-sized quantities. */ #define SUBWORD_SYNC_OP(OP, PFX_OP, INF_OP, TYPE, WIDTH, RETURN) \ TYPE HIDDEN \ NAME##_##RETURN (OP, WIDTH) (TYPE *ptr, TYPE val) \ { \ int *wordptr = (int *) ((unsigned long) ptr & ~3); \ unsigned int mask, shift, oldval, newval; \ int failure; \ \ shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \ mask = MASK_##WIDTH << shift; \ \ do { \ oldval = *wordptr; \ newval = ((PFX_OP (((oldval & mask) >> shift) \ INF_OP (unsigned int) val)) << shift) & mask; \ newval |= oldval & ~mask; \ failure = __kernel_cmpxchg (oldval, newval, wordptr); \ } while (failure != 0); \ \ return (RETURN & mask) >> shift; \ } SUBWORD_SYNC_OP (add, , +, unsigned short, 2, oldval) SUBWORD_SYNC_OP (sub, , -, unsigned short, 2, oldval) SUBWORD_SYNC_OP (or, , |, unsigned short, 2, oldval) SUBWORD_SYNC_OP (and, , &, unsigned short, 2, oldval) SUBWORD_SYNC_OP (xor, , ^, unsigned short, 2, oldval) SUBWORD_SYNC_OP (nand, ~, &, unsigned short, 2, oldval) SUBWORD_SYNC_OP (add, , +, unsigned char, 1, oldval) SUBWORD_SYNC_OP (sub, , -, unsigned char, 1, oldval) SUBWORD_SYNC_OP (or, , |, unsigned char, 1, oldval) SUBWORD_SYNC_OP (and, , &, unsigned char, 1, oldval) SUBWORD_SYNC_OP (xor, , ^, unsigned char, 1, oldval) SUBWORD_SYNC_OP (nand, ~, &, unsigned char, 1, oldval) #define OP_AND_FETCH_WORD(OP, PFX_OP, INF_OP) \ int HIDDEN \ __sync_##OP##_and_fetch_4 (int *ptr, int val) \ { \ int tmp, failure; \ \ do { \ tmp = *ptr; \ failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr); \ } while (failure != 0); \ \ return PFX_OP (tmp INF_OP val); \ } OP_AND_FETCH_WORD (add, , +) OP_AND_FETCH_WORD (sub, , -) OP_AND_FETCH_WORD (or, , |) OP_AND_FETCH_WORD (and, , &) OP_AND_FETCH_WORD (xor, , ^) OP_AND_FETCH_WORD (nand, ~, &) SUBWORD_SYNC_OP (add, , +, unsigned short, 2, newval) SUBWORD_SYNC_OP (sub, , -, unsigned short, 2, newval) SUBWORD_SYNC_OP (or, , |, unsigned short, 2, newval) SUBWORD_SYNC_OP (and, , &, unsigned short, 2, newval) SUBWORD_SYNC_OP (xor, , ^, unsigned short, 2, newval) SUBWORD_SYNC_OP (nand, ~, &, unsigned short, 2, newval) SUBWORD_SYNC_OP (add, , +, unsigned char, 1, newval) SUBWORD_SYNC_OP (sub, , -, unsigned char, 1, newval) SUBWORD_SYNC_OP (or, , |, unsigned char, 1, newval) SUBWORD_SYNC_OP (and, , &, unsigned char, 1, newval) SUBWORD_SYNC_OP (xor, , ^, unsigned char, 1, newval) SUBWORD_SYNC_OP (nand, ~, &, unsigned char, 1, newval) int HIDDEN __sync_val_compare_and_swap_4 (int *ptr, int oldval, int newval) { int actual_oldval, fail; while (1) { actual_oldval = *ptr; if (oldval != actual_oldval) return actual_oldval; fail = __kernel_cmpxchg (actual_oldval, newval, ptr); if (!fail) return oldval; } } #define SUBWORD_VAL_CAS(TYPE, WIDTH) \ TYPE HIDDEN \ __sync_val_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval, \ TYPE newval) \ { \ int *wordptr = (int *)((unsigned long) ptr & ~3), fail; \ unsigned int mask, shift, actual_oldval, actual_newval; \ \ shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \ mask = MASK_##WIDTH << shift; \ \ while (1) \ { \ actual_oldval = *wordptr; \ \ if (((actual_oldval & mask) >> shift) != (unsigned int) oldval) \ return (actual_oldval & mask) >> shift; \ \ actual_newval = (actual_oldval & ~mask) \ | (((unsigned int) newval << shift) & mask); \ \ fail = __kernel_cmpxchg (actual_oldval, actual_newval, \ wordptr); \ \ if (!fail) \ return oldval; \ } \ } SUBWORD_VAL_CAS (unsigned short, 2) SUBWORD_VAL_CAS (unsigned char, 1) typedef unsigned char bool; bool HIDDEN __sync_bool_compare_and_swap_4 (int *ptr, int oldval, int newval) { int failure = __kernel_cmpxchg (oldval, newval, ptr); return (failure == 0); } #define SUBWORD_BOOL_CAS(TYPE, WIDTH) \ bool HIDDEN \ __sync_bool_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval, \ TYPE newval) \ { \ TYPE actual_oldval \ = __sync_val_compare_and_swap_##WIDTH (ptr, oldval, newval); \ return (oldval == actual_oldval); \ } SUBWORD_BOOL_CAS (unsigned short, 2) SUBWORD_BOOL_CAS (unsigned char, 1) int HIDDEN __sync_lock_test_and_set_4 (int *ptr, int val) { int failure, oldval; do { oldval = *ptr; failure = __kernel_cmpxchg (oldval, val, ptr); } while (failure != 0); return oldval; } #define SUBWORD_TEST_AND_SET(TYPE, WIDTH) \ TYPE HIDDEN \ __sync_lock_test_and_set_##WIDTH (TYPE *ptr, TYPE val) \ { \ int failure; \ unsigned int oldval, newval, shift, mask; \ int *wordptr = (int *) ((unsigned long) ptr & ~3); \ \ shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \ mask = MASK_##WIDTH << shift; \ \ do { \ oldval = *wordptr; \ newval = (oldval & ~mask) \ | (((unsigned int) val << shift) & mask); \ failure = __kernel_cmpxchg (oldval, newval, wordptr); \ } while (failure != 0); \ \ return (oldval & mask) >> shift; \ } SUBWORD_TEST_AND_SET (unsigned short, 2) SUBWORD_TEST_AND_SET (unsigned char, 1) #define SYNC_LOCK_RELEASE(TYPE, WIDTH) \ void HIDDEN \ __sync_lock_release_##WIDTH (TYPE *ptr) \ { \ /* All writes before this point must be seen before we release \ the lock itself. */ \ __builtin_sync (); \ *ptr = 0; \ } SYNC_LOCK_RELEASE (int, 4) SYNC_LOCK_RELEASE (short, 2) SYNC_LOCK_RELEASE (char, 1)