/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2013 Ed Schouten * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #include #include #include #include #include /* * Executing statements with interrupts disabled. */ #if defined(_KERNEL) && !defined(SMP) #define WITHOUT_INTERRUPTS(s) do { \ register_t regs; \ \ regs = intr_disable(); \ do s while (0); \ intr_restore(regs); \ } while (0) #endif /* _KERNEL && !SMP */ /* * Memory barriers. * * It turns out __sync_synchronize() does not emit any code when used * with GCC 4.2. Implement our own version that does work reliably. * * Although __sync_lock_test_and_set() should only perform an acquire * barrier, make it do a full barrier like the other functions. This * should make 's atomic_exchange_explicit() work reliably. */ #if defined(_KERNEL) && !defined(SMP) static inline void do_sync(void) { __asm volatile ("" : : : "memory"); } #else static inline void do_sync(void) { dmb(); } #endif #if defined(__SYNC_ATOMICS) || defined(EMIT_SYNC_ATOMICS) #ifdef __clang__ #pragma redefine_extname __sync_lock_test_and_set_1_c __sync_lock_test_and_set_1 #pragma redefine_extname __sync_lock_test_and_set_2_c __sync_lock_test_and_set_2 #pragma redefine_extname __sync_lock_test_and_set_4_c __sync_lock_test_and_set_4 #pragma redefine_extname __sync_val_compare_and_swap_1_c __sync_val_compare_and_swap_1 #pragma redefine_extname __sync_val_compare_and_swap_2_c __sync_val_compare_and_swap_2 #pragma redefine_extname __sync_val_compare_and_swap_4_c __sync_val_compare_and_swap_4 #pragma redefine_extname __sync_fetch_and_add_1_c __sync_fetch_and_add_1 #pragma redefine_extname __sync_fetch_and_add_2_c __sync_fetch_and_add_2 #pragma redefine_extname __sync_fetch_and_add_4_c __sync_fetch_and_add_4 #pragma redefine_extname __sync_fetch_and_and_1_c __sync_fetch_and_and_1 #pragma redefine_extname __sync_fetch_and_and_2_c __sync_fetch_and_and_2 #pragma redefine_extname __sync_fetch_and_and_4_c __sync_fetch_and_and_4 #pragma redefine_extname __sync_fetch_and_or_1_c __sync_fetch_and_or_1 #pragma redefine_extname __sync_fetch_and_or_2_c __sync_fetch_and_or_2 #pragma redefine_extname __sync_fetch_and_or_4_c __sync_fetch_and_or_4 #pragma redefine_extname __sync_fetch_and_xor_1_c __sync_fetch_and_xor_1 #pragma redefine_extname __sync_fetch_and_xor_2_c __sync_fetch_and_xor_2 #pragma redefine_extname __sync_fetch_and_xor_4_c __sync_fetch_and_xor_4 #pragma redefine_extname __sync_fetch_and_sub_1_c __sync_fetch_and_sub_1 #pragma redefine_extname __sync_fetch_and_sub_2_c __sync_fetch_and_sub_2 #pragma redefine_extname __sync_fetch_and_sub_4_c __sync_fetch_and_sub_4 #endif /* * Old __sync_* API. */ /* Implementations for old GCC versions, lacking support for atomics. */ typedef union { uint8_t v8[4]; uint32_t v32; } reg_t; /* * Given a memory address pointing to an 8-bit or 16-bit integer, return * the address of the 32-bit word containing it. */ static inline uint32_t * round_to_word(void *ptr) { return ((uint32_t *)((intptr_t)ptr & ~3)); } /* * Utility functions for loading and storing 8-bit and 16-bit integers * in 32-bit words at an offset corresponding with the location of the * atomic variable. */ static inline void put_1(reg_t *r, const uint8_t *offset_ptr, uint8_t val) { size_t offset; offset = (intptr_t)offset_ptr & 3; r->v8[offset] = val; } static inline uint8_t get_1(const reg_t *r, const uint8_t *offset_ptr) { size_t offset; offset = (intptr_t)offset_ptr & 3; return (r->v8[offset]); } static inline void put_2(reg_t *r, const uint16_t *offset_ptr, uint16_t val) { size_t offset; union { uint16_t in; uint8_t out[2]; } bytes; offset = (intptr_t)offset_ptr & 3; bytes.in = val; r->v8[offset] = bytes.out[0]; r->v8[offset + 1] = bytes.out[1]; } static inline uint16_t get_2(const reg_t *r, const uint16_t *offset_ptr) { size_t offset; union { uint8_t in[2]; uint16_t out; } bytes; offset = (intptr_t)offset_ptr & 3; bytes.in[0] = r->v8[offset]; bytes.in[1] = r->v8[offset + 1]; return (bytes.out); } /* * 8-bit and 16-bit routines. * * These operations are not natively supported by the CPU, so we use * some shifting and bitmasking on top of the 32-bit instructions. */ #define EMIT_LOCK_TEST_AND_SET_N(N, uintN_t) \ uintN_t \ __sync_lock_test_and_set_##N##_c(uintN_t *mem, uintN_t val) \ { \ uint32_t *mem32; \ reg_t val32, negmask, old; \ uint32_t temp1, temp2; \ \ mem32 = round_to_word(mem); \ val32.v32 = 0x00000000; \ put_##N(&val32, mem, val); \ negmask.v32 = 0xffffffff; \ put_##N(&negmask, mem, 0); \ \ do_sync(); \ __asm volatile ( \ "1:" \ "\tldrex %0, %6\n" /* Load old value. */ \ "\tand %2, %5, %0\n" /* Remove the old value. */ \ "\torr %2, %2, %4\n" /* Put in the new value. */ \ "\tstrex %3, %2, %1\n" /* Attempt to store. */ \ "\tcmp %3, #0\n" /* Did it succeed? */ \ "\tbne 1b\n" /* Spin if failed. */ \ : "=&r" (old.v32), "=m" (*mem32), "=&r" (temp1), \ "=&r" (temp2) \ : "r" (val32.v32), "r" (negmask.v32), "m" (*mem32)); \ return (get_##N(&old, mem)); \ } EMIT_LOCK_TEST_AND_SET_N(1, uint8_t) EMIT_LOCK_TEST_AND_SET_N(2, uint16_t) #define EMIT_VAL_COMPARE_AND_SWAP_N(N, uintN_t) \ uintN_t \ __sync_val_compare_and_swap_##N##_c(uintN_t *mem, uintN_t expected, \ uintN_t desired) \ { \ uint32_t *mem32; \ reg_t expected32, desired32, posmask, old; \ uint32_t negmask, temp1, temp2; \ \ mem32 = round_to_word(mem); \ expected32.v32 = 0x00000000; \ put_##N(&expected32, mem, expected); \ desired32.v32 = 0x00000000; \ put_##N(&desired32, mem, desired); \ posmask.v32 = 0x00000000; \ put_##N(&posmask, mem, ~0); \ negmask = ~posmask.v32; \ \ do_sync(); \ __asm volatile ( \ "1:" \ "\tldrex %0, %8\n" /* Load old value. */ \ "\tand %2, %6, %0\n" /* Isolate the old value. */ \ "\tcmp %2, %4\n" /* Compare to expected value. */\ "\tbne 2f\n" /* Values are unequal. */ \ "\tand %2, %7, %0\n" /* Remove the old value. */ \ "\torr %2, %5\n" /* Put in the new value. */ \ "\tstrex %3, %2, %1\n" /* Attempt to store. */ \ "\tcmp %3, #0\n" /* Did it succeed? */ \ "\tbne 1b\n" /* Spin if failed. */ \ "2:" \ : "=&r" (old), "=m" (*mem32), "=&r" (temp1), \ "=&r" (temp2) \ : "r" (expected32.v32), "r" (desired32.v32), \ "r" (posmask.v32), "r" (negmask), "m" (*mem32)); \ return (get_##N(&old, mem)); \ } EMIT_VAL_COMPARE_AND_SWAP_N(1, uint8_t) EMIT_VAL_COMPARE_AND_SWAP_N(2, uint16_t) #define EMIT_ARITHMETIC_FETCH_AND_OP_N(N, uintN_t, name, op) \ uintN_t \ __sync_##name##_##N##_c(uintN_t *mem, uintN_t val) \ { \ uint32_t *mem32; \ reg_t val32, posmask, old; \ uint32_t negmask, temp1, temp2; \ \ mem32 = round_to_word(mem); \ val32.v32 = 0x00000000; \ put_##N(&val32, mem, val); \ posmask.v32 = 0x00000000; \ put_##N(&posmask, mem, ~0); \ negmask = ~posmask.v32; \ \ do_sync(); \ __asm volatile ( \ "1:" \ "\tldrex %0, %7\n" /* Load old value. */ \ "\t"op" %2, %0, %4\n" /* Calculate new value. */ \ "\tand %2, %5\n" /* Isolate the new value. */ \ "\tand %3, %6, %0\n" /* Remove the old value. */ \ "\torr %2, %2, %3\n" /* Put in the new value. */ \ "\tstrex %3, %2, %1\n" /* Attempt to store. */ \ "\tcmp %3, #0\n" /* Did it succeed? */ \ "\tbne 1b\n" /* Spin if failed. */ \ : "=&r" (old.v32), "=m" (*mem32), "=&r" (temp1), \ "=&r" (temp2) \ : "r" (val32.v32), "r" (posmask.v32), "r" (negmask), \ "m" (*mem32)); \ return (get_##N(&old, mem)); \ } EMIT_ARITHMETIC_FETCH_AND_OP_N(1, uint8_t, fetch_and_add, "add") EMIT_ARITHMETIC_FETCH_AND_OP_N(1, uint8_t, fetch_and_sub, "sub") EMIT_ARITHMETIC_FETCH_AND_OP_N(2, uint16_t, fetch_and_add, "add") EMIT_ARITHMETIC_FETCH_AND_OP_N(2, uint16_t, fetch_and_sub, "sub") #define EMIT_BITWISE_FETCH_AND_OP_N(N, uintN_t, name, op, idempotence) \ uintN_t \ __sync_##name##_##N##_c(uintN_t *mem, uintN_t val) \ { \ uint32_t *mem32; \ reg_t val32, old; \ uint32_t temp1, temp2; \ \ mem32 = round_to_word(mem); \ val32.v32 = idempotence ? 0xffffffff : 0x00000000; \ put_##N(&val32, mem, val); \ \ do_sync(); \ __asm volatile ( \ "1:" \ "\tldrex %0, %5\n" /* Load old value. */ \ "\t"op" %2, %4, %0\n" /* Calculate new value. */ \ "\tstrex %3, %2, %1\n" /* Attempt to store. */ \ "\tcmp %3, #0\n" /* Did it succeed? */ \ "\tbne 1b\n" /* Spin if failed. */ \ : "=&r" (old.v32), "=m" (*mem32), "=&r" (temp1), \ "=&r" (temp2) \ : "r" (val32.v32), "m" (*mem32)); \ return (get_##N(&old, mem)); \ } EMIT_BITWISE_FETCH_AND_OP_N(1, uint8_t, fetch_and_and, "and", 1) EMIT_BITWISE_FETCH_AND_OP_N(1, uint8_t, fetch_and_or, "orr", 0) EMIT_BITWISE_FETCH_AND_OP_N(1, uint8_t, fetch_and_xor, "eor", 0) EMIT_BITWISE_FETCH_AND_OP_N(2, uint16_t, fetch_and_and, "and", 1) EMIT_BITWISE_FETCH_AND_OP_N(2, uint16_t, fetch_and_or, "orr", 0) EMIT_BITWISE_FETCH_AND_OP_N(2, uint16_t, fetch_and_xor, "eor", 0) /* * 32-bit routines. */ uint32_t __sync_lock_test_and_set_4_c(uint32_t *mem, uint32_t val) { uint32_t old, temp; do_sync(); __asm volatile ( "1:" "\tldrex %0, %4\n" /* Load old value. */ "\tstrex %2, %3, %1\n" /* Attempt to store. */ "\tcmp %2, #0\n" /* Did it succeed? */ "\tbne 1b\n" /* Spin if failed. */ : "=&r" (old), "=m" (*mem), "=&r" (temp) : "r" (val), "m" (*mem)); return (old); } uint32_t __sync_val_compare_and_swap_4_c(uint32_t *mem, uint32_t expected, uint32_t desired) { uint32_t old, temp; do_sync(); __asm volatile ( "1:" "\tldrex %0, %5\n" /* Load old value. */ "\tcmp %0, %3\n" /* Compare to expected value. */ "\tbne 2f\n" /* Values are unequal. */ "\tstrex %2, %4, %1\n" /* Attempt to store. */ "\tcmp %2, #0\n" /* Did it succeed? */ "\tbne 1b\n" /* Spin if failed. */ "2:" : "=&r" (old), "=m" (*mem), "=&r" (temp) : "r" (expected), "r" (desired), "m" (*mem)); return (old); } #define EMIT_FETCH_AND_OP_4(name, op) \ uint32_t \ __sync_##name##_4##_c(uint32_t *mem, uint32_t val) \ { \ uint32_t old, temp1, temp2; \ \ do_sync(); \ __asm volatile ( \ "1:" \ "\tldrex %0, %5\n" /* Load old value. */ \ "\t"op" %2, %0, %4\n" /* Calculate new value. */ \ "\tstrex %3, %2, %1\n" /* Attempt to store. */ \ "\tcmp %3, #0\n" /* Did it succeed? */ \ "\tbne 1b\n" /* Spin if failed. */ \ : "=&r" (old), "=m" (*mem), "=&r" (temp1), \ "=&r" (temp2) \ : "r" (val), "m" (*mem)); \ return (old); \ } EMIT_FETCH_AND_OP_4(fetch_and_add, "add") EMIT_FETCH_AND_OP_4(fetch_and_and, "and") EMIT_FETCH_AND_OP_4(fetch_and_or, "orr") EMIT_FETCH_AND_OP_4(fetch_and_sub, "sub") EMIT_FETCH_AND_OP_4(fetch_and_xor, "eor") #ifndef __clang__ __strong_reference(__sync_lock_test_and_set_1_c, __sync_lock_test_and_set_1); __strong_reference(__sync_lock_test_and_set_2_c, __sync_lock_test_and_set_2); __strong_reference(__sync_lock_test_and_set_4_c, __sync_lock_test_and_set_4); __strong_reference(__sync_val_compare_and_swap_1_c, __sync_val_compare_and_swap_1); __strong_reference(__sync_val_compare_and_swap_2_c, __sync_val_compare_and_swap_2); __strong_reference(__sync_val_compare_and_swap_4_c, __sync_val_compare_and_swap_4); __strong_reference(__sync_fetch_and_add_1_c, __sync_fetch_and_add_1); __strong_reference(__sync_fetch_and_add_2_c, __sync_fetch_and_add_2); __strong_reference(__sync_fetch_and_add_4_c, __sync_fetch_and_add_4); __strong_reference(__sync_fetch_and_and_1_c, __sync_fetch_and_and_1); __strong_reference(__sync_fetch_and_and_2_c, __sync_fetch_and_and_2); __strong_reference(__sync_fetch_and_and_4_c, __sync_fetch_and_and_4); __strong_reference(__sync_fetch_and_sub_1_c, __sync_fetch_and_sub_1); __strong_reference(__sync_fetch_and_sub_2_c, __sync_fetch_and_sub_2); __strong_reference(__sync_fetch_and_sub_4_c, __sync_fetch_and_sub_4); __strong_reference(__sync_fetch_and_or_1_c, __sync_fetch_and_or_1); __strong_reference(__sync_fetch_and_or_2_c, __sync_fetch_and_or_2); __strong_reference(__sync_fetch_and_or_4_c, __sync_fetch_and_or_4); __strong_reference(__sync_fetch_and_xor_1_c, __sync_fetch_and_xor_1); __strong_reference(__sync_fetch_and_xor_2_c, __sync_fetch_and_xor_2); __strong_reference(__sync_fetch_and_xor_4_c, __sync_fetch_and_xor_4); #endif #endif /* __SYNC_ATOMICS */