| |
| #include "config.h" |
| #include <pthread.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <assert.h> |
| |
| /* Simple test program, no race. Parent and child both modify x and |
| use the hardware bus lock (implicitly, since XCHG r,m on x86/amd64 |
| does not require an explicit LOCK prefix.). */ |
| |
| #undef PLAT_x86_darwin |
| #undef PLAT_amd64_darwin |
| #undef PLAT_x86_linux |
| #undef PLAT_amd64_linux |
| #undef PLAT_ppc32_linux |
| #undef PLAT_ppc64_linux |
| #undef PLAT_arm_linux |
| #undef PLAT_s390x_linux |
| |
| #if defined(__APPLE__) && defined(__i386__) |
| # define PLAT_x86_darwin 1 |
| #elif defined(__APPLE__) && defined(__x86_64__) |
| # define PLAT_amd64_darwin 1 |
| #elif defined(__linux__) && defined(__i386__) |
| # define PLAT_x86_linux 1 |
| #elif defined(__linux__) && defined(__x86_64__) |
| # define PLAT_amd64_linux 1 |
| #elif defined(__linux__) && defined(__powerpc__) && !defined(__powerpc64__) |
| # define PLAT_ppc32_linux 1 |
| #elif defined(__linux__) && defined(__powerpc__) && defined(__powerpc64__) |
| # define PLAT_ppc64_linux 1 |
| #elif defined(__linux__) && defined(__arm__) |
| # define PLAT_arm_linux 1 |
| #elif defined(__linux__) && defined(__s390x__) |
| # define PLAT_s390x_linux 1 |
| #endif |
| |
| |
| #if defined(PLAT_amd64_linux) || defined(PLAT_x86_linux) \ |
| || defined(PLAT_amd64_darwin) || defined(PLAT_x86_darwin) |
| # define XCHG_M_R(_addr,_lval) \ |
| __asm__ __volatile__( \ |
| "xchgl %0, %1" \ |
| : /*out*/ "+r"(_lval) \ |
| : /*in*/ "m"(_addr) \ |
| : "memory", "cc" \ |
| ) |
| # define XCHG_M_R_with_redundant_LOCK(_addr,_lval) \ |
| __asm__ __volatile__( \ |
| "lock xchgl %0, %1" \ |
| : /*out*/ "+r"(_lval) \ |
| : /*in*/ "m"(_addr) \ |
| : "memory", "cc" \ |
| ) |
| |
| #elif defined(PLAT_ppc32_linux) || defined(PLAT_ppc64_linux) \ |
| || defined(PLAT_arm_linux) || defined(PLAT_s390x_linux) |
| # if defined(HAVE_BUILTIN_ATOMIC) |
| # define XCHG_M_R(_addr,_lval) \ |
| do { \ |
| int tmp; \ |
| while ((tmp = *(int*)(& _addr)), \ |
| ! __sync_bool_compare_and_swap((int*)&_addr, tmp, _lval)) \ |
| ; \ |
| _lval = tmp; \ |
| } while (0) |
| # else |
| # warning "XCHG_M_R() implementation is missing. Either" \ |
| "provide one or use a newer gcc version." |
| # define XCHG_M_R(_addr,_lval) \ |
| do { int tmp = *(int*)(& _addr); \ |
| *(int*)(& _addr) = (_lval); \ |
| _lval = tmp; \ |
| } while (0) |
| # endif |
| # define XCHG_M_R_with_redundant_LOCK(_addr,_lval) \ |
| XCHG_M_R(_addr,_lval) |
| |
| #else |
| # error "Unsupported architecture" |
| |
| #endif |
| |
| int x = 0; |
| |
| void* child_fn ( void* arg ) |
| { |
| int v = 12345; |
| XCHG_M_R_with_redundant_LOCK(x, v); |
| assert(v == 0 || v == 6789); |
| return NULL; |
| } |
| |
| int main ( void ) |
| { |
| int v = 6789; |
| pthread_t child; |
| |
| if (pthread_create(&child, NULL, child_fn, NULL)) { |
| perror("pthread_create"); |
| exit(1); |
| } |
| |
| XCHG_M_R(x, v); |
| assert(v == 0 || v == 12345); |
| |
| if (pthread_join(child, NULL)) { |
| perror("pthread join"); |
| exit(1); |
| } |
| |
| if (v == 0 || v == 12345) |
| printf("success\n"); |
| else |
| printf("failure\n"); |
| |
| return v; |
| } |