1 2 /* FIXME: this is basically a bad test as it is scheduling- 3 sensitive. Sometimes the output is: 4 5 child: new value 6 6 child: new value 10 7 done, x = 10 8 9 and sometimes 10 11 child: new value 10 12 done, x = 10 13 */ 14 15 #include <pthread.h> 16 #include <stdio.h> 17 #include <stdlib.h> 18 #include <unistd.h> 19 20 /* Simple test program, no race. Parent writes atomically to a counter 21 whilst child reads it. When counter reaches a prearranged value, 22 child joins back to parent. Parent (writer) uses hardware bus lock; 23 child is only reading and so does not need to use a bus lock. */ 24 25 #undef PLAT_x86_darwin 26 #undef PLAT_amd64_darwin 27 #undef PLAT_x86_linux 28 #undef PLAT_amd64_linux 29 #undef PLAT_ppc32_linux 30 #undef PLAT_ppc64_linux 31 #undef PLAT_arm_linux 32 #undef PLAT_arm64_linux 33 #undef PLAT_s390x_linux 34 #undef PLAT_mips32_linux 35 #undef PLAT_mips64_linux 36 #undef PLAT_x86_solaris 37 #undef PLAT_amd64_solaris 38 39 #if defined(__APPLE__) && defined(__i386__) 40 # define PLAT_x86_darwin 1 41 #elif defined(__APPLE__) && defined(__x86_64__) 42 # define PLAT_amd64_darwin 1 43 #elif defined(__linux__) && defined(__i386__) 44 # define PLAT_x86_linux 1 45 #elif defined(__linux__) && defined(__x86_64__) 46 # define PLAT_amd64_linux 1 47 #elif defined(__linux__) && defined(__powerpc__) && !defined(__powerpc64__) 48 # define PLAT_ppc32_linux 1 49 #elif defined(__linux__) && defined(__powerpc__) && defined(__powerpc64__) 50 # define PLAT_ppc64_linux 1 51 #elif defined(__linux__) && defined(__arm__) && !defined(__aarch64__) 52 # define PLAT_arm_linux 1 53 #elif defined(__linux__) && defined(__aarch64__) && !defined(__arm__) 54 # define PLAT_arm64_linux 1 55 #elif defined(__linux__) && defined(__s390x__) 56 # define PLAT_s390x_linux 1 57 #elif defined(__linux__) && defined(__mips__) 58 #if (__mips==64) 59 # define PLAT_mips64_linux 1 60 #else 61 # define PLAT_mips32_linux 1 62 #endif 63 #elif defined(__sun__) && defined(__i386__) 64 # define PLAT_x86_solaris 1 65 #elif defined(__sun__) && defined(__x86_64__) 66 # define PLAT_amd64_solaris 1 67 #endif 68 69 70 #if defined(PLAT_amd64_linux) || defined(PLAT_x86_linux) \ 71 || defined(PLAT_amd64_darwin) || defined(PLAT_x86_darwin) \ 72 || defined(PLAT_amd64_solaris) || defined(PLAT_x86_solaris) 73 # define INC(_lval,_lqual) \ 74 __asm__ __volatile__ ( \ 75 "lock ; incl (%0)" : /*out*/ : /*in*/"r"(&(_lval)) : "memory", "cc" ) 76 #elif defined(PLAT_ppc32_linux) || defined(PLAT_ppc64_linux) 77 # define INC(_lval,_lqual) \ 78 __asm__ __volatile__( \ 79 "1:\n" \ 80 " lwarx 15,0,%0\n" \ 81 " addi 15,15,1\n" \ 82 " stwcx. 15,0,%0\n" \ 83 " bne- 1b\n" \ 84 : /*out*/ : /*in*/ "b"(&(_lval)) \ 85 : /*trash*/ "r15", "cr0", "memory" \ 86 ) 87 #elif defined(PLAT_arm_linux) 88 # define INC(_lval,_lqual) \ 89 __asm__ __volatile__( \ 90 "1:\n" \ 91 " ldrex r8, [%0, #0]\n" \ 92 " add r8, r8, #1\n" \ 93 " strex r9, r8, [%0, #0]\n" \ 94 " cmp r9, #0\n" \ 95 " bne 1b\n" \ 96 : /*out*/ : /*in*/ "r"(&(_lval)) \ 97 : /*trash*/ "r8", "r9", "cc", "memory" \ 98 ); 99 #elif defined(PLAT_arm64_linux) 100 # define INC(_lval,_lqual) \ 101 __asm__ __volatile__( \ 102 "1:\n" \ 103 " ldxr w8, [%0, #0]\n" \ 104 " add w8, w8, #1\n" \ 105 " stxr w9, w8, [%0, #0]\n" \ 106 " cmp w9, #0\n" \ 107 " bne 1b\n" \ 108 : /*out*/ : /*in*/ "r"(&(_lval)) \ 109 : /*trash*/ "x8", "x9", "cc", "memory" \ 110 ); 111 #elif defined(PLAT_s390x_linux) 112 # define INC(_lval,_lqual) \ 113 __asm__ __volatile__( \ 114 "1: l 0,%0\n" \ 115 " lr 1,0\n" \ 116 " ahi 1,1\n" \ 117 " cs 0,1,%0\n" \ 118 " jl 1b\n" \ 119 : "+m" (_lval) :: "cc", "0","1" \ 120 ) 121 #elif defined(PLAT_mips32_linux) || defined(PLAT_mips64_linux) 122 # define INC(_lval,_lqual) \ 123 __asm__ __volatile__ ( \ 124 "L1xyzzy1" _lqual":\n" \ 125 " move $t0, %0\n" \ 126 " ll $t1, 0($t0)\n" \ 127 " addiu $t1, $t1, 1\n" \ 128 " sc $t1, 0($t0)\n" \ 129 " beqz $t1, L1xyzzy1" _lqual \ 130 : /*out*/ : /*in*/ "r"(&(_lval)) \ 131 : /*trash*/ "t0", "t1", "memory" \ 132 ) 133 #else 134 # error "Fix Me for this platform" 135 #endif 136 137 138 139 #define LIMIT 10 140 141 volatile int x = 0; 142 143 void* child_fn ( void* arg ) 144 { 145 int q = 0; 146 int oldx = 0; 147 struct timespec ts = { 0, 1000 * 1000 }; 148 149 while (1) { 150 q = (x >= LIMIT); 151 if (x != oldx) { 152 oldx = x; 153 printf("child: new value %d\n", oldx); 154 fflush(stdout); 155 } 156 if (q) break; 157 nanosleep(&ts, 0); 158 } 159 return NULL; 160 } 161 162 int main ( void ) 163 { 164 pthread_t child; 165 int i; 166 167 if (pthread_create(&child, NULL, child_fn, NULL)) { 168 perror("pthread_create"); 169 exit(1); 170 } 171 172 for (i = 0; i < LIMIT; i++) { 173 INC(x, "main"); 174 if (i == 5) sleep(1); /* make sure child doesn't starve */ 175 } 176 177 if (pthread_join(child, NULL)) { 178 perror("pthread join"); 179 exit(1); 180 } 181 182 printf("done, x = %d\n", x); 183 184 return 0; 185 } 186
