| |
| /* This is an example of a program which does atomic memory operations |
| between two processes which share a page. Valgrind 3.4.1 and |
| earlier produce incorrect answers because it does not preserve |
| atomicity of the relevant instructions in the generated code; but |
| the post-DCAS-merge versions of Valgrind do behave correctly. */ |
| |
| /* On ARM, this can be compiled into either ARM or Thumb code, so as |
| to test both A and T encodings of LDREX/STREX et al. Also on ARM, |
| it tests doubleword atomics (LDREXD, STREXD) which I don't think it |
| does on any other platform. */ |
| |
| #include <stdlib.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <assert.h> |
| #include <unistd.h> |
| #include <sys/wait.h> |
| #include "tests/sys_mman.h" |
| |
| #define NNN 3456987 |
| |
| #define IS_8_ALIGNED(_ptr) (0 == (((unsigned long)(_ptr)) & 7)) |
| |
| |
| __attribute__((noinline)) void atomic_add_8bit ( char* p, int n ) |
| { |
| #if defined(VGA_x86) |
| unsigned long block[2]; |
| block[0] = (unsigned long)p; |
| block[1] = n; |
| __asm__ __volatile__( |
| "movl 0(%%esi),%%eax" "\n\t" |
| "movl 4(%%esi),%%ebx" "\n\t" |
| "lock; addb %%bl,(%%eax)" "\n" |
| : : "S"(&block[0])/* S means "esi only" */ : "memory","cc","eax","ebx" |
| ); |
| #elif defined(VGA_amd64) |
| unsigned long block[2]; |
| block[0] = (unsigned long)p; |
| block[1] = n; |
| __asm__ __volatile__( |
| "movq 0(%%rsi),%%rax" "\n\t" |
| "movq 8(%%rsi),%%rbx" "\n\t" |
| "lock; addb %%bl,(%%rax)" "\n" |
| : : "S"(&block[0])/* S means "rsi only" */ : "memory","cc","rax","rbx" |
| ); |
| #elif defined(VGA_ppc32) |
| /* Nasty hack. Does correctly atomically do *p += n, but only if p |
| is 4-aligned -- guaranteed by caller. */ |
| unsigned long success; |
| do { |
| __asm__ __volatile__( |
| "lwarx 15,0,%1" "\n\t" |
| "add 15,15,%2" "\n\t" |
| "stwcx. 15,0,%1" "\n\t" |
| "mfcr %0" "\n\t" |
| "srwi %0,%0,29" "\n\t" |
| "andi. %0,%0,1" "\n" |
| : /*out*/"=b"(success) |
| : /*in*/ "b"(p), "b"(((unsigned long)n) << 24) |
| : /*trash*/ "memory", "cc", "r15" |
| ); |
| } while (success != 1); |
| #elif defined(VGA_ppc64) |
| /* Nasty hack. Does correctly atomically do *p += n, but only if p |
| is 8-aligned -- guaranteed by caller. */ |
| unsigned long success; |
| do { |
| __asm__ __volatile__( |
| "ldarx 15,0,%1" "\n\t" |
| "add 15,15,%2" "\n\t" |
| "stdcx. 15,0,%1" "\n\t" |
| "mfcr %0" "\n\t" |
| "srwi %0,%0,29" "\n\t" |
| "andi. %0,%0,1" "\n" |
| : /*out*/"=b"(success) |
| : /*in*/ "b"(p), "b"(((unsigned long)n) << 56) |
| : /*trash*/ "memory", "cc", "r15" |
| ); |
| } while (success != 1); |
| #elif defined(VGA_arm) |
| unsigned int block[3] |
| = { (unsigned int)p, (unsigned int)n, 0xFFFFFFFF }; |
| do { |
| __asm__ __volatile__( |
| "mov r5, %0" "\n\t" |
| "ldr r9, [r5, #0]" "\n\t" // p |
| "ldr r10, [r5, #4]" "\n\t" // n |
| "ldrexb r8, [r9]" "\n\t" |
| "add r8, r8, r10" "\n\t" |
| "strexb r4, r8, [r9]" "\n\t" |
| "str r4, [r5, #8]" "\n\t" |
| : /*out*/ |
| : /*in*/ "r"(&block[0]) |
| : /*trash*/ "memory", "cc", "r5", "r8", "r9", "r10", "r4" |
| ); |
| } while (block[2] != 0); |
| #elif defined(VGA_s390x) |
| int dummy; |
| __asm__ __volatile__( |
| " l 0,%0\n\t" |
| "0: st 0,%1\n\t" |
| " icm 1,1,%1\n\t" |
| " ar 1,%2\n\t" |
| " stcm 1,1,%1\n\t" |
| " l 1,%1\n\t" |
| " cs 0,1,%0\n\t" |
| " jl 0b\n\t" |
| : "+m" (*p), "+m" (dummy) |
| : "d" (n) |
| : "cc", "memory", "0", "1"); |
| #else |
| # error "Unsupported arch" |
| #endif |
| } |
| |
| |
| __attribute__((noinline)) void atomic_add_16bit ( short* p, int n ) |
| { |
| #if defined(VGA_x86) |
| unsigned long block[2]; |
| block[0] = (unsigned long)p; |
| block[1] = n; |
| __asm__ __volatile__( |
| "movl 0(%%esi),%%eax" "\n\t" |
| "movl 4(%%esi),%%ebx" "\n\t" |
| "lock; addw %%bx,(%%eax)" "\n" |
| : : "S"(&block[0])/* S means "esi only" */ : "memory","cc","eax","ebx" |
| ); |
| #elif defined(VGA_amd64) |
| unsigned long block[2]; |
| block[0] = (unsigned long)p; |
| block[1] = n; |
| __asm__ __volatile__( |
| "movq 0(%%rsi),%%rax" "\n\t" |
| "movq 8(%%rsi),%%rbx" "\n\t" |
| "lock; addw %%bx,(%%rax)" "\n" |
| : : "S"(&block[0])/* S means "rsi only" */ : "memory","cc","rax","rbx" |
| ); |
| #elif defined(VGA_ppc32) |
| /* Nasty hack. Does correctly atomically do *p += n, but only if p |
| is 8-aligned -- guaranteed by caller. */ |
| unsigned long success; |
| do { |
| __asm__ __volatile__( |
| "lwarx 15,0,%1" "\n\t" |
| "add 15,15,%2" "\n\t" |
| "stwcx. 15,0,%1" "\n\t" |
| "mfcr %0" "\n\t" |
| "srwi %0,%0,29" "\n\t" |
| "andi. %0,%0,1" "\n" |
| : /*out*/"=b"(success) |
| : /*in*/ "b"(p), "b"(((unsigned long)n) << 16) |
| : /*trash*/ "memory", "cc", "r15" |
| ); |
| } while (success != 1); |
| #elif defined(VGA_ppc64) |
| /* Nasty hack. Does correctly atomically do *p += n, but only if p |
| is 8-aligned -- guaranteed by caller. */ |
| unsigned long success; |
| do { |
| __asm__ __volatile__( |
| "ldarx 15,0,%1" "\n\t" |
| "add 15,15,%2" "\n\t" |
| "stdcx. 15,0,%1" "\n\t" |
| "mfcr %0" "\n\t" |
| "srwi %0,%0,29" "\n\t" |
| "andi. %0,%0,1" "\n" |
| : /*out*/"=b"(success) |
| : /*in*/ "b"(p), "b"(((unsigned long)n) << 48) |
| : /*trash*/ "memory", "cc", "r15" |
| ); |
| } while (success != 1); |
| #elif defined(VGA_arm) |
| unsigned int block[3] |
| = { (unsigned int)p, (unsigned int)n, 0xFFFFFFFF }; |
| do { |
| __asm__ __volatile__( |
| "mov r5, %0" "\n\t" |
| "ldr r9, [r5, #0]" "\n\t" // p |
| "ldr r10, [r5, #4]" "\n\t" // n |
| "ldrexh r8, [r9]" "\n\t" |
| "add r8, r8, r10" "\n\t" |
| "strexh r4, r8, [r9]" "\n\t" |
| "str r4, [r5, #8]" "\n\t" |
| : /*out*/ |
| : /*in*/ "r"(&block[0]) |
| : /*trash*/ "memory", "cc", "r5", "r8", "r9", "r10", "r4" |
| ); |
| } while (block[2] != 0); |
| #elif defined(VGA_s390x) |
| int dummy; |
| __asm__ __volatile__( |
| " l 0,%0\n\t" |
| "0: st 0,%1\n\t" |
| " icm 1,3,%1\n\t" |
| " ar 1,%2\n\t" |
| " stcm 1,3,%1\n\t" |
| " l 1,%1\n\t" |
| " cs 0,1,%0\n\t" |
| " jl 0b\n\t" |
| : "+m" (*p), "+m" (dummy) |
| : "d" (n) |
| : "cc", "memory", "0", "1"); |
| #else |
| # error "Unsupported arch" |
| #endif |
| } |
| |
| __attribute__((noinline)) void atomic_add_32bit ( int* p, int n ) |
| { |
| #if defined(VGA_x86) |
| unsigned long block[2]; |
| block[0] = (unsigned long)p; |
| block[1] = n; |
| __asm__ __volatile__( |
| "movl 0(%%esi),%%eax" "\n\t" |
| "movl 4(%%esi),%%ebx" "\n\t" |
| "lock; addl %%ebx,(%%eax)" "\n" |
| : : "S"(&block[0])/* S means "esi only" */ : "memory","cc","eax","ebx" |
| ); |
| #elif defined(VGA_amd64) |
| unsigned long block[2]; |
| block[0] = (unsigned long)p; |
| block[1] = n; |
| __asm__ __volatile__( |
| "movq 0(%%rsi),%%rax" "\n\t" |
| "movq 8(%%rsi),%%rbx" "\n\t" |
| "lock; addl %%ebx,(%%rax)" "\n" |
| : : "S"(&block[0])/* S means "rsi only" */ : "memory","cc","rax","rbx" |
| ); |
| #elif defined(VGA_ppc32) |
| unsigned long success; |
| do { |
| __asm__ __volatile__( |
| "lwarx 15,0,%1" "\n\t" |
| "add 15,15,%2" "\n\t" |
| "stwcx. 15,0,%1" "\n\t" |
| "mfcr %0" "\n\t" |
| "srwi %0,%0,29" "\n\t" |
| "andi. %0,%0,1" "\n" |
| : /*out*/"=b"(success) |
| : /*in*/ "b"(p), "b"(n) |
| : /*trash*/ "memory", "cc", "r15" |
| ); |
| } while (success != 1); |
| #elif defined(VGA_ppc64) |
| /* Nasty hack. Does correctly atomically do *p += n, but only if p |
| is 8-aligned -- guaranteed by caller. */ |
| unsigned long success; |
| do { |
| __asm__ __volatile__( |
| "ldarx 15,0,%1" "\n\t" |
| "add 15,15,%2" "\n\t" |
| "stdcx. 15,0,%1" "\n\t" |
| "mfcr %0" "\n\t" |
| "srwi %0,%0,29" "\n\t" |
| "andi. %0,%0,1" "\n" |
| : /*out*/"=b"(success) |
| : /*in*/ "b"(p), "b"(((unsigned long)n) << 32) |
| : /*trash*/ "memory", "cc", "r15" |
| ); |
| } while (success != 1); |
| #elif defined(VGA_arm) |
| unsigned int block[3] |
| = { (unsigned int)p, (unsigned int)n, 0xFFFFFFFF }; |
| do { |
| __asm__ __volatile__( |
| "mov r5, %0" "\n\t" |
| "ldr r9, [r5, #0]" "\n\t" // p |
| "ldr r10, [r5, #4]" "\n\t" // n |
| "ldrex r8, [r9]" "\n\t" |
| "add r8, r8, r10" "\n\t" |
| "strex r4, r8, [r9]" "\n\t" |
| "str r4, [r5, #8]" "\n\t" |
| : /*out*/ |
| : /*in*/ "r"(&block[0]) |
| : /*trash*/ "memory", "cc", "r5", "r8", "r9", "r10", "r4" |
| ); |
| } while (block[2] != 0); |
| #elif defined(VGA_s390x) |
| __asm__ __volatile__( |
| " l 0,%0\n\t" |
| "0: lr 1,0\n\t" |
| " ar 1,%1\n\t" |
| " cs 0,1,%0\n\t" |
| " jl 0b\n\t" |
| : "+m" (*p) |
| : "d" (n) |
| : "cc", "memory", "0", "1"); |
| #else |
| # error "Unsupported arch" |
| #endif |
| } |
| |
| __attribute__((noinline)) void atomic_add_64bit ( long long int* p, int n ) |
| { |
| #if defined(VGA_x86) || defined(VGA_ppc32) |
| /* do nothing; is not supported */ |
| #elif defined(VGA_amd64) |
| // this is a bit subtle. It relies on the fact that, on a 64-bit platform, |
| // sizeof(unsigned long long int) == sizeof(unsigned long) == sizeof(void*) |
| unsigned long long int block[2]; |
| block[0] = (unsigned long long int)(unsigned long)p; |
| block[1] = n; |
| __asm__ __volatile__( |
| "movq 0(%%rsi),%%rax" "\n\t" |
| "movq 8(%%rsi),%%rbx" "\n\t" |
| "lock; addq %%rbx,(%%rax)" "\n" |
| : : "S"(&block[0])/* S means "rsi only" */ : "memory","cc","rax","rbx" |
| ); |
| #elif defined(VGA_ppc64) |
| unsigned long success; |
| do { |
| __asm__ __volatile__( |
| "ldarx 15,0,%1" "\n\t" |
| "add 15,15,%2" "\n\t" |
| "stdcx. 15,0,%1" "\n\t" |
| "mfcr %0" "\n\t" |
| "srwi %0,%0,29" "\n\t" |
| "andi. %0,%0,1" "\n" |
| : /*out*/"=b"(success) |
| : /*in*/ "b"(p), "b"(n) |
| : /*trash*/ "memory", "cc", "r15" |
| ); |
| } while (success != 1); |
| #elif defined(VGA_arm) |
| unsigned long long int block[3] |
| = { (unsigned long long int)(unsigned long)p, |
| (unsigned long long int)n, |
| 0xFFFFFFFFFFFFFFFFULL }; |
| do { |
| __asm__ __volatile__( |
| "mov r5, %0" "\n\t" |
| "ldr r8, [r5, #0]" "\n\t" // p |
| "ldrd r2, r3, [r5, #8]" "\n\t" // n |
| "ldrexd r0, r1, [r8]" "\n\t" |
| "adds r2, r2, r0" "\n\t" |
| "adc r3, r3, r1" "\n\t" |
| "strexd r1, r2, r3, [r8]" "\n\t" |
| "str r1, [r5, #16]" "\n\t" |
| : /*out*/ |
| : /*in*/ "r"(&block[0]) |
| : /*trash*/ "memory", "cc", "r5", "r0", "r1", "r8", "r2", "r3" |
| ); |
| } while (block[2] != 0xFFFFFFFF00000000ULL); |
| #elif defined(VGA_s390x) |
| __asm__ __volatile__( |
| " lg 0,%0\n\t" |
| "0: lgr 1,0\n\t" |
| " agr 1,%1\n\t" |
| " csg 0,1,%0\n\t" |
| " jl 0b\n\t" |
| : "+m" (*p) |
| : "d" (n) |
| : "cc", "memory", "0", "1"); |
| #else |
| # error "Unsupported arch" |
| #endif |
| } |
| |
| int main ( int argc, char** argv ) |
| { |
| int i, status; |
| char* page; |
| char* p8; |
| short* p16; |
| int* p32; |
| long long int* p64; |
| pid_t child, p2; |
| |
| printf("parent, pre-fork\n"); |
| |
| page = mmap( 0, sysconf(_SC_PAGESIZE), |
| PROT_READ|PROT_WRITE, |
| MAP_ANONYMOUS|MAP_SHARED, -1, 0 ); |
| if (page == MAP_FAILED) { |
| perror("mmap failed"); |
| exit(1); |
| } |
| |
| p8 = (char*)(page+0); |
| p16 = (short*)(page+256); |
| p32 = (int*)(page+512); |
| p64 = (long long int*)(page+768); |
| |
| assert( IS_8_ALIGNED(p8) ); |
| assert( IS_8_ALIGNED(p16) ); |
| assert( IS_8_ALIGNED(p32) ); |
| assert( IS_8_ALIGNED(p64) ); |
| |
| memset(page, 0, 1024); |
| |
| *p8 = 0; |
| *p16 = 0; |
| *p32 = 0; |
| *p64 = 0; |
| |
| child = fork(); |
| if (child == -1) { |
| perror("fork() failed\n"); |
| return 1; |
| } |
| |
| if (child == 0) { |
| /* --- CHILD --- */ |
| printf("child\n"); |
| for (i = 0; i < NNN; i++) { |
| atomic_add_8bit(p8, 1); |
| atomic_add_16bit(p16, 1); |
| atomic_add_32bit(p32, 1); |
| atomic_add_64bit(p64, 98765 ); /* ensure we hit the upper 32 bits */ |
| } |
| return 1; |
| /* NOTREACHED */ |
| |
| } |
| |
| /* --- PARENT --- */ |
| |
| printf("parent\n"); |
| |
| for (i = 0; i < NNN; i++) { |
| atomic_add_8bit(p8, 1); |
| atomic_add_16bit(p16, 1); |
| atomic_add_32bit(p32, 1); |
| atomic_add_64bit(p64, 98765 ); /* ensure we hit the upper 32 bits */ |
| } |
| |
| p2 = waitpid(child, &status, 0); |
| assert(p2 == child); |
| |
| /* assert that child finished normally */ |
| assert(WIFEXITED(status)); |
| |
| printf("FINAL VALUES: 8 bit %d, 16 bit %d, 32 bit %d, 64 bit %lld\n", |
| (int)(*(signed char*)p8), (int)(*p16), *p32, *p64 ); |
| |
| if (-74 == (int)(*(signed char*)p8) |
| && 32694 == (int)(*p16) |
| && 6913974 == *p32 |
| && (0LL == *p64 || 682858642110LL == *p64)) { |
| printf("PASS\n"); |
| } else { |
| printf("FAIL -- see source code for expected values\n"); |
| } |
| |
| printf("parent exits\n"); |
| |
| return 0; |
| } |
