diff options
Diffstat (limited to 'libgo/runtime/mem.c')
| -rw-r--r-- | libgo/runtime/mem.c | 55 |
1 files changed, 45 insertions, 10 deletions
diff --git a/libgo/runtime/mem.c b/libgo/runtime/mem.c index 78f7c51faf2..8e374863b8e 100644 --- a/libgo/runtime/mem.c +++ b/libgo/runtime/mem.c @@ -26,19 +26,33 @@ static int dev_zero = -1; #endif -static _Bool +static int32 addrspace_free(void *v __attribute__ ((unused)), uintptr n __attribute__ ((unused))) { #ifdef HAVE_MINCORE size_t page_size = getpagesize(); - size_t off; - char one_byte; + int32 errval; + uintptr chunk; + uintptr off; + + // NOTE: vec must be just 1 byte long here. + // Mincore returns ENOMEM if any of the pages are unmapped, + // but we want to know that all of the pages are unmapped. + // To make these the same, we can only ask about one page + // at a time. See golang.org/issue/7476. + static byte vec[1]; errno = 0; - for(off = 0; off < n; off += page_size) - if(mincore((char *)v + off, page_size, (void *)&one_byte) != -1 - || errno != ENOMEM) + for(off = 0; off < n; off += chunk) { + chunk = page_size * sizeof vec; + if(chunk > (n - off)) + chunk = n - off; + errval = mincore((int8*)v + off, chunk, vec); + // ENOMEM means unmapped, which is what we want. + // Anything else we assume means the pages are mapped. + if(errval == 0 || errno != ENOMEM) return 0; + } #endif return 1; } @@ -115,8 +129,27 @@ runtime_SysFree(void *v, uintptr n, uint64 *stat) runtime_munmap(v, n); } +void +runtime_SysFault(void *v, uintptr n) +{ + int fd = -1; + +#ifdef USE_DEV_ZERO + if (dev_zero == -1) { + dev_zero = open("/dev/zero", O_RDONLY); + if (dev_zero < 0) { + runtime_printf("open /dev/zero: errno=%d\n", errno); + exit(2); + } + } + fd = dev_zero; +#endif + + runtime_mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE|MAP_FIXED, fd, 0); +} + void* -runtime_SysReserve(void *v, uintptr n) +runtime_SysReserve(void *v, uintptr n, bool *reserved) { int fd = -1; void *p; @@ -136,13 +169,14 @@ runtime_SysReserve(void *v, uintptr n) // much address space. Instead, assume that the reservation is okay // if we can reserve at least 64K and check the assumption in SysMap. // Only user-mode Linux (UML) rejects these requests. - if(sizeof(void*) == 8 && (uintptr)v >= 0xffffffffU) { + if(sizeof(void*) == 8 && (n >> 16) > 1LLU<<16) { p = mmap_fixed(v, 64<<10, PROT_NONE, MAP_ANON|MAP_PRIVATE, fd, 0); if (p != v) { runtime_munmap(p, 64<<10); return nil; } runtime_munmap(p, 64<<10); + *reserved = false; return v; } @@ -153,11 +187,12 @@ runtime_SysReserve(void *v, uintptr n) p = runtime_mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE|MAP_NORESERVE, fd, 0); if(p == MAP_FAILED) return nil; + *reserved = true; return p; } void -runtime_SysMap(void *v, uintptr n, uint64 *stat) +runtime_SysMap(void *v, uintptr n, bool reserved, uint64 *stat) { void *p; int fd = -1; @@ -176,7 +211,7 @@ runtime_SysMap(void *v, uintptr n, uint64 *stat) #endif // On 64-bit, we don't actually have v reserved, so tread carefully. - if(sizeof(void*) == 8 && (uintptr)v >= 0xffffffffU) { + if(!reserved) { p = mmap_fixed(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, fd, 0); if(p == MAP_FAILED && errno == ENOMEM) runtime_throw("runtime: out of memory"); |