diff options
Diffstat (limited to 'src/pkg/runtime/mem_linux.c')
| -rw-r--r-- | src/pkg/runtime/mem_linux.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/src/pkg/runtime/mem_linux.c b/src/pkg/runtime/mem_linux.c index b0f295633..635594c36 100644 --- a/src/pkg/runtime/mem_linux.c +++ b/src/pkg/runtime/mem_linux.c @@ -11,6 +11,7 @@ enum { _PAGE_SIZE = 4096, + EACCES = 13, }; static int32 @@ -19,15 +20,22 @@ addrspace_free(void *v, uintptr n) int32 errval; uintptr chunk; uintptr off; - static byte vec[4096]; + + // 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]; for(off = 0; off < n; off += chunk) { chunk = _PAGE_SIZE * sizeof vec; if(chunk > (n - off)) chunk = n - off; errval = runtime·mincore((int8*)v + off, chunk, vec); - // errval is 0 if success, or -(error_code) if error. - if (errval == 0 || errval != -ENOMEM) + // ENOMEM means unmapped, which is what we want. + // Anything else we assume means the pages are mapped. + if (errval != -ENOMEM) return 0; } return 1; @@ -91,8 +99,14 @@ runtime·SysFree(void *v, uintptr n, uint64 *stat) runtime·munmap(v, n); } +void +runtime·SysFault(void *v, uintptr n) +{ + runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE|MAP_FIXED, -1, 0); +} + void* -runtime·SysReserve(void *v, uintptr n) +runtime·SysReserve(void *v, uintptr n, bool *reserved) { void *p; @@ -100,7 +114,7 @@ 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 > 1LL<<32) { p = mmap_fixed(v, 64<<10, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0); if (p != v) { if(p >= (void*)4096) @@ -108,24 +122,26 @@ runtime·SysReserve(void *v, uintptr n) return nil; } runtime·munmap(p, 64<<10); + *reserved = false; return v; } p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0); if((uintptr)p < 4096) 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; runtime·xadd64(stat, n); // 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, -1, 0); if(p == (void*)ENOMEM) runtime·throw("runtime: out of memory"); |