diff options
Diffstat (limited to 'src/pkg/runtime/mem_linux.c')
| -rw-r--r-- | src/pkg/runtime/mem_linux.c | 40 |
1 files changed, 26 insertions, 14 deletions
diff --git a/src/pkg/runtime/mem_linux.c b/src/pkg/runtime/mem_linux.c index fdf02c2ca..b3e79cc41 100644 --- a/src/pkg/runtime/mem_linux.c +++ b/src/pkg/runtime/mem_linux.c @@ -34,6 +34,21 @@ addrspace_free(void *v, uintptr n) return 1; } +static void * +mmap_fixed(byte *v, uintptr n, int32 prot, int32 flags, int32 fd, uint32 offset) +{ + void *p; + + p = runtime·mmap(v, n, prot, flags, fd, offset); + if(p != v && addrspace_free(v, n)) { + // On some systems, mmap ignores v without + // MAP_FIXED, so retry if the address space is free. + if(p > (void*)4096) + runtime·munmap(p, n); + p = runtime·mmap(v, n, prot, flags|MAP_FIXED, fd, offset); + } + return p; +} void* runtime·SysAlloc(uintptr n) @@ -73,14 +88,19 @@ runtime·SysReserve(void *v, uintptr n) // On 64-bit, people with ulimit -v set complain if we reserve too // much address space. Instead, assume that the reservation is okay - // and check the assumption in SysMap. - if(sizeof(void*) == 8) + // 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) { + p = mmap_fixed(v, 64<<10, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0); + if (p != v) + return nil; + runtime·munmap(p, 64<<10); return v; + } p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0); - if((uintptr)p < 4096 || -(uintptr)p < 4096) { + if((uintptr)p < 4096 || -(uintptr)p < 4096) return nil; - } return p; } @@ -92,16 +112,8 @@ runtime·SysMap(void *v, uintptr n) mstats.sys += n; // On 64-bit, we don't actually have v reserved, so tread carefully. - if(sizeof(void*) == 8) { - p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0); - if(p != v && addrspace_free(v, n)) { - // On some systems, mmap ignores v without - // MAP_FIXED, so retry if the address space is free. - if(p > (void*)4096) { - runtime·munmap(p, n); - } - p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0); - } + if(sizeof(void*) == 8 && (uintptr)v >= 0xffffffffU) { + p = mmap_fixed(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0); if(p == (void*)ENOMEM) runtime·throw("runtime: out of memory"); if(p != v) { |