diff options
Diffstat (limited to 'arch/um/os-Linux/sys-i386/task_size.c')
| -rw-r--r-- | arch/um/os-Linux/sys-i386/task_size.c | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/arch/um/os-Linux/sys-i386/task_size.c b/arch/um/os-Linux/sys-i386/task_size.c index ccb49b0aff5..be04c1e183b 100644 --- a/arch/um/os-Linux/sys-i386/task_size.c +++ b/arch/um/os-Linux/sys-i386/task_size.c @@ -63,7 +63,7 @@ static int page_ok(unsigned long page) return ok; } -unsigned long os_get_task_size(void) +unsigned long os_get_top_address(void) { struct sigaction sa, old; unsigned long bottom = 0; @@ -76,9 +76,9 @@ unsigned long os_get_task_size(void) * hosts, but shouldn't hurt otherwise. */ unsigned long top = 0xffffd000 >> UM_KERN_PAGE_SHIFT; - unsigned long test; + unsigned long test, original; - printf("Locating the top of the address space ... "); + printf("Locating the bottom of the address space ... "); fflush(stdout); /* @@ -89,16 +89,31 @@ unsigned long os_get_task_size(void) sigemptyset(&sa.sa_mask); sa.sa_flags = SA_NODEFER; if (sigaction(SIGSEGV, &sa, &old)) { - perror("os_get_task_size"); + perror("os_get_top_address"); exit(1); } - if (!page_ok(bottom)) { - fprintf(stderr, "Address 0x%x no good?\n", - bottom << UM_KERN_PAGE_SHIFT); + /* Manually scan the address space, bottom-up, until we find + * the first valid page (or run out of them). + */ + for (bottom = 0; bottom < top; bottom++) { + if (page_ok(bottom)) + break; + } + + /* If we've got this far, we ran out of pages. */ + if (bottom == top) { + fprintf(stderr, "Unable to determine bottom of address " + "space.\n"); exit(1); } + printf("0x%x\n", bottom << UM_KERN_PAGE_SHIFT); + printf("Locating the top of the address space ... "); + fflush(stdout); + + original = bottom; + /* This could happen with a 4G/4G split */ if (page_ok(top)) goto out; @@ -114,7 +129,7 @@ unsigned long os_get_task_size(void) out: /* Restore the old SIGSEGV handling */ if (sigaction(SIGSEGV, &old, NULL)) { - perror("os_get_task_size"); + perror("os_get_top_address"); exit(1); } top <<= UM_KERN_PAGE_SHIFT; |