diff options
| -rw-r--r-- | arch/um/include/os.h | 2 | ||||
| -rw-r--r-- | arch/um/kernel/um_arch.c | 2 | ||||
| -rw-r--r-- | arch/um/os-Linux/sys-i386/task_size.c | 38 | ||||
| -rw-r--r-- | arch/um/os-Linux/sys-x86_64/task_size.c | 2 |
4 files changed, 32 insertions, 12 deletions
diff --git a/arch/um/include/os.h b/arch/um/include/os.h index 32c799e3a49..2d0a2a69cf9 100644 --- a/arch/um/include/os.h +++ b/arch/um/include/os.h @@ -298,6 +298,6 @@ extern int os_arch_prctl(int pid, int code, unsigned long *addr); extern int get_pty(void); /* sys-$ARCH/task_size.c */ -extern unsigned long os_get_task_size(void); +extern unsigned long os_get_top_address(void); #endif diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index 9cecb42eb49..d1fe2224dda 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -273,7 +273,7 @@ int __init linux_main(int argc, char **argv) if (have_root == 0) add_arg(DEFAULT_COMMAND_LINE); - host_task_size = os_get_task_size(); + host_task_size = os_get_top_address(); /* * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps * out diff --git a/arch/um/os-Linux/sys-i386/task_size.c b/arch/um/os-Linux/sys-i386/task_size.c index 48d211b3d9a..4d26d5d6431 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); /* @@ -88,14 +88,32 @@ unsigned long os_get_task_size(void) sa.sa_handler = segfault; sigemptyset(&sa.sa_mask); sa.sa_flags = SA_NODEFER; - sigaction(SIGSEGV, &sa, &old); + if (sigaction(SIGSEGV, &sa, &old)) { + 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; @@ -110,8 +128,10 @@ unsigned long os_get_task_size(void) out: /* Restore the old SIGSEGV handling */ - sigaction(SIGSEGV, &old, NULL); - + if (sigaction(SIGSEGV, &old, NULL)) { + perror("os_get_top_address"); + exit(1); + } top <<= UM_KERN_PAGE_SHIFT; printf("0x%x\n", top); fflush(stdout); diff --git a/arch/um/os-Linux/sys-x86_64/task_size.c b/arch/um/os-Linux/sys-x86_64/task_size.c index fad6f57f8ee..26a0dd1f349 100644 --- a/arch/um/os-Linux/sys-x86_64/task_size.c +++ b/arch/um/os-Linux/sys-x86_64/task_size.c @@ -1,4 +1,4 @@ -unsigned long os_get_task_size(unsigned long shift) +unsigned long os_get_top_address(unsigned long shift) { /* The old value of CONFIG_TOP_ADDR */ return 0x7fc0000000; |