There are no supported stack-grows-up targets. We were putting
the guard page at the highest address, i.e. the bottom of the stack.
Use the maximum of host and guest page size for the guard size.
Signed-off-by: Richard Henderson <r...@twiddle.net>
---
linux-user/elfload.c | 29 ++++++++++++++++-------------
1 files changed, 16 insertions(+), 13 deletions(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 5853a30..464160a 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1002,28 +1002,31 @@ static abi_ulong copy_elf_strings(int argc,char **
argv, void **page,
static abi_ulong setup_arg_pages(abi_ulong p, struct linux_binprm *bprm,
struct image_info *info)
{
- abi_ulong stack_base, size, error;
+ abi_ulong stack_base, size, error, guard;
int i;
/* Create enough stack to hold everything. If we don't use
- * it for args, we'll use it for something else...
- */
+ it for args, we'll use it for something else. */
size = guest_stack_size;
- if (size < MAX_ARG_PAGES*TARGET_PAGE_SIZE)
+ if (size < MAX_ARG_PAGES*TARGET_PAGE_SIZE) {
size = MAX_ARG_PAGES*TARGET_PAGE_SIZE;
- error = target_mmap(0,
- size + qemu_host_page_size,
- PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS,
- -1, 0);
+ }
+ guard = TARGET_PAGE_SIZE;
+ if (guard < qemu_real_host_page_size) {
+ guard = qemu_real_host_page_size;
+ }
+
+ error = target_mmap(0, size + guard, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (error == -1) {
- perror("stk mmap");
+ perror("mmap stack");
exit(-1);
}
- /* we reserve one extra page at the top of the stack as guard */
- target_mprotect(error + size, qemu_host_page_size, PROT_NONE);
- stack_base = error + size - MAX_ARG_PAGES*TARGET_PAGE_SIZE;
+ /* We reserve one extra page at the top of the stack as guard. */
+ target_mprotect(error, guard, PROT_NONE);
+
+ stack_base = error + guard + size - MAX_ARG_PAGES*TARGET_PAGE_SIZE;
p += stack_base;
for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
--
1.6.6.1
