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| author | Richard Henderson <rth@twiddle.net> | 2010-07-27 10:25:35 -0700 |
|---|---|---|
| committer | Edgar E. Iglesias <edgar.iglesias@gmail.com> | 2010-07-29 08:32:28 +0200 |
| commit | 60dcbcb5b1a0d185be607b03fc7a15bf1bab4bec (patch) | |
| tree | e03c2c91877c167340cf1048251283812d31ae46 /linux-user | |
| parent | 9058abdd180843473d440958c79a1a781be723c1 (diff) | |
| download | qemu-60dcbcb5b1a0d185be607b03fc7a15bf1bab4bec.zip qemu-60dcbcb5b1a0d185be607b03fc7a15bf1bab4bec.tar.gz qemu-60dcbcb5b1a0d185be607b03fc7a15bf1bab4bec.tar.bz2 | |
linux-user: Put the stack guard page at the top.
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 <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Diffstat (limited to 'linux-user')
| -rw-r--r-- | linux-user/elfload.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 86872b2..01020c5 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -1002,29 +1002,32 @@ 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); - info->stack_limit = error; - 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); + + info->stack_limit = error + guard; + stack_base = info->stack_limit + size - MAX_ARG_PAGES*TARGET_PAGE_SIZE; p += stack_base; for (i = 0 ; i < MAX_ARG_PAGES ; i++) { |