diff options
Diffstat (limited to 'libc/arch-x86/bionic/_exit_with_stack_teardown.S')
| -rw-r--r-- | libc/arch-x86/bionic/_exit_with_stack_teardown.S | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/libc/arch-x86/bionic/_exit_with_stack_teardown.S b/libc/arch-x86/bionic/_exit_with_stack_teardown.S new file mode 100644 index 0000000..83a504d --- /dev/null +++ b/libc/arch-x86/bionic/_exit_with_stack_teardown.S @@ -0,0 +1,34 @@ +#include <sys/linux-syscalls.h> + +.text +.type _exit_with_stack_teardown, @function +.globl _exit_with_stack_teardown +.align 4 + +/* + * void _exit_with_stack_teardown(void *stackBase, int stackSize, int *retCode) + */ + +_exit_with_stack_teardown: + /* we can trash %ebx here since this call should never return. */ + /* We can also take advantage of the fact that the linux syscall trap + * handler saves all the registers, so we don't need a stack to keep + * the retCode argument for exit while doing the munmap */ + + /* TODO(dmtriyz): No one expects this code to return, so even if + * munmap fails, we have to exit. This should probably be fixed, but + * since ARM side does the same thing, leave it as is. + */ + mov 4(%esp), %ebx /* stackBase */ + mov 8(%esp), %ecx /* stackSize */ + mov 12(%esp), %edx /* retCode, not used for munmap */ + mov $__NR_munmap, %eax + int $0x80 + mov %edx, %ebx /* retrieve the retCode */ + movl $__NR_exit, %eax + int $0x80 + /* exit does not return */ + /* can't have a ret here since we no longer have a usable stack. Seems + * that presently, 'hlt' will cause the program to segfault.. but this + * should never happen :) */ + hlt |