| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* Copyright (C) 2019 ARM Limited */ |
| |
| #include <asm/unistd.h> |
| |
| .section .rodata, "a" |
| call_fmt: |
| .asciz "Calling sigreturn with fake sigframe sized:%zd at SP @%08lX\n" |
| |
| .text |
| |
| .globl fake_sigreturn |
| |
| /* fake_sigreturn x0:&sigframe, x1:sigframe_size, x2:misalign_bytes */ |
| fake_sigreturn: |
| stp x29, x30, [sp, #-16]! |
| mov x29, sp |
| |
| mov x20, x0 |
| mov x21, x1 |
| mov x22, x2 |
| |
| /* create space on the stack for fake sigframe 16 bytes-aligned */ |
| add x0, x21, x22 |
| add x0, x0, #15 |
| bic x0, x0, #15 /* round_up(sigframe_size + misalign_bytes, 16) */ |
| sub sp, sp, x0 |
| add x23, sp, x22 /* new sigframe base with misaligment if any */ |
| |
| ldr x0, =call_fmt |
| mov x1, x21 |
| mov x2, x23 |
| bl printf |
| |
| /* memcpy the provided content, while still keeping SP aligned */ |
| mov x0, x23 |
| mov x1, x20 |
| mov x2, x21 |
| bl memcpy |
| |
| /* |
| * Here saving a last minute SP to current->token acts as a marker: |
| * if we got here, we are successfully faking a sigreturn; in other |
| * words we are sure no bad fatal signal has been raised till now |
| * for unrelated reasons, so we should consider the possibly observed |
| * fatal signal like SEGV coming from Kernel restore_sigframe() and |
| * triggered as expected from our test-case. |
| * For simplicity this assumes that current field 'token' is laid out |
| * as first in struct tdescr |
| */ |
| ldr x0, current |
| str x23, [x0] |
| /* finally move SP to misaligned address...if any requested */ |
| mov sp, x23 |
| |
| mov x8, #__NR_rt_sigreturn |
| svc #0 |
| |
| /* |
| * Above sigreturn should not return...looping here leads to a timeout |
| * and ensure proper and clean test failure, instead of jumping around |
| * on a potentially corrupted stack. |
| */ |
| b . |
