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| /* 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 .
|
|
