Diffstat (limited to 'tools/testing/selftests/arm64/signal/signals.S')
1 files changed, 64 insertions, 0 deletions
diff --git a/tools/testing/selftests/arm64/signal/signals.S b/tools/testing/selftests/arm64/signal/signals.S
new file mode 100644
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 ARM Limited */
+.section .rodata, "a"
+ .asciz "Calling sigreturn with fake sigframe sized:%zd at SP @%08lX\n"
+/* fake_sigreturn x0:&sigframe, x1:sigframe_size, x2:misalign_bytes */
+ 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 .