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authorSzabolcs Nagy <szabolcs.nagy@arm.com>2021-12-01 11:37:44 +0000
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2024-01-02 15:43:30 +0000
commita7373e457f0b5953d230f7756627036b1711dcc3 (patch)
tree637d990fb97e2d9018cd682c5db199cb76fd7712 /sysdeps/aarch64
parentd3c32ae207d4fc3e48bb47ce1b9f2c6cf0f35c4f (diff)
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aarch64: Add longjmp support for SME
For the ZA lazy saving scheme to work, longjmp has to call
__libc_arm_za_disable.

In ld.so we assume ZA is not used so longjmp does not need
special support there.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/aarch64')
-rw-r--r--sysdeps/aarch64/__longjmp.S22
1 files changed, 22 insertions, 0 deletions
diff --git a/sysdeps/aarch64/__longjmp.S b/sysdeps/aarch64/__longjmp.S
index 2c8ff54112..7b6add751e 100644
--- a/sysdeps/aarch64/__longjmp.S
+++ b/sysdeps/aarch64/__longjmp.S
@@ -49,6 +49,28 @@ ENTRY (__longjmp)
 
 	PTR_ARG (0)
 
+#if IS_IN(libc)
+	/* Disable ZA state of SME in libc.a and libc.so, but not in ld.so.  */
+# if HAVE_AARCH64_PAC_RET
+	PACIASP
+	cfi_window_save
+# endif
+	stp	x29, x30, [sp, -16]!
+	cfi_adjust_cfa_offset (16)
+	cfi_rel_offset (x29, 0)
+	cfi_rel_offset (x30, 8)
+	mov	x29, sp
+	bl	__libc_arm_za_disable
+	ldp	x29, x30, [sp], 16
+	cfi_adjust_cfa_offset (-16)
+	cfi_restore (x29)
+	cfi_restore (x30)
+# if HAVE_AARCH64_PAC_RET
+	AUTIASP
+	cfi_window_save
+# endif
+#endif
+
 	ldp	x19, x20, [x0, #JB_X19<<3]
 	ldp	x21, x22, [x0, #JB_X21<<3]
 	ldp	x23, x24, [x0, #JB_X23<<3]