[glibc/release/2.40/master] aarch64: Disable ZA state of SME in setjmp and sigsetjmp

[Yury Khrustalev]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=cdc1665bb188319b5f16ee05c04de7f2ba580e27

commit cdc1665bb188319b5f16ee05c04de7f2ba580e27
Author: Yury Khrustalev <yury.khrustalev@arm.com>
Date:   Mon Apr 28 15:12:04 2025 +0100

    aarch64: Disable ZA state of SME in setjmp and sigsetjmp
    
    Due to the nature of the ZA state, setjmp() should clear it in the
    same manner as it is already done by longjmp.
    
    Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>
    (cherry picked from commit a7f6fd976c17b82dc198290b4ab7087f35855a0e)
    (cherry picked from commit 1f57ffdf35334ab245544cbb88f3abf2e6c77c54)

Diff:
---
 sysdeps/aarch64/setjmp.S | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/sysdeps/aarch64/setjmp.S b/sysdeps/aarch64/setjmp.S
index 43fdb1b2fb..e0c65cf035 100644
--- a/sysdeps/aarch64/setjmp.S
+++ b/sysdeps/aarch64/setjmp.S
@@ -37,6 +37,29 @@ ENTRY (__sigsetjmp)
 	PTR_ARG (0)
 
 1:
+
+#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
+
 	stp	x19, x20, [x0, #JB_X19<<3]
 	stp	x21, x22, [x0, #JB_X21<<3]
 	stp	x23, x24, [x0, #JB_X23<<3]