diff --git a/sysdeps/unix/sysv/linux/aarch64/setcontext.S b/sysdeps/unix/sysv/linux/aarch64/setcontext.S
index d220c41..2a70cc2 100644
--- a/sysdeps/unix/sysv/linux/aarch64/setcontext.S
+++ b/sysdeps/unix/sysv/linux/aarch64/setcontext.S
@@ -22,63 +22,100 @@
 #include "ucontext_i.h"
 #include "ucontext-internal.h"
 
-/* int setcontext (const ucontext_t *ucp) */
+/*  int __setcontext (const ucontext_t *ucp)
 
-	.text
-
-ENTRY(__setcontext)
-
-	/* Create a signal frame on the stack:
-
-		fp
-		lr
-		...
-	   sp-> rt_sigframe
-	 */
-
-	stp     x29, x30, [sp, -16]!
-	cfi_adjust_cfa_offset (16)
-	cfi_rel_offset (x29, 0)
-	cfi_rel_offset (x30, 8)
-
-        mov     x29, sp
-	cfi_def_cfa_register (x29)
-
-	/* Allocate space for the sigcontext.  */
-	mov	w3, #((RT_SIGFRAME_SIZE + SP_ALIGN_SIZE) & SP_ALIGN_MASK)
-	sub	sp, sp,	x3
+  Restores the machine context in UCP and thereby resumes execution
+  in that context.
 
-	/* Compute the base address of the ucontext structure.  */
-	add	x1, sp, #RT_SIGFRAME_UCONTEXT
+  This implementation is intended to be used for *synchronous* context
+  switches only.  Therefore, it does not have to restore anything
+  other than the PRESERVED state.  */
 
-	/* Only ucontext is required in the frame, *copy* it in.  */
-
-#if UCONTEXT_SIZE % 16
-#error The implementation of setcontext.S assumes sizeof(ucontext_t) % 16 == 0
-#endif
-
-	mov	x2, #UCONTEXT_SIZE / 16
-0:
-	ldp	x3, x4, [x0], #16
-	stp	x3, x4, [x1], #16
-	sub	x2, x2, 1
-	cbnz	x2, 0b
+	.text
 
-	/* rt_sigreturn () -- no arguments, sp points to struct rt_sigframe.  */
-	mov	x8, SYS_ify (rt_sigreturn)
+ENTRY(__setcontext)
+	/* Save a copy of UCP.  */
+	mov	x9, x0
+
+	/* Set the signal mask with
+	   rt_sigprocmask (SIG_SETMASK, mask, NULL, _NSIG/8).  */
+	mov	x0, #SIG_SETMASK
+	ldr	x1, [x9, UCONTEXT_SIGMASK]
+	mov	x2, #0
+	mov	x3, #_NSIG8
+	mov	x8, SYS_ify (rt_sigprocmask)
 	svc	0
-
-	/* Ooops we failed.  Recover the stack */
-
-	mov	sp, x29
-	cfi_def_cfa_register (sp)
-
-        ldp     x29, x30, [sp], 16
-	cfi_adjust_cfa_offset (16)
-	cfi_restore (x29)
-	cfi_restore (x30)
+	cbz	x0, 1f
 	b	C_SYMBOL_NAME(__syscall_error)
-
+1:
+	/* Restore the general purpose registers.  */
+	mov	x0, x9
+	cfi_def_cfa(x0, 0)
+	cfi_offset(x18, oX0 + 18 * SZREG)
+	cfi_offset(x19, oX0 + 19 * SZREG)
+	cfi_offset(x20, oX0 + 20 * SZREG)
+	cfi_offset(x21, oX0 + 21 * SZREG)
+	cfi_offset(x22, oX0 + 22 * SZREG)
+	cfi_offset(x23, oX0 + 23 * SZREG)
+	cfi_offset(x24, oX0 + 24 * SZREG)
+	cfi_offset(x25, oX0 + 25 * SZREG)
+	cfi_offset(x26, oX0 + 26 * SZREG)
+	cfi_offset(x27, oX0 + 27 * SZREG)
+	cfi_offset(x28, oX0 + 28 * SZREG)
+	cfi_offset(x29, oX0 + 29 * SZREG)
+	cfi_offset(x30, oX0 + 30 * SZREG)
+
+	cfi_offset( d8, oV0 + 8 * SZVREG)
+	cfi_offset( d9, oV0 + 9 * SZVREG)
+	cfi_offset(d10, oV0 + 10 * SZVREG)
+	cfi_offset(d11, oV0 + 11 * SZVREG)
+	cfi_offset(d12, oV0 + 12 * SZVREG)
+	cfi_offset(d13, oV0 + 13 * SZVREG)
+	cfi_offset(d14, oV0 + 14 * SZVREG)
+	cfi_offset(d15, oV0 + 15 * SZVREG)
+	ldp	x18, x19, [x0, oX0 + 18 * SZREG]
+	ldp	x20, x21, [x0, oX0 + 20 * SZREG]
+	ldp	x22, x23, [x0, oX0 + 22 * SZREG]
+	ldp	x24, x25, [x0, oX0 + 24 * SZREG]
+	ldp	x26, x27, [x0, oX0 + 26 * SZREG]
+	ldp	x28, x29, [x0, oX0 + 28 * SZREG]
+	ldr     x30,      [x0, oX0 + 30 * SZREG]
+	ldr     x2, [x0, oSP]
+	mov	sp, x2
+
+	/* Check for FP SIMD context.  */
+	add     x2, x0, #oEXTENSION
+
+	mov	w3, #(FPSIMD_MAGIC & 0xffff)
+	movk	w3, #(FPSIMD_MAGIC >> 16), lsl #16
+	ldr	w1, [x2, #oHEAD + oMAGIC]
+	cmp	w1, w3
+	b.ne	2f
+
+	/* Restore the FP SIMD context.  */
+	add	x3, x2, #oV0 + 8 * SZVREG
+	ldp	 d8,  d9, [x3], #2 * SZVREG
+	ldp	d10, d11, [x3], #2 * SZVREG
+	ldp	d12, d13, [x3], #2 * SZVREG
+	ldp	d14, d15, [x3], #2 * SZVREG
+
+	add	x3, x2, oFPSR
+
+	ldr	w4, [x3]
+	msr	fpsr, x4
+
+	ldr	w4, [x3, oFPCR - oFPSR]
+	msr	fpcr, x4
+
+2:
+	ldr     x16, [x0, oPC]
+	/* Restore arg registers.  */
+	ldp	x2, x3, [x0, oX0 + 2 * SZREG]
+	ldp	x4, x5, [x0, oX0 + 4 * SZREG]
+	ldp	x6, x7, [x0, oX0 + 6 * SZREG]
+	ldp	x0, x1, [x0, oX0 + 0 * SZREG]
+	/* Jump to the new pc value.  */
+	br	x16
 PSEUDO_END (__setcontext)
 weak_alias (__setcontext, setcontext)
 
