libc: add {get,set,swap,make}context user context manipulation functions

Add the obsolescent SUSv3 family of user context manipulating functions
for arm, i386, mips, x86_64.

Signed-off-by: Timon ter Braak <timonterbraak@gmail.com>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

7 files changed, 804 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/mips/Makefile.arch b/libc/sysdeps/linux/mips/Makefile.arch
index fce99f813..00b933149 100644
--- a/libc/sysdeps/linux/mips/Makefile.arch
+++ b/libc/sysdeps/linux/mips/Makefile.arch
@@ -27,3 +27,7 @@ ASFLAGS-syscall_error.S += -D_LIBC_REENTRANT
 
 ARCH_HEADERS := sgidefs.h
 # regdef.h
+
+ifeq ($(UCLIBC_HAS_CONTEXT_FUNCS),y)
+SSRC += makecontext.S setcontext.S getcontext.S swapcontext.S
+endif
diff --git a/libc/sysdeps/linux/mips/getcontext.S b/libc/sysdeps/linux/mips/getcontext.S
new file mode 100644
index 000000000..c4ad081b0
--- /dev/null
+++ b/libc/sysdeps/linux/mips/getcontext.S
@@ -0,0 +1,148 @@
+/* Save current context.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Maciej W. Rozycki <macro@codesourcery.com>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <sys/asm.h>
+#include <sys/fpregdef.h>
+#include <sys/regdef.h>
+
+#include "ucontext_i.h"
+
+/* int getcontext (ucontext_t *ucp) */
+
+	.text
+LOCALSZ = 0
+MASK = 0x00000000
+#ifdef __PIC__
+LOCALSZ = 1						/* save gp */
+# if _MIPS_SIM != _ABIO32
+MASK = 0x10000000
+# endif
+#endif
+FRAMESZ = ((LOCALSZ * SZREG) + ALSZ) & ALMASK
+GPOFF = FRAMESZ - (1 * SZREG)
+
+NESTED (__getcontext, FRAMESZ, ra)
+	.mask	MASK, 0
+	.fmask	0x00000000, 0
+
+#ifdef __PIC__
+	SETUP_GP
+
+	move	a2, sp
+# define _SP a2
+
+# if _MIPS_SIM != _ABIO32
+	move	a3, gp
+#  define _GP a3
+# endif
+
+	PTR_ADDIU sp, -FRAMESZ
+	SETUP_GP64 (GPOFF, __getcontext)
+	SAVE_GP (GPOFF)
+
+#else  /* ! __PIC__ */
+# define _SP sp
+# define _GP gp
+
+#endif /* ! __PIC__ */
+
+#ifdef PROF
+	.set	noat
+	move	AT, ra
+	jal	_mcount
+	.set	at
+#endif
+
+	/* Store a magic flag.	*/
+	li	v1, 1
+	REG_S	v1, (0 * SZREG + MCONTEXT_GREGS)(a0)	/* zero */
+
+	REG_S	s0, (16 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s1, (17 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s2, (18 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s3, (19 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s4, (20 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s5, (21 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s6, (22 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s7, (23 * SZREG + MCONTEXT_GREGS)(a0)
+#if ! defined (__PIC__) || _MIPS_SIM != _ABIO32
+	REG_S	_GP, (28 * SZREG + MCONTEXT_GREGS)(a0)
+#endif
+	REG_S	_SP, (29 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	fp, (30 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	ra, (31 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	ra, MCONTEXT_PC(a0)
+
+#ifdef __mips_hard_float
+# if _MIPS_SIM == _ABI64
+	s.d	fs0, (24 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs1, (25 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs2, (26 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs3, (27 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs4, (28 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs5, (29 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs6, (30 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs7, (31 * SZREG + MCONTEXT_FPREGS)(a0)
+
+# else  /* _MIPS_SIM != _ABI64 */
+	s.d	fs0, (20 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs1, (22 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs2, (24 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs3, (26 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs4, (28 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs5, (30 * SZREG + MCONTEXT_FPREGS)(a0)
+
+# endif /* _MIPS_SIM != _ABI64 */
+
+	cfc1	v1, fcr31
+	sw	v1, MCONTEXT_FPC_CSR(a0)
+#endif /* __mips_hard_float */
+
+/* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */
+	li	a3, _NSIG8
+	PTR_ADDU a2, a0, UCONTEXT_SIGMASK
+	move	a1, zero
+	li	a0, SIG_BLOCK
+
+	li	v0, SYS_ify (rt_sigprocmask)
+	syscall
+	bnez	a3, 99f
+
+#ifdef __PIC__
+	RESTORE_GP64
+	PTR_ADDIU sp, FRAMESZ
+#endif
+	move	v0, zero
+	jr	ra
+
+99:
+#ifdef __PIC__
+	PTR_LA	t9, JUMPTARGET (__syscall_error)
+	RESTORE_GP64
+	PTR_ADDIU sp, FRAMESZ
+	jr	t9
+
+#else  /* ! __PIC__ */
+
+	j	JUMPTARGET (__syscall_error)
+#endif /* ! __PIC__ */
+PSEUDO_END (__getcontext)
+
+weak_alias (__getcontext, getcontext)
diff --git a/libc/sysdeps/linux/mips/kernel_rt_sigframe.h b/libc/sysdeps/linux/mips/kernel_rt_sigframe.h
new file mode 100644
index 000000000..77ffaf68d
--- /dev/null
+++ b/libc/sysdeps/linux/mips/kernel_rt_sigframe.h
@@ -0,0 +1,10 @@
+/* Linux kernel RT signal frame. */
+typedef struct kernel_rt_sigframe
+  {
+    uint32_t rs_ass[4];
+    uint32_t rs_code[2];
+    siginfo_t rs_info;
+    struct ucontext rs_uc;
+    uint32_t rs_altcode[8] __attribute__ ((__aligned__ (1 << 7)));
+  }
+kernel_rt_sigframe_t;
diff --git a/libc/sysdeps/linux/mips/makecontext.S b/libc/sysdeps/linux/mips/makecontext.S
new file mode 100644
index 000000000..6427339a6
--- /dev/null
+++ b/libc/sysdeps/linux/mips/makecontext.S
@@ -0,0 +1,188 @@
+/* Modify saved context.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Maciej W. Rozycki <macro@codesourcery.com>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <sys/asm.h>
+#include <sys/fpregdef.h>
+#include <sys/regdef.h>
+
+#include "ucontext_i.h"
+
+/* int makecontext (ucontext_t *ucp, (void *func) (), int argc, ...) */
+
+	.text
+LOCALSZ = 0
+ARGSZ = 0
+MASK = 0x00000000
+#ifdef __PIC__
+LOCALSZ = 1						/* save gp */
+#endif
+#if _MIPS_SIM != _ABIO32
+ARGSZ = 5						/* save a3-a7 */
+# ifdef __PIC__
+MASK = 0x10000000
+# endif
+#endif
+FRAMESZ = (((ARGSZ + LOCALSZ) * SZREG) + ALSZ) & ALMASK
+GPOFF = FRAMESZ - ((ARGSZ + 1) * SZREG)
+#if _MIPS_SIM != _ABIO32
+A3OFF = FRAMESZ - (5 * SZREG)				/* callee-allocated */
+A4OFF = FRAMESZ - (4 * SZREG)
+A5OFF = FRAMESZ - (3 * SZREG)
+A6OFF = FRAMESZ - (2 * SZREG)
+A7OFF = FRAMESZ - (1 * SZREG)
+NARGREGS = 8
+#else
+A3OFF = FRAMESZ + (3 * SZREG)				/* caller-allocated */
+NARGREGS = 4
+#endif
+
+NESTED (__makecontext, FRAMESZ, ra)
+	.mask	MASK, -(ARGSZ * SZREG)
+	.fmask	0x00000000, 0
+
+98:
+#ifdef __PIC__
+	SETUP_GP
+#endif
+
+	PTR_ADDIU sp, -FRAMESZ
+
+#ifdef __PIC__
+	SETUP_GP64 (GPOFF, __makecontext)
+	SAVE_GP (GPOFF)
+#endif
+
+#ifdef PROF
+	.set	noat
+	move	AT, ra
+	jal	_mcount
+	.set	at
+#endif
+
+	/* Store args to be passed.  */
+	REG_S	a3, A3OFF(sp)
+#if _MIPS_SIM != _ABIO32
+	REG_S	a4, A4OFF(sp)
+	REG_S	a5, A5OFF(sp)
+	REG_S	a6, A6OFF(sp)
+	REG_S	a7, A7OFF(sp)
+#endif
+
+	/* Store a magic flag.  */
+	li	v1, 1
+	REG_S	v1, (0 * SZREG + MCONTEXT_GREGS)(a0)	/* zero */
+
+	/* Set up the stack.  */
+	PTR_L	t0, STACK_SP(a0)
+	PTR_L	t2, STACK_SIZE(a0)
+	PTR_ADDIU t1, sp, A3OFF
+	PTR_ADDU t0, t2
+	and	t0, ALMASK
+	blez	a2, 2f					/* no arguments */
+
+	/* Store register arguments.  */
+	PTR_ADDIU t2, a0, MCONTEXT_GREGS + 4 * SZREG
+	move	t3, zero
+0:
+	addiu	t3, 1
+	REG_L	v1, (t1)
+	PTR_ADDIU t1, SZREG
+	REG_S	v1, (t2)
+	PTR_ADDIU t2, SZREG
+	bgeu	t3, a2, 2f				/* all done */
+	bltu	t3, NARGREGS, 0b			/* next */
+
+	/* Make room for stack arguments.  */
+	PTR_SUBU t2, a2, t3
+	PTR_SLL	t2, 3
+	PTR_SUBU t0, t2
+	and	t0, ALMASK
+
+	/* Store stack arguments.  */
+	move	t2, t0
+1:
+	addiu	t3, 1
+	REG_L	v1, (t1)
+	PTR_ADDIU t1, SZREG
+	REG_S	v1, (t2)
+	PTR_ADDIU t2, SZREG
+	bltu	t3, a2, 1b				/* next */
+
+2:
+#if _MIPS_SIM == _ABIO32
+	/* Make room for a0-a3 storage.  */
+	PTR_ADDIU t0, -(NARGSAVE * SZREG)
+#endif
+	PTR_L	v1, UCONTEXT_LINK(a0)
+#ifdef __PIC__
+	PTR_ADDIU t9, 99f - 98b
+#else
+	PTR_LA	t9, 99f
+#endif
+	REG_S	t0, (29 * SZREG + MCONTEXT_GREGS)(a0)	/* sp */
+	REG_S	v1, (16 * SZREG + MCONTEXT_GREGS)(a0)	/* s0 */
+#ifdef __PIC__
+	REG_S	gp, (17 * SZREG + MCONTEXT_GREGS)(a0)	/* s1 */
+#endif
+	REG_S	t9, (31 * SZREG + MCONTEXT_GREGS)(a0)	/* ra */
+	REG_S	a1, MCONTEXT_PC(a0)
+
+#ifdef __PIC__
+	RESTORE_GP64
+	PTR_ADDIU sp, FRAMESZ
+#endif
+	jr	ra
+
+99:
+#ifdef __PIC__
+	move	gp, s1
+#endif
+	move	a0, zero
+	beqz	s0, 0f
+
+	/* setcontext (ucp) */
+	move	a0, s0
+#ifdef __PIC__
+	PTR_LA	t9, JUMPTARGET (__setcontext)
+	jalr	t9
+# if _MIPS_SIM == _ABIO32
+	move	gp, s1
+# endif
+#else
+	jal	JUMPTARGET (__setcontext)
+#endif
+	move	a0, v0
+
+0:
+	/* exit (a0) */
+#ifdef __PIC__
+	PTR_LA	t9, HIDDEN_JUMPTARGET (exit)
+	jalr	t9
+#else
+	jal	HIDDEN_JUMPTARGET (exit)
+#endif
+
+	/* You don't exist, you won't feel anything.  */
+1:
+	lb	zero, (zero)
+	b	1b
+PSEUDO_END (__makecontext)
+
+weak_alias (__makecontext, makecontext)
diff --git a/libc/sysdeps/linux/mips/setcontext.S b/libc/sysdeps/linux/mips/setcontext.S
new file mode 100644
index 000000000..d3cde0e50
--- /dev/null
+++ b/libc/sysdeps/linux/mips/setcontext.S
@@ -0,0 +1,191 @@
+/* Set current context.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Maciej W. Rozycki <macro@codesourcery.com>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <sys/asm.h>
+#include <sys/fpregdef.h>
+#include <sys/regdef.h>
+
+#include "ucontext_i.h"
+
+/* int setcontext (const ucontext_t *ucp) */
+
+	.text
+LOCALSZ = 0
+ARGSZ = 0
+MASK = 0x00000000
+#ifdef __PIC__
+LOCALSZ = 1						/* save gp */
+#endif
+#if _MIPS_SIM != _ABIO32
+ARGSZ = 1						/* save a0 */
+# ifdef __PIC__
+MASK = 0x10000000
+# endif
+#endif
+FRAMESZ = (((ARGSZ + LOCALSZ) * SZREG) + ALSZ) & ALMASK
+GPOFF = FRAMESZ - ((ARGSZ + 1) * SZREG)
+#if _MIPS_SIM != _ABIO32
+A0OFF = FRAMESZ - (1 * SZREG)				/* callee-allocated */
+#else
+A0OFF = FRAMESZ + (0 * SZREG)				/* caller-allocated */
+#endif
+
+NESTED (__setcontext, FRAMESZ, ra)
+	.mask	MASK, -(ARGSZ * SZREG)
+	.fmask	0x00000000, 0
+
+#ifdef __PIC__
+	SETUP_GP
+#endif
+
+	PTR_ADDIU sp, -FRAMESZ
+
+#ifdef __PIC__
+	SETUP_GP64 (GPOFF, __setcontext)
+	SAVE_GP (GPOFF)
+#endif
+
+#ifdef PROF
+	.set	noat
+	move	AT, ra
+	jal	_mcount
+	.set	at
+#endif
+
+	/* Check for the magic flag.  */
+	li	v0, 1
+	REG_L	v1, (0 * SZREG + MCONTEXT_GREGS)(a0)	/* zero */
+	bne	v0, v1, 98f
+
+	REG_S	a0, A0OFF(sp)
+
+/* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, NULL, _NSIG8) */
+	li	a3, _NSIG8
+	move	a2, zero
+	PTR_ADDU a1, a0, UCONTEXT_SIGMASK
+	li	a0, SIG_SETMASK
+
+	li	v0, SYS_ify (rt_sigprocmask)
+	syscall
+	bnez	a3, 99f
+
+	REG_L	v0, A0OFF(sp)
+
+#ifdef __mips_hard_float
+# if _MIPS_SIM == _ABI64
+	l.d	fs0, (24 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs1, (25 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs2, (26 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs3, (27 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs4, (28 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs5, (29 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs6, (30 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs7, (31 * SZREG + MCONTEXT_FPREGS)(v0)
+
+# else  /* _MIPS_SIM != _ABI64 */
+	l.d	fs0, (20 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs1, (22 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs2, (24 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs3, (26 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs4, (28 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs5, (30 * SZREG + MCONTEXT_FPREGS)(v0)
+
+# endif /* _MIPS_SIM != _ABI64 */
+
+	lw	v1, MCONTEXT_FPC_CSR(v0)
+	ctc1	v1, fcr31
+#endif /* __mips_hard_float */
+
+	/* Note the contents of argument registers will be random
+	   unless makecontext() has been called.  */
+	REG_L	a0, (4 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a1, (5 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a2, (6 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a3, (7 * SZREG + MCONTEXT_GREGS)(v0)
+#if _MIPS_SIM != _ABIO32
+	REG_L	a4, (8 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a5, (9 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a6, (10 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a7, (11 * SZREG + MCONTEXT_GREGS)(v0)
+#endif
+
+	REG_L	s0, (16 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s1, (17 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s2, (18 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s3, (19 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s4, (20 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s5, (21 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s6, (22 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s7, (23 * SZREG + MCONTEXT_GREGS)(v0)
+#if ! defined (__PIC__) || _MIPS_SIM != _ABIO32
+	REG_L	gp, (28 * SZREG + MCONTEXT_GREGS)(v0)
+#endif
+	REG_L	sp, (29 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	fp, (30 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	ra, (31 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	t9, MCONTEXT_PC(v0)
+
+	move	v0, zero
+	jr	t9
+
+98:
+	/* This is a context obtained from a signal handler.
+	   Perform a full restore by pushing the context
+	   passed onto a simulated signal frame on the stack
+	   and call the signal return syscall as if a signal
+	   handler exited normally.  */
+	PTR_ADDIU sp, -((RT_SIGFRAME_SIZE + ALSZ) & ALMASK)
+
+	/* Only ucontext is referred to from rt_sigreturn,
+	   copy it.  */
+	PTR_ADDIU t1, sp, RT_SIGFRAME_UCONTEXT
+	li	t3, ((UCONTEXT_SIZE + SZREG - 1) / SZREG) - 1
+0:
+	REG_L	t2, (a0)
+	PTR_ADDIU a0, SZREG
+	REG_S	t2, (t1)
+	PTR_ADDIU t1, SZREG
+	.set	noreorder
+	bgtz	t3, 0b
+	 addiu	t3, -1
+	.set	reorder
+
+/* rt_sigreturn () -- no arguments, sp points to struct rt_sigframe.  */
+	li	v0, SYS_ify (rt_sigreturn)
+	syscall
+
+	/* Restore the stack and fall through to the error
+	   path.  Successful rt_sigreturn never returns to
+	   its calling place.  */
+	PTR_ADDIU sp, ((RT_SIGFRAME_SIZE + ALSZ) & ALMASK)
+99:
+#ifdef __PIC__
+	PTR_LA	t9, JUMPTARGET (__syscall_error)
+	RESTORE_GP64
+	PTR_ADDIU sp, FRAMESZ
+	jr	t9
+
+#else  /* ! __PIC__ */
+
+	j	JUMPTARGET (__syscall_error)
+#endif /* ! __PIC__ */
+PSEUDO_END (__setcontext)
+
+weak_alias (__setcontext, setcontext)
diff --git a/libc/sysdeps/linux/mips/swapcontext.S b/libc/sysdeps/linux/mips/swapcontext.S
new file mode 100644
index 000000000..c7ac19b9f
--- /dev/null
+++ b/libc/sysdeps/linux/mips/swapcontext.S
@@ -0,0 +1,211 @@
+/* Save and set current context.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Maciej W. Rozycki <macro@codesourcery.com>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <sys/asm.h>
+#include <sys/fpregdef.h>
+#include <sys/regdef.h>
+
+#include "ucontext_i.h"
+
+/* int swapcontext (ucontext_t *oucp, const ucontext_t *ucp) */
+
+	.text
+LOCALSZ = 0
+ARGSZ = 0
+MASK = 0x00000000
+#ifdef __PIC__
+LOCALSZ = 1						/* save gp */
+#endif
+#if _MIPS_SIM != _ABIO32
+ARGSZ = 1						/* save a1 */
+# ifdef __PIC__
+MASK = 0x10000000
+# endif
+#endif
+FRAMESZ = (((ARGSZ + LOCALSZ) * SZREG) + ALSZ) & ALMASK
+GPOFF = FRAMESZ - ((ARGSZ + 1) * SZREG)
+#if _MIPS_SIM != _ABIO32
+A1OFF = FRAMESZ - (1 * SZREG)				/* callee-allocated */
+#else
+A1OFF = FRAMESZ + (1 * SZREG)				/* caller-allocated */
+#endif
+
+NESTED (__swapcontext, FRAMESZ, ra)
+	.mask	MASK, -(ARGSZ * SZREG)
+	.fmask	0x00000000, 0
+
+#ifdef __PIC__
+	SETUP_GP
+
+	move	a2, sp
+# define _SP a2
+
+# if _MIPS_SIM != _ABIO32
+	move	a3, gp
+#  define _GP a3
+# endif
+
+	PTR_ADDIU sp, -FRAMESZ
+	SETUP_GP64 (GPOFF, __swapcontext)
+	SAVE_GP (GPOFF)
+
+#else  /* ! __PIC__ */
+# define _SP sp
+# define _GP gp
+
+#endif /* ! __PIC__ */
+
+#ifdef PROF
+	.set	noat
+	move	AT, ra
+	jal	_mcount
+	.set	at
+#endif
+
+	/* Store a magic flag.	*/
+	li	v1, 1
+	REG_S	v1, (0 * SZREG + MCONTEXT_GREGS)(a0)	/* zero */
+
+	REG_S	s0, (16 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s1, (17 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s2, (18 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s3, (19 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s4, (20 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s5, (21 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s6, (22 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	s7, (23 * SZREG + MCONTEXT_GREGS)(a0)
+#if ! defined (__PIC__) || _MIPS_SIM != _ABIO32
+	REG_S	_GP, (28 * SZREG + MCONTEXT_GREGS)(a0)
+#endif
+	REG_S	_SP, (29 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	fp, (30 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	ra, (31 * SZREG + MCONTEXT_GREGS)(a0)
+	REG_S	ra, MCONTEXT_PC(a0)
+
+#ifdef __mips_hard_float
+# if _MIPS_SIM == _ABI64
+	s.d	fs0, (24 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs1, (25 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs2, (26 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs3, (27 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs4, (28 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs5, (29 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs6, (30 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs7, (31 * SZREG + MCONTEXT_FPREGS)(a0)
+
+# else  /* _MIPS_SIM != _ABI64 */
+	s.d	fs0, (20 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs1, (22 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs2, (24 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs3, (26 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs4, (28 * SZREG + MCONTEXT_FPREGS)(a0)
+	s.d	fs5, (30 * SZREG + MCONTEXT_FPREGS)(a0)
+
+# endif /* _MIPS_SIM != _ABI64 */
+
+	cfc1	v1, fcr31
+	sw	v1, MCONTEXT_FPC_CSR(a0)
+#endif /* __mips_hard_float */
+
+	REG_S	a1, A1OFF(sp)
+
+/* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, &oucp->uc_sigmask, _NSIG8) */
+	li	a3, _NSIG8
+	PTR_ADDU a2, a0, UCONTEXT_SIGMASK
+	PTR_ADDU a1, a1, UCONTEXT_SIGMASK
+	li	a0, SIG_SETMASK
+
+	li	v0, SYS_ify (rt_sigprocmask)
+	syscall
+	bnez	a3, 99f
+
+	REG_L	v0, A1OFF(sp)
+
+#ifdef __mips_hard_float
+# if _MIPS_SIM == _ABI64
+	l.d	fs0, (24 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs1, (25 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs2, (26 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs3, (27 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs4, (28 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs5, (29 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs6, (30 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs7, (31 * SZREG + MCONTEXT_FPREGS)(v0)
+
+# else  /* _MIPS_SIM != _ABI64 */
+	l.d	fs0, (20 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs1, (22 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs2, (24 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs3, (26 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs4, (28 * SZREG + MCONTEXT_FPREGS)(v0)
+	l.d	fs5, (30 * SZREG + MCONTEXT_FPREGS)(v0)
+
+# endif /* _MIPS_SIM != _ABI64 */
+
+	lw	v1, MCONTEXT_FPC_CSR(v0)
+	ctc1	v1, fcr31
+#endif /* __mips_hard_float */
+
+	/* Note the contents of argument registers will be random
+	   unless makecontext() has been called.  */
+	REG_L	a0, (4 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a1, (5 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a2, (6 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a3, (7 * SZREG + MCONTEXT_GREGS)(v0)
+#if _MIPS_SIM != _ABIO32
+	REG_L	a4, (8 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a5, (9 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a6, (10 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	a7, (11 * SZREG + MCONTEXT_GREGS)(v0)
+#endif
+
+	REG_L	s0, (16 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s1, (17 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s2, (18 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s3, (19 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s4, (20 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s5, (21 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s6, (22 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	s7, (23 * SZREG + MCONTEXT_GREGS)(v0)
+#if ! defined (__PIC__) || _MIPS_SIM != _ABIO32
+	REG_L	gp, (28 * SZREG + MCONTEXT_GREGS)(v0)
+#endif
+	REG_L	sp, (29 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	fp, (30 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	ra, (31 * SZREG + MCONTEXT_GREGS)(v0)
+	REG_L	t9, MCONTEXT_PC(v0)
+
+	move	v0, zero
+	jr	t9
+
+99:
+#ifdef __PIC__
+	PTR_LA	t9, JUMPTARGET (__syscall_error)
+	RESTORE_GP64
+	PTR_ADDIU sp, FRAMESZ
+	jr	t9
+
+#else  /* ! __PIC__ */
+
+	j	JUMPTARGET (__syscall_error)
+#endif /* ! __PIC__ */
+PSEUDO_END (__swapcontext)
+
+weak_alias (__swapcontext, swapcontext)
diff --git a/libc/sysdeps/linux/mips/ucontext_i.sym b/libc/sysdeps/linux/mips/ucontext_i.sym
new file mode 100644
index 000000000..f14b88640
--- /dev/null
+++ b/libc/sysdeps/linux/mips/ucontext_i.sym
@@ -0,0 +1,52 @@
+#include <inttypes.h>
+#include <signal.h>
+#include <stddef.h>
+#include <sys/ucontext.h>
+
+#include <kernel_rt_sigframe.h>
+
+-- Constants used by the rt_sigprocmask call.
+
+SIG_BLOCK
+SIG_SETMASK
+
+_NSIG8				(_NSIG / 8)
+
+-- Offsets of the fields in the kernel rt_sigframe_t structure.
+#define rt_sigframe(member)	offsetof (kernel_rt_sigframe_t, member)
+
+RT_SIGFRAME_UCONTEXT		rt_sigframe (rs_uc)
+
+RT_SIGFRAME_SIZE		sizeof (kernel_rt_sigframe_t)
+
+-- Offsets of the fields in the ucontext_t structure.
+#define ucontext(member)	offsetof (ucontext_t, member)
+#define stack(member)		ucontext (uc_stack.member)
+#define mcontext(member)	ucontext (uc_mcontext.member)
+
+UCONTEXT_FLAGS			ucontext (uc_flags)
+UCONTEXT_LINK			ucontext (uc_link)
+UCONTEXT_STACK			ucontext (uc_stack)
+UCONTEXT_MCONTEXT		ucontext (uc_mcontext)
+UCONTEXT_SIGMASK		ucontext (uc_sigmask)
+
+STACK_SP			stack (ss_sp)
+STACK_SIZE			stack (ss_size)
+STACK_FLAGS			stack (ss_flags)
+
+MCONTEXT_GREGS			mcontext (gregs)
+MCONTEXT_FPREGS			mcontext (fpregs)
+MCONTEXT_MDHI			mcontext (mdhi)
+MCONTEXT_HI1			mcontext (hi1)
+MCONTEXT_HI2			mcontext (hi2)
+MCONTEXT_HI3			mcontext (hi3)
+MCONTEXT_MDLO			mcontext (mdlo)
+MCONTEXT_LO1			mcontext (lo1)
+MCONTEXT_LO2			mcontext (lo2)
+MCONTEXT_LO3			mcontext (lo3)
+MCONTEXT_PC			mcontext (pc)
+MCONTEXT_FPC_CSR		mcontext (fpc_csr)
+MCONTEXT_USED_MATH		mcontext (used_math)
+MCONTEXT_DSP			mcontext (dsp)
+
+UCONTEXT_SIZE			sizeof (ucontext_t)