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>

1 files changed, 211 insertions, 0 deletions

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)