sparc: add deprecated context switching functions

Ported over from glibc mostly without changes.
Lightly tested with mongrel2 in qemu-system-sparc.

7 files changed, 477 insertions, 0 deletions

diff --git a/extra/Configs/Config.sparc b/extra/Configs/Config.sparc
index 47c8ac289..8b5da330f 100644
--- a/extra/Configs/Config.sparc
+++ b/extra/Configs/Config.sparc
@@ -11,6 +11,7 @@ config FORCE_OPTIONS_FOR_ARCH
 	bool
 	default y
 	select ARCH_BIG_ENDIAN
+	select ARCH_HAS_UCONTEXT
 	select ARCH_HAS_DEPRECATED_SYSCALLS
 
 choice
diff --git a/libc/sysdeps/linux/sparc/Makefile.arch b/libc/sysdeps/linux/sparc/Makefile.arch
index 0173effbf..92ea7d93f 100644
--- a/libc/sysdeps/linux/sparc/Makefile.arch
+++ b/libc/sysdeps/linux/sparc/Makefile.arch
@@ -13,6 +13,9 @@ SSRC-y := \
 
 SSRC-$(if $(UCLIBC_HAS_THREADS_NATIVE),,y) += fork.S vfork.S clone.S
 
+CSRC-$(UCLIBC_HAS_CONTEXT_FUNCS) += makecontext.c
+SSRC-$(UCLIBC_HAS_CONTEXT_FUNCS) += getcontext.S setcontext.S swapcontext.S
+
 # check weather __LONG_DOUBLE_128__ is defined (long double support)
 UCLIBC_SPARC_HAS_LONG_DOUBLE=$(shell if [ "x`$(CC) -E -dM -xc /dev/null 2>&1 | grep __LONG_DOUBLE_128__`" != "x" ]; then echo "y"; fi)
 ifeq ($(UCLIBC_SPARC_HAS_LONG_DOUBLE),y)
diff --git a/libc/sysdeps/linux/sparc/getcontext.S b/libc/sysdeps/linux/sparc/getcontext.S
new file mode 100644
index 000000000..615a2c190
--- /dev/null
+++ b/libc/sysdeps/linux/sparc/getcontext.S
@@ -0,0 +1,84 @@
+/* Save current context.
+   Copyright (C) 2008-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by David S. Miller <davem@davemloft.net>, 2008.
+
+   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 "ucontext_i.h"
+
+/*  int __getcontext (ucontext_t *ucp)
+
+  Saves the machine context in UCP such that when it is activated,
+  it appears as if __getcontext() returned again.
+
+  This implementation is intended to be used for *synchronous* context
+  switches only.  Therefore, it does not have to save anything
+  other than the PRESERVED state.  */
+
+
+ENTRY(__getcontext)
+	save	%sp, -112, %sp
+	st	%g0, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_PSR]
+
+	/* In reality, we only use the GREG_PC value when setting
+	   or swapping contexts.  But we fill in NPC for completeness.  */
+	add	%i7, 8, %o0
+	st	%o0, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_PC]
+	add	%o0, 4, %o0
+	st	%o0, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_NPC]
+
+	rd	%y, %o1
+	st	%o1, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_Y]
+
+	st	%g1, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G1]
+	st	%g2, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G2]
+	st	%g3, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G3]
+	st	%g4, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G4]
+	st	%g5, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G5]
+	st	%g6, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G6]
+	st	%g7, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G7]
+
+	mov	SIG_BLOCK, %o0
+	clr	%o1
+	add	%i0, UC_SIGMASK, %o2
+	mov	8, %o3
+	mov	__NR_rt_sigprocmask, %g1
+	ta	0x10
+
+	/* Zero, success, return value.  */
+	st	%g0, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O0]
+	st	%i1, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O1]
+	st	%i2, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O2]
+	st	%i3, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O3]
+	st	%i4, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O4]
+	st	%i5, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O5]
+	st	%i6, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O6]
+	st	%i7, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O7]
+
+	st	%g0, [%i0 + UC_MCONTEXT + MC_GWINS]
+
+	/* Do not save FPU state, it is volatile across calls.  */
+	stb	%g0, [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_EN]
+
+	st	%g0, [%i0 + UC_MCONTEXT + MC_XRS + XRS_ID]
+	st	%g0, [%i0 + UC_MCONTEXT + MC_XRS + XRS_PTR]
+	jmpl	%i7 + 8, %g0
+	 restore %g0, %g0, %o0
+END(__getcontext)
+
+weak_alias (__getcontext, getcontext)
diff --git a/libc/sysdeps/linux/sparc/makecontext.c b/libc/sysdeps/linux/sparc/makecontext.c
new file mode 100644
index 000000000..3a9f70cc5
--- /dev/null
+++ b/libc/sysdeps/linux/sparc/makecontext.c
@@ -0,0 +1,92 @@
+/* Create new context.
+   Copyright (C) 2008-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by David S. Miller <davem@davemloft.net>, 2008.
+
+   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 <stdarg.h>
+#include <stdint.h>
+#include <ucontext.h>
+
+/* Sets up the outgoing arguments and the program counter for a user
+   context for the requested function call.
+
+   Returning to the correct parent context is pretty simple on
+   Sparc.  We only need to link up the register windows correctly.
+   Since global registers are clobbered by calls, we need not be
+   concerned about those, and thus is all could be worked out without
+   using a trampoline.
+
+   Except that we must deal with the signal mask, thus a trampoline
+   is unavoidable. 32-bit stackframe layout:
+	      +-----------------------------------------+
+	      | 7th and further parameters		|
+	      +-----------------------------------------+
+	      | backup storage for initial 6 parameters |
+	      +-----------------------------------------+
+	      | struct return pointer			|
+	      +-----------------------------------------+
+	      | 8 incoming registers			|
+	      +-----------------------------------------+
+	      | 8 local registers			|
+     %sp -->  +-----------------------------------------+
+
+*/
+
+void
+__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
+{
+  extern void __start_context (void);
+  unsigned long int *sp;
+  va_list ap;
+  int i;
+
+  sp = (unsigned long int *) (ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+  sp -= 16 + 7 + argc;
+  sp = (unsigned long int *) (((uintptr_t) sp) & ~(8 - 1));
+
+  for (i = 0; i < 8; i++)
+    sp[i + 8] = ucp->uc_mcontext.gregs[REG_O0 + i];
+
+  /* The struct return pointer is essentially unused, so we can
+     place the link there.  */
+  sp[16] = (unsigned long int) ucp->uc_link;
+
+  va_start (ap, argc);
+
+  /* Fill in outgoing arguments, including those which will
+     end up being passed on the stack.  */
+  for (i = 0; i < argc; i++)
+    {
+      unsigned long int arg = va_arg (ap, unsigned long int);
+      if (i < 6)
+	ucp->uc_mcontext.gregs[REG_O0 + i] = arg;
+      else
+	sp[i + 23 - 6] = arg;
+    }
+
+  va_end (ap);
+
+  ucp->uc_mcontext.gregs[REG_O6] = (unsigned long int) sp;
+
+  ucp->uc_mcontext.gregs[REG_O7] = ((unsigned long int) __start_context) - 8;
+
+  ucp->uc_mcontext.gregs[REG_PC] = (unsigned long int) func;
+  ucp->uc_mcontext.gregs[REG_nPC] = ucp->uc_mcontext.gregs[REG_PC] + 4;
+}
+
+weak_alias (__makecontext, makecontext)
diff --git a/libc/sysdeps/linux/sparc/setcontext.S b/libc/sysdeps/linux/sparc/setcontext.S
new file mode 100644
index 000000000..f9da21563
--- /dev/null
+++ b/libc/sysdeps/linux/sparc/setcontext.S
@@ -0,0 +1,118 @@
+/* Install given context.
+   Copyright (C) 2008-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by David S. Miller <davem@davemloft.net>, 2008.
+
+   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 "ucontext_i.h"
+
+#define ST_FLUSH_WINDOWS 3
+
+/*  int __setcontext (const ucontext_t *ucp)
+
+  Restores the machine context in UCP and thereby resumes execution
+  in that context.
+
+  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.  */
+
+ENTRY(__setcontext)
+	save	%sp, -112, %sp
+
+	mov	SIG_SETMASK, %o0
+	add	%i0, UC_SIGMASK, %o1
+	clr	%o2
+	mov	8, %o3
+	mov	__NR_rt_sigprocmask, %g1
+	ta	0x10
+
+	/* This is a bit on the expensive side, and we could optimize
+	   the unwind similar to how the 32-bit sparc longjmp code
+	   does if performance of this routine really matters.  */
+	ta	ST_FLUSH_WINDOWS
+
+	ldub	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_EN], %g1
+	cmp	%g1, 0
+	be	1f
+	 nop
+	ld	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_FSR], %fsr
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D0], %f0
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D2], %f2
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D4], %f4
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D6], %f6
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D8], %f8
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D10], %f10
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D12], %f12
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D14], %f14
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D16], %f16
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D18], %f18
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D20], %f20
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D22], %f22
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D24], %f24
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D26], %f26
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D28], %f28
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D30], %f30
+1:
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_Y], %g1
+	wr	%g1, 0x0, %y
+
+	/* We specifically do not restore %g1 since we need it here as
+	   a temporary.  */
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G2], %g2
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G3], %g3
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G4], %g4
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G5], %g5
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G6], %g6
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G7], %g7
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O1], %i1
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O2], %i2
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O3], %i3
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O4], %i4
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O5], %i5
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O6], %i6
+	restore
+	ld	[%o0 + UC_MCONTEXT + MC_GREGS + GREG_O7], %o7
+	ld	[%o0 + UC_MCONTEXT + MC_GREGS + GREG_PC], %g1
+	jmpl	%g1, %g0
+	 ld	[%o0 + UC_MCONTEXT + MC_GREGS + GREG_O0], %o0
+END(__setcontext)
+
+weak_alias (__setcontext, setcontext)
+
+/* This is the helper code which gets called if a function which is
+   registered with 'makecontext' returns.  In this case we have to
+   install the context listed in the uc_link element of the context
+   'makecontext' manipulated at the time of the 'makecontext' call.
+   If the pointer is NULL the process must terminate.  */
+
+ENTRY(__start_context)
+	ld	[%sp + (16 * 4)], %g1
+	cmp	%g1, 0
+	be,a	1f
+	 clr	%o0
+	call	__setcontext
+	 mov	%g1, %o0
+	/* If this returns (which can happen if the syscall fails) we'll
+	   exit the program with the return error value (-1).  */
+1:	call	HIDDEN_JUMPTARGET(exit)
+	 nop
+	/* The 'exit' call should never return.  In case it does cause
+	   the process to terminate.  */
+	unimp
+END(__start_context)
diff --git a/libc/sysdeps/linux/sparc/swapcontext.S b/libc/sysdeps/linux/sparc/swapcontext.S
new file mode 100644
index 000000000..7dc7e2ebf
--- /dev/null
+++ b/libc/sysdeps/linux/sparc/swapcontext.S
@@ -0,0 +1,118 @@
+/* Save current context and install the given one.
+   Copyright (C) 2008-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by David S. Miller <davem@davemloft.net>, 2008.
+
+   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 "ucontext_i.h"
+
+#define ST_FLUSH_WINDOWS 3
+
+/* int __swapcontext (ucontext_t *oucp, const ucontext_t *ucp);
+
+  Saves the machine context in oucp such that when it is activated,
+  it appears as if __swapcontext() returned again, restores the
+  machine context in ucp and thereby resumes execution in that
+  context.
+
+  This implementation is intended to be used for *synchronous* context
+  switches only.  Therefore, it does not have to save anything
+  other than the PRESERVED state.  */
+
+ENTRY(__swapcontext)
+	save	%sp, -112, %sp
+	ta	ST_FLUSH_WINDOWS
+	st	%g0, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_PSR]
+	add	%i7, 8, %o0
+	st	%o0, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_PC]
+	add	%o0, 4, %o0
+	st	%o0, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_NPC]
+	rd	%y, %o1
+	st	%o1, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_Y]
+	st	%g1, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G1]
+	st	%g2, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G2]
+	st	%g3, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G3]
+	st	%g4, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G4]
+	st	%g5, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G5]
+	st	%g6, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G6]
+	st	%g7, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G7]
+	st	%g0, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O0]
+	st	%i1, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O1]
+	st	%i2, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O2]
+	st	%i3, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O3]
+	st	%i4, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O4]
+	st	%i5, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O5]
+	st	%i6, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O6]
+	st	%i7, [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O7]
+	st	%g0, [%i0 + UC_MCONTEXT + MC_GWINS]
+	stb	%g0, [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_EN]
+	st	%g0, [%i0 + UC_MCONTEXT + MC_XRS + XRS_ID]
+	st	%g0, [%i0 + UC_MCONTEXT + MC_XRS + XRS_PTR]
+
+	mov	SIG_SETMASK, %o0
+	add	%i1, UC_SIGMASK, %o1
+	add	%i0, UC_SIGMASK, %o2
+	mov	8, %o3
+	mov	__NR_rt_sigprocmask, %g1
+	ta	0x10
+
+	mov	%i1, %i0
+	ldub	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_EN], %g1
+	cmp	%g1, 0
+	be	1f
+	 nop
+	ld	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_FSR], %fsr
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D0], %f0
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D2], %f2
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D4], %f4
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D6], %f6
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D8], %f8
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D10], %f10
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D12], %f12
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D14], %f14
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D16], %f16
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D18], %f18
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D20], %f20
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D22], %f22
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D24], %f24
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D26], %f26
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D28], %f28
+	ldd	[%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D30], %f30
+1:
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_Y], %g1
+	wr	%g1, 0x0, %y
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G2], %g2
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G3], %g3
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G4], %g4
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G5], %g5
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G6], %g6
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_G7], %g7
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O1], %i1
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O2], %i2
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O3], %i3
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O4], %i4
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O5], %i5
+	ld	[%i0 + UC_MCONTEXT + MC_GREGS + GREG_O6], %i6
+	restore
+	ld	[%o0 + UC_MCONTEXT + MC_GREGS + GREG_O7], %o7
+	ld	[%o0 + UC_MCONTEXT + MC_GREGS + GREG_PC], %g1
+	jmpl	%g1, %g0
+	 ld	[%o0 + UC_MCONTEXT + MC_GREGS + GREG_O0], %o0
+END(__swapcontext)
+
+weak_alias (__swapcontext, swapcontext)
diff --git a/libc/sysdeps/linux/sparc/ucontext_i.sym b/libc/sysdeps/linux/sparc/ucontext_i.sym
new file mode 100644
index 000000000..544030ce8
--- /dev/null
+++ b/libc/sysdeps/linux/sparc/ucontext_i.sym
@@ -0,0 +1,61 @@
+#include <stddef.h>
+#include <signal.h>
+#include <sys/ucontext.h>
+
+--
+
+SIG_BLOCK
+SIG_SETMASK
+
+UC_FLAGS	offsetof (ucontext_t, uc_flags)
+UC_LINK		offsetof (ucontext_t, uc_link)
+UC_SIGMASK	offsetof (ucontext_t, uc_sigmask)
+UC_STACK	offsetof (ucontext_t, uc_stack)
+UC_MCONTEXT	offsetof (ucontext_t, uc_mcontext)
+MC_GREGS	offsetof (mcontext_t, gregs)
+MC_GWINS	offsetof (mcontext_t, gwins)
+MC_FPREGS	offsetof (mcontext_t, fpregs)
+MC_XRS		offsetof (mcontext_t, xrs)
+MC_FILLER	offsetof (mcontext_t, filler)
+GREG_PSR	(REG_PSR * sizeof(greg_t))
+GREG_PC		(REG_PC * sizeof(greg_t))
+GREG_NPC	(REG_nPC * sizeof(greg_t))
+GREG_Y		(REG_Y * sizeof(greg_t))
+GREG_G1		(REG_G1 * sizeof(greg_t))
+GREG_G2		(REG_G2 * sizeof(greg_t))
+GREG_G3		(REG_G3 * sizeof(greg_t))
+GREG_G4		(REG_G4 * sizeof(greg_t))
+GREG_G5		(REG_G5 * sizeof(greg_t))
+GREG_G6		(REG_G6 * sizeof(greg_t))
+GREG_G7		(REG_G7 * sizeof(greg_t))
+GREG_O0		(REG_O0 * sizeof(greg_t))
+GREG_O1		(REG_O1 * sizeof(greg_t))
+GREG_O2		(REG_O2 * sizeof(greg_t))
+GREG_O3		(REG_O3 * sizeof(greg_t))
+GREG_O4		(REG_O4 * sizeof(greg_t))
+GREG_O5		(REG_O5 * sizeof(greg_t))
+GREG_O6		(REG_O6 * sizeof(greg_t))
+GREG_O7		(REG_O7 * sizeof(greg_t))
+FPU_D0		offsetof (fpregset_t, fpu_fr.fpu_dregs[0])
+FPU_D2		offsetof (fpregset_t, fpu_fr.fpu_dregs[1])
+FPU_D4		offsetof (fpregset_t, fpu_fr.fpu_dregs[2])
+FPU_D6		offsetof (fpregset_t, fpu_fr.fpu_dregs[3])
+FPU_D8		offsetof (fpregset_t, fpu_fr.fpu_dregs[4])
+FPU_D10		offsetof (fpregset_t, fpu_fr.fpu_dregs[5])
+FPU_D12		offsetof (fpregset_t, fpu_fr.fpu_dregs[6])
+FPU_D14		offsetof (fpregset_t, fpu_fr.fpu_dregs[7])
+FPU_D16		offsetof (fpregset_t, fpu_fr.fpu_dregs[8])
+FPU_D18		offsetof (fpregset_t, fpu_fr.fpu_dregs[9])
+FPU_D20		offsetof (fpregset_t, fpu_fr.fpu_dregs[10])
+FPU_D22		offsetof (fpregset_t, fpu_fr.fpu_dregs[11])
+FPU_D24		offsetof (fpregset_t, fpu_fr.fpu_dregs[12])
+FPU_D26		offsetof (fpregset_t, fpu_fr.fpu_dregs[13])
+FPU_D28		offsetof (fpregset_t, fpu_fr.fpu_dregs[14])
+FPU_D30		offsetof (fpregset_t, fpu_fr.fpu_dregs[15])
+FPU_Q		offsetof (fpregset_t, fpu_q)
+FPU_FSR		offsetof (fpregset_t, fpu_fsr)
+FPU_QCNT	offsetof (fpregset_t, fpu_qcnt)
+FPU_Q_ENTRY_SZ	offsetof (fpregset_t, fpu_q_entrysize)
+FPU_EN		offsetof (fpregset_t, fpu_en)
+XRS_ID		offsetof (xrs_t, xrs_id)
+XRS_PTR		offsetof (xrs_t, xrs_ptr)