1 files changed, 122 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/riscv64/swapcontext.S b/libc/sysdeps/linux/riscv64/swapcontext.S
new file mode 100644
index 000000000..f5e12b2db
--- /dev/null
+++ b/libc/sysdeps/linux/riscv64/swapcontext.S
@@ -0,0 +1,122 @@
+/* Save and set current context.
+   Copyright (C) 2009-2018 Free Software Foundation, Inc.
+
+   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 "ucontext-macros.h"
+
+/* int swapcontext (ucontext_t *oucp, const ucontext_t *ucp) */
+
+LEAF (swapcontext)
+	mv	t0, a1			/* Save ucp into t0.  */
+
+	SAVE_INT_REG (ra,   0, a0)
+	SAVE_INT_REG (ra,   1, a0)
+	SAVE_INT_REG (sp,   2, a0)
+	SAVE_INT_REG (s0,   8, a0)
+	SAVE_INT_REG (s1,   9, a0)
+	SAVE_INT_REG (x0,  10, a0)	/* return 0 by overwriting a0.  */
+	SAVE_INT_REG (s2,  18, a0)
+	SAVE_INT_REG (s3,  19, a0)
+	SAVE_INT_REG (s4,  20, a0)
+	SAVE_INT_REG (s5,  21, a0)
+	SAVE_INT_REG (s6,  22, a0)
+	SAVE_INT_REG (s7,  23, a0)
+	SAVE_INT_REG (s8,  24, a0)
+	SAVE_INT_REG (s9,  25, a0)
+	SAVE_INT_REG (s10, 26, a0)
+	SAVE_INT_REG (s11, 27, a0)
+
+#ifndef __riscv_float_abi_soft
+	frsr a1
+
+	SAVE_FP_REG (fs0,   8, a0)
+	SAVE_FP_REG (fs1,   9, a0)
+	SAVE_FP_REG (fs2,  18, a0)
+	SAVE_FP_REG (fs3,  19, a0)
+	SAVE_FP_REG (fs4,  20, a0)
+	SAVE_FP_REG (fs5,  21, a0)
+	SAVE_FP_REG (fs6,  22, a0)
+	SAVE_FP_REG (fs7,  23, a0)
+	SAVE_FP_REG (fs8,  24, a0)
+	SAVE_FP_REG (fs9,  25, a0)
+	SAVE_FP_REG (fs10, 26, a0)
+	SAVE_FP_REG (fs11, 27, a0)
+
+	sw	a1, MCONTEXT_FSR(a0)
+#endif /* __riscv_float_abi_soft */
+
+/* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, &oucp->uc_sigmask, _NSIG8) */
+	li	a3, _NSIG8
+	add	a2, a0, UCONTEXT_SIGMASK
+	add     a1, t0, UCONTEXT_SIGMASK
+	li	a0, SIG_SETMASK
+
+	li	a7, SYS_ify (rt_sigprocmask)
+	scall
+
+	bltz	a0, 99f
+
+#ifndef __riscv_float_abi_soft
+	lw	t1, MCONTEXT_FSR(t0)
+
+	RESTORE_FP_REG (fs0,   8, t0)
+	RESTORE_FP_REG (fs1,   9, t0)
+	RESTORE_FP_REG (fs2,  18, t0)
+	RESTORE_FP_REG (fs3,  19, t0)
+	RESTORE_FP_REG (fs4,  20, t0)
+	RESTORE_FP_REG (fs5,  21, t0)
+	RESTORE_FP_REG (fs6,  22, t0)
+	RESTORE_FP_REG (fs7,  23, t0)
+	RESTORE_FP_REG (fs8,  24, t0)
+	RESTORE_FP_REG (fs9,  25, t0)
+	RESTORE_FP_REG (fs10, 26, t0)
+	RESTORE_FP_REG (fs11, 27, t0)
+
+	fssr	t1
+#endif /* __riscv_float_abi_soft */
+
+	/* Note the contents of argument registers will be random
+	   unless makecontext() has been called.  */
+	RESTORE_INT_REG (t1,   0, t0)
+	RESTORE_INT_REG (ra,   1, t0)
+	RESTORE_INT_REG (sp,   2, t0)
+	RESTORE_INT_REG (s0,   8, t0)
+	RESTORE_INT_REG (s1,   9, t0)
+	RESTORE_INT_REG (a0,  10, t0)
+	RESTORE_INT_REG (a1,  11, t0)
+	RESTORE_INT_REG (a2,  12, t0)
+	RESTORE_INT_REG (a3,  13, t0)
+	RESTORE_INT_REG (a4,  14, t0)
+	RESTORE_INT_REG (a5,  15, t0)
+	RESTORE_INT_REG (a6,  16, t0)
+	RESTORE_INT_REG (a7,  17, t0)
+	RESTORE_INT_REG (s2,  18, t0)
+	RESTORE_INT_REG (s3,  19, t0)
+	RESTORE_INT_REG (s4,  20, t0)
+	RESTORE_INT_REG (s5,  21, t0)
+	RESTORE_INT_REG (s6,  22, t0)
+	RESTORE_INT_REG (s7,  23, t0)
+	RESTORE_INT_REG (s8,  24, t0)
+	RESTORE_INT_REG (s9,  25, t0)
+	RESTORE_INT_REG (s10, 26, t0)
+	RESTORE_INT_REG (s11, 27, t0)
+
+	jr	t1
+
+
+99:	j	__syscall_error
+
+PSEUDO_END (swapcontext)