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Diffstat (limited to 'libc/sysdeps/linux/riscv32/setcontext.S')
-rw-r--r--libc/sysdeps/linux/riscv32/setcontext.S112
1 files changed, 112 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/riscv32/setcontext.S b/libc/sysdeps/linux/riscv32/setcontext.S
new file mode 100644
index 000000000..15cc17bd8
--- /dev/null
+++ b/libc/sysdeps/linux/riscv32/setcontext.S
@@ -0,0 +1,112 @@
+/* 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 __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. */
+
+ .text
+LEAF (setcontext)
+
+ mv t0, a0 /* Save ucp into t0. */
+
+/* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, NULL, _NSIG8) */
+ li a3, _NSIG8
+ mv a2, zero
+ add a1, a0, UCONTEXT_SIGMASK
+ li a0, SIG_SETMASK
+
+ li a7, SYS_ify (rt_sigprocmask)
+ scall
+
+ bltz a0, 99f
+
+ cfi_def_cfa (t0, 0)
+
+#ifndef __riscv_float_abi_soft
+ lw t1, MCONTEXT_FSR(t0)
+
+ RESTORE_FP_REG_CFI (fs0, 8, t0)
+ RESTORE_FP_REG_CFI (fs1, 9, t0)
+ RESTORE_FP_REG_CFI (fs2, 18, t0)
+ RESTORE_FP_REG_CFI (fs3, 19, t0)
+ RESTORE_FP_REG_CFI (fs4, 20, t0)
+ RESTORE_FP_REG_CFI (fs5, 21, t0)
+ RESTORE_FP_REG_CFI (fs6, 22, t0)
+ RESTORE_FP_REG_CFI (fs7, 23, t0)
+ RESTORE_FP_REG_CFI (fs8, 24, t0)
+ RESTORE_FP_REG_CFI (fs9, 25, t0)
+ RESTORE_FP_REG_CFI (fs10, 26, t0)
+ RESTORE_FP_REG_CFI (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_CFI (ra, 1, t0)
+ RESTORE_INT_REG (sp, 2, t0)
+ RESTORE_INT_REG_CFI (s0, 8, t0)
+ RESTORE_INT_REG_CFI (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_CFI (s2, 18, t0)
+ RESTORE_INT_REG_CFI (s3, 19, t0)
+ RESTORE_INT_REG_CFI (s4, 20, t0)
+ RESTORE_INT_REG_CFI (s5, 21, t0)
+ RESTORE_INT_REG_CFI (s6, 22, t0)
+ RESTORE_INT_REG_CFI (s7, 23, t0)
+ RESTORE_INT_REG_CFI (s8, 24, t0)
+ RESTORE_INT_REG_CFI (s9, 25, t0)
+ RESTORE_INT_REG_CFI (s10, 26, t0)
+ RESTORE_INT_REG_CFI (s11, 27, t0)
+
+ jr t1
+
+99: j __syscall_error
+
+PSEUDO_END (setcontext)
+
+LEAF (start_context)
+
+ /* Terminate call stack by noting ra == 0. Happily, s0 == 0 here. */
+ cfi_register (ra, s0)
+
+ /* Call the function passed to makecontext. */
+ jalr s1
+
+ /* Invoke subsequent context if present, else exit(0). */
+ mv a0, s2
+ beqz s2, 1f
+ jal setcontext
+1: j exit
+
+PSEUDO_END (start_context)