1 files changed, 74 insertions, 0 deletions
diff --git a/libc/ports/sysdeps/unix/sysv/linux/aarch64/makecontext.c b/libc/ports/sysdeps/unix/sysv/linux/aarch64/makecontext.c
new file mode 100644
index 000000000..ae32f321f
--- /dev/null
+++ b/libc/ports/sysdeps/unix/sysv/linux/aarch64/makecontext.c
@@ -0,0 +1,74 @@
+/* Create new context.
+   Copyright (C) 2002-2012 Free Software Foundation, Inc.
+
+   This file is part of the GNU C Library.
+
+   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>
+
+
+/* makecontext sets up a stack and the registers for the
+   user context.  The stack looks like this:
+
+               +-----------------------+
+	       | padding as required   |
+               +-----------------------+
+    sp ->      | parameter 7-n         |
+               +-----------------------+
+
+   The registers are set up like this:
+     %x0 .. %x7: parameter 1 to 8
+     %x19   : uc_link
+     %sp    : stack pointer.
+*/
+
+void
+__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
+{
+  extern void __startcontext (void);
+  unsigned long int *sp;
+  va_list ap;
+  int i;
+
+  sp = (unsigned long int *)
+    ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+
+  /* Allocate stack arguments.  */
+  sp -= argc < 8 ? 0 : argc - 8;
+
+  /* Keep the stack aligned.  */
+  sp = (unsigned long int *) (((uintptr_t) sp) & -16L);
+
+  ucp->uc_mcontext.regs[19] = (uintptr_t) ucp->uc_link;
+  ucp->uc_mcontext.sp = (uintptr_t) sp;
+  ucp->uc_mcontext.pc = (uintptr_t) func;
+  ucp->uc_mcontext.regs[29] = (uintptr_t) 0;
+  ucp->uc_mcontext.regs[30] = (uintptr_t) &__startcontext;
+
+  va_start (ap, argc);
+  for (i = 0; i < argc; ++i)
+    if (i < 8)
+      ucp->uc_mcontext.regs[i] = va_arg (ap, unsigned long int);
+    else
+      sp[i - 8] = va_arg (ap, unsigned long int);
+
+  va_end (ap);
+}
+
+weak_alias (__makecontext, makecontext)