| /* Copyright (C) 2012-2014 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 <stdarg.h> |
| #include <ucontext.h> |
| |
| /* Number of arguments that go in registers. */ |
| #define NREG_ARGS 4 |
| |
| /* Take a context previously prepared via getcontext() and set to |
| call func() with the given int only args. */ |
| void |
| __makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...) |
| { |
| extern void __startcontext (void); |
| unsigned long *funcstack; |
| va_list vl; |
| unsigned long *regptr; |
| unsigned int reg; |
| int misaligned; |
| |
| /* Start at the top of stack. */ |
| funcstack = (unsigned long *) (ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); |
| |
| /* Ensure the stack stays eight byte aligned. */ |
| misaligned = ((unsigned long) funcstack & 4) != 0; |
| |
| if ((argc > NREG_ARGS) && (argc & 1) != 0) |
| misaligned = !misaligned; |
| |
| if (misaligned) |
| funcstack -= 1; |
| |
| va_start (vl, argc); |
| |
| /* Reserve space for the on-stack arguments. */ |
| if (argc > NREG_ARGS) |
| funcstack -= (argc - NREG_ARGS); |
| |
| ucp->uc_mcontext.arm_sp = (unsigned long) funcstack; |
| ucp->uc_mcontext.arm_pc = (unsigned long) func; |
| |
| /* Exit to startcontext() with the next context in R4 */ |
| ucp->uc_mcontext.arm_r4 = (unsigned long) ucp->uc_link; |
| ucp->uc_mcontext.arm_lr = (unsigned long) __startcontext; |
| |
| /* The first four arguments go into registers. */ |
| regptr = &(ucp->uc_mcontext.arm_r0); |
| |
| for (reg = 0; (reg < argc) && (reg < NREG_ARGS); reg++) |
| *regptr++ = va_arg (vl, unsigned long); |
| |
| /* And the remainder on the stack. */ |
| for (; reg < argc; reg++) |
| *funcstack++ = va_arg (vl, unsigned long); |
| |
| va_end (vl); |
| } |
| weak_alias (__makecontext, makecontext) |
