| /* Create new context. |
| Copyright (C) 2008-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Helge Deller <deller@gmx.de>, 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 <libintl.h> |
| #include <stdarg.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <sysdep.h> |
| #include <ucontext.h> |
| |
| /* POSIX only supports integer arguments. */ |
| |
| /* Stack must be 64-byte aligned at all times. */ |
| #define STACK_ALIGN 64 |
| /* Size of frame marker in unsigned long words. */ |
| #define FRAME_SIZE_UL 8 |
| /* Size of frame marker in bytes. */ |
| #define FRAME_SIZE_BYTES (8 * sizeof(unsigned long)) |
| /* Size of X arguments in bytes. */ |
| #define ARGS(x) (x * sizeof(unsigned long)) |
| |
| void |
| __makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...) |
| { |
| unsigned long *sp, *osp; |
| va_list ap; |
| int i; |
| |
| /* Create a 64-byte aligned frame to store args. Use ss_sp if |
| it is available, otherwise be robust and use the currently |
| saved stack pointer. */ |
| if (ucp->uc_stack.ss_sp && ucp->uc_stack.ss_size) |
| osp = (unsigned long *)ucp->uc_stack.ss_sp; |
| else |
| osp = (unsigned long *)ucp->uc_mcontext.sc_gr[30]; |
| |
| sp = (unsigned long *)((((unsigned long) osp) |
| + FRAME_SIZE_BYTES + ARGS(argc) + STACK_ALIGN) |
| & ~(STACK_ALIGN - 1)); |
| |
| /* Use new frame. */ |
| ucp->uc_mcontext.sc_gr[30] = ((unsigned long) sp); |
| |
| /* Finish frame setup. */ |
| if (ucp->uc_link) |
| { |
| /* Returning to the next context and next frame. */ |
| sp[-4/sizeof(unsigned long)] = ucp->uc_link->uc_mcontext.sc_gr[30]; |
| sp[-20/sizeof(unsigned long)] = ucp->uc_link->uc_mcontext.sc_gr[2]; |
| } |
| else |
| { |
| /* This is the main context. No frame marker, and no return address. */ |
| sp[-4/sizeof(unsigned long)] = 0x0; |
| sp[-20/sizeof(unsigned long)] = 0x0; |
| } |
| |
| /* Store address to jump to. */ |
| ucp->uc_mcontext.sc_gr[2] = (unsigned long) func; |
| |
| /* Process arguments. */ |
| va_start (ap, argc); |
| for (i = 0; i < argc; ++i) |
| { |
| if (i < 4) |
| { |
| ucp->uc_mcontext.sc_gr[26-i] = va_arg (ap, int); |
| continue; |
| } |
| |
| if ((i < 8) && (sizeof(unsigned long) == 8)) |
| { |
| /* 64bit: r19-r22 are arg7-arg4. */ |
| ucp->uc_mcontext.sc_gr[22+4-i] = va_arg (ap, int); |
| continue; |
| } |
| |
| /* All other arguments go on the stack. */ |
| sp[-1 * (FRAME_SIZE_UL + 1 + i)] = va_arg (ap, int); |
| } |
| va_end (ap); |
| } |
| weak_alias(__makecontext, makecontext) |
| |
