| /* Create new context. |
| 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 <sysdep.h> |
| |
| #include "ucontext_i.h" |
| |
| |
| ENTRY(__makecontext) |
| move.l 4(%sp), %a0 |
| |
| /* Get the address of the function we are supposed to run. */ |
| move.l 8(%sp), oPC(%a0) |
| |
| /* Compute the address of the stack. The information comes from |
| to us_stack element. */ |
| move.l oSS_SP(%a0), %a1 |
| add.l oSS_SIZE(%a0), %a1 |
| |
| /* Remember the number of parameters for the exit handler since |
| it has to remove them. We store the number in the D7 register |
| which the function we will call must preserve. */ |
| move.l 12(%sp), %d1 |
| move.l %d1, oGREGS+7*4(%a0) |
| |
| /* Make room on the new stack for the parameters. |
| Room for the arguments, return address (== 1f) and |
| oLINK pointer is needed. */ |
| neg.l %d1 |
| lea -8(%a1,%d1.l*4), %a1 |
| neg.l %d1 |
| |
| /* Store the future stack pointer. */ |
| move.l %a1, oSP(%a0) |
| |
| /* Put the next context on the new stack (from the uc_link |
| element). */ |
| move.l oLINK(%a0), 4(%a1,%d1.l*4) |
| |
| /* Copy all the parameters. */ |
| 1: subq.l #1,%d1 |
| jmi 2f |
| move.l 16(%sp,%d1.l*4), 4(%a1,%d1.l*4) |
| jra 1b |
| 2: |
| |
| /* If the function we call returns we must continue with the |
| context which is given in the uc_link element. To do this |
| set the return address for the function the user provides |
| to a little bit of helper code which does the magic (see |
| below). */ |
| lea 1f(%pc), %a0 |
| move.l %a0, (%a1) |
| /* 'makecontext' returns no value. */ |
| rts |
| |
| /* This is the helper code which gets called if a function which |
| is registered with 'makecontext' returns. In this case we |
| have to install the context listed in the uc_link element of |
| the context 'makecontext' manipulated at the time of the |
| 'makecontext' call. If the pointer is NULL the process must |
| terminate. */ |
| cfi_endproc |
| 1: |
| /* This removes the parameters passed to the function given to |
| 'makecontext' from the stack. D7 contains the number of |
| parameters (see above). */ |
| lea (%sp,%d7.l*4), %sp |
| |
| tst.l (%sp) /* Check the next context. */ |
| jeq 2f /* If it is zero exit. */ |
| |
| jbsr JUMPTARGET(__setcontext) |
| /* If this returns (which can happen if the syscall fails) we'll |
| exit the program with the return error value (-1). */ |
| |
| move.l %d0, (%sp) |
| 2: jbsr HIDDEN_JUMPTARGET(exit) |
| /* The 'exit' call should never return. In case it does cause |
| the process to terminate. */ |
| illegal |
| cfi_startproc |
| END(__makecontext) |
| |
| weak_alias (__makecontext, makecontext) |
