mirror of
https://sourceware.org/git/glibc.git
synced 2025-11-02 09:33:31 +03:00
93 lines
3.1 KiB
C
93 lines
3.1 KiB
C
/* Create new context.
|
|
Copyright (C) 2008 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by David S. Miller <davem@davemloft.net>, 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 <sysdep.h>
|
|
#include <stdarg.h>
|
|
#include <stdint.h>
|
|
#include <ucontext.h>
|
|
|
|
/* Sets up the outgoing arguments and the program counter for a user
|
|
context for the requested function call.
|
|
|
|
Returning to the correct parent context is pretty simple on
|
|
Sparc. We only need to link up the register windows correctly.
|
|
Since global registers are clobbered by calls, we need not be
|
|
concernred about those, and thus is all could be worked out without
|
|
using a trampoline.
|
|
|
|
Except that we must deal with the signal mask, thus a trampoline
|
|
is unavoidable. 32-bit stackframe layout:
|
|
+-----------------------------------------+
|
|
| 7th and further parameters |
|
|
+-----------------------------------------+
|
|
| backup storage for initial 6 parameters |
|
|
+-----------------------------------------+
|
|
| struct return pointer |
|
|
+-----------------------------------------+
|
|
| 8 incoming registers |
|
|
+-----------------------------------------+
|
|
| 8 local registers |
|
|
%sp --> +-----------------------------------------+
|
|
|
|
*/
|
|
|
|
void
|
|
__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
|
|
{
|
|
extern void __start_context (void);
|
|
unsigned long int *sp;
|
|
va_list ap;
|
|
int i;
|
|
|
|
sp = (unsigned long int *) (ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
|
|
sp -= 16 + 7 + argc;
|
|
sp = (unsigned long int *) (((uintptr_t) sp) & ~(8 - 1));
|
|
|
|
for (i = 0; i < 8; i++)
|
|
sp[i + 8] = ucp->uc_mcontext.gregs[REG_O0 + i];
|
|
|
|
/* The struct return pointer is essentially unused, so we can
|
|
place the link there. */
|
|
sp[16] = (unsigned long int) ucp->uc_link;
|
|
|
|
va_start (ap, argc);
|
|
|
|
/* Fill in outgoing arguments, including those which will
|
|
end up being passed on the stack. */
|
|
for (i = 0; i < argc; i++)
|
|
{
|
|
unsigned long int arg = va_arg (ap, unsigned long int);
|
|
if (i < 6)
|
|
ucp->uc_mcontext.gregs[REG_O0 + i] = arg;
|
|
else
|
|
sp[i + 23 - 6] = arg;
|
|
}
|
|
|
|
va_end (ap);
|
|
|
|
ucp->uc_mcontext.gregs[REG_O6] = (unsigned long int) sp;
|
|
|
|
ucp->uc_mcontext.gregs[REG_O7] = ((unsigned long int) __start_context) - 8;
|
|
|
|
ucp->uc_mcontext.gregs[REG_PC] = (unsigned long int) func;
|
|
ucp->uc_mcontext.gregs[REG_nPC] = ucp->uc_mcontext.gregs[REG_PC] + 4;
|
|
}
|
|
|
|
weak_alias (__makecontext, makecontext)
|