mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-02 09:40:13 +00:00
131fafa7da
The getcontext, and setcontext functions should not adjust the stack, and should load the stack pointer from the machine context. Calling makecontext should create a frame for spilled incoming arguments, and sync uc_stack.ss_sp to the machine context. We do not support calling getcontext, modifying ss_sp, and calling setcontext directly.
102 lines
3.1 KiB
C
102 lines
3.1 KiB
C
/* Create new context.
|
|
Copyright (C) 2008, 2010 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, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
#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)
|
|
|