mirror of
https://git.savannah.gnu.org/git/guile.git
synced 2025-04-30 03:40:34 +02:00
33bc19d30e
git-archimport-id: bonzini@gnu.org--2004b/lightning--stable--1.2--patch-15 git-archimport-id: bonzini@gnu.org--2004b/lightning--stable--1.2--patch-16
91 lines
3.1 KiB
C
91 lines
3.1 KiB
C
/******************************** -*- C -*- ****************************
|
|
*
|
|
* Platform-independent layer inline functions (i386)
|
|
*
|
|
***********************************************************************/
|
|
|
|
|
|
/***********************************************************************
|
|
*
|
|
* Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
|
|
* Written by Paolo Bonzini.
|
|
*
|
|
* This file is part of GNU lightning.
|
|
*
|
|
* GNU lightning 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, or (at your option)
|
|
* any later version.
|
|
*
|
|
* GNU lightning 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 GNU lightning; see the file COPYING.LESSER; if not, write to the
|
|
* Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
|
|
* MA 02110-1301, USA.
|
|
*
|
|
***********************************************************************/
|
|
|
|
|
|
|
|
#ifndef __lightning_funcs_h
|
|
#define __lightning_funcs_h
|
|
|
|
#ifdef __linux__
|
|
#include <unistd.h>
|
|
#include <sys/mman.h>
|
|
#endif
|
|
|
|
static void
|
|
jit_flush_code(void *dest, void *end)
|
|
{
|
|
/* On the x86, the PROT_EXEC bits are not handled by the MMU.
|
|
However, the kernel can emulate this by setting the code
|
|
segment's limit to the end address of the highest page
|
|
whose PROT_EXEC bit is set.
|
|
|
|
Linux kernels that do so and that disable by default the
|
|
execution of the data and stack segment are becoming more
|
|
and more common (Fedora, for example), so we implement our
|
|
jit_flush_code as an mprotect. */
|
|
#ifdef __linux__
|
|
static unsigned long prev_page = 0, prev_length = 0;
|
|
int page, length;
|
|
#ifdef PAGESIZE
|
|
const int page_size = PAGESIZE;
|
|
#else
|
|
static int page_size = -1;
|
|
if (page_size == -1)
|
|
page_size = sysconf (_SC_PAGESIZE);
|
|
#endif
|
|
|
|
page = (long) dest & ~(page_size - 1);
|
|
length = ((char *) end - (char *) page + page_size - 1) & ~(page_size - 1);
|
|
|
|
/* Simple-minded attempt at optimizing the common case where a single
|
|
chunk of memory is used to compile multiple functions. */
|
|
if (page >= prev_page && page + length <= prev_page + prev_length)
|
|
return;
|
|
|
|
mprotect ((void *) page, length, PROT_READ | PROT_WRITE | PROT_EXEC);
|
|
|
|
/* See if we can extend the previously mprotect'ed memory area towards
|
|
higher addresses: the starting address remains the same as before. */
|
|
if (page >= prev_page && page <= prev_page + prev_length)
|
|
prev_length = page + length - prev_page;
|
|
|
|
/* See if we can extend the previously mprotect'ed memory area towards
|
|
lower addresses: the highest address remains the same as before. */
|
|
else if (page < prev_page && page + length <= prev_page + prev_length)
|
|
prev_length += prev_page - page, prev_page = page;
|
|
|
|
/* Nothing to do, replace the area. */
|
|
else
|
|
prev_page = page, prev_length = length;
|
|
#endif
|
|
}
|
|
|
|
#endif /* __lightning_funcs_h */
|