xen-vtx-unstable

view linux-2.6-xen-sparse/arch/xen/kernel/fixup.c @ 6774:4d899a738d59

merge?
author cl349@firebug.cl.cam.ac.uk
date Tue Sep 13 15:05:49 2005 +0000 (2005-09-13)
parents dd668f7527cb
children
line source
1 /******************************************************************************
2 * fixup.c
3 *
4 * Binary-rewriting of certain IA32 instructions, on notification by Xen.
5 * Used to avoid repeated slow emulation of common instructions used by the
6 * user-space TLS (Thread-Local Storage) libraries.
7 *
8 * **** NOTE ****
9 * Issues with the binary rewriting have caused it to be removed. Instead
10 * we rely on Xen's emulator to boot the kernel, and then print a banner
11 * message recommending that the user disables /lib/tls.
12 *
13 * Copyright (c) 2004, K A Fraser
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 *
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 * GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public License
26 * along with this program; if not, write to the Free Software
27 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 */
30 #include <linux/config.h>
31 #include <linux/init.h>
32 #include <linux/sched.h>
33 #include <linux/slab.h>
34 #include <linux/kernel.h>
35 #include <linux/delay.h>
36 #include <linux/version.h>
38 #define DP(_f, _args...) printk(KERN_ALERT " " _f "\n" , ## _args )
40 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
41 #define __LINKAGE fastcall
42 #else
43 #define __LINKAGE asmlinkage
44 #endif
46 __LINKAGE void do_fixup_4gb_segment(struct pt_regs *regs, long error_code)
47 {
48 static unsigned long printed = 0;
49 char info[100];
50 int i;
52 if ( !test_and_set_bit(0, &printed) )
53 {
54 HYPERVISOR_vm_assist(VMASST_CMD_disable,
55 VMASST_TYPE_4gb_segments_notify);
57 sprintf(info, "%s (pid=%d)", current->comm, current->tgid);
59 DP("");
60 DP("***************************************************************");
61 DP("***************************************************************");
62 DP("** WARNING: Currently emulating unsupported memory accesses **");
63 DP("** in /lib/tls libraries. The emulation is very **");
64 DP("** slow. To ensure full performance you should **");
65 DP("** execute the following as root: **");
66 DP("** mv /lib/tls /lib/tls.disabled **");
67 DP("** Offending process: %-38.38s **", info);
68 DP("***************************************************************");
69 DP("***************************************************************");
70 DP("");
72 for ( i = 5; i > 0; i-- )
73 {
74 printk("Pausing... %d", i);
75 mdelay(1000);
76 printk("\b\b\b\b\b\b\b\b\b\b\b\b");
77 }
78 printk("Continuing...\n\n");
79 }
80 }
82 static int __init fixup_init(void)
83 {
84 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments_notify);
85 return 0;
86 }
87 __initcall(fixup_init);