X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fi386%2Fkernel%2Ffixup.c;fp=arch%2Fi386%2Fkernel%2Ffixup.c;h=15a8f207898e677ef7ac194aac2d1b6c2d497bc4;hb=1db395853d4f30d6120458bd279ede1f882a8525;hp=0000000000000000000000000000000000000000;hpb=34a75f0025b9cf803b6a88db032e6ad6950c9313;p=linux-2.6.git

diff --git a/arch/i386/kernel/fixup.c b/arch/i386/kernel/fixup.c
new file mode 100644
index 000000000..15a8f2078
--- /dev/null
+++ b/arch/i386/kernel/fixup.c
@@ -0,0 +1,86 @@
+/******************************************************************************
+ * fixup.c
+ * 
+ * Binary-rewriting of certain IA32 instructions, on notification by Xen.
+ * Used to avoid repeated slow emulation of common instructions used by the
+ * user-space TLS (Thread-Local Storage) libraries.
+ * 
+ * **** NOTE ****
+ *  Issues with the binary rewriting have caused it to be removed. Instead
+ *  we rely on Xen's emulator to boot the kernel, and then print a banner
+ *  message recommending that the user disables /lib/tls.
+ * 
+ * Copyright (c) 2004, K A Fraser
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/version.h>
+
+#define DP(_f, _args...) printk(KERN_ALERT "  " _f "\n" , ## _args )
+
+fastcall void do_fixup_4gb_segment(struct pt_regs *regs, long error_code)
+{
+	static unsigned long printed = 1;
+	char info[100];
+	int i;
+
+	if (test_and_set_bit(0, &printed))
+		return;
+
+	HYPERVISOR_vm_assist(
+		VMASST_CMD_disable, VMASST_TYPE_4gb_segments_notify);
+
+	sprintf(info, "%s (pid=%d)", current->comm, current->tgid);
+
+
+	DP("");
+	DP("***************************************************************");
+	DP("***************************************************************");
+	DP("** WARNING: Currently emulating unsupported memory accesses  **");
+	DP("**          in /lib/tls glibc libraries. The emulation is    **");
+	DP("**          slow. To ensure full performance you should      **");
+	DP("**          install a 'xen-friendly' (nosegneg) version of   **");
+	DP("**          the library, or disable tls support by executing **");
+	DP("**          the following as root:                           **");
+	DP("**          mv /lib/tls /lib/tls.disabled                    **");
+	DP("** Offending process: %-38.38s **", info);
+	DP("***************************************************************");
+	DP("***************************************************************");
+	DP("");
+
+	for (i = 5; i > 0; i--) {
+		touch_softlockup_watchdog();
+		printk("Pausing... %d", i);
+		mdelay(1000);
+		printk("\b\b\b\b\b\b\b\b\b\b\b\b");
+	}
+
+	printk("Continuing...\n\n");
+}
+
+static int __init fixup_init(void)
+{
+	HYPERVISOR_vm_assist(
+		VMASST_CMD_enable, VMASST_TYPE_4gb_segments_notify);
+	return 0;
+}
+__initcall(fixup_init);