lguest: Fix guest crash when CONFIG_X86_USE_3DNOW=y
One of the very first things lguest_init() does is a memcpy. On
Athlon/Duron/K7 or CyrixIII/VIA-C3 or Geode GX/LX, this tries to use
MMX.
memcpy -> _mmx_memcpy -> kernel_fpu_begin -> clts -> paravirt_ops.clts
But we haven't set paravirt_ops.clts yet, so we do the native version
and crash. The simplest solution is to use __memcpy.
Thanks to Michael Rasenberger for the bug report.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/lguest/lguest.c b/drivers/lguest/lguest.c
index 6e135ac..ee1c6d0 100644
--- a/drivers/lguest/lguest.c
+++ b/drivers/lguest/lguest.c
@@ -964,11 +964,12 @@
{
/* Copy boot parameters first: the Launcher put the physical location
* in %esi, and head.S converted that to a virtual address and handed
- * it to us. */
- memcpy(&boot_params, boot, PARAM_SIZE);
+ * it to us. We use "__memcpy" because "memcpy" sometimes tries to do
+ * tricky things to go faster, and we're not ready for that. */
+ __memcpy(&boot_params, boot, PARAM_SIZE);
/* The boot parameters also tell us where the command-line is: save
* that, too. */
- memcpy(boot_command_line, __va(boot_params.hdr.cmd_line_ptr),
+ __memcpy(boot_command_line, __va(boot_params.hdr.cmd_line_ptr),
COMMAND_LINE_SIZE);
/* We're under lguest, paravirt is enabled, and we're running at