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authorTejun Heo <tj@kernel.org>2009-02-09 14:17:39 +0100
committerIngo Molnar <mingo@elte.hu>2009-02-10 00:39:14 +0100
commitd315760ffa261c15ff92699ac6f514112543d7ca (patch)
tree3f7d185cf97a06e6686521a23a1c78d1809a51c4 /arch/x86/kernel/traps.c
parentx86: math_emu info cleanup (diff)
downloadlinux-d315760ffa261c15ff92699ac6f514112543d7ca.tar.xz
linux-d315760ffa261c15ff92699ac6f514112543d7ca.zip
x86: fix math_emu register frame access
do_device_not_available() is the handler for #NM and it declares that it takes a unsigned long and calls math_emu(), which takes a long argument and surprisingly expects the stack frame starting at the zero argument would match struct math_emu_info, which isn't true regardless of configuration in the current code. This patch makes do_device_not_available() take struct pt_regs like other exception handlers and initialize struct math_emu_info with pointer to it and pass pointer to the math_emu_info to math_emulate() like normal C functions do. This way, unless gcc makes a copy of struct pt_regs in do_device_not_available(), the register frame is correctly accessed regardless of kernel configuration or compiler used. This doesn't fix all math_emu problems but it at least gets it somewhat working. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/traps.c')
-rw-r--r--arch/x86/kernel/traps.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 98c2d055284b..7932338d7cb3 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -896,7 +896,7 @@ asmlinkage void math_state_restore(void)
EXPORT_SYMBOL_GPL(math_state_restore);
#ifndef CONFIG_MATH_EMULATION
-asmlinkage void math_emulate(long arg)
+void math_emulate(struct math_emu_info *info)
{
printk(KERN_EMERG
"math-emulation not enabled and no coprocessor found.\n");
@@ -906,16 +906,19 @@ asmlinkage void math_emulate(long arg)
}
#endif /* CONFIG_MATH_EMULATION */
-dotraplinkage void __kprobes
-do_device_not_available(struct pt_regs *regs, long error)
+dotraplinkage void __kprobes do_device_not_available(struct pt_regs regs)
{
#ifdef CONFIG_X86_32
if (read_cr0() & X86_CR0_EM) {
- conditional_sti(regs);
- math_emulate(0);
+ struct math_emu_info info = { };
+
+ conditional_sti(&regs);
+
+ info.regs = &regs;
+ math_emulate(&info);
} else {
math_state_restore(); /* interrupts still off */
- conditional_sti(regs);
+ conditional_sti(&regs);
}
#else
math_state_restore();