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>
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 2ee0a3b..cf3bb05 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -41,7 +41,7 @@
dotraplinkage void do_overflow(struct pt_regs *, long);
dotraplinkage void do_bounds(struct pt_regs *, long);
dotraplinkage void do_invalid_op(struct pt_regs *, long);
-dotraplinkage void do_device_not_available(struct pt_regs *, long);
+dotraplinkage void do_device_not_available(struct pt_regs);
dotraplinkage void do_coprocessor_segment_overrun(struct pt_regs *, long);
dotraplinkage void do_invalid_TSS(struct pt_regs *, long);
dotraplinkage void do_segment_not_present(struct pt_regs *, long);
@@ -77,7 +77,7 @@
extern int kstack_depth_to_print;
void math_error(void __user *);
-asmlinkage void math_emulate(long);
+void math_emulate(struct math_emu_info *);
#ifdef CONFIG_X86_32
unsigned long patch_espfix_desc(unsigned long, unsigned long);
#else