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/math-emu/get_address.c b/arch/x86/math-emu/get_address.c
index 62daa7f..420b3b6 100644
--- a/arch/x86/math-emu/get_address.c
+++ b/arch/x86/math-emu/get_address.c
@@ -29,43 +29,43 @@
#define FPU_WRITE_BIT 0x10
static int reg_offset[] = {
- offsetof(struct math_emu_info, regs.ax),
- offsetof(struct math_emu_info, regs.cx),
- offsetof(struct math_emu_info, regs.dx),
- offsetof(struct math_emu_info, regs.bx),
- offsetof(struct math_emu_info, regs.sp),
- offsetof(struct math_emu_info, regs.bp),
- offsetof(struct math_emu_info, regs.si),
- offsetof(struct math_emu_info, regs.di)
+ offsetof(struct pt_regs, ax),
+ offsetof(struct pt_regs, cx),
+ offsetof(struct pt_regs, dx),
+ offsetof(struct pt_regs, bx),
+ offsetof(struct pt_regs, sp),
+ offsetof(struct pt_regs, bp),
+ offsetof(struct pt_regs, si),
+ offsetof(struct pt_regs, di)
};
-#define REG_(x) (*(long *)(reg_offset[(x)]+(u_char *) FPU_info))
+#define REG_(x) (*(long *)(reg_offset[(x)] + (u_char *)FPU_info->regs))
static int reg_offset_vm86[] = {
- offsetof(struct math_emu_info, regs.cs),
- offsetof(struct math_emu_info, vm86.ds),
- offsetof(struct math_emu_info, vm86.es),
- offsetof(struct math_emu_info, vm86.fs),
- offsetof(struct math_emu_info, vm86.gs),
- offsetof(struct math_emu_info, regs.ss),
- offsetof(struct math_emu_info, vm86.ds)
+ offsetof(struct pt_regs, cs),
+ offsetof(struct kernel_vm86_regs, ds),
+ offsetof(struct kernel_vm86_regs, es),
+ offsetof(struct kernel_vm86_regs, fs),
+ offsetof(struct kernel_vm86_regs, gs),
+ offsetof(struct pt_regs, ss),
+ offsetof(struct kernel_vm86_regs, ds)
};
#define VM86_REG_(x) (*(unsigned short *) \
- (reg_offset_vm86[((unsigned)x)]+(u_char *) FPU_info))
+ (reg_offset_vm86[((unsigned)x)] + (u_char *)FPU_info->regs))
static int reg_offset_pm[] = {
- offsetof(struct math_emu_info, regs.cs),
- offsetof(struct math_emu_info, regs.ds),
- offsetof(struct math_emu_info, regs.es),
- offsetof(struct math_emu_info, regs.fs),
- offsetof(struct math_emu_info, regs.ds), /* dummy, not saved on stack */
- offsetof(struct math_emu_info, regs.ss),
- offsetof(struct math_emu_info, regs.ds)
+ offsetof(struct pt_regs, cs),
+ offsetof(struct pt_regs, ds),
+ offsetof(struct pt_regs, es),
+ offsetof(struct pt_regs, fs),
+ offsetof(struct pt_regs, ds), /* dummy, not saved on stack */
+ offsetof(struct pt_regs, ss),
+ offsetof(struct pt_regs, ds)
};
#define PM_REG_(x) (*(unsigned short *) \
- (reg_offset_pm[((unsigned)x)]+(u_char *) FPU_info))
+ (reg_offset_pm[((unsigned)x)] + (u_char *)FPU_info->regs))
/* Decode the SIB byte. This function assumes mod != 0 */
static int sib(int mod, unsigned long *fpu_eip)
@@ -346,34 +346,34 @@
}
switch (rm) {
case 0:
- address += FPU_info->regs.bx + FPU_info->regs.si;
+ address += FPU_info->regs->bx + FPU_info->regs->si;
break;
case 1:
- address += FPU_info->regs.bx + FPU_info->regs.di;
+ address += FPU_info->regs->bx + FPU_info->regs->di;
break;
case 2:
- address += FPU_info->regs.bp + FPU_info->regs.si;
+ address += FPU_info->regs->bp + FPU_info->regs->si;
if (addr_modes.override.segment == PREFIX_DEFAULT)
addr_modes.override.segment = PREFIX_SS_;
break;
case 3:
- address += FPU_info->regs.bp + FPU_info->regs.di;
+ address += FPU_info->regs->bp + FPU_info->regs->di;
if (addr_modes.override.segment == PREFIX_DEFAULT)
addr_modes.override.segment = PREFIX_SS_;
break;
case 4:
- address += FPU_info->regs.si;
+ address += FPU_info->regs->si;
break;
case 5:
- address += FPU_info->regs.di;
+ address += FPU_info->regs->di;
break;
case 6:
- address += FPU_info->regs.bp;
+ address += FPU_info->regs->bp;
if (addr_modes.override.segment == PREFIX_DEFAULT)
addr_modes.override.segment = PREFIX_SS_;
break;
case 7:
- address += FPU_info->regs.bx;
+ address += FPU_info->regs->bx;
break;
}
