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x86: fix math_emu register frame access

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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>
This commit is contained in:
Tejun Heo
2009-02-09 22:17:39 +09:00
committed by Ingo Molnar
parent ae6af41f5a
commit d315760ffa
7 changed files with 55 additions and 56 deletions
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16
arch/x86/math-emu/fpu_system.h
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@ -16,10 +16,6 @@
#include <linux/kernel.h>
#include <linux/mm.h>
/* This sets the pointer FPU_info to point to the argument part
of the stack frame of math_emulate() */
#define SETUP_DATA_AREA(arg) FPU_info = (struct math_emu_info *) &arg
/* s is always from a cpu register, and the cpu does bounds checking
* during register load --> no further bounds checks needed */
#define LDT_DESCRIPTOR(s) (((struct desc_struct *)current->mm->context.ldt)[(s) >> 3])
@ -38,12 +34,12 @@
#define I387 (current->thread.xstate)
#define FPU_info (I387->soft.info)
#define FPU_CS (*(unsigned short *) &(FPU_info->regs.cs))
#define FPU_SS (*(unsigned short *) &(FPU_info->regs.ss))
#define FPU_DS (*(unsigned short *) &(FPU_info->regs.ds))
#define FPU_EAX (FPU_info->regs.ax)
#define FPU_EFLAGS (FPU_info->regs.flags)
#define FPU_EIP (FPU_info->regs.ip)
#define FPU_CS (*(unsigned short *) &(FPU_info->regs->cs))
#define FPU_SS (*(unsigned short *) &(FPU_info->regs->ss))
#define FPU_DS (*(unsigned short *) &(FPU_info->regs->ds))
#define FPU_EAX (FPU_info->regs->ax)
#define FPU_EFLAGS (FPU_info->regs->flags)
#define FPU_EIP (FPU_info->regs->ip)
#define FPU_ORIG_EIP (FPU_info->___orig_eip)
#define FPU_lookahead (I387->soft.lookahead)