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Commit 01565479 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Merge x86 fixes from Ingo Molnar:
 "Two followup fixes related to the previous LDT fix"

Also applied a further FPU emulation fix from Andy Lutomirski to the
branch before actually merging it.

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
  x86/ldt: Further fix FPU emulation
  x86/ldt: Correct FPU emulation access to LDT
  x86/ldt: Correct LDT access in single stepping logic
parents 8ed1f0e2 12e244f4

arch/x86/kernel/step.c

+2 −2
Original line number Diff line number Diff line
@@ -28,11 +28,11 @@ unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *re 
		struct desc_struct *desc;

		unsigned long base;



		seg &= ~7UL;

		seg >>= 3;



		mutex_lock(&child->mm->context.lock);

		if (unlikely(!child->mm->context.ldt ||

			     (seg >> 3) >= child->mm->context.ldt->size))

			     seg >= child->mm->context.ldt->size))

			addr = -1L; /* bogus selector, access would fault */

		else {

			desc = &child->mm->context.ldt->entries[seg];

arch/x86/math-emu/fpu_entry.c

+1 −2
Original line number Diff line number Diff line
@@ -29,7 +29,6 @@ 


#include <asm/uaccess.h>

#include <asm/traps.h>

#include <asm/desc.h>

#include <asm/user.h>

#include <asm/fpu/internal.h>
@@ -181,7 +180,7 @@ void math_emulate(struct math_emu_info *info) 
			math_abort(FPU_info, SIGILL);

		}



		code_descriptor = LDT_DESCRIPTOR(FPU_CS);

		code_descriptor = FPU_get_ldt_descriptor(FPU_CS);

		if (SEG_D_SIZE(code_descriptor)) {

			/* The above test may be wrong, the book is not clear */

			/* Segmented 32 bit protected mode */

arch/x86/math-emu/fpu_system.h

+18 −3
Original line number Diff line number Diff line
@@ -16,9 +16,24 @@ 
#include <linux/kernel.h>

#include <linux/mm.h>



/* 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])

#include <asm/desc.h>

#include <asm/mmu_context.h>



static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg)

{

	static struct desc_struct zero_desc;

	struct desc_struct ret = zero_desc;



#ifdef CONFIG_MODIFY_LDT_SYSCALL

	seg >>= 3;

	mutex_lock(&current->mm->context.lock);

	if (current->mm->context.ldt && seg < current->mm->context.ldt->size)

		ret = current->mm->context.ldt->entries[seg];

	mutex_unlock(&current->mm->context.lock);

#endif

	return ret;

}



#define SEG_D_SIZE(x)		((x).b & (3 << 21))

#define SEG_G_BIT(x)		((x).b & (1 << 23))

#define SEG_GRANULARITY(x)	(((x).b & (1 << 23)) ? 4096 : 1)

arch/x86/math-emu/get_address.c

+1 −2
Original line number Diff line number Diff line
@@ -20,7 +20,6 @@ 
#include <linux/stddef.h>



#include <asm/uaccess.h>

#include <asm/desc.h>



#include "fpu_system.h"

#include "exception.h"
@@ -158,7 +157,7 @@ static long pm_address(u_char FPU_modrm, u_char segment, 
		addr->selector = PM_REG_(segment);

	}



	descriptor = LDT_DESCRIPTOR(PM_REG_(segment));

	descriptor = FPU_get_ldt_descriptor(addr->selector);

	base_address = SEG_BASE_ADDR(descriptor);

	address = base_address + offset;

	limit = base_address