Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
+22
-9
+2
-2
arch/x86/kernel/step.c
+2
-2
arch/x86/kernel/step.c
···
28
28
struct desc_struct *desc;
29
29
unsigned long base;
30
30
31
-
seg &= ~7UL;
31
+
seg >>= 3;
32
32
33
33
mutex_lock(&child->mm->context.lock);
34
34
if (unlikely(!child->mm->context.ldt ||
35
-
(seg >> 3) >= child->mm->context.ldt->size))
35
+
seg >= child->mm->context.ldt->size))
36
36
addr = -1L; /* bogus selector, access would fault */
37
37
else {
38
38
desc = &child->mm->context.ldt->entries[seg];
+1
-2
arch/x86/math-emu/fpu_entry.c
+1
-2
arch/x86/math-emu/fpu_entry.c
···
29
29
30
30
#include <asm/uaccess.h>
31
31
#include <asm/traps.h>
32
-
#include <asm/desc.h>
33
32
#include <asm/user.h>
34
33
#include <asm/fpu/internal.h>
35
34
···
180
181
math_abort(FPU_info, SIGILL);
181
182
}
182
183
183
-
code_descriptor = LDT_DESCRIPTOR(FPU_CS);
184
+
code_descriptor = FPU_get_ldt_descriptor(FPU_CS);
184
185
if (SEG_D_SIZE(code_descriptor)) {
185
186
/* The above test may be wrong, the book is not clear */
186
187
/* Segmented 32 bit protected mode */
+18
-3
arch/x86/math-emu/fpu_system.h
+18
-3
arch/x86/math-emu/fpu_system.h
···
16
16
#include <linux/kernel.h>
17
17
#include <linux/mm.h>
18
18
19
-
/* s is always from a cpu register, and the cpu does bounds checking
20
-
* during register load --> no further bounds checks needed */
21
-
#define LDT_DESCRIPTOR(s) (((struct desc_struct *)current->mm->context.ldt)[(s) >> 3])
19
+
#include <asm/desc.h>
20
+
#include <asm/mmu_context.h>
21
+
22
+
static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg)
23
+
{
24
+
static struct desc_struct zero_desc;
25
+
struct desc_struct ret = zero_desc;
26
+
27
+
#ifdef CONFIG_MODIFY_LDT_SYSCALL
28
+
seg >>= 3;
29
+
mutex_lock(¤t->mm->context.lock);
30
+
if (current->mm->context.ldt && seg < current->mm->context.ldt->size)
31
+
ret = current->mm->context.ldt->entries[seg];
32
+
mutex_unlock(¤t->mm->context.lock);
33
+
#endif
34
+
return ret;
35
+
}
36
+
22
37
#define SEG_D_SIZE(x) ((x).b & (3 << 21))
23
38
#define SEG_G_BIT(x) ((x).b & (1 << 23))
24
39
#define SEG_GRANULARITY(x) (((x).b & (1 << 23)) ? 4096 : 1)
+1
-2
arch/x86/math-emu/get_address.c
+1
-2
arch/x86/math-emu/get_address.c
···
20
20
#include <linux/stddef.h>
21
21
22
22
#include <asm/uaccess.h>
23
-
#include <asm/desc.h>
24
23
25
24
#include "fpu_system.h"
26
25
#include "exception.h"
···
157
158
addr->selector = PM_REG_(segment);
158
159
}
159
160
160
-
descriptor = LDT_DESCRIPTOR(PM_REG_(segment));
161
+
descriptor = FPU_get_ldt_descriptor(addr->selector);
161
162
base_address = SEG_BASE_ADDR(descriptor);
162
163
address = base_address + offset;
163
164
limit = base_address