[tip:x86/asm] x86: Use get_desc_base()

tip-bot for Akinobu Mita
2009-07-20T12:01:55Z

Commit-ID: 254e0a6bff87ab8b22293c4bd1443507df698407
Gitweb: http://git.kernel.org/tip/254e0a6bff87ab8b22293c4bd1443507df698407
Author: Akinobu Mita <akinobu.mita@gmail.com>
AuthorDate: Sun, 19 Jul 2009 00:08:54 +0900
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 19 Jul 2009 18:27:51 +0200

x86: Use get_desc_base()

Use get_desc_base() to get the base address in desc_struct

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
LKML-Reference: <20090718150853.GA11294@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
arch/x86/kernel/doublefault_32.c | 4 +---
arch/x86/kernel/step.c | 9 ++++-----
2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/doublefault_32.c b/arch/x86/kernel/doublefault_32.c
index b4f14c6..37250fe 100644
--- a/arch/x86/kernel/doublefault_32.c
+++ b/arch/x86/kernel/doublefault_32.c
@@ -27,9 +27,7 @@ static void doublefault_fn(void)

if (ptr_ok(gdt)) {
gdt += GDT_ENTRY_TSS << 3;
- tss = *(u16 *)(gdt+2);
- tss += *(u8 *)(gdt+4) << 16;
- tss += *(u8 *)(gdt+7) << 24;
+ tss = get_desc_base((struct desc_struct *)gdt);
printk(KERN_EMERG "double fault, tss at %08lx\n", tss);

if (ptr_ok(tss)) {
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
index e8b9863..3149032 100644
--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -4,6 +4,7 @@
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/ptrace.h>
+#include <asm/desc.h>

unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs)
{
@@ -23,7 +24,7 @@ unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *re
* and APM bios ones we just ignore here.
*/
if ((seg & SEGMENT_TI_MASK) == SEGMENT_LDT) {
- u32 *desc;
+ struct desc_struct *desc;
unsigned long base;

seg &= ~7UL;
@@ -33,12 +34,10 @@ unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *re
addr = -1L; /* bogus selector, access would fault */
else {
desc = child->mm->context.ldt + seg;
- base = ((desc[0] >> 16) |
- ((desc[1] & 0xff) << 16) |
- (desc[1] & 0xff000000));
+ base = get_desc_base(desc);

/* 16-bit code segment? */
- if (!((desc[1] >> 22) & 1))
+ if (!desc->d)
addr &= 0xffff;
addr += base;
}