From: Zachary Amsden <zach@vmware.com>
Add some convenient descriptor access functions and move them all into desc.h
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
arch/i386/kernel/kprobes.c | 8 ++++----
arch/i386/mm/fault.c | 7 ++++---
include/asm-i386/desc.h | 32 ++++++++++++++++++++++----------
3 files changed, 30 insertions(+), 17 deletions(-)
diff -puN arch/i386/kernel/kprobes.c~i386--add-some-descriptor-convenience-functions arch/i386/kernel/kprobes.c
--- devel/arch/i386/kernel/kprobes.c~i386--add-some-descriptor-convenience-functions 2005-09-07 20:10:34.000000000 -0700
+++ devel-akpm/arch/i386/kernel/kprobes.c 2005-09-07 20:10:34.000000000 -0700
@@ -156,7 +156,6 @@ static int __kprobes kprobe_handler(stru
struct kprobe *p;
int ret = 0;
kprobe_opcode_t *addr = NULL;
- unsigned long *lp;
/* We're in an interrupt, but this is clear and BUG()-safe. */
preempt_disable();
@@ -164,9 +163,10 @@ static int __kprobes kprobe_handler(stru
* calculate the address by reading the base address from the LDT entry.
*/
if (segment_from_ldt(regs->xcs) && (current->mm)) {
- lp = (unsigned long *) ((unsigned long)(segment_index(regs->xcs) * 8)
- + (char *) current->mm->context.ldt);
- addr = (kprobe_opcode_t *) (get_desc_base(lp) + regs->eip -
+ struct desc_struct *desc;
+ desc = (struct desc_struct *) ((char *) current->mm->context.ldt +
+ (segment_index(regs->xcs) * 8));
+ addr = (kprobe_opcode_t *) (get_desc_base(desc) + regs->eip -
sizeof(kprobe_opcode_t));
} else {
addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
diff -puN arch/i386/mm/fault.c~i386--add-some-descriptor-convenience-functions arch/i386/mm/fault.c
--- devel/arch/i386/mm/fault.c~i386--add-some-descriptor-convenience-functions 2005-09-07 20:10:34.000000000 -0700
+++ devel-akpm/arch/i386/mm/fault.c 2005-09-07 20:10:34.000000000 -0700
@@ -75,7 +75,8 @@ static inline unsigned long get_segment_
{
unsigned long eip = regs->eip;
unsigned seg = regs->xcs & 0xffff;
- u32 seg_ar, seg_limit, base, *desc;
+ u32 seg_ar, seg_limit, base;
+ struct desc_struct *desc;
/* The standard kernel/user address space limit. */
*eip_limit = (seg & 3) ? USER_DS.seg : KERNEL_DS.seg;
@@ -108,12 +109,12 @@ static inline unsigned long get_segment_
desc = (void *)desc + (seg & ~7);
} else {
/* Must disable preemption while reading the GDT. */
- desc = (u32 *)&per_cpu(cpu_gdt_table, get_cpu());
+ desc = per_cpu(cpu_gdt_table, get_cpu());
desc = (void *)desc + (seg & ~7);
}
/* Decode the code segment base from the descriptor */
- base = get_desc_base((unsigned long *)desc);
+ base = get_desc_base(desc);
if (segment_from_ldt(seg)) {
up(¤t->mm->context.sem);
diff -puN include/asm-i386/desc.h~i386--add-some-descriptor-convenience-functions include/asm-i386/desc.h
--- devel/include/asm-i386/desc.h~i386--add-some-descriptor-convenience-functions 2005-09-07 20:10:34.000000000 -0700
+++ devel-akpm/include/asm-i386/desc.h 2005-09-07 20:10:34.000000000 -0700
@@ -14,6 +14,28 @@
#include <asm/mmu.h>
+#define desc_empty(desc) \
+ (!((desc)->a + (desc)->b))
+
+#define desc_equal(desc1, desc2) \
+ (((desc1)->a == (desc2)->a) && ((desc1)->b == (desc2)->b))
+
+static inline unsigned long get_desc_base(struct desc_struct *desc)
+{
+ unsigned long base;
+ base = ((desc->a >> 16) & 0x0000ffff) |
+ ((desc->b << 16) & 0x00ff0000) |
+ (desc->b & 0xff000000);
+ return base;
+}
+
+static inline unsigned long get_desc_limit(struct desc_struct *desc)
+{
+ unsigned long limit;
+ limit = (desc->a & 0x0ffff) | (desc->b & 0xf0000);
+ return limit;
+}
+
extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
DECLARE_PER_CPU(struct desc_struct, cpu_gdt_table[GDT_ENTRIES]);
@@ -111,15 +133,5 @@ static inline void load_LDT(mm_context_t
put_cpu();
}
-static inline unsigned long get_desc_base(unsigned long *desc)
-{
- unsigned long base;
- base = ((desc[0] >> 16) & 0x0000ffff) |
- ((desc[1] << 16) & 0x00ff0000) |
- (desc[1] & 0xff000000);
- return base;
-}
-
#endif /* !__ASSEMBLY__ */
-
#endif
_