From: Zachary Amsden Add some convenient descriptor access functions and move them all into desc.h Signed-off-by: Zachary Amsden Signed-off-by: Andrew Morton --- 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 2005-08-17 22:43:02.000000000 -0700 +++ devel-akpm/arch/i386/kernel/kprobes.c 2005-08-17 22:43:02.000000000 -0700 @@ -155,7 +155,6 @@ static int kprobe_handler(struct pt_regs 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(); @@ -163,9 +162,10 @@ static int kprobe_handler(struct pt_regs * 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 2005-08-17 22:43:02.000000000 -0700 +++ devel-akpm/arch/i386/mm/fault.c 2005-08-17 22:43:02.000000000 -0700 @@ -74,7 +74,8 @@ 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; @@ -107,12 +108,12 @@ 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 2005-08-17 22:43:02.000000000 -0700 +++ devel-akpm/include/asm-i386/desc.h 2005-08-17 22:43:02.000000000 -0700 @@ -14,6 +14,28 @@ #include +#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 _