diff options
Diffstat (limited to 'arch/x86/kernel/step.c')
| -rw-r--r-- | arch/x86/kernel/step.c | 84 |
1 files changed, 0 insertions, 84 deletions
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index 80b37181a42b..2ef1a5f8d675 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -5,90 +5,6 @@ #include <linux/mm.h> #include <linux/ptrace.h> -#ifdef CONFIG_X86_32 -#include <linux/uaccess.h> - -#include <asm/desc.h> - -/* - * Return EIP plus the CS segment base. The segment limit is also - * adjusted, clamped to the kernel/user address space (whichever is - * appropriate), and returned in *eip_limit. - * - * The segment is checked, because it might have been changed by another - * task between the original faulting instruction and here. - * - * If CS is no longer a valid code segment, or if EIP is beyond the - * limit, or if it is a kernel address when CS is not a kernel segment, - * then the returned value will be greater than *eip_limit. - * - * This is slow, but is very rarely executed. - */ -unsigned long get_segment_eip(struct pt_regs *regs, - unsigned long *eip_limit) -{ - unsigned long ip = regs->ip; - unsigned seg = regs->cs & 0xffff; - u32 seg_ar, seg_limit, base, *desc; - - /* Unlikely, but must come before segment checks. */ - if (unlikely(regs->flags & VM_MASK)) { - base = seg << 4; - *eip_limit = base + 0xffff; - return base + (ip & 0xffff); - } - - /* The standard kernel/user address space limit. */ - *eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg; - - /* By far the most common cases. */ - if (likely(SEGMENT_IS_FLAT_CODE(seg))) - return ip; - - /* Check the segment exists, is within the current LDT/GDT size, - that kernel/user (ring 0..3) has the appropriate privilege, - that it's a code segment, and get the limit. */ - __asm__("larl %3,%0; lsll %3,%1" - : "=&r" (seg_ar), "=r" (seg_limit) : "0" (0), "rm" (seg)); - if ((~seg_ar & 0x9800) || ip > seg_limit) { - *eip_limit = 0; - return 1; /* So that returned ip > *eip_limit. */ - } - - /* Get the GDT/LDT descriptor base. - When you look for races in this code remember that - LDT and other horrors are only used in user space. */ - if (seg & (1<<2)) { - /* Must lock the LDT while reading it. */ - mutex_lock(¤t->mm->context.lock); - desc = current->mm->context.ldt; - desc = (void *)desc + (seg & ~7); - } else { - /* Must disable preemption while reading the GDT. */ - desc = (u32 *)get_cpu_gdt_table(get_cpu()); - desc = (void *)desc + (seg & ~7); - } - - /* Decode the code segment base from the descriptor */ - base = get_desc_base((struct desc_struct *)desc); - - if (seg & (1<<2)) - mutex_unlock(¤t->mm->context.lock); - else - put_cpu(); - - /* Adjust EIP and segment limit, and clamp at the kernel limit. - It's legitimate for segments to wrap at 0xffffffff. */ - seg_limit += base; - if (seg_limit < *eip_limit && seg_limit >= base) - *eip_limit = seg_limit; - return ip + base; -} -#endif - -#ifdef CONFIG_X86_32 -static -#endif unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs) { unsigned long addr, seg; |