static void doublefault_fn(void)
{
struct desc_ptr gdt_desc = {0, 0};
unsigned long gdt, tss;
native_store_gdt(&gdt_desc);
gdt = (unsigned long)gdt_desc.address;
printk(KERN_EMERG "PANIC: double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);
if (ptr_ok(gdt)) {
gdt += GDT_ENTRY_TSS << 3;
tss = get_desc_base((struct desc_struct *)gdt);
printk(KERN_EMERG "double fault, tss at %08lx\n", tss);
if (ptr_ok(tss)) {
struct x86_hw_tss *t = (struct x86_hw_tss *)tss;
printk(KERN_EMERG "eip = %08lx, esp = %08lx\n",
t->ip, t->sp);
printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
t->ax, t->bx, t->cx, t->dx);
printk(KERN_EMERG "esi = %08lx, edi = %08lx\n",
t->si, t->di);
}
}
for (;;)
cpu_relax();
}
static void fill_user_desc(struct user_desc *info, int idx,
const struct desc_struct *desc)
{
memset(info, 0, sizeof(*info));
info->entry_number = idx;
info->base_addr = get_desc_base(desc);
info->limit = get_desc_limit(desc);
info->seg_32bit = desc->d;
info->contents = desc->type >> 2;
info->read_exec_only = !(desc->type & 2);
info->limit_in_pages = desc->g;
info->seg_not_present = !desc->p;
info->useable = desc->avl;
#ifdef CONFIG_X86_64
info->lm = desc->l;
#endif
}
/*
* Interrupts are disabled on entry as trap3 is an interrupt gate and they
* remain disabled thorough out this function.
*/
static int kprobe_handler(struct pt_regs *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();
/* Check if the application is using LDT entry for its code segment and
* calculate the address by reading the base address from the LDT entry.
*/
if ((regs->xcs & 4) && (current->mm)) {
lp = (unsigned long *) ((unsigned long)((regs->xcs >> 3) * 8)
+ (char *) current->mm->context.ldt);
addr = (kprobe_opcode_t *) (get_desc_base(lp) + regs->eip -
sizeof(kprobe_opcode_t));
} else {
unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs)
{
unsigned long addr, seg;
addr = regs->ip;
seg = regs->cs & 0xffff;
if (v8086_mode(regs)) {
addr = (addr & 0xffff) + (seg << 4);
return addr;
}
/*
* We'll assume that the code segments in the GDT
* are all zero-based. That is largely true: the
* TLS segments are used for data, and the PNPBIOS
* and APM bios ones we just ignore here.
*/
if ((seg & SEGMENT_TI_MASK) == SEGMENT_LDT) {
struct desc_struct *desc;
unsigned long base;
seg >>= 3;
mutex_lock(&child->mm->context.lock);
if (unlikely(!child->mm->context.ldt ||
seg >= child->mm->context.ldt->size))
addr = -1L; /* bogus selector, access would fault */
else {
desc = &child->mm->context.ldt->entries[seg];
base = get_desc_base(desc);
/* 16-bit code segment? */
if (!desc->d)
addr &= 0xffff;
addr += base;
}
mutex_unlock(&child->mm->context.lock);
}
return addr;
}
/*
* Interrupts are disabled on entry as trap3 is an interrupt gate and they
* remain disabled thorough out this function.
*/
static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
kprobe_opcode_t *addr = NULL;
unsigned long *lp;
struct kprobe_ctlblk *kcb;
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
*/
preempt_disable();
kcb = get_kprobe_ctlblk();
/* Check if the application is using LDT entry for its code segment and
* calculate the address by reading the base address from the LDT entry.
*/
if ((regs->xcs & 4) && (current->mm)) {
lp = (unsigned long *) ((unsigned long)((regs->xcs >> 3) * 8)
+ (char *) current->mm->context.ldt);
addr = (kprobe_opcode_t *) (get_desc_base(lp) + regs->eip -
sizeof(kprobe_opcode_t));
} else {
