u32 *desc;
unsigned long base;
- down(&child->mm->context.sem);
- desc = child->mm->context.ldt + (seg & ~7);
- base = (desc[0] >> 16) | ((desc[1] & 0xff) << 16) | (desc[1] & 0xff000000);
+ seg &= ~7UL;
- /* 16-bit code segment? */
- if (!((desc[1] >> 22) & 1))
- addr &= 0xffff;
- addr += base;
+ down(&child->mm->context.sem);
+ if (unlikely((seg >> 3) >= child->mm->context.size))
+ 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));
+
+ /* 16-bit code segment? */
+ if (!((desc[1] >> 22) & 1))
+ addr &= 0xffff;
+ addr += base;
+ }
up(&child->mm->context.sem);
}
return addr;
u32 *desc;
unsigned long base;
- down(&child->mm->context.sem);
- desc = child->mm->context.ldt + (seg & ~7);
- base = (desc[0] >> 16) | ((desc[1] & 0xff) << 16) | (desc[1] & 0xff000000);
+ seg &= ~7UL;
- /* 16-bit code segment? */
- if (!((desc[1] >> 22) & 1))
- addr &= 0xffff;
- addr += base;
+ down(&child->mm->context.sem);
+ if (unlikely((seg >> 3) >= child->mm->context.size))
+ 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));
+
+ /* 16-bit code segment? */
+ if (!((desc[1] >> 22) & 1))
+ addr &= 0xffff;
+ addr += base;
+ }
up(&child->mm->context.sem);
}
+
return addr;
}