diff options
Diffstat (limited to 'arch/x86_64/kernel/ldt_64.c')
| -rw-r--r-- | arch/x86_64/kernel/ldt_64.c | 252 |
1 files changed, 0 insertions, 252 deletions
diff --git a/arch/x86_64/kernel/ldt_64.c b/arch/x86_64/kernel/ldt_64.c deleted file mode 100644 index bc9ffd5c19c..00000000000 --- a/arch/x86_64/kernel/ldt_64.c +++ /dev/null @@ -1,252 +0,0 @@ -/* - * linux/arch/x86_64/kernel/ldt.c - * - * Copyright (C) 1992 Krishna Balasubramanian and Linus Torvalds - * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> - * Copyright (C) 2002 Andi Kleen - * - * This handles calls from both 32bit and 64bit mode. - */ - -#include <linux/errno.h> -#include <linux/sched.h> -#include <linux/string.h> -#include <linux/mm.h> -#include <linux/smp.h> -#include <linux/vmalloc.h> -#include <linux/slab.h> - -#include <asm/uaccess.h> -#include <asm/system.h> -#include <asm/ldt.h> -#include <asm/desc.h> -#include <asm/proto.h> - -#ifdef CONFIG_SMP /* avoids "defined but not used" warnig */ -static void flush_ldt(void *null) -{ - if (current->active_mm) - load_LDT(¤t->active_mm->context); -} -#endif - -static int alloc_ldt(mm_context_t *pc, unsigned mincount, int reload) -{ - void *oldldt; - void *newldt; - unsigned oldsize; - - if (mincount <= (unsigned)pc->size) - return 0; - oldsize = pc->size; - mincount = (mincount+511)&(~511); - if (mincount*LDT_ENTRY_SIZE > PAGE_SIZE) - newldt = vmalloc(mincount*LDT_ENTRY_SIZE); - else - newldt = kmalloc(mincount*LDT_ENTRY_SIZE, GFP_KERNEL); - - if (!newldt) - return -ENOMEM; - - if (oldsize) - memcpy(newldt, pc->ldt, oldsize*LDT_ENTRY_SIZE); - oldldt = pc->ldt; - memset(newldt+oldsize*LDT_ENTRY_SIZE, 0, (mincount-oldsize)*LDT_ENTRY_SIZE); - wmb(); - pc->ldt = newldt; - wmb(); - pc->size = mincount; - wmb(); - if (reload) { -#ifdef CONFIG_SMP - cpumask_t mask; - - preempt_disable(); - mask = cpumask_of_cpu(smp_processor_id()); - load_LDT(pc); - if (!cpus_equal(current->mm->cpu_vm_mask, mask)) - smp_call_function(flush_ldt, NULL, 1, 1); - preempt_enable(); -#else - load_LDT(pc); -#endif - } - if (oldsize) { - if (oldsize*LDT_ENTRY_SIZE > PAGE_SIZE) - vfree(oldldt); - else - kfree(oldldt); - } - return 0; -} - -static inline int copy_ldt(mm_context_t *new, mm_context_t *old) -{ - int err = alloc_ldt(new, old->size, 0); - if (err < 0) - return err; - memcpy(new->ldt, old->ldt, old->size*LDT_ENTRY_SIZE); - return 0; -} - -/* - * we do not have to muck with descriptors here, that is - * done in switch_mm() as needed. - */ -int init_new_context(struct task_struct *tsk, struct mm_struct *mm) -{ - struct mm_struct * old_mm; - int retval = 0; - - init_MUTEX(&mm->context.sem); - mm->context.size = 0; - old_mm = current->mm; - if (old_mm && old_mm->context.size > 0) { - down(&old_mm->context.sem); - retval = copy_ldt(&mm->context, &old_mm->context); - up(&old_mm->context.sem); - } - return retval; -} - -/* - * - * Don't touch the LDT register - we're already in the next thread. - */ -void destroy_context(struct mm_struct *mm) -{ - if (mm->context.size) { - if ((unsigned)mm->context.size*LDT_ENTRY_SIZE > PAGE_SIZE) - vfree(mm->context.ldt); - else - kfree(mm->context.ldt); - mm->context.size = 0; - } -} - -static int read_ldt(void __user * ptr, unsigned long bytecount) -{ - int err; - unsigned long size; - struct mm_struct * mm = current->mm; - - if (!mm->context.size) - return 0; - if (bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES) - bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES; - - down(&mm->context.sem); - size = mm->context.size*LDT_ENTRY_SIZE; - if (size > bytecount) - size = bytecount; - - err = 0; - if (copy_to_user(ptr, mm->context.ldt, size)) - err = -EFAULT; - up(&mm->context.sem); - if (err < 0) - goto error_return; - if (size != bytecount) { - /* zero-fill the rest */ - if (clear_user(ptr+size, bytecount-size) != 0) { - err = -EFAULT; - goto error_return; - } - } - return bytecount; -error_return: - return err; -} - -static int read_default_ldt(void __user * ptr, unsigned long bytecount) -{ - /* Arbitrary number */ - /* x86-64 default LDT is all zeros */ - if (bytecount > 128) - bytecount = 128; - if (clear_user(ptr, bytecount)) - return -EFAULT; - return bytecount; -} - -static int write_ldt(void __user * ptr, unsigned long bytecount, int oldmode) -{ - struct task_struct *me = current; - struct mm_struct * mm = me->mm; - __u32 entry_1, entry_2, *lp; - int error; - struct user_desc ldt_info; - - error = -EINVAL; - - if (bytecount != sizeof(ldt_info)) - goto out; - error = -EFAULT; - if (copy_from_user(&ldt_info, ptr, bytecount)) - goto out; - - error = -EINVAL; - if (ldt_info.entry_number >= LDT_ENTRIES) - goto out; - if (ldt_info.contents == 3) { - if (oldmode) - goto out; - if (ldt_info.seg_not_present == 0) - goto out; - } - - down(&mm->context.sem); - if (ldt_info.entry_number >= (unsigned)mm->context.size) { - error = alloc_ldt(¤t->mm->context, ldt_info.entry_number+1, 1); - if (error < 0) - goto out_unlock; - } - - lp = (__u32 *) ((ldt_info.entry_number << 3) + (char *) mm->context.ldt); - - /* Allow LDTs to be cleared by the user. */ - if (ldt_info.base_addr == 0 && ldt_info.limit == 0) { - if (oldmode || LDT_empty(&ldt_info)) { - entry_1 = 0; - entry_2 = 0; - goto install; - } - } - - entry_1 = LDT_entry_a(&ldt_info); - entry_2 = LDT_entry_b(&ldt_info); - if (oldmode) - entry_2 &= ~(1 << 20); - - /* Install the new entry ... */ -install: - *lp = entry_1; - *(lp+1) = entry_2; - error = 0; - -out_unlock: - up(&mm->context.sem); -out: - return error; -} - -asmlinkage int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount) -{ - int ret = -ENOSYS; - - switch (func) { - case 0: - ret = read_ldt(ptr, bytecount); - break; - case 1: - ret = write_ldt(ptr, bytecount, 1); - break; - case 2: - ret = read_default_ldt(ptr, bytecount); - break; - case 0x11: - ret = write_ldt(ptr, bytecount, 0); - break; - } - return ret; -} |