-/*
- * sys_alloc_thread_area: get a yet unused TLS descriptor index.
- */
-static int get_free_idx(void)
-{
- struct thread_struct *t = ¤t->thread;
- int idx;
-
- for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
- if (desc_empty(t->tls_array + idx))
- return idx + GDT_ENTRY_TLS_MIN;
- return -ESRCH;
-}
-
-/*
- * Set a given TLS descriptor:
- */
-asmlinkage int sys_set_thread_area(struct user_desc __user *u_info)
-{
- struct thread_struct *t = ¤t->thread;
- struct user_desc info;
- struct desc_struct *desc;
- int cpu, idx;
-
- if (copy_from_user(&info, u_info, sizeof(info)))
- return -EFAULT;
- idx = info.entry_number;
-
- /*
- * index -1 means the kernel should try to find and
- * allocate an empty descriptor:
- */
- if (idx == -1) {
- idx = get_free_idx();
- if (idx < 0)
- return idx;
- if (put_user(idx, &u_info->entry_number))
- return -EFAULT;
- }
-
- if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
- return -EINVAL;
-
- desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN;
-
- /*
- * We must not get preempted while modifying the TLS.
- */
- cpu = get_cpu();
-
- if (LDT_empty(&info)) {
- desc->a = 0;
- desc->b = 0;
- } else {
- desc->a = LDT_entry_a(&info);
- desc->b = LDT_entry_b(&info);
- }
- load_TLS(t, cpu);
-
- put_cpu();
-
- return 0;
-}
-
-/*
- * Get the current Thread-Local Storage area:
- */
-
-#define GET_BASE(desc) ( \
- (((desc)->a >> 16) & 0x0000ffff) | \
- (((desc)->b << 16) & 0x00ff0000) | \
- ( (desc)->b & 0xff000000) )
-
-#define GET_LIMIT(desc) ( \
- ((desc)->a & 0x0ffff) | \
- ((desc)->b & 0xf0000) )
-
-#define GET_32BIT(desc) (((desc)->b >> 22) & 1)
-#define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
-#define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
-#define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
-#define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
-#define GET_USEABLE(desc) (((desc)->b >> 20) & 1)
-
-asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
-{
- struct user_desc info;
- struct desc_struct *desc;
- int idx;
-
- if (get_user(idx, &u_info->entry_number))
- return -EFAULT;
- if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
- return -EINVAL;
-
- memset(&info, 0, sizeof(info));
-
- desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
-
- info.entry_number = idx;
- info.base_addr = GET_BASE(desc);
- info.limit = GET_LIMIT(desc);
- info.seg_32bit = GET_32BIT(desc);
- info.contents = GET_CONTENTS(desc);
- info.read_exec_only = !GET_WRITABLE(desc);
- info.limit_in_pages = GET_LIMIT_PAGES(desc);
- info.seg_not_present = !GET_PRESENT(desc);
- info.useable = GET_USEABLE(desc);
-
- if (copy_to_user(u_info, &info, sizeof(info)))
- return -EFAULT;
- return 0;
-}
-