x86: TLS cleanup

This consolidates the four different places that implemented the same
encoding magic for the GDT-slot 32-bit TLS support.  The old tls32.c was
renamed and is now only slightly modified to be the shared implementation.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 5 insertions, 136 deletions

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 631af167bc51..4d66a56280d3 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -501,32 +501,15 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
                 set_tsk_thread_flag(p, TIF_IO_BITMAP);
         }
 
+        err = 0;
+
         /*
          * Set a new TLS for the child thread?
          */
-        if (clone_flags & CLONE_SETTLS) {
-                struct desc_struct *desc;
-                struct user_desc info;
-                int idx;
-
-                err = -EFAULT;
-                if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info)))
-                        goto out;
-                err = -EINVAL;
-                if (LDT_empty(&info))
-                        goto out;
-
-                idx = info.entry_number;
-                if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
-                        goto out;
-
-                desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
-                desc->a = LDT_entry_a(&info);
-                desc->b = LDT_entry_b(&info);
-        }
+        if (clone_flags & CLONE_SETTLS)
+                err = do_set_thread_area(p, -1,
+                        (struct user_desc __user *)childregs->esi, 0);
 
-        err = 0;
- out:
         if (err && p->thread.io_bitmap_ptr) {
                 kfree(p->thread.io_bitmap_ptr);
                 p->thread.io_bitmap_max = 0;
@@ -872,120 +855,6 @@ unsigned long get_wchan(struct task_struct *p)
         return 0;
 }
 
-/*
- * sys_alloc_thread_area: get a yet unused TLS descriptor index.
- */
-static int get_free_idx(void)
-{
-        struct thread_struct *t = &current->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 = &current->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;
-}
-
 unsigned long arch_align_stack(unsigned long sp)
 {
         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)