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>

7 files changed, 66 insertions, 296 deletions

diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 2499a324feaa..0db0a6291bbd 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -643,8 +643,8 @@ ia32_sys_call_table:
         .quad compat_sys_futex          /* 240 */
         .quad compat_sys_sched_setaffinity
         .quad compat_sys_sched_getaffinity
-        .quad sys32_set_thread_area
-        .quad sys32_get_thread_area
+        .quad sys_set_thread_area
+        .quad sys_get_thread_area
         .quad compat_sys_io_setup       /* 245 */
         .quad sys_io_destroy
         .quad compat_sys_io_getevents
diff --git a/arch/x86/kernel/Makefile_32 b/arch/x86/kernel/Makefile_32
index 2c9596b9349c..9a6577a746ba 100644
--- a/arch/x86/kernel/Makefile_32
+++ b/arch/x86/kernel/Makefile_32
@@ -10,6 +10,7 @@ obj-y	:= process_32.o signal_32.o entry_32.o traps_32.o irq_32.o \
                 pci-dma_32.o i386_ksyms_32.o i387_32.o bootflag.o e820_32.o\
                 quirks.o i8237.o topology.o alternative.o i8253.o tsc_32.o io_delay.o rtc.o
 
+obj-y                           += tls.o
 obj-$(CONFIG_STACKTRACE)        += stacktrace.o
 obj-y                           += cpu/
 obj-y                           += acpi/
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)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 9ea1d7546f80..ccc9d68d5a58 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -524,7 +524,8 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long rsp,
         if (clone_flags & CLONE_SETTLS) {
 #ifdef CONFIG_IA32_EMULATION
                 if (test_thread_flag(TIF_IA32))
-                        err = ia32_child_tls(p, childregs); 
+                        err = do_set_thread_area(p, -1,
+                                (struct user_desc __user *)childregs->rsi, 0);
                 else                    
 #endif   
                         err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8); 
diff --git a/arch/x86/kernel/ptrace_32.c b/arch/x86/kernel/ptrace_32.c
index ff5431cc03ee..09227cfb7c4c 100644
--- a/arch/x86/kernel/ptrace_32.c
+++ b/arch/x86/kernel/ptrace_32.c
@@ -276,85 +276,6 @@ void ptrace_disable(struct task_struct *child)
         clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 }
 
-/*
- * Perform get_thread_area on behalf of the traced child.
- */
-static int
-ptrace_get_thread_area(struct task_struct *child,
-                       int idx, struct user_desc __user *user_desc)
-{
-        struct user_desc info;
-        struct desc_struct *desc;
-
-/*
- * 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)
-
-        if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
-                return -EINVAL;
-
-        desc = child->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(user_desc, &info, sizeof(info)))
-                return -EFAULT;
-
-        return 0;
-}
-
-/*
- * Perform set_thread_area on behalf of the traced child.
- */
-static int
-ptrace_set_thread_area(struct task_struct *child,
-                       int idx, struct user_desc __user *user_desc)
-{
-        struct user_desc info;
-        struct desc_struct *desc;
-
-        if (copy_from_user(&info, user_desc, sizeof(info)))
-                return -EFAULT;
-
-        if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
-                return -EINVAL;
-
-        desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
-        if (LDT_empty(&info)) {
-                desc->a = 0;
-                desc->b = 0;
-        } else {
-                desc->a = LDT_entry_a(&info);
-                desc->b = LDT_entry_b(&info);
-        }
-
-        return 0;
-}
-
 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 {
         struct user * dummy = NULL;
@@ -601,13 +522,17 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
         }
 
         case PTRACE_GET_THREAD_AREA:
-                ret = ptrace_get_thread_area(child, addr,
-                                        (struct user_desc __user *) data);
+                if (addr < 0)
+                        return -EIO;
+                ret = do_get_thread_area(child, addr,
+                                         (struct user_desc __user *) data);
                 break;
 
         case PTRACE_SET_THREAD_AREA:
-                ret = ptrace_set_thread_area(child, addr,
-                                        (struct user_desc __user *) data);
+                if (addr < 0)
+                        return -EIO;
+                ret = do_set_thread_area(child, addr,
+                                         (struct user_desc __user *) data, 0);
                 break;
 
         default:
diff --git a/arch/x86/kernel/ptrace_64.c b/arch/x86/kernel/ptrace_64.c
index 1edece36044c..375fadc23a25 100644
--- a/arch/x86/kernel/ptrace_64.c
+++ b/arch/x86/kernel/ptrace_64.c
@@ -474,23 +474,19 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                    64bit debugger to fully examine them too. Better
                    don't use it against 64bit processes, use
                    PTRACE_ARCH_PRCTL instead. */
-        case PTRACE_SET_THREAD_AREA: {
-                struct user_desc __user *p;
-                int old; 
-                p = (struct user_desc __user *)data;
-                get_user(old,  &p->entry_number); 
-                put_user(addr, &p->entry_number);
-                ret = do_set_thread_area(&child->thread, p);
-                put_user(old,  &p->entry_number); 
-                break;
         case PTRACE_GET_THREAD_AREA:
-                p = (struct user_desc __user *)data;
-                get_user(old,  &p->entry_number); 
-                put_user(addr, &p->entry_number);
-                ret = do_get_thread_area(&child->thread, p);
-                put_user(old,  &p->entry_number); 
+                if (addr < 0)
+                        return -EIO;
+                ret = do_get_thread_area(child, addr,
+                                         (struct user_desc __user *) data);
+
+                break;
+        case PTRACE_SET_THREAD_AREA:
+                if (addr < 0)
+                        return -EIO;
+                ret = do_set_thread_area(child, addr,
+                                         (struct user_desc __user *) data, 0);
                 break;
-        } 
 #endif
                 /* normal 64bit interface to access TLS data. 
                    Works just like arch_prctl, except that the arguments
diff --git a/arch/x86/kernel/tls.c b/arch/x86/kernel/tls.c
index 5291596f19b0..67a377621b12 100644
--- a/arch/x86/kernel/tls.c
+++ b/arch/x86/kernel/tls.c
@@ -19,31 +19,34 @@ static int get_free_idx(void)
         int idx;
 
         for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
-                if (desc_empty((struct n_desc_struct *)(t->tls_array) + idx))
+                if (desc_empty(&t->tls_array[idx]))
                         return idx + GDT_ENTRY_TLS_MIN;
         return -ESRCH;
 }
 
 /*
  * Set a given TLS descriptor:
- * When you want addresses > 32bit use arch_prctl()
  */
-int do_set_thread_area(struct thread_struct *t, struct user_desc __user *u_info)
+int do_set_thread_area(struct task_struct *p, int idx,
+                       struct user_desc __user *u_info,
+                       int can_allocate)
 {
+        struct thread_struct *t = &p->thread;
         struct user_desc info;
-        struct n_desc_struct *desc;
-        int cpu, idx;
+        u32 *desc;
+        int cpu;
 
         if (copy_from_user(&info, u_info, sizeof(info)))
                 return -EFAULT;
 
-        idx = info.entry_number;
+        if (idx == -1)
+                idx = info.entry_number;
 
         /*
          * index -1 means the kernel should try to find and
          * allocate an empty descriptor:
          */
-        if (idx == -1) {
+        if (idx == -1 && can_allocate) {
                 idx = get_free_idx();
                 if (idx < 0)
                         return idx;
@@ -54,7 +57,7 @@ int do_set_thread_area(struct thread_struct *t, struct user_desc __user *u_info)
         if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
                 return -EINVAL;
 
-        desc = ((struct n_desc_struct *)t->tls_array) + idx - GDT_ENTRY_TLS_MIN;
+        desc = (u32 *) &t->tls_array[idx - GDT_ENTRY_TLS_MIN];
 
         /*
          * We must not get preempted while modifying the TLS.
@@ -62,11 +65,11 @@ int do_set_thread_area(struct thread_struct *t, struct user_desc __user *u_info)
         cpu = get_cpu();
 
         if (LDT_empty(&info)) {
-                desc->a = 0;
-                desc->b = 0;
+                desc[0] = 0;
+                desc[1] = 0;
         } else {
-                desc->a = LDT_entry_a(&info);
-                desc->b = LDT_entry_b(&info);
+                desc[0] = LDT_entry_a(&info);
+                desc[1] = LDT_entry_b(&info);
         }
         if (t == &current->thread)
                 load_TLS(t, cpu);
@@ -75,9 +78,9 @@ int do_set_thread_area(struct thread_struct *t, struct user_desc __user *u_info)
         return 0;
 }
 
-asmlinkage long sys32_set_thread_area(struct user_desc __user *u_info)
+asmlinkage int sys_set_thread_area(struct user_desc __user *u_info)
 {
-        return do_set_thread_area(&current->thread, u_info);
+        return do_set_thread_area(current, -1, u_info, 1);
 }
 
 
@@ -85,34 +88,32 @@ asmlinkage long sys32_set_thread_area(struct user_desc __user *u_info)
  * Get the current Thread-Local Storage area:
  */
 
-#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)
-#define GET_LONGMODE(desc)      (((desc)->b >> 21) & 1)
-
-int do_get_thread_area(struct thread_struct *t, struct user_desc __user *u_info)
+#define GET_LIMIT(desc)         (((desc)[0] & 0x0ffff) | ((desc)[1] & 0xf0000))
+#define GET_32BIT(desc)         (((desc)[1] >> 22) & 1)
+#define GET_CONTENTS(desc)      (((desc)[1] >> 10) & 3)
+#define GET_WRITABLE(desc)      (((desc)[1] >>  9) & 1)
+#define GET_LIMIT_PAGES(desc)   (((desc)[1] >> 23) & 1)
+#define GET_PRESENT(desc)       (((desc)[1] >> 15) & 1)
+#define GET_USEABLE(desc)       (((desc)[1] >> 20) & 1)
+#define GET_LONGMODE(desc)      (((desc)[1] >> 21) & 1)
+
+int do_get_thread_area(struct task_struct *p, int idx,
+                       struct user_desc __user *u_info)
 {
+        struct thread_struct *t = &p->thread;
         struct user_desc info;
-        struct n_desc_struct *desc;
-        int idx;
+        u32 *desc;
 
-        if (get_user(idx, &u_info->entry_number))
+        if (idx == -1 && get_user(idx, &u_info->entry_number))
                 return -EFAULT;
         if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
                 return -EINVAL;
 
-        desc = ((struct n_desc_struct *)t->tls_array) + idx - GDT_ENTRY_TLS_MIN;
+        desc = (u32 *) &t->tls_array[idx - GDT_ENTRY_TLS_MIN];
 
         memset(&info, 0, sizeof(struct user_desc));
         info.entry_number = idx;
-        info.base_addr = get_desc_base(desc);
+        info.base_addr = get_desc_base((void *)desc);
         info.limit = GET_LIMIT(desc);
         info.seg_32bit = GET_32BIT(desc);
         info.contents = GET_CONTENTS(desc);
@@ -120,39 +121,16 @@ int do_get_thread_area(struct thread_struct *t, struct user_desc __user *u_info)
         info.limit_in_pages = GET_LIMIT_PAGES(desc);
         info.seg_not_present = !GET_PRESENT(desc);
         info.useable = GET_USEABLE(desc);
+#ifdef CONFIG_X86_64
         info.lm = GET_LONGMODE(desc);
+#endif
 
         if (copy_to_user(u_info, &info, sizeof(info)))
                 return -EFAULT;
         return 0;
 }
 
-asmlinkage long sys32_get_thread_area(struct user_desc __user *u_info)
+asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
 {
-        return do_get_thread_area(&current->thread, u_info);
-}
-
-
-int ia32_child_tls(struct task_struct *p, struct pt_regs *childregs)
-{
-        struct n_desc_struct *desc;
-        struct user_desc info;
-        struct user_desc __user *cp;
-        int idx;
-
-        cp = (void __user *)childregs->rsi;
-        if (copy_from_user(&info, cp, sizeof(info)))
-                return -EFAULT;
-        if (LDT_empty(&info))
-                return -EINVAL;
-
-        idx = info.entry_number;
-        if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
-                return -EINVAL;
-
-        desc = (struct n_desc_struct *)(p->thread.tls_array) + idx - GDT_ENTRY_TLS_MIN;
-        desc->a = LDT_entry_a(&info);
-        desc->b = LDT_entry_b(&info);
-
-        return 0;
+        return do_get_thread_area(current, -1, u_info);
 }