x86/arch_prctl/64: Remove FSBASE/GSBASE < 4G optimization

[cascardo/linux.git] / arch / x86 / kernel / process_64.c

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 24d1b7f..864fe2c 100644 (file)
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -136,25 +136,6 @@ void release_thread(struct task_struct *dead_task)
        }
 }
 
-static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
-{
-       struct user_desc ud = {
-               .base_addr = addr,
-               .limit = 0xfffff,
-               .seg_32bit = 1,
-               .limit_in_pages = 1,
-               .useable = 1,
-       };
-       struct desc_struct *desc = t->thread.tls_array;
-       desc += tls;
-       fill_ldt(desc, &ud);
-}
-
-static inline u32 read_32bit_tls(struct task_struct *t, int tls)
-{
-       return get_desc_base(&t->thread.tls_array[tls]);
-}
-
 int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
                unsigned long arg, struct task_struct *p, unsigned long tls)
 {
@@ -554,25 +535,12 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
                if (addr >= TASK_SIZE_OF(task))
                        return -EPERM;
                cpu = get_cpu();
-               /* handle small bases via the GDT because that's faster to
-                  switch. */
-               if (addr <= 0xffffffff) {
-                       set_32bit_tls(task, GS_TLS, addr);
-                       if (doit) {
-                               load_TLS(&task->thread, cpu);
-                               load_gs_index(GS_TLS_SEL);
-                       }
-                       task->thread.gsindex = GS_TLS_SEL;
-                       task->thread.gs = 0;
-               } else {
-                       task->thread.gsindex = 0;
-                       task->thread.gs = addr;
-                       if (doit) {
-                               load_gs_index(0);
-                               ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr);
-                       }
+               task->thread.gsindex = 0;
+               task->thread.gs = addr;
+               if (doit) {
+                       load_gs_index(0);
+                       ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr);
                }
-               put_cpu();
                break;
        case ARCH_SET_FS:
                /* Not strictly needed for fs, but do it for symmetry
@@ -580,25 +548,12 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
                if (addr >= TASK_SIZE_OF(task))
                        return -EPERM;
                cpu = get_cpu();
-               /* handle small bases via the GDT because that's faster to
-                  switch. */
-               if (addr <= 0xffffffff) {
-                       set_32bit_tls(task, FS_TLS, addr);
-                       if (doit) {
-                               load_TLS(&task->thread, cpu);
-                               loadsegment(fs, FS_TLS_SEL);
-                       }
-                       task->thread.fsindex = FS_TLS_SEL;
-                       task->thread.fs = 0;
-               } else {
-                       task->thread.fsindex = 0;
-                       task->thread.fs = addr;
-                       if (doit) {
-                               /* set the selector to 0 to not confuse
-                                  __switch_to */
-                               loadsegment(fs, 0);
-                               ret = wrmsrl_safe(MSR_FS_BASE, addr);
-                       }
+               task->thread.fsindex = 0;
+               task->thread.fs = addr;
+               if (doit) {
+                       /* set the selector to 0 to not confuse __switch_to */
+                       loadsegment(fs, 0);
+                       ret = wrmsrl_safe(MSR_FS_BASE, addr);
                }
                put_cpu();
                break;
@@ -606,8 +561,6 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
                unsigned long base;
                if (doit)
                        rdmsrl(MSR_FS_BASE, base);
-               else if (task->thread.fsindex == FS_TLS_SEL)
-                       base = read_32bit_tls(task, FS_TLS);
                else
                        base = task->thread.fs;
                ret = put_user(base, (unsigned long __user *)addr);
@@ -617,8 +570,6 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
                unsigned long base;
                if (doit)
                        rdmsrl(MSR_KERNEL_GS_BASE, base);
-               else if (task->thread.gsindex == GS_TLS_SEL)
-                       base = read_32bit_tls(task, GS_TLS);
                else
                        base = task->thread.gs;
                ret = put_user(base, (unsigned long __user *)addr);