1 files changed, 11 insertions, 3 deletions

diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 70dd8e5c6889..fb903e65e079 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -575,8 +575,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         prev->userrsp = read_pda(oldrsp); 
         write_pda(oldrsp, next->userrsp); 
         write_pda(pcurrent, next_p); 
+
         /* This must be here to ensure both math_state_restore() and
-           kernel_fpu_begin() work consistently. */
+           kernel_fpu_begin() work consistently. 
+           And the AMD workaround requires it to be after DS reload. */
         unlazy_fpu(prev_p);
         write_pda(kernelstack,
                   task_stack_page(next_p) + THREAD_SIZE - PDA_STACKOFFSET);
@@ -781,10 +783,16 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
         }
         case ARCH_GET_GS: { 
                 unsigned long base;
+                unsigned gsindex;
                 if (task->thread.gsindex == GS_TLS_SEL)
                         base = read_32bit_tls(task, GS_TLS);
-                else if (doit)
-                        rdmsrl(MSR_KERNEL_GS_BASE, base);
+                else if (doit) {
+                        asm("movl %%gs,%0" : "=r" (gsindex));
+                        if (gsindex)
+                                rdmsrl(MSR_KERNEL_GS_BASE, base);
+                        else
+                                base = task->thread.gs;
+                }
                 else
                         base = task->thread.gs;
                 ret = put_user(base, (unsigned long __user *)addr);