x86, xsave: enable xsave/xrstor on cpus with xsave support

Enables xsave/xrstor by turning on cr4.osxsave on cpu's which have
the xsave support. For now, features that OS supports/enabled are
FP and SSE.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index eb9ddd8efb82..e22a9a9dce8a 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -61,6 +61,11 @@ void __init init_thread_xstate(void)
                 return;
         }
 
+        if (cpu_has_xsave) {
+                xsave_cntxt_init();
+                return;
+        }
+
         if (cpu_has_fxsr)
                 xstate_size = sizeof(struct i387_fxsave_struct);
 #ifdef CONFIG_X86_32
@@ -83,6 +88,13 @@ void __cpuinit fpu_init(void)
 
         write_cr0(oldcr0 & ~(X86_CR0_TS|X86_CR0_EM)); /* clear TS and EM */
 
+        /*
+         * Boot processor to setup the FP and extended state context info.
+         */
+        if (!smp_processor_id())
+                init_thread_xstate();
+        xsave_init();
+
         mxcsr_feature_mask_init();
         /* clean state in init */
         current_thread_info()->status = 0;