x86: Introduce 'struct fpu' and related API

Currently all fpu state access is through tsk->thread.xstate.  Since we wish
to generalize fpu access to non-task contexts, wrap the state in a new
'struct fpu' and convert existing access to use an fpu API.

Signal frame handlers are not converted to the API since they will remain
task context only things.

Signed-off-by: Avi Kivity <avi@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1273135546-29690-3-git-send-email-avi@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 9 insertions, 12 deletions

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 28ad9f4d8b94..f18fd9c15247 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -32,25 +32,22 @@ struct kmem_cache *task_xstate_cachep;
 
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
+        int ret;
+
         *dst = *src;
-        if (src->thread.xstate) {
-                dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
-                                                      GFP_KERNEL);
-                if (!dst->thread.xstate)
-                        return -ENOMEM;
-                WARN_ON((unsigned long)dst->thread.xstate & 15);
-                memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);
+        if (fpu_allocated(&src->thread.fpu)) {
+                memset(&dst->thread.fpu, 0, sizeof(dst->thread.fpu));
+                ret = fpu_alloc(&dst->thread.fpu);
+                if (ret)
+                        return ret;
+                fpu_copy(&dst->thread.fpu, &src->thread.fpu);
         }
         return 0;
 }
 
 void free_thread_xstate(struct task_struct *tsk)
 {
-        if (tsk->thread.xstate) {
-                kmem_cache_free(task_xstate_cachep, tsk->thread.xstate);
-                tsk->thread.xstate = NULL;
-        }
-
+        fpu_free(&tsk->thread.fpu);
         WARN(tsk->thread.ds_ctx, "leaking DS context\n");
 }