x86, xsave: reorganization of signal save/restore fpstate code layout
move 64bit routines that saves/restores fpstate in/from user stack from
signal_64.c to xsave.c
restore_i387_xstate() now handles the condition when user passes
NULL fpstate.
Other misc changes for prepartion of xsave/xrstor sigcontext support.
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>
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 7ad169e..608e72d 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -12,6 +12,85 @@
*/
unsigned int pcntxt_hmask, pcntxt_lmask;
+#ifdef CONFIG_X86_64
+/*
+ * Signal frame handlers.
+ */
+
+int save_i387_xstate(void __user *buf)
+{
+ struct task_struct *tsk = current;
+ int err = 0;
+
+ if (!access_ok(VERIFY_WRITE, buf, sig_xstate_size))
+ return -EACCES;
+
+ BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
+ sizeof(tsk->thread.xstate->fxsave));
+
+ if ((unsigned long)buf % 16)
+ printk("save_i387_xstate: bad fpstate %p\n", buf);
+
+ if (!used_math())
+ return 0;
+ clear_used_math(); /* trigger finit */
+ if (task_thread_info(tsk)->status & TS_USEDFPU) {
+ err = save_i387_checking((struct i387_fxsave_struct __user *)
+ buf);
+ if (err)
+ return err;
+ task_thread_info(tsk)->status &= ~TS_USEDFPU;
+ stts();
+ } else {
+ if (__copy_to_user(buf, &tsk->thread.xstate->fxsave,
+ xstate_size))
+ return -1;
+ }
+ return 1;
+}
+
+/*
+ * This restores directly out of user space. Exceptions are handled.
+ */
+int restore_i387_xstate(void __user *buf)
+{
+ struct task_struct *tsk = current;
+ int err;
+
+ if (!buf) {
+ if (used_math()) {
+ clear_fpu(tsk);
+ clear_used_math();
+ }
+
+ return 0;
+ } else
+ if (!access_ok(VERIFY_READ, buf, sig_xstate_size))
+ return -EACCES;
+
+ if (!used_math()) {
+ err = init_fpu(tsk);
+ if (err)
+ return err;
+ }
+
+ if (!(task_thread_info(current)->status & TS_USEDFPU)) {
+ clts();
+ task_thread_info(current)->status |= TS_USEDFPU;
+ }
+ err = fxrstor_checking((__force struct i387_fxsave_struct *)buf);
+ if (unlikely(err)) {
+ /*
+ * Encountered an error while doing the restore from the
+ * user buffer, clear the fpu state.
+ */
+ clear_fpu(tsk);
+ clear_used_math();
+ }
+ return err;
+}
+#endif
+
/*
* Represents init state for the supported extended state.
*/