x86-64: Clean up 'save/restore_i387()' usage
Suresh Siddha wants to fix a possible FPU leakage in error conditions,
but the fact that save/restore_i387() are inlines in a header file makes
that harder to do than necessary. So start off with an obvious cleanup.
This just moves the x86-64 version of save/restore_i387() out of the
header file, and moves it to the only file that it is actually used in:
arch/x86/kernel/signal_64.c. So exposing it in a header file was wrong
to begin with.
[ Side note: I'd like to fix up some of the games we play with the
32-bit version of these functions too, but that's a separate
matter. The 32-bit versions are shared - under different names
at that! - by both the native x86-32 code and the x86-64 32-bit
compatibility code ]
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index 47c3d24..b45ef8d 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -53,6 +53,59 @@
return do_sigaltstack(uss, uoss, regs->sp);
}
+/*
+ * Signal frame handlers.
+ */
+
+static inline int save_i387(struct _fpstate __user *buf)
+{
+ struct task_struct *tsk = current;
+ int err = 0;
+
+ BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
+ sizeof(tsk->thread.xstate->fxsave));
+
+ if ((unsigned long)buf % 16)
+ printk("save_i387: 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,
+ sizeof(struct i387_fxsave_struct)))
+ return -1;
+ }
+ return 1;
+}
+
+/*
+ * This restores directly out of user space. Exceptions are handled.
+ */
+static inline int restore_i387(struct _fpstate __user *buf)
+{
+ struct task_struct *tsk = current;
+ int err;
+
+ 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;
+ }
+ return restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
+}
/*
* Do a signal return; undo the signal stack.
diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h
index 37672f7..96fa844 100644
--- a/include/asm-x86/i387.h
+++ b/include/asm-x86/i387.h
@@ -137,60 +137,6 @@
task_thread_info(tsk)->status &= ~TS_USEDFPU;
}
-/*
- * Signal frame handlers.
- */
-
-static inline int save_i387(struct _fpstate __user *buf)
-{
- struct task_struct *tsk = current;
- int err = 0;
-
- BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
- sizeof(tsk->thread.xstate->fxsave));
-
- if ((unsigned long)buf % 16)
- printk("save_i387: 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,
- sizeof(struct i387_fxsave_struct)))
- return -1;
- }
- return 1;
-}
-
-/*
- * This restores directly out of user space. Exceptions are handled.
- */
-static inline int restore_i387(struct _fpstate __user *buf)
-{
- struct task_struct *tsk = current;
- int err;
-
- 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;
- }
- return restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
-}
-
#else /* CONFIG_X86_32 */
extern void finit(void);