1 files changed, 36 insertions, 59 deletions

diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h
index 37672f7..1ecdc3e 100644
--- a/include/asm-x86/i387.h
+++ b/include/asm-x86/i387.h
@@ -7,12 +7,13 @@
  * x86-64 work by Andi Kleen 2002
  */
 
-#ifndef _ASM_X86_I387_H
-#define _ASM_X86_I387_H
+#ifndef ASM_X86__I387_H
+#define ASM_X86__I387_H
 
 #include <linux/sched.h>
 #include <linux/kernel_stat.h>
 #include <linux/regset.h>
+#include <linux/hardirq.h>
 #include <asm/asm.h>
 #include <asm/processor.h>
 #include <asm/sigcontext.h>
@@ -24,6 +25,7 @@ extern void mxcsr_feature_mask_init(void);
 extern int init_fpu(struct task_struct *child);
 extern asmlinkage void math_state_restore(void);
 extern void init_thread_xstate(void);
+extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
 
 extern user_regset_active_fn fpregs_active, xfpregs_active;
 extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get;
@@ -62,8 +64,6 @@ static inline int restore_fpu_checking(struct i387_fxsave_struct *fx)
 #else
 		     : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0));
 #endif
-	if (unlikely(err))
-		init_fpu(current);
 	return err;
 }
 
@@ -137,60 +137,6 @@ static inline void __save_init_fpu(struct task_struct *tsk)
 	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);
@@ -290,6 +236,37 @@ static inline void kernel_fpu_end(void)
 	preempt_enable();
 }
 
+/*
+ * Some instructions like VIA's padlock instructions generate a spurious
+ * DNA fault but don't modify SSE registers. And these instructions
+ * get used from interrupt context aswell. To prevent these kernel instructions
+ * in interrupt context interact wrongly with other user/kernel fpu usage, we
+ * should use them only in the context of irq_ts_save/restore()
+ */
+static inline int irq_ts_save(void)
+{
+	/*
+	 * If we are in process context, we are ok to take a spurious DNA fault.
+	 * Otherwise, doing clts() in process context require pre-emption to
+	 * be disabled or some heavy lifting like kernel_fpu_begin()
+	 */
+	if (!in_interrupt())
+		return 0;
+
+	if (read_cr0() & X86_CR0_TS) {
+		clts();
+		return 1;
+	}
+
+	return 0;
+}
+
+static inline void irq_ts_restore(int TS_state)
+{
+	if (TS_state)
+		stts();
+}
+
 #ifdef CONFIG_X86_64
 
 static inline void save_init_fpu(struct task_struct *tsk)
@@ -360,4 +337,4 @@ static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk)
 	}
 }
 
-#endif	/* _ASM_X86_I387_H */
+#endif /* ASM_X86__I387_H */