Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / include / asm-x86_64 / i387.h

diff --git a/include/asm-x86_64/i387.h b/include/asm-x86_64/i387.h
index aa39cfd..cba8a3b 100644 (file)
--- a/include/asm-x86_64/i387.h
+++ b/include/asm-x86_64/i387.h
@@ -30,7 +30,7 @@ extern int save_i387(struct _fpstate __user *buf);
  */
 
 #define unlazy_fpu(tsk) do { \
-       if ((tsk)->thread_info->status & TS_USEDFPU) \
+       if (task_thread_info(tsk)->status & TS_USEDFPU) \
                save_init_fpu(tsk); \
 } while (0)
 
@@ -46,9 +46,9 @@ static inline void tolerant_fwait(void)
 }
 
 #define clear_fpu(tsk) do { \
-       if ((tsk)->thread_info->status & TS_USEDFPU) {          \
+       if (task_thread_info(tsk)->status & TS_USEDFPU) {       \
                tolerant_fwait();                               \
-               (tsk)->thread_info->status &= ~TS_USEDFPU;      \
+               task_thread_info(tsk)->status &= ~TS_USEDFPU;   \
                stts();                                         \
        }                                                       \
 } while (0)
@@ -72,10 +72,28 @@ extern int set_fpregs(struct task_struct *tsk,
 #define set_fpu_swd(t,val) ((t)->thread.i387.fxsave.swd = (val))
 #define set_fpu_fxsr_twd(t,val) ((t)->thread.i387.fxsave.twd = (val))
 
+#define X87_FSW_ES (1 << 7)    /* Exception Summary */
+
+/* AMD CPUs don't save/restore FDP/FIP/FOP unless an exception
+   is pending. Clear the x87 state here by setting it to fixed
+   values. The kernel data segment can be sometimes 0 and sometimes
+   new user value. Both should be ok.
+   Use the PDA as safe address because it should be already in L1. */
+static inline void clear_fpu_state(struct i387_fxsave_struct *fx)
+{
+       if (unlikely(fx->swd & X87_FSW_ES))
+                asm volatile("fnclex");
+       alternative_input(ASM_NOP8 ASM_NOP2,
+                    "    emms\n"               /* clear stack tags */
+                    "    fildl %%gs:0",        /* load to clear state */
+                    X86_FEATURE_FXSAVE_LEAK);
+}
+
 static inline int restore_fpu_checking(struct i387_fxsave_struct *fx) 
 { 
        int err;
-       asm volatile("1:  rex64 ; fxrstor (%[fx])\n\t"
+
+       asm volatile("1:  rex64/fxrstor (%[fx])\n\t"
                     "2:\n"
                     ".section .fixup,\"ax\"\n"
                     "3:  movl $-1,%[err]\n"
@@ -86,7 +104,11 @@ static inline int restore_fpu_checking(struct i387_fxsave_struct *fx)
                     "   .quad  1b,3b\n"
                     ".previous"
                     : [err] "=r" (err)
-                    : [fx] "r" (fx), "0" (0)); 
+#if 0 /* See comment in __fxsave_clear() below. */
+                    : [fx] "r" (fx), "m" (*fx), "0" (0));
+#else
+                    : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0));
+#endif
        if (unlikely(err))
                init_fpu(current);
        return err;
@@ -95,7 +117,8 @@ static inline int restore_fpu_checking(struct i387_fxsave_struct *fx)
 static inline int save_i387_checking(struct i387_fxsave_struct __user *fx) 
 { 
        int err;
-       asm volatile("1:  rex64 ; fxsave (%[fx])\n\t"
+
+       asm volatile("1:  rex64/fxsave (%[fx])\n\t"
                     "2:\n"
                     ".section .fixup,\"ax\"\n"
                     "3:  movl $-1,%[err]\n"
@@ -105,20 +128,54 @@ static inline int save_i387_checking(struct i387_fxsave_struct __user *fx)
                     "   .align 8\n"
                     "   .quad  1b,3b\n"
                     ".previous"
-                    : [err] "=r" (err)
-                    : [fx] "r" (fx), "0" (0)); 
+                    : [err] "=r" (err), "=m" (*fx)
+#if 0 /* See comment in __fxsave_clear() below. */
+                    : [fx] "r" (fx), "0" (0));
+#else
+                    : [fx] "cdaSDb" (fx), "0" (0));
+#endif
        if (unlikely(err))
                __clear_user(fx, sizeof(struct i387_fxsave_struct));
+       /* No need to clear here because the caller clears USED_MATH */
        return err;
 } 
 
+static inline void __fxsave_clear(struct task_struct *tsk)
+{
+       /* Using "rex64; fxsave %0" is broken because, if the memory operand
+          uses any extended registers for addressing, a second REX prefix
+          will be generated (to the assembler, rex64 followed by semicolon
+          is a separate instruction), and hence the 64-bitness is lost. */
+#if 0
+       /* Using "fxsaveq %0" would be the ideal choice, but is only supported
+          starting with gas 2.16. */
+       __asm__ __volatile__("fxsaveq %0"
+                            : "=m" (tsk->thread.i387.fxsave));
+#elif 0
+       /* Using, as a workaround, the properly prefixed form below isn't
+          accepted by any binutils version so far released, complaining that
+          the same type of prefix is used twice if an extended register is
+          needed for addressing (fix submitted to mainline 2005-11-21). */
+       __asm__ __volatile__("rex64/fxsave %0"
+                            : "=m" (tsk->thread.i387.fxsave));
+#else
+       /* This, however, we can work around by forcing the compiler to select
+          an addressing mode that doesn't require extended registers. */
+       __asm__ __volatile__("rex64/fxsave %P2(%1)"
+                            : "=m" (tsk->thread.i387.fxsave)
+                            : "cdaSDb" (tsk),
+                               "i" (offsetof(__typeof__(*tsk),
+                                             thread.i387.fxsave)));
+#endif
+       clear_fpu_state(&tsk->thread.i387.fxsave);
+}
+
 static inline void kernel_fpu_begin(void)
 {
        struct thread_info *me = current_thread_info();
        preempt_disable();
-       if (me->status & TS_USEDFPU) { 
-               asm volatile("rex64 ; fxsave %0 ; fnclex"
-                             : "=m" (me->task->thread.i387.fxsave));
+       if (me->status & TS_USEDFPU) {
+               __fxsave_clear(me->task);
                me->status &= ~TS_USEDFPU;
                return;
        }
@@ -131,11 +188,10 @@ static inline void kernel_fpu_end(void)
        preempt_enable();
 }
 
-static inline void save_init_fpu( struct task_struct *tsk )
+static inline void save_init_fpu(struct task_struct *tsk)
 {
-       asm volatile( "rex64 ; fxsave %0 ; fnclex"
-                     : "=m" (tsk->thread.i387.fxsave));
-       tsk->thread_info->status &= ~TS_USEDFPU;
+       __fxsave_clear(tsk);
+       task_thread_info(tsk)->status &= ~TS_USEDFPU;
        stts();
 }