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Diffstat (limited to 'include/asm-x86_64/i387.h')
-rw-r--r--include/asm-x86_64/i387.h68
1 files changed, 53 insertions, 15 deletions
diff --git a/include/asm-x86_64/i387.h b/include/asm-x86_64/i387.h
index aa39cfd0e001..876eb9a2fe78 100644
--- 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)
@@ -75,7 +75,8 @@ extern int set_fpregs(struct task_struct *tsk,
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 +87,11 @@ 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 +100,8 @@ 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 +111,53 @@ 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));
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
+ __asm__ __volatile__("fnclex");
+}
+
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 +170,10 @@ 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();
}