x86/cpufeature: Replace cpu_has_xmm with boot_cpu_has() usage

[linux-2.6-block.git] / arch / x86 / kernel / fpu / core.c

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 0b1b9abd4d5fe002c2f31d70736dc3d785027305..b05aa68f88c0fcbddbeefe626d0a2c0d17962e70 100644 (file)
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -353,6 +353,69 @@ void fpu__activate_fpstate_write(struct fpu *fpu)
        }
 }
 
+/*
+ * This function must be called before we write the current
+ * task's fpstate.
+ *
+ * This call gets the current FPU register state and moves
+ * it in to the 'fpstate'.  Preemption is disabled so that
+ * no writes to the 'fpstate' can occur from context
+ * swiches.
+ *
+ * Must be followed by a fpu__current_fpstate_write_end().
+ */
+void fpu__current_fpstate_write_begin(void)
+{
+       struct fpu *fpu = &current->thread.fpu;
+
+       /*
+        * Ensure that the context-switching code does not write
+        * over the fpstate while we are doing our update.
+        */
+       preempt_disable();
+
+       /*
+        * Move the fpregs in to the fpu's 'fpstate'.
+        */
+       fpu__activate_fpstate_read(fpu);
+
+       /*
+        * The caller is about to write to 'fpu'.  Ensure that no
+        * CPU thinks that its fpregs match the fpstate.  This
+        * ensures we will not be lazy and skip a XRSTOR in the
+        * future.
+        */
+       fpu->last_cpu = -1;
+}
+
+/*
+ * This function must be paired with fpu__current_fpstate_write_begin()
+ *
+ * This will ensure that the modified fpstate gets placed back in
+ * the fpregs if necessary.
+ *
+ * Note: This function may be called whether or not an _actual_
+ * write to the fpstate occurred.
+ */
+void fpu__current_fpstate_write_end(void)
+{
+       struct fpu *fpu = &current->thread.fpu;
+
+       /*
+        * 'fpu' now has an updated copy of the state, but the
+        * registers may still be out of date.  Update them with
+        * an XRSTOR if they are active.
+        */
+       if (fpregs_active())
+               copy_kernel_to_fpregs(&fpu->state);
+
+       /*
+        * Our update is done and the fpregs/fpstate are in sync
+        * if necessary.  Context switches can happen again.
+        */
+       preempt_enable();
+}
+
 /*
  * 'fpu__restore()' is called to copy FPU registers from
  * the FPU fpstate to the live hw registers and to activate
@@ -463,7 +526,7 @@ static inline unsigned short get_fpu_swd(struct fpu *fpu)
 
 static inline unsigned short get_fpu_mxcsr(struct fpu *fpu)
 {
-       if (cpu_has_xmm) {
+       if (boot_cpu_has(X86_FEATURE_XMM)) {
                return fpu->state.fxsave.mxcsr;
        } else {
                return MXCSR_DEFAULT;