[MIPS] FPU affinity for MT ASE.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

4 files changed, 53 insertions, 1 deletions

diff --git a/include/asm-mips/cpu-features.h b/include/asm-mips/cpu-features.h
index 3f2b6d9ac45e..254e11ed247b 100644
--- a/include/asm-mips/cpu-features.h
+++ b/include/asm-mips/cpu-features.h
@@ -40,7 +40,7 @@
 #define cpu_has_sb1_cache       (cpu_data[0].options & MIPS_CPU_SB1_CACHE)
 #endif
 #ifndef cpu_has_fpu
-#define cpu_has_fpu             (cpu_data[0].options & MIPS_CPU_FPU)
+#define cpu_has_fpu             (current_cpu_data.options & MIPS_CPU_FPU)
 #endif
 #ifndef cpu_has_32fpr
 #define cpu_has_32fpr           (cpu_data[0].options & MIPS_CPU_32FPR)
diff --git a/include/asm-mips/fpu.h b/include/asm-mips/fpu.h
index 9c828b1f8218..b0f50015e252 100644
--- a/include/asm-mips/fpu.h
+++ b/include/asm-mips/fpu.h
@@ -21,6 +21,10 @@
 #include <asm/processor.h>
 #include <asm/current.h>
 
+#ifdef CONFIG_MIPS_MT_FPAFF
+#include <asm/mips_mt.h>
+#endif
+
 struct sigcontext;
 struct sigcontext32;
 
diff --git a/include/asm-mips/processor.h b/include/asm-mips/processor.h
index 786651340de1..0fb75f0762e0 100644
--- a/include/asm-mips/processor.h
+++ b/include/asm-mips/processor.h
@@ -134,6 +134,12 @@ struct thread_struct {
 
         /* Saved fpu/fpu emulator stuff. */
         union mips_fpu_union fpu;
+#ifdef CONFIG_MIPS_MT_FPAFF
+        /* Emulated instruction count */
+        unsigned long emulated_fp;
+        /* Saved per-thread scheduler affinity mask */
+        cpumask_t user_cpus_allowed;
+#endif /* CONFIG_MIPS_MT_FPAFF */
 
         /* Saved state of the DSP ASE, if available. */
         struct mips_dsp_state dsp;
@@ -159,6 +165,12 @@ struct thread_struct {
 #define MF_N32          MF_32BIT_ADDR
 #define MF_N64          0
 
+#ifdef CONFIG_MIPS_MT_FPAFF
+#define FPAFF_INIT 0, INIT_CPUMASK,
+#else
+#define FPAFF_INIT
+#endif /* CONFIG_MIPS_MT_FPAFF */
+
 #define INIT_THREAD  { \
         /* \
          * saved main processor registers \
@@ -174,6 +186,10 @@ struct thread_struct {
          */ \
         INIT_FPU, \
         /* \
+         * fpu affinity state (null if not FPAFF) \
+         */ \
+        FPAFF_INIT \
+        /* \
          * saved dsp/dsp emulator stuff \
          */ \
         INIT_DSP, \
diff --git a/include/asm-mips/system.h b/include/asm-mips/system.h
index 39026690d9e4..261f71d16a07 100644
--- a/include/asm-mips/system.h
+++ b/include/asm-mips/system.h
@@ -155,6 +155,37 @@ extern asmlinkage void *resume(void *last, void *next, void *next_ti);
 
 struct task_struct;
 
+#ifdef CONFIG_MIPS_MT_FPAFF
+
+/*
+ * Handle the scheduler resume end of FPU affinity management.  We do this
+ * inline to try to keep the overhead down. If we have been forced to run on
+ * a "CPU" with an FPU because of a previous high level of FP computation,
+ * but did not actually use the FPU during the most recent time-slice (CU1
+ * isn't set), we undo the restriction on cpus_allowed.
+ *
+ * We're not calling set_cpus_allowed() here, because we have no need to
+ * force prompt migration - we're already switching the current CPU to a
+ * different thread.
+ */
+
+#define switch_to(prev,next,last)                                       \
+do {                                                                    \
+        if (cpu_has_fpu &&                                              \
+            (prev->thread.mflags & MF_FPUBOUND) &&                      \
+             (!(KSTK_STATUS(prev) & ST0_CU1))) {                        \
+                prev->thread.mflags &= ~MF_FPUBOUND;                    \
+                prev->cpus_allowed = prev->thread.user_cpus_allowed;    \
+        }                                                               \
+        if (cpu_has_dsp)                                                \
+                __save_dsp(prev);                                       \
+        next->thread.emulated_fp = 0;                                   \
+        (last) = resume(prev, next, next->thread_info);                 \
+        if (cpu_has_dsp)                                                \
+                __restore_dsp(current);                                 \
+} while(0)
+
+#else
 #define switch_to(prev,next,last)                                       \
 do {                                                                    \
         if (cpu_has_dsp)                                                \
@@ -163,6 +194,7 @@ do {									\
         if (cpu_has_dsp)                                                \
                 __restore_dsp(current);                                 \
 } while(0)
+#endif
 
 /*
  * On SMP systems, when the scheduler does migration-cost autodetection,