MIPS: Simplify FP context access

This patch replaces the fpureg_t typedef with a "union fpureg" enabling
easier access to 32 & 64 bit values. This allows the access macros used
in cp1emu.c to be simplified somewhat. It will also make it easier to
expand the width of the FP registers as will be done in a future
patch in order to support the 128 bit registers introduced with MSA.

No behavioural change is intended by this patch.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6532/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 28 insertions, 3 deletions

diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index 3605b844ad87..49a61bedf40e 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -96,8 +96,33 @@ extern unsigned int vced_count, vcei_count;
 
 
 #define NUM_FPU_REGS    32
+#define FPU_REG_WIDTH   64
 
-typedef __u64 fpureg_t;
+union fpureg {
+        __u32   val32[FPU_REG_WIDTH / 32];
+        __u64   val64[FPU_REG_WIDTH / 64];
+};
+
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+# define FPR_IDX(width, idx)    (idx)
+#else
+# define FPR_IDX(width, idx)    ((FPU_REG_WIDTH / (width)) - 1 - (idx))
+#endif
+
+#define BUILD_FPR_ACCESS(width) \
+static inline u##width get_fpr##width(union fpureg *fpr, unsigned idx)  \
+{                                                                       \
+        return fpr->val##width[FPR_IDX(width, idx)];                    \
+}                                                                       \
+                                                                        \
+static inline void set_fpr##width(union fpureg *fpr, unsigned idx,      \
+                                  u##width val)                         \
+{                                                                       \
+        fpr->val##width[FPR_IDX(width, idx)] = val;                     \
+}
+
+BUILD_FPR_ACCESS(32)
+BUILD_FPR_ACCESS(64)
 
 /*
  * It would be nice to add some more fields for emulator statistics, but there
@@ -107,7 +132,7 @@ typedef __u64 fpureg_t;
  */
 
 struct mips_fpu_struct {
-        fpureg_t        fpr[NUM_FPU_REGS];
+        union fpureg    fpr[NUM_FPU_REGS];
         unsigned int    fcr31;
 };
 
@@ -284,7 +309,7 @@ struct thread_struct {
          * Saved FPU/FPU emulator stuff                         \
          */                                                     \
         .fpu                    = {                             \
-                .fpr            = {0,},                         \
+                .fpr            = {{{0,},},},                   \
                 .fcr31          = 0,                            \
         },                                                      \
         /*                                                      \