MIPS: Fix cpu_has_mips_r2_exec_hazard.

commit 9cdf30bd3bac697fc533988f44a117434a858f69 upstream.

Returns a non-zero value if the current processor implementation requires
an IHB instruction to deal with an instruction hazard as per MIPS R2
architecture specification, zero otherwise.

For a discussion, see http://patchwork.linux-mips.org/patch/9539/.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
[bwh: Backported to 3.2: trim the CPU type list]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h
index ca400f7..0f4991b 100644 (file)
--- a/arch/mips/include/asm/cpu-features.h
+++ b/arch/mips/include/asm/cpu-features.h
@@ -153,8 +153,32 @@
 #define cpu_has_mips_r (cpu_has_mips32r1 | cpu_has_mips32r2 | \
                         cpu_has_mips64r1 | cpu_has_mips64r2)
 
+/*
+ * cpu_has_mips_r2_exec_hazard - return if IHB is required on current processor
+ *
+ * Returns non-zero value if the current processor implementation requires
+ * an IHB instruction to deal with an instruction hazard as per MIPS R2
+ * architecture specification, zero otherwise.
+ */
 #ifndef cpu_has_mips_r2_exec_hazard
-#define cpu_has_mips_r2_exec_hazard cpu_has_mips_r2
+#define cpu_has_mips_r2_exec_hazard                                    \
+({                                                                     \
+       int __res;                                                      \
+                                                                       \
+       switch (current_cpu_type()) {                                   \
+       case CPU_74K:                                                   \
+       case CPU_CAVIUM_OCTEON:                                         \
+       case CPU_CAVIUM_OCTEON_PLUS:                                    \
+       case CPU_CAVIUM_OCTEON2:                                        \
+               __res = 0;                                              \
+               break;                                                  \
+                                                                       \
+       default:                                                        \
+               __res = 1;                                              \
+       }                                                               \
+                                                                       \
+       __res;                                                          \
+})
 #endif
 
 /*