[PATCH 2/8] MIPS: Define the legacy-NaN and 2008-NaN features

From: Maciej W. Rozycki
Date: Thu Nov 12 2015 - 19:47:03 EST


Allocate CPU option bits and define macros for the legacy-NaN and
2008-NaN IEEE Std 754 MIPS architecture features. Unconditionally mark
the legacy-NaN feature as present across hardware and emulated
floating-point configurations.

Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxx>
---
linux-mips-nan-legacy.diff
Index: linux-sfr-test/arch/mips/include/asm/cpu-features.h
===================================================================
--- linux-sfr-test.orig/arch/mips/include/asm/cpu-features.h 2015-10-07 19:33:20.000000000 +0100
+++ linux-sfr-test/arch/mips/include/asm/cpu-features.h 2015-10-07 20:48:14.828556000 +0100
@@ -414,4 +414,11 @@
# define cpu_has_small_pages (cpu_data[0].options & MIPS_CPU_SP)
#endif

+#ifndef cpu_has_nan_legacy
+#define cpu_has_nan_legacy (cpu_data[0].options & MIPS_CPU_NAN_LEGACY)
+#endif
+#ifndef cpu_has_nan_2008
+#define cpu_has_nan_2008 (cpu_data[0].options & MIPS_CPU_NAN_2008)
+#endif
+
#endif /* __ASM_CPU_FEATURES_H */
Index: linux-sfr-test/arch/mips/include/asm/cpu.h
===================================================================
--- linux-sfr-test.orig/arch/mips/include/asm/cpu.h 2015-10-07 19:33:20.000000000 +0100
+++ linux-sfr-test/arch/mips/include/asm/cpu.h 2015-10-07 20:48:14.831542000 +0100
@@ -386,6 +386,8 @@ enum cpu_type_enum {
#define MIPS_CPU_BP_GHIST 0x8000000000ull /* R12K+ Branch Prediction Global History */
#define MIPS_CPU_SP 0x10000000000ull /* Small (1KB) page support */
#define MIPS_CPU_FTLB 0x20000000000ull /* CPU has Fixed-page-size TLB */
+#define MIPS_CPU_NAN_LEGACY 0x40000000000ull /* Legacy NaN implemented */
+#define MIPS_CPU_NAN_2008 0x80000000000ull /* 2008 NaN implemented */

/*
* CPU ASE encodings
Index: linux-sfr-test/arch/mips/kernel/cpu-probe.c
===================================================================
--- linux-sfr-test.orig/arch/mips/kernel/cpu-probe.c 2015-10-07 19:33:20.000000000 +0100
+++ linux-sfr-test/arch/mips/kernel/cpu-probe.c 2015-10-07 20:48:14.836528000 +0100
@@ -137,6 +137,7 @@ static void cpu_set_fpu_opts(struct cpui
}

cpu_set_fpu_fcsr_mask(c);
+ c->options |= MIPS_CPU_NAN_LEGACY;
}

/*
@@ -147,6 +148,7 @@ static void cpu_set_nofpu_opts(struct cp
c->options &= ~MIPS_CPU_FPU;
c->fpu_msk31 = mips_nofpu_msk31;

+ c->options |= MIPS_CPU_NAN_LEGACY;
cpu_set_nofpu_id(c);
}

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