[PATCH v2 1/2] MIPS: cpu-probe: move fpu probing/handling into its own file

From: Thomas Bogendoerfer
Date: Thu Oct 08 2020 - 17:33:41 EST

cpu-probe.c has grown when supporting more and more CPUs and there
are use cases where probing for all the CPUs isn't useful like
running on a R3k system. But still the fpu handling is nearly
the same. For sharing put the fpu code into it's own file.

Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
---
Changes in v2:
removed #ifdef CONFIG_MIPS_FP_SUPPORT in fpu-probe.c
added include fpu-probe.h in fpu-proble.c


arch/mips/kernel/Makefile | 1 +
arch/mips/kernel/cpu-probe.c | 326 +------------------------------------------
arch/mips/kernel/fpu-probe.c | 319 ++++++++++++++++++++++++++++++++++++++++++
arch/mips/kernel/fpu-probe.h | 40 ++++++
4 files changed, 362 insertions(+), 324 deletions(-)
create mode 100644 arch/mips/kernel/fpu-probe.c
create mode 100644 arch/mips/kernel/fpu-probe.h

diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 13a26d254829..026801c21724 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -42,6 +42,7 @@ sw-$(CONFIG_CPU_TX39XX) := r2300_switch.o
sw-$(CONFIG_CPU_CAVIUM_OCTEON) := octeon_switch.o
obj-y += $(sw-y)

+obj-$(CONFIG_MIPS_FP_SUPPORT) += fpu-probe.o
obj-$(CONFIG_CPU_R2300_FPU) += r2300_fpu.o
obj-$(CONFIG_CPU_R4K_FPU) += r4k_fpu.o

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 6be23f205e74..b8e073772bdb 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -28,336 +28,14 @@
#include <asm/spram.h>
#include <linux/uaccess.h>

+#include "fpu-probe.h"
+
#include <asm/mach-loongson64/cpucfg-emul.h>

/* Hardware capabilities */
unsigned int elf_hwcap __read_mostly;
EXPORT_SYMBOL_GPL(elf_hwcap);

-#ifdef CONFIG_MIPS_FP_SUPPORT
-
-/*
- * Get the FPU Implementation/Revision.
- */
-static inline unsigned long cpu_get_fpu_id(void)
-{
- unsigned long tmp, fpu_id;
-
- tmp = read_c0_status();
- __enable_fpu(FPU_AS_IS);
- fpu_id = read_32bit_cp1_register(CP1_REVISION);
- write_c0_status(tmp);
- return fpu_id;
-}
-
-/*
- * Check if the CPU has an external FPU.
- */
-static inline int __cpu_has_fpu(void)
-{
- return (cpu_get_fpu_id() & FPIR_IMP_MASK) != FPIR_IMP_NONE;
-}
-
-/*
- * Determine the FCSR mask for FPU hardware.
- */
-static inline void cpu_set_fpu_fcsr_mask(struct cpuinfo_mips *c)
-{
- unsigned long sr, mask, fcsr, fcsr0, fcsr1;
-
- fcsr = c->fpu_csr31;
- mask = FPU_CSR_ALL_X | FPU_CSR_ALL_E | FPU_CSR_ALL_S | FPU_CSR_RM;
-
- sr = read_c0_status();
- __enable_fpu(FPU_AS_IS);
-
- fcsr0 = fcsr & mask;
- write_32bit_cp1_register(CP1_STATUS, fcsr0);
- fcsr0 = read_32bit_cp1_register(CP1_STATUS);
-
- fcsr1 = fcsr | ~mask;
- write_32bit_cp1_register(CP1_STATUS, fcsr1);
- fcsr1 = read_32bit_cp1_register(CP1_STATUS);
-
- write_32bit_cp1_register(CP1_STATUS, fcsr);
-
- write_c0_status(sr);
-
- c->fpu_msk31 = ~(fcsr0 ^ fcsr1) & ~mask;
-}
-
-/*
- * Determine the IEEE 754 NaN encodings and ABS.fmt/NEG.fmt execution modes
- * supported by FPU hardware.
- */
-static void cpu_set_fpu_2008(struct cpuinfo_mips *c)
-{
- if (c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1 |
- MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
- MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
- MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6)) {
- unsigned long sr, fir, fcsr, fcsr0, fcsr1;
-
- sr = read_c0_status();
- __enable_fpu(FPU_AS_IS);
-
- fir = read_32bit_cp1_register(CP1_REVISION);
- if (fir & MIPS_FPIR_HAS2008) {
- fcsr = read_32bit_cp1_register(CP1_STATUS);
-
- /*
- * MAC2008 toolchain never landed in real world, so we're only
- * testing wether it can be disabled and don't try to enabled
- * it.
- */
- fcsr0 = fcsr & ~(FPU_CSR_ABS2008 | FPU_CSR_NAN2008 | FPU_CSR_MAC2008);
- write_32bit_cp1_register(CP1_STATUS, fcsr0);
- fcsr0 = read_32bit_cp1_register(CP1_STATUS);
-
- fcsr1 = fcsr | FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
- write_32bit_cp1_register(CP1_STATUS, fcsr1);
- fcsr1 = read_32bit_cp1_register(CP1_STATUS);
-
- write_32bit_cp1_register(CP1_STATUS, fcsr);
-
- if (c->isa_level & (MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2)) {
- /*
- * The bit for MAC2008 might be reused by R6 in future,
- * so we only test for R2-R5.
- */
- if (fcsr0 & FPU_CSR_MAC2008)
- c->options |= MIPS_CPU_MAC_2008_ONLY;
- }
-
- if (!(fcsr0 & FPU_CSR_NAN2008))
- c->options |= MIPS_CPU_NAN_LEGACY;
- if (fcsr1 & FPU_CSR_NAN2008)
- c->options |= MIPS_CPU_NAN_2008;
-
- if ((fcsr0 ^ fcsr1) & FPU_CSR_ABS2008)
- c->fpu_msk31 &= ~FPU_CSR_ABS2008;
- else
- c->fpu_csr31 |= fcsr & FPU_CSR_ABS2008;
-
- if ((fcsr0 ^ fcsr1) & FPU_CSR_NAN2008)
- c->fpu_msk31 &= ~FPU_CSR_NAN2008;
- else
- c->fpu_csr31 |= fcsr & FPU_CSR_NAN2008;
- } else {
- c->options |= MIPS_CPU_NAN_LEGACY;
- }
-
- write_c0_status(sr);
- } else {
- c->options |= MIPS_CPU_NAN_LEGACY;
- }
-}
-
-/*
- * IEEE 754 conformance mode to use. Affects the NaN encoding and the
- * ABS.fmt/NEG.fmt execution mode.
- */
-static enum { STRICT, LEGACY, STD2008, RELAXED } ieee754 = STRICT;
-
-/*
- * Set the IEEE 754 NaN encodings and the ABS.fmt/NEG.fmt execution modes
- * to support by the FPU emulator according to the IEEE 754 conformance
- * mode selected. Note that "relaxed" straps the emulator so that it
- * allows 2008-NaN binaries even for legacy processors.
- */
-static void cpu_set_nofpu_2008(struct cpuinfo_mips *c)
-{
- c->options &= ~(MIPS_CPU_NAN_2008 | MIPS_CPU_NAN_LEGACY);
- c->fpu_csr31 &= ~(FPU_CSR_ABS2008 | FPU_CSR_NAN2008);
- c->fpu_msk31 &= ~(FPU_CSR_ABS2008 | FPU_CSR_NAN2008);
-
- switch (ieee754) {
- case STRICT:
- if (c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1 |
- MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
- MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
- MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6)) {
- c->options |= MIPS_CPU_NAN_2008 | MIPS_CPU_NAN_LEGACY;
- } else {
- c->options |= MIPS_CPU_NAN_LEGACY;
- c->fpu_msk31 |= FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
- }
- break;
- case LEGACY:
- c->options |= MIPS_CPU_NAN_LEGACY;
- c->fpu_msk31 |= FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
- break;
- case STD2008:
- c->options |= MIPS_CPU_NAN_2008;
- c->fpu_csr31 |= FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
- c->fpu_msk31 |= FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
- break;
- case RELAXED:
- c->options |= MIPS_CPU_NAN_2008 | MIPS_CPU_NAN_LEGACY;
- break;
- }
-}
-
-/*
- * Override the IEEE 754 NaN encoding and ABS.fmt/NEG.fmt execution mode
- * according to the "ieee754=" parameter.
- */
-static void cpu_set_nan_2008(struct cpuinfo_mips *c)
-{
- switch (ieee754) {
- case STRICT:
- mips_use_nan_legacy = !!cpu_has_nan_legacy;
- mips_use_nan_2008 = !!cpu_has_nan_2008;
- break;
- case LEGACY:
- mips_use_nan_legacy = !!cpu_has_nan_legacy;
- mips_use_nan_2008 = !cpu_has_nan_legacy;
- break;
- case STD2008:
- mips_use_nan_legacy = !cpu_has_nan_2008;
- mips_use_nan_2008 = !!cpu_has_nan_2008;
- break;
- case RELAXED:
- mips_use_nan_legacy = true;
- mips_use_nan_2008 = true;
- break;
- }
-}
-
-/*
- * IEEE 754 NaN encoding and ABS.fmt/NEG.fmt execution mode override
- * settings:
- *
- * strict: accept binaries that request a NaN encoding supported by the FPU
- * legacy: only accept legacy-NaN binaries
- * 2008: only accept 2008-NaN binaries
- * relaxed: accept any binaries regardless of whether supported by the FPU
- */
-static int __init ieee754_setup(char *s)
-{
- if (!s)
- return -1;
- else if (!strcmp(s, "strict"))
- ieee754 = STRICT;
- else if (!strcmp(s, "legacy"))
- ieee754 = LEGACY;
- else if (!strcmp(s, "2008"))
- ieee754 = STD2008;
- else if (!strcmp(s, "relaxed"))
- ieee754 = RELAXED;
- else
- return -1;
-
- if (!(boot_cpu_data.options & MIPS_CPU_FPU))
- cpu_set_nofpu_2008(&boot_cpu_data);
- cpu_set_nan_2008(&boot_cpu_data);
-
- return 0;
-}
-
-early_param("ieee754", ieee754_setup);
-
-/*
- * Set the FIR feature flags for the FPU emulator.
- */
-static void cpu_set_nofpu_id(struct cpuinfo_mips *c)
-{
- u32 value;
-
- value = 0;
- if (c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1 |
- MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
- MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
- MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6))
- value |= MIPS_FPIR_D | MIPS_FPIR_S;
- if (c->isa_level & (MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
- MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
- MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6))
- value |= MIPS_FPIR_F64 | MIPS_FPIR_L | MIPS_FPIR_W;
- if (c->options & MIPS_CPU_NAN_2008)
- value |= MIPS_FPIR_HAS2008;
- c->fpu_id = value;
-}
-
-/* Determined FPU emulator mask to use for the boot CPU with "nofpu". */
-static unsigned int mips_nofpu_msk31;
-
-/*
- * Set options for FPU hardware.
- */
-static void cpu_set_fpu_opts(struct cpuinfo_mips *c)
-{
- c->fpu_id = cpu_get_fpu_id();
- mips_nofpu_msk31 = c->fpu_msk31;
-
- if (c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1 |
- MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
- MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
- MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6)) {
- if (c->fpu_id & MIPS_FPIR_3D)
- c->ases |= MIPS_ASE_MIPS3D;
- if (c->fpu_id & MIPS_FPIR_UFRP)
- c->options |= MIPS_CPU_UFR;
- if (c->fpu_id & MIPS_FPIR_FREP)
- c->options |= MIPS_CPU_FRE;
- }
-
- cpu_set_fpu_fcsr_mask(c);
- cpu_set_fpu_2008(c);
- cpu_set_nan_2008(c);
-}
-
-/*
- * Set options for the FPU emulator.
- */
-static void cpu_set_nofpu_opts(struct cpuinfo_mips *c)
-{
- c->options &= ~MIPS_CPU_FPU;
- c->fpu_msk31 = mips_nofpu_msk31;
-
- cpu_set_nofpu_2008(c);
- cpu_set_nan_2008(c);
- cpu_set_nofpu_id(c);
-}
-
-static int mips_fpu_disabled;
-
-static int __init fpu_disable(char *s)
-{
- cpu_set_nofpu_opts(&boot_cpu_data);
- mips_fpu_disabled = 1;
-
- return 1;
-}
-
-__setup("nofpu", fpu_disable);
-
-#else /* !CONFIG_MIPS_FP_SUPPORT */
-
-#define mips_fpu_disabled 1
-
-static inline unsigned long cpu_get_fpu_id(void)
-{
- return FPIR_IMP_NONE;
-}
-
-static inline int __cpu_has_fpu(void)
-{
- return 0;
-}
-
-static void cpu_set_fpu_opts(struct cpuinfo_mips *c)
-{
- /* no-op */
-}
-
-static void cpu_set_nofpu_opts(struct cpuinfo_mips *c)
-{
- /* no-op */
-}
-
-#endif /* CONFIG_MIPS_FP_SUPPORT */
-
static inline unsigned long cpu_get_msa_id(void)
{
unsigned long status, msa_id;
diff --git a/arch/mips/kernel/fpu-probe.c b/arch/mips/kernel/fpu-probe.c
new file mode 100644
index 000000000000..f36e1023c286
--- /dev/null
+++ b/arch/mips/kernel/fpu-probe.c
@@ -0,0 +1,319 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Processor capabilities determination functions.
+ *
+ * Copyright (C) xxxx the Anonymous
+ * Copyright (C) 1994 - 2006 Ralf Baechle
+ * Copyright (C) 2003, 2004 Maciej W. Rozycki
+ * Copyright (C) 2001, 2004, 2011, 2012 MIPS Technologies, Inc.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+
+#include <asm/bugs.h>
+#include <asm/cpu.h>
+#include <asm/cpu-features.h>
+#include <asm/cpu-type.h>
+#include <asm/elf.h>
+#include <asm/fpu.h>
+#include <asm/mipsregs.h>
+
+#include "fpu-probe.h"
+
+/*
+ * Get the FPU Implementation/Revision.
+ */
+static inline unsigned long cpu_get_fpu_id(void)
+{
+ unsigned long tmp, fpu_id;
+
+ tmp = read_c0_status();
+ __enable_fpu(FPU_AS_IS);
+ fpu_id = read_32bit_cp1_register(CP1_REVISION);
+ write_c0_status(tmp);
+ return fpu_id;
+}
+
+/*
+ * Check if the CPU has an external FPU.
+ */
+int __cpu_has_fpu(void)
+{
+ return (cpu_get_fpu_id() & FPIR_IMP_MASK) != FPIR_IMP_NONE;
+}
+
+/*
+ * Determine the FCSR mask for FPU hardware.
+ */
+static inline void cpu_set_fpu_fcsr_mask(struct cpuinfo_mips *c)
+{
+ unsigned long sr, mask, fcsr, fcsr0, fcsr1;
+
+ fcsr = c->fpu_csr31;
+ mask = FPU_CSR_ALL_X | FPU_CSR_ALL_E | FPU_CSR_ALL_S | FPU_CSR_RM;
+
+ sr = read_c0_status();
+ __enable_fpu(FPU_AS_IS);
+
+ fcsr0 = fcsr & mask;
+ write_32bit_cp1_register(CP1_STATUS, fcsr0);
+ fcsr0 = read_32bit_cp1_register(CP1_STATUS);
+
+ fcsr1 = fcsr | ~mask;
+ write_32bit_cp1_register(CP1_STATUS, fcsr1);
+ fcsr1 = read_32bit_cp1_register(CP1_STATUS);
+
+ write_32bit_cp1_register(CP1_STATUS, fcsr);
+
+ write_c0_status(sr);
+
+ c->fpu_msk31 = ~(fcsr0 ^ fcsr1) & ~mask;
+}
+
+/*
+ * Determine the IEEE 754 NaN encodings and ABS.fmt/NEG.fmt execution modes
+ * supported by FPU hardware.
+ */
+static void cpu_set_fpu_2008(struct cpuinfo_mips *c)
+{
+ if (c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1 |
+ MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
+ MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
+ MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6)) {
+ unsigned long sr, fir, fcsr, fcsr0, fcsr1;
+
+ sr = read_c0_status();
+ __enable_fpu(FPU_AS_IS);
+
+ fir = read_32bit_cp1_register(CP1_REVISION);
+ if (fir & MIPS_FPIR_HAS2008) {
+ fcsr = read_32bit_cp1_register(CP1_STATUS);
+
+ /*
+ * MAC2008 toolchain never landed in real world, so we're only
+ * testing whether it can be disabled and don't try to enabled
+ * it.
+ */
+ fcsr0 = fcsr & ~(FPU_CSR_ABS2008 | FPU_CSR_NAN2008 | FPU_CSR_MAC2008);
+ write_32bit_cp1_register(CP1_STATUS, fcsr0);
+ fcsr0 = read_32bit_cp1_register(CP1_STATUS);
+
+ fcsr1 = fcsr | FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
+ write_32bit_cp1_register(CP1_STATUS, fcsr1);
+ fcsr1 = read_32bit_cp1_register(CP1_STATUS);
+
+ write_32bit_cp1_register(CP1_STATUS, fcsr);
+
+ if (c->isa_level & (MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2)) {
+ /*
+ * The bit for MAC2008 might be reused by R6 in future,
+ * so we only test for R2-R5.
+ */
+ if (fcsr0 & FPU_CSR_MAC2008)
+ c->options |= MIPS_CPU_MAC_2008_ONLY;
+ }
+
+ if (!(fcsr0 & FPU_CSR_NAN2008))
+ c->options |= MIPS_CPU_NAN_LEGACY;
+ if (fcsr1 & FPU_CSR_NAN2008)
+ c->options |= MIPS_CPU_NAN_2008;
+
+ if ((fcsr0 ^ fcsr1) & FPU_CSR_ABS2008)
+ c->fpu_msk31 &= ~FPU_CSR_ABS2008;
+ else
+ c->fpu_csr31 |= fcsr & FPU_CSR_ABS2008;
+
+ if ((fcsr0 ^ fcsr1) & FPU_CSR_NAN2008)
+ c->fpu_msk31 &= ~FPU_CSR_NAN2008;
+ else
+ c->fpu_csr31 |= fcsr & FPU_CSR_NAN2008;
+ } else {
+ c->options |= MIPS_CPU_NAN_LEGACY;
+ }
+
+ write_c0_status(sr);
+ } else {
+ c->options |= MIPS_CPU_NAN_LEGACY;
+ }
+}
+
+/*
+ * IEEE 754 conformance mode to use. Affects the NaN encoding and the
+ * ABS.fmt/NEG.fmt execution mode.
+ */
+static enum { STRICT, LEGACY, STD2008, RELAXED } ieee754 = STRICT;
+
+/*
+ * Set the IEEE 754 NaN encodings and the ABS.fmt/NEG.fmt execution modes
+ * to support by the FPU emulator according to the IEEE 754 conformance
+ * mode selected. Note that "relaxed" straps the emulator so that it
+ * allows 2008-NaN binaries even for legacy processors.
+ */
+static void cpu_set_nofpu_2008(struct cpuinfo_mips *c)
+{
+ c->options &= ~(MIPS_CPU_NAN_2008 | MIPS_CPU_NAN_LEGACY);
+ c->fpu_csr31 &= ~(FPU_CSR_ABS2008 | FPU_CSR_NAN2008);
+ c->fpu_msk31 &= ~(FPU_CSR_ABS2008 | FPU_CSR_NAN2008);
+
+ switch (ieee754) {
+ case STRICT:
+ if (c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1 |
+ MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
+ MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
+ MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6)) {
+ c->options |= MIPS_CPU_NAN_2008 | MIPS_CPU_NAN_LEGACY;
+ } else {
+ c->options |= MIPS_CPU_NAN_LEGACY;
+ c->fpu_msk31 |= FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
+ }
+ break;
+ case LEGACY:
+ c->options |= MIPS_CPU_NAN_LEGACY;
+ c->fpu_msk31 |= FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
+ break;
+ case STD2008:
+ c->options |= MIPS_CPU_NAN_2008;
+ c->fpu_csr31 |= FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
+ c->fpu_msk31 |= FPU_CSR_ABS2008 | FPU_CSR_NAN2008;
+ break;
+ case RELAXED:
+ c->options |= MIPS_CPU_NAN_2008 | MIPS_CPU_NAN_LEGACY;
+ break;
+ }
+}
+
+/*
+ * Override the IEEE 754 NaN encoding and ABS.fmt/NEG.fmt execution mode
+ * according to the "ieee754=" parameter.
+ */
+static void cpu_set_nan_2008(struct cpuinfo_mips *c)
+{
+ switch (ieee754) {
+ case STRICT:
+ mips_use_nan_legacy = !!cpu_has_nan_legacy;
+ mips_use_nan_2008 = !!cpu_has_nan_2008;
+ break;
+ case LEGACY:
+ mips_use_nan_legacy = !!cpu_has_nan_legacy;
+ mips_use_nan_2008 = !cpu_has_nan_legacy;
+ break;
+ case STD2008:
+ mips_use_nan_legacy = !cpu_has_nan_2008;
+ mips_use_nan_2008 = !!cpu_has_nan_2008;
+ break;
+ case RELAXED:
+ mips_use_nan_legacy = true;
+ mips_use_nan_2008 = true;
+ break;
+ }
+}
+
+/*
+ * IEEE 754 NaN encoding and ABS.fmt/NEG.fmt execution mode override
+ * settings:
+ *
+ * strict: accept binaries that request a NaN encoding supported by the FPU
+ * legacy: only accept legacy-NaN binaries
+ * 2008: only accept 2008-NaN binaries
+ * relaxed: accept any binaries regardless of whether supported by the FPU
+ */
+static int __init ieee754_setup(char *s)
+{
+ if (!s)
+ return -1;
+ else if (!strcmp(s, "strict"))
+ ieee754 = STRICT;
+ else if (!strcmp(s, "legacy"))
+ ieee754 = LEGACY;
+ else if (!strcmp(s, "2008"))
+ ieee754 = STD2008;
+ else if (!strcmp(s, "relaxed"))
+ ieee754 = RELAXED;
+ else
+ return -1;
+
+ if (!(boot_cpu_data.options & MIPS_CPU_FPU))
+ cpu_set_nofpu_2008(&boot_cpu_data);
+ cpu_set_nan_2008(&boot_cpu_data);
+
+ return 0;
+}
+
+early_param("ieee754", ieee754_setup);
+
+/*
+ * Set the FIR feature flags for the FPU emulator.
+ */
+static void cpu_set_nofpu_id(struct cpuinfo_mips *c)
+{
+ u32 value;
+
+ value = 0;
+ if (c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1 |
+ MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
+ MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
+ MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6))
+ value |= MIPS_FPIR_D | MIPS_FPIR_S;
+ if (c->isa_level & (MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
+ MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
+ MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6))
+ value |= MIPS_FPIR_F64 | MIPS_FPIR_L | MIPS_FPIR_W;
+ if (c->options & MIPS_CPU_NAN_2008)
+ value |= MIPS_FPIR_HAS2008;
+ c->fpu_id = value;
+}
+
+/* Determined FPU emulator mask to use for the boot CPU with "nofpu". */
+static unsigned int mips_nofpu_msk31;
+
+/*
+ * Set options for FPU hardware.
+ */
+void cpu_set_fpu_opts(struct cpuinfo_mips *c)
+{
+ c->fpu_id = cpu_get_fpu_id();
+ mips_nofpu_msk31 = c->fpu_msk31;
+
+ if (c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1 |
+ MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
+ MIPS_CPU_ISA_M32R5 | MIPS_CPU_ISA_M64R5 |
+ MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6)) {
+ if (c->fpu_id & MIPS_FPIR_3D)
+ c->ases |= MIPS_ASE_MIPS3D;
+ if (c->fpu_id & MIPS_FPIR_UFRP)
+ c->options |= MIPS_CPU_UFR;
+ if (c->fpu_id & MIPS_FPIR_FREP)
+ c->options |= MIPS_CPU_FRE;
+ }
+
+ cpu_set_fpu_fcsr_mask(c);
+ cpu_set_fpu_2008(c);
+ cpu_set_nan_2008(c);
+}
+
+/*
+ * Set options for the FPU emulator.
+ */
+void cpu_set_nofpu_opts(struct cpuinfo_mips *c)
+{
+ c->options &= ~MIPS_CPU_FPU;
+ c->fpu_msk31 = mips_nofpu_msk31;
+
+ cpu_set_nofpu_2008(c);
+ cpu_set_nan_2008(c);
+ cpu_set_nofpu_id(c);
+}
+
+int mips_fpu_disabled;
+
+static int __init fpu_disable(char *s)
+{
+ cpu_set_nofpu_opts(&boot_cpu_data);
+ mips_fpu_disabled = 1;
+
+ return 1;
+}
+
+__setup("nofpu", fpu_disable);
+
diff --git a/arch/mips/kernel/fpu-probe.h b/arch/mips/kernel/fpu-probe.h
new file mode 100644
index 000000000000..951ce50890d0
--- /dev/null
+++ b/arch/mips/kernel/fpu-probe.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <linux/kernel.h>
+
+#include <asm/cpu.h>
+#include <asm/cpu-info.h>
+
+#ifdef CONFIG_MIPS_FP_SUPPORT
+
+extern int mips_fpu_disabled;
+
+int __cpu_has_fpu(void);
+void cpu_set_fpu_opts(struct cpuinfo_mips *c);
+void cpu_set_nofpu_opts(struct cpuinfo_mips *c);
+
+#else /* !CONFIG_MIPS_FP_SUPPORT */
+
+#define mips_fpu_disabled 1
+
+static inline unsigned long cpu_get_fpu_id(void)
+{
+ return FPIR_IMP_NONE;
+}
+
+static inline int __cpu_has_fpu(void)
+{
+ return 0;
+}
+
+static inline void cpu_set_fpu_opts(struct cpuinfo_mips *c)
+{
+ /* no-op */
+}
+
+static inline void cpu_set_nofpu_opts(struct cpuinfo_mips *c)
+{
+ /* no-op */
+}
+
+#endif /* CONFIG_MIPS_FP_SUPPORT */
--
2.16.4