From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- arch/mips/kernel/fpu-probe.c | 321 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 321 insertions(+) create mode 100644 arch/mips/kernel/fpu-probe.c (limited to 'arch/mips/kernel/fpu-probe.c') diff --git a/arch/mips/kernel/fpu-probe.c b/arch/mips/kernel/fpu-probe.c new file mode 100644 index 000000000..e689d6a83 --- /dev/null +++ b/arch/mips/kernel/fpu-probe.c @@ -0,0 +1,321 @@ +// 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 +#include + +#include +#include +#include +#include +#include +#include +#include + +#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); + -- cgit v1.2.3