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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Copied from arch/arm64/kernel/cpufeature.c
- *
- * Copyright (C) 2015 ARM Ltd.
- * Copyright (C) 2017 SiFive
- */
- #include <linux/bitmap.h>
- #include <linux/of.h>
- #include <asm/processor.h>
- #include <asm/hwcap.h>
- #include <asm/smp.h>
- #include <asm/switch_to.h>
- unsigned long elf_hwcap __read_mostly;
- /* Host ISA bitmap */
- static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
- #ifdef CONFIG_FPU
- bool has_fpu __read_mostly;
- #endif
- /**
- * riscv_isa_extension_base() - Get base extension word
- *
- * @isa_bitmap: ISA bitmap to use
- * Return: base extension word as unsigned long value
- *
- * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
- */
- unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap)
- {
- if (!isa_bitmap)
- return riscv_isa[0];
- return isa_bitmap[0];
- }
- EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
- /**
- * __riscv_isa_extension_available() - Check whether given extension
- * is available or not
- *
- * @isa_bitmap: ISA bitmap to use
- * @bit: bit position of the desired extension
- * Return: true or false
- *
- * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
- */
- bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit)
- {
- const unsigned long *bmap = (isa_bitmap) ? isa_bitmap : riscv_isa;
- if (bit >= RISCV_ISA_EXT_MAX)
- return false;
- return test_bit(bit, bmap) ? true : false;
- }
- EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
- #ifdef CONFIG_VECTOR
- bool has_vector __read_mostly;
- #endif
- void riscv_fill_hwcap(void)
- {
- struct device_node *node;
- const char *isa;
- char print_str[BITS_PER_LONG + 1];
- size_t i, j, isa_len;
- static unsigned long isa2hwcap[256] = {0};
- isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
- isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M;
- isa2hwcap['a'] = isa2hwcap['A'] = COMPAT_HWCAP_ISA_A;
- isa2hwcap['f'] = isa2hwcap['F'] = COMPAT_HWCAP_ISA_F;
- isa2hwcap['d'] = isa2hwcap['D'] = COMPAT_HWCAP_ISA_D;
- isa2hwcap['c'] = isa2hwcap['C'] = COMPAT_HWCAP_ISA_C;
- isa2hwcap['v'] = isa2hwcap['V'] = COMPAT_HWCAP_ISA_V;
- elf_hwcap = 0;
- bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
- for_each_of_cpu_node(node) {
- unsigned long this_hwcap = 0;
- unsigned long this_isa = 0;
- if (riscv_of_processor_hartid(node) < 0)
- continue;
- if (of_property_read_string(node, "riscv,isa", &isa)) {
- pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
- continue;
- }
- i = 0;
- isa_len = strlen(isa);
- #if IS_ENABLED(CONFIG_32BIT)
- if (!strncmp(isa, "rv32", 4))
- i += 4;
- #elif IS_ENABLED(CONFIG_64BIT)
- if (!strncmp(isa, "rv64", 4))
- i += 4;
- #endif
- for (; i < isa_len; ++i) {
- this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
- /*
- * TODO: X, Y and Z extension parsing for Host ISA
- * bitmap will be added in-future.
- */
- if ('a' <= isa[i] && isa[i] < 'x')
- this_isa |= (1UL << (isa[i] - 'a'));
- }
- /*
- * All "okay" hart should have same isa. Set HWCAP based on
- * common capabilities of every "okay" hart, in case they don't
- * have.
- */
- if (elf_hwcap)
- elf_hwcap &= this_hwcap;
- else
- elf_hwcap = this_hwcap;
- if (riscv_isa[0])
- riscv_isa[0] &= this_isa;
- else
- riscv_isa[0] = this_isa;
- }
- /* We don't support systems with F but without D, so mask those out
- * here. */
- if ((elf_hwcap & COMPAT_HWCAP_ISA_F) && !(elf_hwcap & COMPAT_HWCAP_ISA_D)) {
- pr_info("This kernel does not support systems with F but not D\n");
- elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
- }
- memset(print_str, 0, sizeof(print_str));
- for (i = 0, j = 0; i < BITS_PER_LONG; i++)
- if (riscv_isa[0] & BIT_MASK(i))
- print_str[j++] = (char)('a' + i);
- pr_info("riscv: ISA extensions %s\n", print_str);
- memset(print_str, 0, sizeof(print_str));
- for (i = 0, j = 0; i < BITS_PER_LONG; i++)
- if (elf_hwcap & BIT_MASK(i))
- print_str[j++] = (char)('a' + i);
- pr_info("riscv: ELF capabilities %s\n", print_str);
- #ifdef CONFIG_FPU
- if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
- has_fpu = true;
- #endif
- #ifdef CONFIG_VECTOR
- if (elf_hwcap & COMPAT_HWCAP_ISA_V)
- has_vector = true;
- #endif
- }
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