1 /* 2 * Copied from arch/arm64/kernel/cpufeature.c 3 * 4 * Copyright (C) 2015 ARM Ltd. 5 * Copyright (C) 2017 SiFive 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include <linux/of.h> 21 #include <asm/processor.h> 22 #include <asm/hwcap.h> 23 24 unsigned long elf_hwcap __read_mostly; 25 26 void riscv_fill_hwcap(void) 27 { 28 struct device_node *node; 29 const char *isa; 30 size_t i; 31 static unsigned long isa2hwcap[256] = {0}; 32 33 isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I; 34 isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M; 35 isa2hwcap['a'] = isa2hwcap['A'] = COMPAT_HWCAP_ISA_A; 36 isa2hwcap['f'] = isa2hwcap['F'] = COMPAT_HWCAP_ISA_F; 37 isa2hwcap['d'] = isa2hwcap['D'] = COMPAT_HWCAP_ISA_D; 38 isa2hwcap['c'] = isa2hwcap['C'] = COMPAT_HWCAP_ISA_C; 39 40 elf_hwcap = 0; 41 42 /* 43 * We don't support running Linux on hertergenous ISA systems. For 44 * now, we just check the ISA of the first processor. 45 */ 46 node = of_find_node_by_type(NULL, "cpu"); 47 if (!node) { 48 pr_warning("Unable to find \"cpu\" devicetree entry"); 49 return; 50 } 51 52 if (of_property_read_string(node, "riscv,isa", &isa)) { 53 pr_warning("Unable to find \"riscv,isa\" devicetree entry"); 54 return; 55 } 56 57 for (i = 0; i < strlen(isa); ++i) 58 elf_hwcap |= isa2hwcap[(unsigned char)(isa[i])]; 59 60 pr_info("elf_hwcap is 0x%lx", elf_hwcap); 61 } 62