2 * Copied from arch/arm64/kernel/cpufeature.c
4 * Copyright (C) 2015 ARM Ltd.
5 * Copyright (C) 2017 SiFive
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.
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.
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/>.
21 #include <asm/processor.h>
22 #include <asm/hwcap.h>
24 unsigned long elf_hwcap __read_mostly;
26 bool has_fpu __read_mostly;
29 void riscv_fill_hwcap(void)
31 struct device_node *node = NULL;
34 static unsigned long isa2hwcap[256] = {0};
36 isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
37 isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M;
38 isa2hwcap['a'] = isa2hwcap['A'] = COMPAT_HWCAP_ISA_A;
39 isa2hwcap['f'] = isa2hwcap['F'] = COMPAT_HWCAP_ISA_F;
40 isa2hwcap['d'] = isa2hwcap['D'] = COMPAT_HWCAP_ISA_D;
41 isa2hwcap['c'] = isa2hwcap['C'] = COMPAT_HWCAP_ISA_C;
46 * We don't support running Linux on hertergenous ISA systems. For
47 * now, we just check the ISA of the first "okay" processor.
49 while ((node = of_find_node_by_type(node, "cpu")))
50 if (riscv_of_processor_hartid(node) >= 0)
53 pr_warning("Unable to find \"cpu\" devicetree entry");
57 if (of_property_read_string(node, "riscv,isa", &isa)) {
58 pr_warning("Unable to find \"riscv,isa\" devicetree entry");
64 for (i = 0; i < strlen(isa); ++i)
65 elf_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
67 /* We don't support systems with F but without D, so mask those out
69 if ((elf_hwcap & COMPAT_HWCAP_ISA_F) && !(elf_hwcap & COMPAT_HWCAP_ISA_D)) {
70 pr_info("This kernel does not support systems with F but not D");
71 elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
74 pr_info("elf_hwcap is 0x%lx", elf_hwcap);
77 if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))