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732e8e4130
On the Hifive-U platform, cpu 0 is a masked cpu with less capabilities than the other cpus. Ignore it for the purpose of determining the hardware capabilities of the system. Signed-off-by: Andreas Schwab <schwab@suse.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
79 lines
2.3 KiB
C
79 lines
2.3 KiB
C
/*
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* Copied from arch/arm64/kernel/cpufeature.c
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*
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* Copyright (C) 2015 ARM Ltd.
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* Copyright (C) 2017 SiFive
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/of.h>
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#include <asm/processor.h>
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#include <asm/hwcap.h>
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unsigned long elf_hwcap __read_mostly;
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#ifdef CONFIG_FPU
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bool has_fpu __read_mostly;
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#endif
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void riscv_fill_hwcap(void)
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{
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struct device_node *node = NULL;
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const char *isa;
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size_t i;
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static unsigned long isa2hwcap[256] = {0};
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isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
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isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M;
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isa2hwcap['a'] = isa2hwcap['A'] = COMPAT_HWCAP_ISA_A;
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isa2hwcap['f'] = isa2hwcap['F'] = COMPAT_HWCAP_ISA_F;
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isa2hwcap['d'] = isa2hwcap['D'] = COMPAT_HWCAP_ISA_D;
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isa2hwcap['c'] = isa2hwcap['C'] = COMPAT_HWCAP_ISA_C;
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elf_hwcap = 0;
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/*
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* We don't support running Linux on hertergenous ISA systems. For
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* now, we just check the ISA of the first "okay" processor.
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*/
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while ((node = of_find_node_by_type(node, "cpu")))
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if (riscv_of_processor_hartid(node) >= 0)
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break;
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if (!node) {
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pr_warning("Unable to find \"cpu\" devicetree entry");
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return;
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}
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if (of_property_read_string(node, "riscv,isa", &isa)) {
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pr_warning("Unable to find \"riscv,isa\" devicetree entry");
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return;
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}
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for (i = 0; i < strlen(isa); ++i)
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elf_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
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/* We don't support systems with F but without D, so mask those out
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* here. */
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if ((elf_hwcap & COMPAT_HWCAP_ISA_F) && !(elf_hwcap & COMPAT_HWCAP_ISA_D)) {
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pr_info("This kernel does not support systems with F but not D");
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elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
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}
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pr_info("elf_hwcap is 0x%lx", elf_hwcap);
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#ifdef CONFIG_FPU
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if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
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has_fpu = true;
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#endif
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}
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