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/*
* Copied from arch/arm64/kernel/cpufeature.c
*
* Copyright (C) 2015 ARM Ltd.
* Copyright (C) 2017 SiFive
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/of.h>
#include <asm/processor.h>
#include <asm/hwcap.h>
unsigned long elf_hwcap __read_mostly;
#ifdef CONFIG_FPU
bool has_fpu __read_mostly;
#endif
void riscv_fill_hwcap(void)
{
struct device_node *node = NULL;
const char *isa;
size_t i;
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;
elf_hwcap = 0;
/*
* We don't support running Linux on hertergenous ISA systems. For
* now, we just check the ISA of the first "okay" processor.
*/
while ((node = of_find_node_by_type(node, "cpu")))
if (riscv_of_processor_hartid(node) >= 0)
break;
if (!node) {
pr_warning("Unable to find \"cpu\" devicetree entry");
return;
}
if (of_property_read_string(node, "riscv,isa", &isa)) {
pr_warning("Unable to find \"riscv,isa\" devicetree entry");
return;
}
for (i = 0; i < strlen(isa); ++i)
elf_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
/* 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");
elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
}
pr_info("elf_hwcap is 0x%lx", elf_hwcap);
#ifdef CONFIG_FPU
if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
has_fpu = true;
#endif
}
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