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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/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;
#ifdef CONFIG_FPU
bool has_fpu __read_mostly;
#endif
void riscv_fill_hwcap(void)
{
struct device_node *node;
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;
for_each_of_cpu_node(node) {
unsigned long this_hwcap = 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;
}
for (i = 0; i < strlen(isa); ++i)
this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
/*
* 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;
}
/* 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;
}
pr_info("elf_hwcap is 0x%lx\n", elf_hwcap);
#ifdef CONFIG_FPU
if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
has_fpu = true;
#endif
}
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