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18ffa046c5
When a new cpu feature is available, the cpu feature bits will have some initial value, which is incremented when the feature is updated. This patch changes 'register_value' to be 'min_field_value', and checks the feature bits value (interpreted as a signed int) is greater than this minimum. Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
78 lines
1.9 KiB
C
78 lines
1.9 KiB
C
/*
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* Contains CPU feature definitions
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*
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* Copyright (C) 2015 ARM Ltd.
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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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#define pr_fmt(fmt) "alternatives: " fmt
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#include <linux/types.h>
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#include <asm/cpu.h>
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#include <asm/cpufeature.h>
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static bool
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feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
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{
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int val = cpuid_feature_extract_field(reg, entry->field_pos);
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return val >= entry->min_field_value;
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}
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static bool
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has_id_aa64pfr0_feature(const struct arm64_cpu_capabilities *entry)
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{
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u64 val;
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val = read_cpuid(id_aa64pfr0_el1);
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return feature_matches(val, entry);
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}
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static const struct arm64_cpu_capabilities arm64_features[] = {
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{
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.desc = "GIC system register CPU interface",
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.capability = ARM64_HAS_SYSREG_GIC_CPUIF,
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.matches = has_id_aa64pfr0_feature,
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.field_pos = 24,
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.min_field_value = 1,
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},
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{},
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};
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void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
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const char *info)
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{
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int i;
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for (i = 0; caps[i].desc; i++) {
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if (!caps[i].matches(&caps[i]))
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continue;
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if (!cpus_have_cap(caps[i].capability))
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pr_info("%s %s\n", info, caps[i].desc);
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cpus_set_cap(caps[i].capability);
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}
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/* second pass allows enable() to consider interacting capabilities */
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for (i = 0; caps[i].desc; i++) {
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if (cpus_have_cap(caps[i].capability) && caps[i].enable)
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caps[i].enable();
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}
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}
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void check_local_cpu_features(void)
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{
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check_cpu_capabilities(arm64_features, "detected feature");
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}
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