db25a9625d
cpu_has_feature()/mmu_has_feature() are only able to check a single feature at a time, but there is no enforcement of that. In fact, as fixed in the previous commit, there was code that was passing multiple values to cpu_has_feature(). So add a check that only a single feature is passed using popcount. Note that the test allows 0 or 1 bits to be set, because some code relies on cpu_has_feature(0) being false, the check with CPU_FTRS_POSSIBLE ensures that. See for example CPU_FTR_PPC_LE. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240509121248.270878-3-mpe@ellerman.id.au
56 lines
1.3 KiB
C
56 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_POWERPC_CPU_HAS_FEATURE_H
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#define __ASM_POWERPC_CPU_HAS_FEATURE_H
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#ifndef __ASSEMBLY__
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#include <linux/bug.h>
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#include <asm/cputable.h>
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static __always_inline bool early_cpu_has_feature(unsigned long feature)
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{
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return !!((CPU_FTRS_ALWAYS & feature) ||
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(CPU_FTRS_POSSIBLE & cur_cpu_spec->cpu_features & feature));
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}
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#ifdef CONFIG_JUMP_LABEL_FEATURE_CHECKS
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#include <linux/jump_label.h>
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#define NUM_CPU_FTR_KEYS BITS_PER_LONG
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extern struct static_key_true cpu_feature_keys[NUM_CPU_FTR_KEYS];
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static __always_inline bool cpu_has_feature(unsigned long feature)
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{
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int i;
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BUILD_BUG_ON(!__builtin_constant_p(feature));
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BUILD_BUG_ON(__builtin_popcountl(feature) > 1);
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#ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
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if (!static_key_feature_checks_initialized) {
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printk("Warning! cpu_has_feature() used prior to jump label init!\n");
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dump_stack();
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return early_cpu_has_feature(feature);
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}
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#endif
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if (CPU_FTRS_ALWAYS & feature)
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return true;
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if (!(CPU_FTRS_POSSIBLE & feature))
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return false;
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i = __builtin_ctzl(feature);
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return static_branch_likely(&cpu_feature_keys[i]);
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}
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#else
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static __always_inline bool cpu_has_feature(unsigned long feature)
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{
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return early_cpu_has_feature(feature);
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}
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#endif
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_POWERPC_CPU_HAS_FEATURE_H */
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