xref: /linux/arch/powerpc/include/asm/cpu_has_feature.h (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_POWERPC_CPU_HAS_FEATURE_H
3 #define __ASM_POWERPC_CPU_HAS_FEATURE_H
4 
5 #ifndef __ASSEMBLY__
6 
7 #include <linux/bug.h>
8 #include <asm/cputable.h>
9 
10 static __always_inline bool early_cpu_has_feature(unsigned long feature)
11 {
12 	return !!((CPU_FTRS_ALWAYS & feature) ||
13 		  (CPU_FTRS_POSSIBLE & cur_cpu_spec->cpu_features & feature));
14 }
15 
16 #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECKS
17 #include <linux/jump_label.h>
18 
19 #define NUM_CPU_FTR_KEYS	BITS_PER_LONG
20 
21 extern struct static_key_true cpu_feature_keys[NUM_CPU_FTR_KEYS];
22 
23 static __always_inline bool cpu_has_feature(unsigned long feature)
24 {
25 	int i;
26 
27 	BUILD_BUG_ON(!__builtin_constant_p(feature));
28 	BUILD_BUG_ON(__builtin_popcountl(feature) > 1);
29 
30 #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
31 	if (!static_key_feature_checks_initialized) {
32 		printk("Warning! cpu_has_feature() used prior to jump label init!\n");
33 		dump_stack();
34 		return early_cpu_has_feature(feature);
35 	}
36 #endif
37 
38 	if (CPU_FTRS_ALWAYS & feature)
39 		return true;
40 
41 	if (!(CPU_FTRS_POSSIBLE & feature))
42 		return false;
43 
44 	i = __builtin_ctzl(feature);
45 	return static_branch_likely(&cpu_feature_keys[i]);
46 }
47 #else
48 static __always_inline bool cpu_has_feature(unsigned long feature)
49 {
50 	return early_cpu_has_feature(feature);
51 }
52 #endif
53 
54 #endif /* __ASSEMBLY__ */
55 #endif /* __ASM_POWERPC_CPU_HAS_FEATURE_H */
56