xref: /linux/arch/powerpc/include/asm/cpu_has_feature.h (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
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 #ifndef __clang__ /* clang can't cope with this */
28 	BUILD_BUG_ON(!__builtin_constant_p(feature));
29 #endif
30 
31 #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
32 	if (!static_key_feature_checks_initialized) {
33 		printk("Warning! cpu_has_feature() used prior to jump label init!\n");
34 		dump_stack();
35 		return early_cpu_has_feature(feature);
36 	}
37 #endif
38 
39 	if (CPU_FTRS_ALWAYS & feature)
40 		return true;
41 
42 	if (!(CPU_FTRS_POSSIBLE & feature))
43 		return false;
44 
45 	i = __builtin_ctzl(feature);
46 	return static_branch_likely(&cpu_feature_keys[i]);
47 }
48 #else
49 static __always_inline bool cpu_has_feature(unsigned long feature)
50 {
51 	return early_cpu_has_feature(feature);
52 }
53 #endif
54 
55 #endif /* __ASSEMBLY__ */
56 #endif /* __ASM_POWERPC_CPU_HAS_FEATURE_H */
57