1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2021 Sifive.
4  */
5 
6 #ifndef __ASM_ALTERNATIVE_H
7 #define __ASM_ALTERNATIVE_H
8 
9 #include <asm/alternative-macros.h>
10 
11 #ifndef __ASSEMBLY__
12 
13 #ifdef CONFIG_RISCV_ALTERNATIVE
14 
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/types.h>
18 #include <linux/stddef.h>
19 #include <asm/hwcap.h>
20 
21 #define PATCH_ID_CPUFEATURE_ID(p)		lower_16_bits(p)
22 #define PATCH_ID_CPUFEATURE_VALUE(p)		upper_16_bits(p)
23 
24 #define RISCV_ALTERNATIVES_BOOT		0 /* alternatives applied during regular boot */
25 #define RISCV_ALTERNATIVES_MODULE	1 /* alternatives applied during module-init */
26 #define RISCV_ALTERNATIVES_EARLY_BOOT	2 /* alternatives applied before mmu start */
27 
28 /* add the relative offset to the address of the offset to get the absolute address */
29 #define __ALT_PTR(a, f)			((void *)&(a)->f + (a)->f)
30 #define ALT_OLD_PTR(a)			__ALT_PTR(a, old_offset)
31 #define ALT_ALT_PTR(a)			__ALT_PTR(a, alt_offset)
32 
33 void probe_vendor_features(unsigned int cpu);
34 void __init apply_boot_alternatives(void);
35 void __init apply_early_boot_alternatives(void);
36 void apply_module_alternatives(void *start, size_t length);
37 
38 void riscv_alternative_fix_offsets(void *alt_ptr, unsigned int len,
39 				   int patch_offset);
40 
41 struct alt_entry {
42 	s32 old_offset;		/* offset relative to original instruction or data  */
43 	s32 alt_offset;		/* offset relative to replacement instruction or data */
44 	u16 vendor_id;		/* CPU vendor ID */
45 	u16 alt_len;		/* The replacement size */
46 	u32 patch_id;		/* The patch ID (erratum ID or cpufeature ID) */
47 };
48 
49 void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
50 			      unsigned long archid, unsigned long impid,
51 			      unsigned int stage);
52 void thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
53 			     unsigned long archid, unsigned long impid,
54 			     unsigned int stage);
55 
56 void thead_feature_probe_func(unsigned int cpu, unsigned long archid,
57 			      unsigned long impid);
58 
59 void riscv_cpufeature_patch_func(struct alt_entry *begin, struct alt_entry *end,
60 				 unsigned int stage);
61 
62 #else /* CONFIG_RISCV_ALTERNATIVE */
63 
64 static inline void probe_vendor_features(unsigned int cpu) { }
65 static inline void apply_boot_alternatives(void) { }
66 static inline void apply_early_boot_alternatives(void) { }
67 static inline void apply_module_alternatives(void *start, size_t length) { }
68 
69 #endif /* CONFIG_RISCV_ALTERNATIVE */
70 
71 #endif
72 #endif
73