1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_ALTERNATIVE_MACROS_H
3 #define __ASM_ALTERNATIVE_MACROS_H
4 
5 #ifdef CONFIG_RISCV_ERRATA_ALTERNATIVE
6 
7 #ifdef __ASSEMBLY__
8 
9 .macro ALT_ENTRY oldptr newptr vendor_id errata_id new_len
10 	RISCV_PTR \oldptr
11 	RISCV_PTR \newptr
12 	REG_ASM \vendor_id
13 	REG_ASM \new_len
14 	.word	\errata_id
15 .endm
16 
17 .macro ALT_NEW_CONTENT vendor_id, errata_id, enable = 1, new_c : vararg
18 	.if \enable
19 	.pushsection .alternative, "a"
20 	ALT_ENTRY 886b, 888f, \vendor_id, \errata_id, 889f - 888f
21 	.popsection
22 	.subsection 1
23 888 :
24 	\new_c
25 889 :
26 	.previous
27 	.org    . - (889b - 888b) + (887b - 886b)
28 	.org    . - (887b - 886b) + (889b - 888b)
29 	.endif
30 .endm
31 
32 .macro __ALTERNATIVE_CFG old_c, new_c, vendor_id, errata_id, enable
33 886 :
34 	\old_c
35 887 :
36 	ALT_NEW_CONTENT \vendor_id, \errata_id, \enable, \new_c
37 .endm
38 
39 #define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
40 	__ALTERNATIVE_CFG old_c, new_c, vendor_id, errata_id, IS_ENABLED(CONFIG_k)
41 
42 #else /* !__ASSEMBLY__ */
43 
44 #include <asm/asm.h>
45 #include <linux/stringify.h>
46 
47 #define ALT_ENTRY(oldptr, newptr, vendor_id, errata_id, newlen) \
48 	RISCV_PTR " " oldptr "\n" \
49 	RISCV_PTR " " newptr "\n" \
50 	REG_ASM " " vendor_id "\n" \
51 	REG_ASM " " newlen "\n" \
52 	".word " errata_id "\n"
53 
54 #define ALT_NEW_CONTENT(vendor_id, errata_id, enable, new_c) \
55 	".if " __stringify(enable) " == 1\n"				\
56 	".pushsection .alternative, \"a\"\n"				\
57 	ALT_ENTRY("886b", "888f", __stringify(vendor_id), __stringify(errata_id), "889f - 888f") \
58 	".popsection\n"							\
59 	".subsection 1\n"						\
60 	"888 :\n"							\
61 	new_c "\n"							\
62 	"889 :\n"							\
63 	".previous\n"							\
64 	".org	. - (887b - 886b) + (889b - 888b)\n"			\
65 	".org	. - (889b - 888b) + (887b - 886b)\n"			\
66 	".endif\n"
67 
68 #define __ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, enable) \
69 	"886 :\n"	\
70 	old_c "\n"	\
71 	"887 :\n"	\
72 	ALT_NEW_CONTENT(vendor_id, errata_id, enable, new_c)
73 
74 #define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k)	\
75 	__ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, IS_ENABLED(CONFIG_k))
76 
77 #endif /* __ASSEMBLY__ */
78 
79 #else /* !CONFIG_RISCV_ERRATA_ALTERNATIVE*/
80 #ifdef __ASSEMBLY__
81 
82 .macro __ALTERNATIVE_CFG old_c
83 	\old_c
84 .endm
85 
86 #define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
87 	__ALTERNATIVE_CFG old_c
88 
89 #else /* !__ASSEMBLY__ */
90 
91 #define __ALTERNATIVE_CFG(old_c)  \
92 	old_c "\n"
93 
94 #define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
95 	__ALTERNATIVE_CFG(old_c)
96 
97 #endif /* __ASSEMBLY__ */
98 #endif /* CONFIG_RISCV_ERRATA_ALTERNATIVE */
99 /*
100  * Usage:
101  *   ALTERNATIVE(old_content, new_content, vendor_id, errata_id, CONFIG_k)
102  * in the assembly code. Otherwise,
103  *   asm(ALTERNATIVE(old_content, new_content, vendor_id, errata_id, CONFIG_k));
104  *
105  * old_content: The old content which is probably replaced with new content.
106  * new_content: The new content.
107  * vendor_id: The CPU vendor ID.
108  * errata_id: The errata ID.
109  * CONFIG_k: The Kconfig of this errata. When Kconfig is disabled, the old
110  *	     content will alwyas be executed.
111  */
112 #define ALTERNATIVE(old_content, new_content, vendor_id, errata_id, CONFIG_k) \
113 	_ALTERNATIVE_CFG(old_content, new_content, vendor_id, errata_id, CONFIG_k)
114 
115 /*
116  * A vendor wants to replace an old_content, but another vendor has used
117  * ALTERNATIVE() to patch its customized content at the same location. In
118  * this case, this vendor can create a new macro ALTERNATIVE_2() based
119  * on the following sample code and then replace ALTERNATIVE() with
120  * ALTERNATIVE_2() to append its customized content.
121  *
122  * .macro __ALTERNATIVE_CFG_2 old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
123  *                                   new_c_2, vendor_id_2, errata_id_2, enable_2
124  * 886 :
125  *      \old_c
126  * 887 :
127  *      ALT_NEW_CONTENT \vendor_id_1, \errata_id_1, \enable_1, \new_c_1
128  *      ALT_NEW_CONTENT \vendor_id_2, \errata_id_2, \enable_2, \new_c_2
129  * .endm
130  *
131  * #define _ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
132  *                                   new_c_2, vendor_id_2, errata_id_2, CONFIG_k_2) \
133  *        __ALTERNATIVE_CFG_2 old_c, new_c_1, vendor_id_1, errata_id_1, IS_ENABLED(CONFIG_k_1), \
134  *                                   new_c_2, vendor_id_2, errata_id_2, IS_ENABLED(CONFIG_k_2) \
135  *
136  * #define ALTERNATIVE_2(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
137  *                                    new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2) \
138  *         _ALTERNATIVE_CFG_2(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
139  *                                         new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2)
140  *
141  */
142 #endif
143