arch/riscv/include/asm/alternative-macros.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_ALTERNATIVE_MACROS_H
   3 #define __ASM_ALTERNATIVE_MACROS_H
   4
   5 #ifdef CONFIG_RISCV_ALTERNATIVE
   6
   7 #ifdef __ASSEMBLY__
   8
   9 .macro ALT_ENTRY oldptr newptr vendor_id patch_id new_len
  10         .4byte \oldptr - .
  11         .4byte \newptr - .
  12         .2byte \vendor_id
  13         .2byte \new_len
  14         .4byte \patch_id
  15 .endm
  16
  17 .macro ALT_NEW_CONTENT vendor_id, patch_id, enable = 1, new_c
  18         .if \enable
  19         .pushsection .alternative, "a"
  20         ALT_ENTRY 886b, 888f, \vendor_id, \patch_id, 889f - 888f
  21         .popsection
  22         .subsection 1
  23 888 :
  24         .option push
  25         .option norvc
  26         .option norelax
  27         \new_c
  28         .option pop
  29 889 :
  30         .org    . - (889b - 888b) + (887b - 886b)
  31         .org    . - (887b - 886b) + (889b - 888b)
  32         .previous
  33         .endif
  34 .endm
  35
  36 .macro ALTERNATIVE_CFG old_c, new_c, vendor_id, patch_id, enable
  37 886 :
  38         .option push
  39         .option norvc
  40         .option norelax
  41         \old_c
  42         .option pop
  43 887 :
  44         ALT_NEW_CONTENT \vendor_id, \patch_id, \enable, "\new_c"
  45 .endm
  46
  47 .macro ALTERNATIVE_CFG_2 old_c, new_c_1, vendor_id_1, patch_id_1, enable_1,     \
  48                                 new_c_2, vendor_id_2, patch_id_2, enable_2
  49         ALTERNATIVE_CFG "\old_c", "\new_c_1", \vendor_id_1, \patch_id_1, \enable_1
  50         ALT_NEW_CONTENT \vendor_id_2, \patch_id_2, \enable_2, "\new_c_2"
  51 .endm
  52
  53 #define __ALTERNATIVE_CFG(...)          ALTERNATIVE_CFG __VA_ARGS__
  54 #define __ALTERNATIVE_CFG_2(...)        ALTERNATIVE_CFG_2 __VA_ARGS__
  55
  56 #else /* !__ASSEMBLY__ */
  57
  58 #include <asm/asm.h>
  59 #include <linux/stringify.h>
  60
  61 #define ALT_ENTRY(oldptr, newptr, vendor_id, patch_id, newlen)          \
  62         ".4byte ((" oldptr ") - .) \n"                                  \
  63         ".4byte ((" newptr ") - .) \n"                                  \
  64         ".2byte " vendor_id "\n"                                        \
  65         ".2byte " newlen "\n"                                           \
  66         ".4byte " patch_id "\n"
  67
  68 #define ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)             \
  69         ".if " __stringify(enable) " == 1\n"                            \
  70         ".pushsection .alternative, \"a\"\n"                            \
  71         ALT_ENTRY("886b", "888f", __stringify(vendor_id), __stringify(patch_id), "889f - 888f") \
  72         ".popsection\n"                                                 \
  73         ".subsection 1\n"                                               \
  74         "888 :\n"                                                       \
  75         ".option push\n"                                                \
  76         ".option norvc\n"                                               \
  77         ".option norelax\n"                                             \
  78         new_c "\n"                                                      \
  79         ".option pop\n"                                                 \
  80         "889 :\n"                                                       \
  81         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
  82         ".org   . - (889b - 888b) + (887b - 886b)\n"                    \
  83         ".previous\n"                                                   \
  84         ".endif\n"
  85
  86 #define __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, enable)    \
  87         "886 :\n"                                                       \
  88         ".option push\n"                                                \
  89         ".option norvc\n"                                               \
  90         ".option norelax\n"                                             \
  91         old_c "\n"                                                      \
  92         ".option pop\n"                                                 \
  93         "887 :\n"                                                       \
  94         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
  95
  96 #define __ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, patch_id_1, enable_1,  \
  97                                    new_c_2, vendor_id_2, patch_id_2, enable_2)  \
  98         __ALTERNATIVE_CFG(old_c, new_c_1, vendor_id_1, patch_id_1, enable_1)    \
  99         ALT_NEW_CONTENT(vendor_id_2, patch_id_2, enable_2, new_c_2)
 100
 101 #endif /* __ASSEMBLY__ */
 102
 103 #define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, CONFIG_k)   \
 104         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
 105
 106 #define _ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, patch_id_1, CONFIG_k_1,         \
 107                                   new_c_2, vendor_id_2, patch_id_2, CONFIG_k_2)         \
 108         __ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, patch_id_1, IS_ENABLED(CONFIG_k_1),    \
 109                                    new_c_2, vendor_id_2, patch_id_2, IS_ENABLED(CONFIG_k_2))
 110
 111 #else /* CONFIG_RISCV_ALTERNATIVE */
 112 #ifdef __ASSEMBLY__
 113
 114 .macro ALTERNATIVE_CFG old_c
 115         \old_c
 116 .endm
 117
 118 #define _ALTERNATIVE_CFG(old_c, ...)    \
 119         ALTERNATIVE_CFG old_c
 120
 121 #define _ALTERNATIVE_CFG_2(old_c, ...)  \
 122         ALTERNATIVE_CFG old_c
 123
 124 #else /* !__ASSEMBLY__ */
 125
 126 #define __ALTERNATIVE_CFG(old_c)        \
 127         old_c "\n"
 128
 129 #define _ALTERNATIVE_CFG(old_c, ...)    \
 130         __ALTERNATIVE_CFG(old_c)
 131
 132 #define _ALTERNATIVE_CFG_2(old_c, ...)  \
 133         __ALTERNATIVE_CFG(old_c)
 134
 135 #endif /* __ASSEMBLY__ */
 136 #endif /* CONFIG_RISCV_ALTERNATIVE */
 137
 138 /*
 139  * Usage:
 140  *   ALTERNATIVE(old_content, new_content, vendor_id, patch_id, CONFIG_k)
 141  * in the assembly code. Otherwise,
 142  *   asm(ALTERNATIVE(old_content, new_content, vendor_id, patch_id, CONFIG_k));
 143  *
 144  * old_content: The old content which is probably replaced with new content.
 145  * new_content: The new content.
 146  * vendor_id: The CPU vendor ID.
 147  * patch_id: The patch ID (erratum ID or cpufeature ID).
 148  * CONFIG_k: The Kconfig of this patch ID. When Kconfig is disabled, the old
 149  *           content will alwyas be executed.
 150  */
 151 #define ALTERNATIVE(old_content, new_content, vendor_id, patch_id, CONFIG_k) \
 152         _ALTERNATIVE_CFG(old_content, new_content, vendor_id, patch_id, CONFIG_k)
 153
 154 /*
 155  * A vendor wants to replace an old_content, but another vendor has used
 156  * ALTERNATIVE() to patch its customized content at the same location. In
 157  * this case, this vendor can create a new macro ALTERNATIVE_2() based
 158  * on the following sample code and then replace ALTERNATIVE() with
 159  * ALTERNATIVE_2() to append its customized content.
 160  */
 161 #define ALTERNATIVE_2(old_content, new_content_1, vendor_id_1, patch_id_1, CONFIG_k_1,          \
 162                                    new_content_2, vendor_id_2, patch_id_2, CONFIG_k_2)          \
 163         _ALTERNATIVE_CFG_2(old_content, new_content_1, vendor_id_1, patch_id_1, CONFIG_k_1,     \
 164                                         new_content_2, vendor_id_2, patch_id_2, CONFIG_k_2)
 165
 166 #endif