arch/loongarch/include/asm/alternative-asm.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_ALTERNATIVE_ASM_H
   3 #define _ASM_ALTERNATIVE_ASM_H
   4
   5 #ifdef __ASSEMBLY__
   6
   7 #include <asm/asm.h>
   8
   9 /*
  10  * Issue one struct alt_instr descriptor entry (need to put it into
  11  * the section .altinstructions, see below). This entry contains
  12  * enough information for the alternatives patching code to patch an
  13  * instruction. See apply_alternatives().
  14  */
  15 .macro altinstruction_entry orig alt feature orig_len alt_len
  16         .long \orig - .
  17         .long \alt - .
  18         .short \feature
  19         .byte \orig_len
  20         .byte \alt_len
  21 .endm
  22
  23 /*
  24  * Define an alternative between two instructions. If @feature is
  25  * present, early code in apply_alternatives() replaces @oldinstr with
  26  * @newinstr. ".fill" directive takes care of proper instruction padding
  27  * in case @newinstr is longer than @oldinstr.
  28  */
  29 .macro ALTERNATIVE oldinstr, newinstr, feature
  30 140 :
  31         \oldinstr
  32 141 :
  33         .fill - (((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)) / 4, 4, 0x03400000
  34 142 :
  35
  36         .pushsection .altinstructions, "a"
  37         altinstruction_entry 140b, 143f, \feature, 142b-140b, 144f-143f
  38         .popsection
  39
  40         .subsection 1
  41 143 :
  42         \newinstr
  43 144 :
  44         .previous
  45 .endm
  46
  47 #define old_len                 (141b-140b)
  48 #define new_len1                (144f-143f)
  49 #define new_len2                (145f-144f)
  50
  51 #define alt_max_short(a, b)     ((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
  52
  53 /*
  54  * Same as ALTERNATIVE macro above but for two alternatives. If CPU
  55  * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
  56  * @feature2, it replaces @oldinstr with @feature2.
  57  */
  58 .macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
  59 140 :
  60         \oldinstr
  61 141 :
  62         .fill - ((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \
  63                 (alt_max_short(new_len1, new_len2) - (old_len)) / 4, 4, 0x03400000
  64 142 :
  65
  66         .pushsection .altinstructions, "a"
  67         altinstruction_entry 140b, 143f, \feature1, 142b-140b, 144f-143f, 142b-141b
  68         altinstruction_entry 140b, 144f, \feature2, 142b-140b, 145f-144f, 142b-141b
  69         .popsection
  70
  71         .subsection 1
  72 143 :
  73         \newinstr1
  74 144 :
  75         \newinstr2
  76 145 :
  77         .previous
  78 .endm
  79
  80 #endif  /*  __ASSEMBLY__  */
  81
  82 #endif /* _ASM_ALTERNATIVE_ASM_H */