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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_ALTERNATIVE_ASM_H
#define _ASM_ALTERNATIVE_ASM_H
#ifdef __ASSEMBLY__
#include <asm/asm.h>
/*
* Issue one struct alt_instr descriptor entry (need to put it into
* the section .altinstructions, see below). This entry contains
* enough information for the alternatives patching code to patch an
* instruction. See apply_alternatives().
*/
.macro altinstruction_entry orig alt feature orig_len alt_len
.long \orig - .
.long \alt - .
.short \feature
.byte \orig_len
.byte \alt_len
.endm
/*
* Define an alternative between two instructions. If @feature is
* present, early code in apply_alternatives() replaces @oldinstr with
* @newinstr. ".fill" directive takes care of proper instruction padding
* in case @newinstr is longer than @oldinstr.
*/
.macro ALTERNATIVE oldinstr, newinstr, feature
140 :
\oldinstr
141 :
.fill - (((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)) / 4, 4, 0x03400000
142 :
.pushsection .altinstructions, "a"
altinstruction_entry 140b, 143f, \feature, 142b-140b, 144f-143f
.popsection
.subsection 1
143 :
\newinstr
144 :
.previous
.endm
#define old_len (141b-140b)
#define new_len1 (144f-143f)
#define new_len2 (145f-144f)
#define alt_max_short(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
/*
* Same as ALTERNATIVE macro above but for two alternatives. If CPU
* has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
* @feature2, it replaces @oldinstr with @feature2.
*/
.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
140 :
\oldinstr
141 :
.fill - ((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \
(alt_max_short(new_len1, new_len2) - (old_len)) / 4, 4, 0x03400000
142 :
.pushsection .altinstructions, "a"
altinstruction_entry 140b, 143f, \feature1, 142b-140b, 144f-143f, 142b-141b
altinstruction_entry 140b, 144f, \feature2, 142b-140b, 145f-144f, 142b-141b
.popsection
.subsection 1
143 :
\newinstr1
144 :
\newinstr2
145 :
.previous
.endm
#endif /* __ASSEMBLY__ */
#endif /* _ASM_ALTERNATIVE_ASM_H */
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