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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_S390_ALTERNATIVE_H
#define _ASM_S390_ALTERNATIVE_H
#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/stringify.h>
struct alt_instr {
s32 instr_offset; /* original instruction */
s32 repl_offset; /* offset to replacement instruction */
u16 facility; /* facility bit set for replacement */
u8 instrlen; /* length of original instruction */
} __packed;
void apply_alternative_instructions(void);
void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
/*
* +---------------------------------+
* |661: |662:
* | oldinstr |
* +---------------------------------+
*
* .altinstr_replacement section
* +---------------------------------+
* |6641: |6651:
* | alternative instr 1 |
* +---------------------------------+
* |6642: |6652:
* | alternative instr 2 |
* +---------------------------------+
*
* .altinstructions section
* +---------------------------------+
* | alt_instr entries for each |
* | alternative instr |
* +---------------------------------+
*/
#define b_altinstr(num) "664"#num
#define e_altinstr(num) "665"#num
#define oldinstr_len "662b-661b"
#define altinstr_len(num) e_altinstr(num)"b-"b_altinstr(num)"b"
#define OLDINSTR(oldinstr) \
"661:\n\t" oldinstr "\n662:\n"
#define ALTINSTR_ENTRY(facility, num) \
"\t.long 661b - .\n" /* old instruction */ \
"\t.long " b_altinstr(num)"b - .\n" /* alt instruction */ \
"\t.word " __stringify(facility) "\n" /* facility bit */ \
"\t.byte " oldinstr_len "\n" /* instruction len */ \
"\t.org . - (" oldinstr_len ") + (" altinstr_len(num) ")\n" \
"\t.org . - (" altinstr_len(num) ") + (" oldinstr_len ")\n"
#define ALTINSTR_REPLACEMENT(altinstr, num) /* replacement */ \
b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n"
/* alternative assembly primitive: */
#define ALTERNATIVE(oldinstr, altinstr, facility) \
".pushsection .altinstr_replacement, \"ax\"\n" \
ALTINSTR_REPLACEMENT(altinstr, 1) \
".popsection\n" \
OLDINSTR(oldinstr) \
".pushsection .altinstructions,\"a\"\n" \
ALTINSTR_ENTRY(facility, 1) \
".popsection\n"
#define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2)\
".pushsection .altinstr_replacement, \"ax\"\n" \
ALTINSTR_REPLACEMENT(altinstr1, 1) \
ALTINSTR_REPLACEMENT(altinstr2, 2) \
".popsection\n" \
OLDINSTR(oldinstr) \
".pushsection .altinstructions,\"a\"\n" \
ALTINSTR_ENTRY(facility1, 1) \
ALTINSTR_ENTRY(facility2, 2) \
".popsection\n"
/*
* Alternative instructions for different CPU types or capabilities.
*
* This allows to use optimized instructions even on generic binary
* kernels.
*
* oldinstr is padded with jump and nops at compile time if altinstr is
* longer. altinstr is padded with jump and nops at run-time during patching.
*
* For non barrier like inlines please define new variants
* without volatile and memory clobber.
*/
#define alternative(oldinstr, altinstr, facility) \
asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility) : : : "memory")
#define alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \
asm_inline volatile(ALTERNATIVE_2(oldinstr, altinstr1, facility1, \
altinstr2, facility2) ::: "memory")
/* Alternative inline assembly with input. */
#define alternative_input(oldinstr, newinstr, feature, input...) \
asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
: : input)
/* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, altinstr, facility, output, input...) \
asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility) \
: output : input)
/* Use this macro if more than one output parameter is needed. */
#define ASM_OUTPUT2(a...) a
/* Use this macro if clobbers are needed without inputs. */
#define ASM_NO_INPUT_CLOBBER(clobber...) : clobber
#endif /* __ASSEMBLY__ */
#endif /* _ASM_S390_ALTERNATIVE_H */