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