151 lines
5 KiB
C
151 lines
5 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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u8 replacementlen; /* length of new 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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* |661: |662: |6620 |663:
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* +-----------+---------------------+
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* | oldinstr | oldinstr_padding |
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* | +----------+----------+
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* | | | |
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* | | >6 bytes |6/4/2 nops|
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* | |6 bytes jg----------->
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* +-----------+---------------------+
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* ^^ static padding ^^
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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 | padding
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* +---------------------+- - - - - -+
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* ^ runtime ^
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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 e_oldinstr_pad_end "663"
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#define oldinstr_len "662b-661b"
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#define oldinstr_total_len e_oldinstr_pad_end"b-661b"
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#define altinstr_len(num) e_altinstr(num)"b-"b_altinstr(num)"b"
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#define oldinstr_pad_len(num) \
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"-(((" altinstr_len(num) ")-(" oldinstr_len ")) > 0) * " \
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"((" altinstr_len(num) ")-(" oldinstr_len "))"
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#define INSTR_LEN_SANITY_CHECK(len) \
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".if " len " > 254\n" \
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"\t.error \"cpu alternatives does not support instructions " \
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"blocks > 254 bytes\"\n" \
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".endif\n" \
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".if (" len ") %% 2\n" \
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"\t.error \"cpu alternatives instructions length is odd\"\n" \
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".endif\n"
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#define OLDINSTR_PADDING(oldinstr, num) \
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".if " oldinstr_pad_len(num) " > 6\n" \
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"\tjg " e_oldinstr_pad_end "f\n" \
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"6620:\n" \
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"\t.fill (" oldinstr_pad_len(num) " - (6620b-662b)) / 2, 2, 0x0700\n" \
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".else\n" \
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"\t.fill " oldinstr_pad_len(num) " / 6, 6, 0xc0040000\n" \
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"\t.fill " oldinstr_pad_len(num) " %% 6 / 4, 4, 0x47000000\n" \
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"\t.fill " oldinstr_pad_len(num) " %% 6 %% 4 / 2, 2, 0x0700\n" \
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".endif\n"
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#define OLDINSTR(oldinstr, num) \
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"661:\n\t" oldinstr "\n662:\n" \
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OLDINSTR_PADDING(oldinstr, num) \
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e_oldinstr_pad_end ":\n" \
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INSTR_LEN_SANITY_CHECK(oldinstr_len)
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#define OLDINSTR_2(oldinstr, num1, num2) \
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"661:\n\t" oldinstr "\n662:\n" \
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".if " altinstr_len(num1) " < " altinstr_len(num2) "\n" \
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OLDINSTR_PADDING(oldinstr, num2) \
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".else\n" \
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OLDINSTR_PADDING(oldinstr, num1) \
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".endif\n" \
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e_oldinstr_pad_end ":\n" \
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INSTR_LEN_SANITY_CHECK(oldinstr_len)
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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_total_len "\n" /* source len */ \
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"\t.byte " altinstr_len(num) "\n" /* alt instruction len */
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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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INSTR_LEN_SANITY_CHECK(altinstr_len(num))
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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, 1) \
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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_2(oldinstr, 1, 2) \
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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 volatile(ALTERNATIVE(oldinstr, altinstr, facility) : : : "memory")
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#define alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \
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asm volatile(ALTERNATIVE_2(oldinstr, altinstr1, facility1, \
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altinstr2, facility2) ::: "memory")
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_S390_ALTERNATIVE_H */
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