cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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alternative.h (4054B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _ASM_S390_ALTERNATIVE_H
      3#define _ASM_S390_ALTERNATIVE_H
      4
      5#ifndef __ASSEMBLY__
      6
      7#include <linux/types.h>
      8#include <linux/stddef.h>
      9#include <linux/stringify.h>
     10
     11struct alt_instr {
     12	s32 instr_offset;	/* original instruction */
     13	s32 repl_offset;	/* offset to replacement instruction */
     14	u16 facility;		/* facility bit set for replacement */
     15	u8  instrlen;		/* length of original instruction */
     16} __packed;
     17
     18void apply_alternative_instructions(void);
     19void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
     20
     21/*
     22 * +---------------------------------+
     23 * |661:			     |662:
     24 * | oldinstr			     |
     25 * +---------------------------------+
     26 *
     27 * .altinstr_replacement section
     28 * +---------------------------------+
     29 * |6641:			     |6651:
     30 * | alternative instr 1	     |
     31 * +---------------------------------+
     32 * |6642:			     |6652:
     33 * | alternative instr 2	     |
     34 * +---------------------------------+
     35 *
     36 * .altinstructions section
     37 * +---------------------------------+
     38 * | alt_instr entries for each      |
     39 * | alternative instr		     |
     40 * +---------------------------------+
     41 */
     42
     43#define b_altinstr(num)		"664"#num
     44#define e_altinstr(num)		"665"#num
     45#define oldinstr_len		"662b-661b"
     46#define altinstr_len(num)	e_altinstr(num)"b-"b_altinstr(num)"b"
     47
     48#define OLDINSTR(oldinstr) \
     49	"661:\n\t" oldinstr "\n662:\n"
     50
     51#define ALTINSTR_ENTRY(facility, num)					\
     52	"\t.long 661b - .\n"			/* old instruction */	\
     53	"\t.long " b_altinstr(num)"b - .\n"	/* alt instruction */	\
     54	"\t.word " __stringify(facility) "\n"	/* facility bit    */	\
     55	"\t.byte " oldinstr_len "\n"		/* instruction len */	\
     56	"\t.org . - (" oldinstr_len ") + (" altinstr_len(num) ")\n"	\
     57	"\t.org . - (" altinstr_len(num) ") + (" oldinstr_len ")\n"
     58
     59#define ALTINSTR_REPLACEMENT(altinstr, num)	/* replacement */	\
     60	b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n"
     61
     62/* alternative assembly primitive: */
     63#define ALTERNATIVE(oldinstr, altinstr, facility) \
     64	".pushsection .altinstr_replacement, \"ax\"\n"			\
     65	ALTINSTR_REPLACEMENT(altinstr, 1)				\
     66	".popsection\n"							\
     67	OLDINSTR(oldinstr)						\
     68	".pushsection .altinstructions,\"a\"\n"				\
     69	ALTINSTR_ENTRY(facility, 1)					\
     70	".popsection\n"
     71
     72#define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2)\
     73	".pushsection .altinstr_replacement, \"ax\"\n"			\
     74	ALTINSTR_REPLACEMENT(altinstr1, 1)				\
     75	ALTINSTR_REPLACEMENT(altinstr2, 2)				\
     76	".popsection\n"							\
     77	OLDINSTR(oldinstr)						\
     78	".pushsection .altinstructions,\"a\"\n"				\
     79	ALTINSTR_ENTRY(facility1, 1)					\
     80	ALTINSTR_ENTRY(facility2, 2)					\
     81	".popsection\n"
     82
     83/*
     84 * Alternative instructions for different CPU types or capabilities.
     85 *
     86 * This allows to use optimized instructions even on generic binary
     87 * kernels.
     88 *
     89 * oldinstr is padded with jump and nops at compile time if altinstr is
     90 * longer. altinstr is padded with jump and nops at run-time during patching.
     91 *
     92 * For non barrier like inlines please define new variants
     93 * without volatile and memory clobber.
     94 */
     95#define alternative(oldinstr, altinstr, facility)			\
     96	asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility) : : : "memory")
     97
     98#define alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \
     99	asm_inline volatile(ALTERNATIVE_2(oldinstr, altinstr1, facility1,   \
    100				   altinstr2, facility2) ::: "memory")
    101
    102/* Alternative inline assembly with input. */
    103#define alternative_input(oldinstr, newinstr, feature, input...)	\
    104	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature)	\
    105		: : input)
    106
    107/* Like alternative_input, but with a single output argument */
    108#define alternative_io(oldinstr, altinstr, facility, output, input...)	\
    109	asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility)	\
    110		: output : input)
    111
    112/* Use this macro if more than one output parameter is needed. */
    113#define ASM_OUTPUT2(a...) a
    114
    115/* Use this macro if clobbers are needed without inputs. */
    116#define ASM_NO_INPUT_CLOBBER(clobber...) : clobber
    117
    118#endif /* __ASSEMBLY__ */
    119
    120#endif /* _ASM_S390_ALTERNATIVE_H */