248 строки
6.5 KiB
C
248 строки
6.5 KiB
C
#ifndef __ASM_ALTERNATIVE_H
|
|
#define __ASM_ALTERNATIVE_H
|
|
|
|
#include <asm/cpucaps.h>
|
|
#include <asm/insn.h>
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/types.h>
|
|
#include <linux/stddef.h>
|
|
#include <linux/stringify.h>
|
|
|
|
struct alt_instr {
|
|
s32 orig_offset; /* offset to original instruction */
|
|
s32 alt_offset; /* offset to replacement instruction */
|
|
u16 cpufeature; /* cpufeature bit set for replacement */
|
|
u8 orig_len; /* size of original instruction(s) */
|
|
u8 alt_len; /* size of new instruction(s), <= orig_len */
|
|
};
|
|
|
|
void __init apply_alternatives_all(void);
|
|
void apply_alternatives(void *start, size_t length);
|
|
|
|
#define ALTINSTR_ENTRY(feature) \
|
|
" .word 661b - .\n" /* label */ \
|
|
" .word 663f - .\n" /* new instruction */ \
|
|
" .hword " __stringify(feature) "\n" /* feature bit */ \
|
|
" .byte 662b-661b\n" /* source len */ \
|
|
" .byte 664f-663f\n" /* replacement len */
|
|
|
|
/*
|
|
* alternative assembly primitive:
|
|
*
|
|
* If any of these .org directive fail, it means that insn1 and insn2
|
|
* don't have the same length. This used to be written as
|
|
*
|
|
* .if ((664b-663b) != (662b-661b))
|
|
* .error "Alternatives instruction length mismatch"
|
|
* .endif
|
|
*
|
|
* but most assemblers die if insn1 or insn2 have a .inst. This should
|
|
* be fixed in a binutils release posterior to 2.25.51.0.2 (anything
|
|
* containing commit 4e4d08cf7399b606 or c1baaddf8861).
|
|
*/
|
|
#define __ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg_enabled) \
|
|
".if "__stringify(cfg_enabled)" == 1\n" \
|
|
"661:\n\t" \
|
|
oldinstr "\n" \
|
|
"662:\n" \
|
|
".pushsection .altinstructions,\"a\"\n" \
|
|
ALTINSTR_ENTRY(feature) \
|
|
".popsection\n" \
|
|
".pushsection .altinstr_replacement, \"a\"\n" \
|
|
"663:\n\t" \
|
|
newinstr "\n" \
|
|
"664:\n\t" \
|
|
".popsection\n\t" \
|
|
".org . - (664b-663b) + (662b-661b)\n\t" \
|
|
".org . - (662b-661b) + (664b-663b)\n" \
|
|
".endif\n"
|
|
|
|
#define _ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg, ...) \
|
|
__ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg))
|
|
|
|
#else
|
|
|
|
#include <asm/assembler.h>
|
|
|
|
.macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len
|
|
.word \orig_offset - .
|
|
.word \alt_offset - .
|
|
.hword \feature
|
|
.byte \orig_len
|
|
.byte \alt_len
|
|
.endm
|
|
|
|
.macro alternative_insn insn1, insn2, cap, enable = 1
|
|
.if \enable
|
|
661: \insn1
|
|
662: .pushsection .altinstructions, "a"
|
|
altinstruction_entry 661b, 663f, \cap, 662b-661b, 664f-663f
|
|
.popsection
|
|
.pushsection .altinstr_replacement, "ax"
|
|
663: \insn2
|
|
664: .popsection
|
|
.org . - (664b-663b) + (662b-661b)
|
|
.org . - (662b-661b) + (664b-663b)
|
|
.endif
|
|
.endm
|
|
|
|
/*
|
|
* Alternative sequences
|
|
*
|
|
* The code for the case where the capability is not present will be
|
|
* assembled and linked as normal. There are no restrictions on this
|
|
* code.
|
|
*
|
|
* The code for the case where the capability is present will be
|
|
* assembled into a special section to be used for dynamic patching.
|
|
* Code for that case must:
|
|
*
|
|
* 1. Be exactly the same length (in bytes) as the default code
|
|
* sequence.
|
|
*
|
|
* 2. Not contain a branch target that is used outside of the
|
|
* alternative sequence it is defined in (branches into an
|
|
* alternative sequence are not fixed up).
|
|
*/
|
|
|
|
/*
|
|
* Begin an alternative code sequence.
|
|
*/
|
|
.macro alternative_if_not cap
|
|
.set .Lasm_alt_mode, 0
|
|
.pushsection .altinstructions, "a"
|
|
altinstruction_entry 661f, 663f, \cap, 662f-661f, 664f-663f
|
|
.popsection
|
|
661:
|
|
.endm
|
|
|
|
.macro alternative_if cap
|
|
.set .Lasm_alt_mode, 1
|
|
.pushsection .altinstructions, "a"
|
|
altinstruction_entry 663f, 661f, \cap, 664f-663f, 662f-661f
|
|
.popsection
|
|
.pushsection .altinstr_replacement, "ax"
|
|
.align 2 /* So GAS knows label 661 is suitably aligned */
|
|
661:
|
|
.endm
|
|
|
|
/*
|
|
* Provide the other half of the alternative code sequence.
|
|
*/
|
|
.macro alternative_else
|
|
662:
|
|
.if .Lasm_alt_mode==0
|
|
.pushsection .altinstr_replacement, "ax"
|
|
.else
|
|
.popsection
|
|
.endif
|
|
663:
|
|
.endm
|
|
|
|
/*
|
|
* Complete an alternative code sequence.
|
|
*/
|
|
.macro alternative_endif
|
|
664:
|
|
.if .Lasm_alt_mode==0
|
|
.popsection
|
|
.endif
|
|
.org . - (664b-663b) + (662b-661b)
|
|
.org . - (662b-661b) + (664b-663b)
|
|
.endm
|
|
|
|
/*
|
|
* Provides a trivial alternative or default sequence consisting solely
|
|
* of NOPs. The number of NOPs is chosen automatically to match the
|
|
* previous case.
|
|
*/
|
|
.macro alternative_else_nop_endif
|
|
alternative_else
|
|
nops (662b-661b) / AARCH64_INSN_SIZE
|
|
alternative_endif
|
|
.endm
|
|
|
|
#define _ALTERNATIVE_CFG(insn1, insn2, cap, cfg, ...) \
|
|
alternative_insn insn1, insn2, cap, IS_ENABLED(cfg)
|
|
|
|
.macro user_alt, label, oldinstr, newinstr, cond
|
|
9999: alternative_insn "\oldinstr", "\newinstr", \cond
|
|
_ASM_EXTABLE 9999b, \label
|
|
.endm
|
|
|
|
/*
|
|
* Generate the assembly for UAO alternatives with exception table entries.
|
|
* This is complicated as there is no post-increment or pair versions of the
|
|
* unprivileged instructions, and USER() only works for single instructions.
|
|
*/
|
|
#ifdef CONFIG_ARM64_UAO
|
|
.macro uao_ldp l, reg1, reg2, addr, post_inc
|
|
alternative_if_not ARM64_HAS_UAO
|
|
8888: ldp \reg1, \reg2, [\addr], \post_inc;
|
|
8889: nop;
|
|
nop;
|
|
alternative_else
|
|
ldtr \reg1, [\addr];
|
|
ldtr \reg2, [\addr, #8];
|
|
add \addr, \addr, \post_inc;
|
|
alternative_endif
|
|
|
|
_asm_extable 8888b,\l;
|
|
_asm_extable 8889b,\l;
|
|
.endm
|
|
|
|
.macro uao_stp l, reg1, reg2, addr, post_inc
|
|
alternative_if_not ARM64_HAS_UAO
|
|
8888: stp \reg1, \reg2, [\addr], \post_inc;
|
|
8889: nop;
|
|
nop;
|
|
alternative_else
|
|
sttr \reg1, [\addr];
|
|
sttr \reg2, [\addr, #8];
|
|
add \addr, \addr, \post_inc;
|
|
alternative_endif
|
|
|
|
_asm_extable 8888b,\l;
|
|
_asm_extable 8889b,\l;
|
|
.endm
|
|
|
|
.macro uao_user_alternative l, inst, alt_inst, reg, addr, post_inc
|
|
alternative_if_not ARM64_HAS_UAO
|
|
8888: \inst \reg, [\addr], \post_inc;
|
|
nop;
|
|
alternative_else
|
|
\alt_inst \reg, [\addr];
|
|
add \addr, \addr, \post_inc;
|
|
alternative_endif
|
|
|
|
_asm_extable 8888b,\l;
|
|
.endm
|
|
#else
|
|
.macro uao_ldp l, reg1, reg2, addr, post_inc
|
|
USER(\l, ldp \reg1, \reg2, [\addr], \post_inc)
|
|
.endm
|
|
.macro uao_stp l, reg1, reg2, addr, post_inc
|
|
USER(\l, stp \reg1, \reg2, [\addr], \post_inc)
|
|
.endm
|
|
.macro uao_user_alternative l, inst, alt_inst, reg, addr, post_inc
|
|
USER(\l, \inst \reg, [\addr], \post_inc)
|
|
.endm
|
|
#endif
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
|
|
/*
|
|
* Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature));
|
|
*
|
|
* Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature, CONFIG_FOO));
|
|
* N.B. If CONFIG_FOO is specified, but not selected, the whole block
|
|
* will be omitted, including oldinstr.
|
|
*/
|
|
#define ALTERNATIVE(oldinstr, newinstr, ...) \
|
|
_ALTERNATIVE_CFG(oldinstr, newinstr, __VA_ARGS__, 1)
|
|
|
|
#endif /* __ASM_ALTERNATIVE_H */
|