394 lines
12 KiB
C
394 lines
12 KiB
C
|
/* SPDX-License-Identifier: GPL-2.0 */
|
||
|
|
#ifndef _ASM_X86_ALTERNATIVE_H
|
||
|
|
#define _ASM_X86_ALTERNATIVE_H
|
||
|
|
|
||
|
|
#include <linux/types.h>
|
||
|
|
#include <linux/stringify.h>
|
||
|
|
#include <asm/asm.h>
|
||
|
|
|
||
|
|
#define ALTINSTR_FLAG_INV (1 << 15)
|
||
|
|
#define ALT_NOT(feat) ((feat) | ALTINSTR_FLAG_INV)
|
||
|
|
|
||
|
|
#ifndef __ASSEMBLY__
|
||
|
|
|
||
|
|
#include <linux/stddef.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Alternative inline assembly for SMP.
|
||
|
|
*
|
||
|
|
* The LOCK_PREFIX macro defined here replaces the LOCK and
|
||
|
|
* LOCK_PREFIX macros used everywhere in the source tree.
|
||
|
|
*
|
||
|
|
* SMP alternatives use the same data structures as the other
|
||
|
|
* alternatives and the X86_FEATURE_UP flag to indicate the case of a
|
||
|
|
* UP system running a SMP kernel. The existing apply_alternatives()
|
||
|
|
* works fine for patching a SMP kernel for UP.
|
||
|
|
*
|
||
|
|
* The SMP alternative tables can be kept after boot and contain both
|
||
|
|
* UP and SMP versions of the instructions to allow switching back to
|
||
|
|
* SMP at runtime, when hotplugging in a new CPU, which is especially
|
||
|
|
* useful in virtualized environments.
|
||
|
|
*
|
||
|
|
* The very common lock prefix is handled as special case in a
|
||
|
|
* separate table which is a pure address list without replacement ptr
|
||
|
|
* and size information. That keeps the table sizes small.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifdef CONFIG_SMP
|
||
|
|
#define LOCK_PREFIX_HERE \
|
||
|
|
".pushsection .smp_locks,\"a\"\n" \
|
||
|
|
".balign 4\n" \
|
||
|
|
".long 671f - .\n" /* offset */ \
|
||
|
|
".popsection\n" \
|
||
|
|
"671:"
|
||
|
|
|
||
|
|
#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "
|
||
|
|
|
||
|
|
#else /* ! CONFIG_SMP */
|
||
|
|
#define LOCK_PREFIX_HERE ""
|
||
|
|
#define LOCK_PREFIX ""
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* objtool annotation to ignore the alternatives and only consider the original
|
||
|
|
* instruction(s).
|
||
|
|
*/
|
||
|
|
#define ANNOTATE_IGNORE_ALTERNATIVE \
|
||
|
|
"999:\n\t" \
|
||
|
|
".pushsection .discard.ignore_alts\n\t" \
|
||
|
|
".long 999b - .\n\t" \
|
||
|
|
".popsection\n\t"
|
||
|
|
|
||
|
|
struct alt_instr {
|
||
|
|
s32 instr_offset; /* original instruction */
|
||
|
|
s32 repl_offset; /* offset to replacement instruction */
|
||
|
|
u16 cpuid; /* cpuid bit set for replacement */
|
||
|
|
u8 instrlen; /* length of original instruction */
|
||
|
|
u8 replacementlen; /* length of new instruction */
|
||
|
|
} __packed;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Debug flag that can be tested to see whether alternative
|
||
|
|
* instructions were patched in already:
|
||
|
|
*/
|
||
|
|
extern int alternatives_patched;
|
||
|
|
|
||
|
|
extern void alternative_instructions(void);
|
||
|
|
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
|
||
|
|
extern void apply_retpolines(s32 *start, s32 *end);
|
||
|
|
extern void apply_ibt_endbr(s32 *start, s32 *end);
|
||
|
|
|
||
|
|
struct module;
|
||
|
|
|
||
|
|
#ifdef CONFIG_SMP
|
||
|
|
extern void alternatives_smp_module_add(struct module *mod, char *name,
|
||
|
|
void *locks, void *locks_end,
|
||
|
|
void *text, void *text_end);
|
||
|
|
extern void alternatives_smp_module_del(struct module *mod);
|
||
|
|
extern void alternatives_enable_smp(void);
|
||
|
|
extern int alternatives_text_reserved(void *start, void *end);
|
||
|
|
extern bool skip_smp_alternatives;
|
||
|
|
#else
|
||
|
|
static inline void alternatives_smp_module_add(struct module *mod, char *name,
|
||
|
|
void *locks, void *locks_end,
|
||
|
|
void *text, void *text_end) {}
|
||
|
|
static inline void alternatives_smp_module_del(struct module *mod) {}
|
||
|
|
static inline void alternatives_enable_smp(void) {}
|
||
|
|
static inline int alternatives_text_reserved(void *start, void *end)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
#endif /* CONFIG_SMP */
|
||
|
|
|
||
|
|
#define b_replacement(num) "664"#num
|
||
|
|
#define e_replacement(num) "665"#num
|
||
|
|
|
||
|
|
#define alt_end_marker "663"
|
||
|
|
#define alt_slen "662b-661b"
|
||
|
|
#define alt_total_slen alt_end_marker"b-661b"
|
||
|
|
#define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f"
|
||
|
|
|
||
|
|
#define OLDINSTR(oldinstr, num) \
|
||
|
|
"# ALT: oldnstr\n" \
|
||
|
|
"661:\n\t" oldinstr "\n662:\n" \
|
||
|
|
"# ALT: padding\n" \
|
||
|
|
".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \
|
||
|
|
"((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" \
|
||
|
|
alt_end_marker ":\n"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* gas compatible max based on the idea from:
|
||
|
|
* http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
|
||
|
|
*
|
||
|
|
* The additional "-" is needed because gas uses a "true" value of -1.
|
||
|
|
*/
|
||
|
|
#define alt_max_short(a, b) "((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Pad the second replacement alternative with additional NOPs if it is
|
||
|
|
* additionally longer than the first replacement alternative.
|
||
|
|
*/
|
||
|
|
#define OLDINSTR_2(oldinstr, num1, num2) \
|
||
|
|
"# ALT: oldinstr2\n" \
|
||
|
|
"661:\n\t" oldinstr "\n662:\n" \
|
||
|
|
"# ALT: padding2\n" \
|
||
|
|
".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * " \
|
||
|
|
"(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n" \
|
||
|
|
alt_end_marker ":\n"
|
||
|
|
|
||
|
|
#define OLDINSTR_3(oldinsn, n1, n2, n3) \
|
||
|
|
"# ALT: oldinstr3\n" \
|
||
|
|
"661:\n\t" oldinsn "\n662:\n" \
|
||
|
|
"# ALT: padding3\n" \
|
||
|
|
".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
|
||
|
|
" - (" alt_slen ")) > 0) * " \
|
||
|
|
"(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
|
||
|
|
" - (" alt_slen ")), 0x90\n" \
|
||
|
|
alt_end_marker ":\n"
|
||
|
|
|
||
|
|
#define ALTINSTR_ENTRY(feature, num) \
|
||
|
|
" .long 661b - .\n" /* label */ \
|
||
|
|
" .long " b_replacement(num)"f - .\n" /* new instruction */ \
|
||
|
|
" .word " __stringify(feature) "\n" /* feature bit */ \
|
||
|
|
" .byte " alt_total_slen "\n" /* source len */ \
|
||
|
|
" .byte " alt_rlen(num) "\n" /* replacement len */
|
||
|
|
|
||
|
|
#define ALTINSTR_REPLACEMENT(newinstr, num) /* replacement */ \
|
||
|
|
"# ALT: replacement " #num "\n" \
|
||
|
|
b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"
|
||
|
|
|
||
|
|
/* alternative assembly primitive: */
|
||
|
|
#define ALTERNATIVE(oldinstr, newinstr, feature) \
|
||
|
|
OLDINSTR(oldinstr, 1) \
|
||
|
|
".pushsection .altinstructions,\"a\"\n" \
|
||
|
|
ALTINSTR_ENTRY(feature, 1) \
|
||
|
|
".popsection\n" \
|
||
|
|
".pushsection .altinstr_replacement, \"ax\"\n" \
|
||
|
|
ALTINSTR_REPLACEMENT(newinstr, 1) \
|
||
|
|
".popsection\n"
|
||
|
|
|
||
|
|
#define ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)\
|
||
|
|
OLDINSTR_2(oldinstr, 1, 2) \
|
||
|
|
".pushsection .altinstructions,\"a\"\n" \
|
||
|
|
ALTINSTR_ENTRY(feature1, 1) \
|
||
|
|
ALTINSTR_ENTRY(feature2, 2) \
|
||
|
|
".popsection\n" \
|
||
|
|
".pushsection .altinstr_replacement, \"ax\"\n" \
|
||
|
|
ALTINSTR_REPLACEMENT(newinstr1, 1) \
|
||
|
|
ALTINSTR_REPLACEMENT(newinstr2, 2) \
|
||
|
|
".popsection\n"
|
||
|
|
|
||
|
|
/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
|
||
|
|
#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
|
||
|
|
ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
|
||
|
|
newinstr_yes, feature)
|
||
|
|
|
||
|
|
#define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \
|
||
|
|
OLDINSTR_3(oldinsn, 1, 2, 3) \
|
||
|
|
".pushsection .altinstructions,\"a\"\n" \
|
||
|
|
ALTINSTR_ENTRY(feat1, 1) \
|
||
|
|
ALTINSTR_ENTRY(feat2, 2) \
|
||
|
|
ALTINSTR_ENTRY(feat3, 3) \
|
||
|
|
".popsection\n" \
|
||
|
|
".pushsection .altinstr_replacement, \"ax\"\n" \
|
||
|
|
ALTINSTR_REPLACEMENT(newinsn1, 1) \
|
||
|
|
ALTINSTR_REPLACEMENT(newinsn2, 2) \
|
||
|
|
ALTINSTR_REPLACEMENT(newinsn3, 3) \
|
||
|
|
".popsection\n"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Alternative instructions for different CPU types or capabilities.
|
||
|
|
*
|
||
|
|
* This allows to use optimized instructions even on generic binary
|
||
|
|
* kernels.
|
||
|
|
*
|
||
|
|
* length of oldinstr must be longer or equal the length of newinstr
|
||
|
|
* It can be padded with nops as needed.
|
||
|
|
*
|
||
|
|
* For non barrier like inlines please define new variants
|
||
|
|
* without volatile and memory clobber.
|
||
|
|
*/
|
||
|
|
#define alternative(oldinstr, newinstr, feature) \
|
||
|
|
asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory")
|
||
|
|
|
||
|
|
#define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \
|
||
|
|
asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory")
|
||
|
|
|
||
|
|
#define alternative_ternary(oldinstr, feature, newinstr_yes, newinstr_no) \
|
||
|
|
asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) ::: "memory")
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Alternative inline assembly with input.
|
||
|
|
*
|
||
|
|
* Peculiarities:
|
||
|
|
* No memory clobber here.
|
||
|
|
* Argument numbers start with 1.
|
||
|
|
* Leaving an unused argument 0 to keep API compatibility.
|
||
|
|
*/
|
||
|
|
#define alternative_input(oldinstr, newinstr, feature, input...) \
|
||
|
|
asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
|
||
|
|
: : "i" (0), ## input)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This is similar to alternative_input. But it has two features and
|
||
|
|
* respective instructions.
|
||
|
|
*
|
||
|
|
* If CPU has feature2, newinstr2 is used.
|
||
|
|
* Otherwise, if CPU has feature1, newinstr1 is used.
|
||
|
|
* Otherwise, oldinstr is used.
|
||
|
|
*/
|
||
|
|
#define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, \
|
||
|
|
feature2, input...) \
|
||
|
|
asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \
|
||
|
|
newinstr2, feature2) \
|
||
|
|
: : "i" (0), ## input)
|
||
|
|
|
||
|
|
/* Like alternative_input, but with a single output argument */
|
||
|
|
#define alternative_io(oldinstr, newinstr, feature, output, input...) \
|
||
|
|
asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
|
||
|
|
: output : "i" (0), ## input)
|
||
|
|
|
||
|
|
/* Like alternative_io, but for replacing a direct call with another one. */
|
||
|
|
#define alternative_call(oldfunc, newfunc, feature, output, input...) \
|
||
|
|
asm_inline volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \
|
||
|
|
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Like alternative_call, but there are two features and respective functions.
|
||
|
|
* If CPU has feature2, function2 is used.
|
||
|
|
* Otherwise, if CPU has feature1, function1 is used.
|
||
|
|
* Otherwise, old function is used.
|
||
|
|
*/
|
||
|
|
#define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2, \
|
||
|
|
output, input...) \
|
||
|
|
asm_inline volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\
|
||
|
|
"call %P[new2]", feature2) \
|
||
|
|
: output, ASM_CALL_CONSTRAINT \
|
||
|
|
: [old] "i" (oldfunc), [new1] "i" (newfunc1), \
|
||
|
|
[new2] "i" (newfunc2), ## input)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* use this macro(s) if you need more than one output parameter
|
||
|
|
* in alternative_io
|
||
|
|
*/
|
||
|
|
#define ASM_OUTPUT2(a...) a
|
||
|
|
|
||
|
|
/*
|
||
|
|
* use this macro if you need clobbers but no inputs in
|
||
|
|
* alternative_{input,io,call}()
|
||
|
|
*/
|
||
|
|
#define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr
|
||
|
|
|
||
|
|
#else /* __ASSEMBLY__ */
|
||
|
|
|
||
|
|
#ifdef CONFIG_SMP
|
||
|
|
.macro LOCK_PREFIX
|
||
|
|
672: lock
|
||
|
|
.pushsection .smp_locks,"a"
|
||
|
|
.balign 4
|
||
|
|
.long 672b - .
|
||
|
|
.popsection
|
||
|
|
.endm
|
||
|
|
#else
|
||
|
|
.macro LOCK_PREFIX
|
||
|
|
.endm
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* objtool annotation to ignore the alternatives and only consider the original
|
||
|
|
* instruction(s).
|
||
|
|
*/
|
||
|
|
.macro ANNOTATE_IGNORE_ALTERNATIVE
|
||
|
|
.Lannotate_\@:
|
||
|
|
.pushsection .discard.ignore_alts
|
||
|
|
.long .Lannotate_\@ - .
|
||
|
|
.popsection
|
||
|
|
.endm
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Issue one struct alt_instr descriptor entry (need to put it into
|
||
|
|
* the section .altinstructions, see below). This entry contains
|
||
|
|
* enough information for the alternatives patching code to patch an
|
||
|
|
* instruction. See apply_alternatives().
|
||
|
|
*/
|
||
|
|
.macro altinstruction_entry orig alt feature orig_len alt_len
|
||
|
|
.long \orig - .
|
||
|
|
.long \alt - .
|
||
|
|
.word \feature
|
||
|
|
.byte \orig_len
|
||
|
|
.byte \alt_len
|
||
|
|
.endm
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Define an alternative between two instructions. If @feature is
|
||
|
|
* present, early code in apply_alternatives() replaces @oldinstr with
|
||
|
|
* @newinstr. ".skip" directive takes care of proper instruction padding
|
||
|
|
* in case @newinstr is longer than @oldinstr.
|
||
|
|
*/
|
||
|
|
.macro ALTERNATIVE oldinstr, newinstr, feature
|
||
|
|
140:
|
||
|
|
\oldinstr
|
||
|
|
141:
|
||
|
|
.skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90
|
||
|
|
142:
|
||
|
|
|
||
|
|
.pushsection .altinstructions,"a"
|
||
|
|
altinstruction_entry 140b,143f,\feature,142b-140b,144f-143f
|
||
|
|
.popsection
|
||
|
|
|
||
|
|
.pushsection .altinstr_replacement,"ax"
|
||
|
|
143:
|
||
|
|
\newinstr
|
||
|
|
144:
|
||
|
|
.popsection
|
||
|
|
.endm
|
||
|
|
|
||
|
|
#define old_len 141b-140b
|
||
|
|
#define new_len1 144f-143f
|
||
|
|
#define new_len2 145f-144f
|
||
|
|
|
||
|
|
/*
|
||
|
|
* gas compatible max based on the idea from:
|
||
|
|
* http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
|
||
|
|
*
|
||
|
|
* The additional "-" is needed because gas uses a "true" value of -1.
|
||
|
|
*/
|
||
|
|
#define alt_max_short(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Same as ALTERNATIVE macro above but for two alternatives. If CPU
|
||
|
|
* has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
|
||
|
|
* @feature2, it replaces @oldinstr with @feature2.
|
||
|
|
*/
|
||
|
|
.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
|
||
|
|
140:
|
||
|
|
\oldinstr
|
||
|
|
141:
|
||
|
|
.skip -((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \
|
||
|
|
(alt_max_short(new_len1, new_len2) - (old_len)),0x90
|
||
|
|
142:
|
||
|
|
|
||
|
|
.pushsection .altinstructions,"a"
|
||
|
|
altinstruction_entry 140b,143f,\feature1,142b-140b,144f-143f
|
||
|
|
altinstruction_entry 140b,144f,\feature2,142b-140b,145f-144f
|
||
|
|
.popsection
|
||
|
|
|
||
|
|
.pushsection .altinstr_replacement,"ax"
|
||
|
|
143:
|
||
|
|
\newinstr1
|
||
|
|
144:
|
||
|
|
\newinstr2
|
||
|
|
145:
|
||
|
|
.popsection
|
||
|
|
.endm
|
||
|
|
|
||
|
|
/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
|
||
|
|
#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
|
||
|
|
ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
|
||
|
|
newinstr_yes, feature
|
||
|
|
|
||
|
|
#endif /* __ASSEMBLY__ */
|
||
|
|
|
||
|
|
#endif /* _ASM_X86_ALTERNATIVE_H */
|