#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/stringify.h>
#include <asm/asm.h>
#include <asm/cpufeature.h>

Data Structures
struct	alt_instr

struct	text_poke_param

Macros
#define	LOCK_PREFIX_HERE ""

#define	LOCK_PREFIX ""

#define	OLDINSTR(oldinstr) "661:\n\t" oldinstr "\n662:\n"

#define	b_replacement(number) "663"#number

#define	e_replacement(number) "664"#number

#define	alt_slen "662b-661b"

#define	alt_rlen(number) e_replacement(number)"f-"b_replacement(number)"f"

#define	ALTINSTR_ENTRY(feature, number)

#define	DISCARD_ENTRY(number)

#define	ALTINSTR_REPLACEMENT(newinstr, feature, number)

#define	ALTERNATIVE(oldinstr, newinstr, feature)

#define	ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)

#define	alternative(oldinstr, newinstr, feature) asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory")

#define	alternative_input(oldinstr, newinstr, feature, input...)

#define	alternative_io(oldinstr, newinstr, feature, output, input...)

#define	alternative_call(oldfunc, newfunc, feature, output, input...)

#define	alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2,output, input...)

#define	ASM_OUTPUT2(a...) a

#define	ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr

#define	__parainstructions NULL

#define	__parainstructions_end NULL

Functions
void	alternative_instructions (void)

void	apply_alternatives (struct alt_instr start, struct alt_instr end)

void *	text_poke_early (void addr, const void opcode, size_t len)

void *	text_poke (void addr, const void opcode, size_t len)

void *	text_poke_smp (void addr, const void opcode, size_t len)

void	text_poke_smp_batch (struct text_poke_param *params, int n)

Macro Definition Documentation

#define __parainstructions NULL

Definition at line 206 of file alternative.h.

#define __parainstructions_end NULL

Definition at line 207 of file alternative.h.

#define alt_rlen ( number ) e_replacement(number)"f-"b_replacement(number)"f"

Definition at line 84 of file alternative.h.

#define alt_slen "662b-661b"

Definition at line 83 of file alternative.h.

#define ALTERNATIVE	(	oldinstr,
		newinstr,
		feature
	)

Value:

OLDINSTR(oldinstr)                      \
    ".pushsection .altinstructions,\"a\"\n"             \
    ALTINSTR_ENTRY(feature, 1)                  \
    ".popsection\n"                         \
    ".pushsection .discard,\"aw\",@progbits\n"          \
    DISCARD_ENTRY(1)                        \
    ".popsection\n"                         \
    ".pushsection .altinstr_replacement, \"ax\"\n"          \
    ALTINSTR_REPLACEMENT(newinstr, feature, 1)          \
    ".popsection"

Definition at line 100 of file alternative.h.

#define alternative	(	oldinstr,
		newinstr,
		feature
	)	asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory")

Definition at line 145 of file alternative.h.

#define ALTERNATIVE_2	(	oldinstr,
		newinstr1,
		feature1,
		newinstr2,
		feature2
	)

Value:

OLDINSTR(oldinstr)                      \
    ".pushsection .altinstructions,\"a\"\n"             \
    ALTINSTR_ENTRY(feature1, 1)                 \
    ALTINSTR_ENTRY(feature2, 2)                 \
    ".popsection\n"                         \
    ".pushsection .discard,\"aw\",@progbits\n"          \
    DISCARD_ENTRY(1)                        \
    DISCARD_ENTRY(2)                        \
    ".popsection\n"                         \
    ".pushsection .altinstr_replacement, \"ax\"\n"          \
    ALTINSTR_REPLACEMENT(newinstr1, feature1, 1)            \
    ALTINSTR_REPLACEMENT(newinstr2, feature2, 2)            \
    ".popsection"

Definition at line 112 of file alternative.h.

#define alternative_call	(	oldfunc,
		newfunc,
		feature,
		output,
		input...
	)

Value:

asm volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \

: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

Definition at line 169 of file alternative.h.

#define alternative_call_2	(	oldfunc,
		newfunc1,
		feature1,
		newfunc2,
		feature2,
		output,
		input...
	)

Value:

asm volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\
        "call %P[new2]", feature2)                    \
        : output : [old] "i" (oldfunc), [new1] "i" (newfunc1),        \
        [new2] "i" (newfunc2), ## input)

Definition at line 179 of file alternative.h.

#define alternative_input	(	oldinstr,
		newinstr,
		feature,
		input...
	)

Value:

asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \

: : "i" (0), ## input)

Definition at line 159 of file alternative.h.

#define alternative_io	(	oldinstr,
		newinstr,
		feature,
		output,
		input...
	)

Value:

asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \

: output : "i" (0), ## input)

Definition at line 164 of file alternative.h.

#define ALTINSTR_ENTRY	(	feature,
		number
	)

Value:

" .long 661b - .\n"             /* label           */ \
    " .long " b_replacement(number)"f - .\n"    /* new instruction */ \
    " .word " __stringify(feature) "\n"     /* feature bit     */ \
    " .byte " alt_slen "\n"             /* source len      */ \
    " .byte " alt_rlen(number) "\n"         /* replacement len */

Definition at line 86 of file alternative.h.

#define ALTINSTR_REPLACEMENT	(	newinstr,
		feature,
		number
	)

Value:

/* replacement */ \

b_replacement(number)":\n\t" newinstr "\n" e_replacement(number) ":\n\t"

Definition at line 96 of file alternative.h.

#define ASM_NO_INPUT_CLOBBER ( clbr... ) "i" (0) : clbr

Definition at line 196 of file alternative.h.

#define ASM_OUTPUT2 ( a... ) a

Definition at line 190 of file alternative.h.

#define b_replacement ( number ) "663"#number

Definition at line 80 of file alternative.h.

#define DISCARD_ENTRY ( number )

Value:

/* rlen <= slen */ \

" .byte 0xff + (" alt_rlen(number) ") - (" alt_slen ")\n"

Definition at line 93 of file alternative.h.

#define e_replacement ( number ) "664"#number

Definition at line 81 of file alternative.h.

#define LOCK_PREFIX ""

Definition at line 42 of file alternative.h.

#define LOCK_PREFIX_HERE ""

Definition at line 41 of file alternative.h.

#define OLDINSTR ( oldinstr ) "661:\n\t" oldinstr "\n662:\n"

Definition at line 78 of file alternative.h.

Function Documentation

void alternative_instructions ( void )

Definition at line 486 of file alternative.c.

void apply_alternatives	(	struct alt_instr *	start,
		struct alt_instr *	end
	)

Definition at line 395 of file um_arch.c.

void* text_poke	(	void *	addr,
		const void *	opcode,
		size_t	len
	)

text_poke - Update instructions on a live kernel : address to modify : source of the copy : length to copy

Only atomic text poke/set should be allowed when not doing early patching. It means the size must be writable atomically and the address must be aligned in a way that permits an atomic write. It also makes sure we fit on a single page.

Note: Must be called under text_mutex.

Definition at line 564 of file alternative.c.

void *__init_or_module text_poke_early	(	void *	addr,
		const void *	opcode,
		size_t	len
	)

text_poke_early - Update instructions on a live kernel at boot time : address to modify : source of the copy : length to copy

When you use this code to patch more than one byte of an instruction you need to make sure that other CPUs cannot execute this code in parallel. Also no thread must be currently preempted in the middle of these instructions. And on the local CPU you need to be protected again NMI or MCE handlers seeing an inconsistent instruction while you patch.

Definition at line 538 of file alternative.c.

void* text_poke_smp	(	void *	addr,
		const void *	opcode,
		size_t	len
	)

text_poke_smp - Update instructions on a live kernel on SMP : address to modify : source of the copy : length to copy

Modify multi-byte instruction by using stop_machine() on SMP. This allows user to poke/set multi-byte text on SMP. Only non-NMI/MCE code modifying should be allowed, since stop_machine() does not protect code against NMI and MCE.

Note: Must be called under get_online_cpus() and text_mutex.

Definition at line 657 of file alternative.c.

void text_poke_smp_batch	(	struct text_poke_param *	params,
		int	n
	)

text_poke_smp_batch - Update instructions on a live kernel on SMP : an array of text_poke parameters
: the number of elements in params.

Modify multi-byte instruction by using stop_machine() on SMP. Since the stop_machine() is heavy task, it is better to aggregate text_poke requests and do it once if possible.

Note: Must be called under get_online_cpus() and text_mutex.

Definition at line 685 of file alternative.c.

Data Structures

Macros

Functions

Macro Definition Documentation

Function Documentation