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Commit 8b5a10fc authored by Jan Beulich's avatar Jan Beulich Committed by H. Peter Anvin
Browse files

x86: properly annotate alternatives.c 



Some of the NOPs tables aren't used on 64-bits, quite some code and
data is needed post-init for module loading only, and a couple of
functions aren't used outside that file (i.e. can be static, and don't
need to be exported).

The change to __INITDATA/__INITRODATA is needed to avoid an assembler
warning.

Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
LKML-Reference: <4A8BC8A00200007800010823@vpn.id2.novell.com>
Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent c7425314

arch/x86/include/asm/alternative.h

+0 −7
Original line number Diff line number Diff line
@@ -73,8 +73,6 @@ static inline void alternatives_smp_module_del(struct module *mod) {} 
static inline void alternatives_smp_switch(int smp) {}

#endif	/* CONFIG_SMP */



const unsigned char *const *find_nop_table(void);



/* alternative assembly primitive: */

#define ALTERNATIVE(oldinstr, newinstr, feature)			\

									\
@@ -144,8 +142,6 @@ static inline void apply_paravirt(struct paravirt_patch_site *start, 
#define __parainstructions_end	NULL

#endif



extern void add_nops(void *insns, unsigned int len);



/*

 * Clear and restore the kernel write-protection flag on the local CPU.

 * Allows the kernel to edit read-only pages.
@@ -161,10 +157,7 @@ extern void add_nops(void *insns, unsigned int len); 
 * Intel's errata.

 * On the local CPU you need to be protected again NMI or MCE handlers seeing an

 * inconsistent instruction while you patch.

 * The _early version expects the memory to already be RW.

 */



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

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



#endif /* _ASM_X86_ALTERNATIVE_H */

arch/x86/kernel/alternative.c

+32 −24
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
#include <linux/sched.h>

#include <linux/mutex.h>

#include <linux/list.h>

#include <linux/stringify.h>

#include <linux/kprobes.h>

#include <linux/mm.h>

#include <linux/vmalloc.h>
@@ -32,7 +33,7 @@ __setup("smp-alt-boot", bootonly); 
#define smp_alt_once 1

#endif



static int debug_alternative;

static int __initdata_or_module debug_alternative;



static int __init debug_alt(char *str)

{
@@ -51,7 +52,7 @@ static int __init setup_noreplace_smp(char *str) 
__setup("noreplace-smp", setup_noreplace_smp);



#ifdef CONFIG_PARAVIRT

static int noreplace_paravirt = 0;

static int __initdata_or_module noreplace_paravirt = 0;



static int __init setup_noreplace_paravirt(char *str)

{
@@ -64,16 +65,17 @@ __setup("noreplace-paravirt", setup_noreplace_paravirt); 
#define DPRINTK(fmt, args...) if (debug_alternative) \

	printk(KERN_DEBUG fmt, args)



#ifdef GENERIC_NOP1

#if defined(GENERIC_NOP1) && !defined(CONFIG_X86_64)

/* Use inline assembly to define this because the nops are defined

   as inline assembly strings in the include files and we cannot

   get them easily into strings. */

asm("\t.section .rodata, \"a\"\nintelnops: "

asm("\t" __stringify(__INITRODATA_OR_MODULE) "\nintelnops: "

	GENERIC_NOP1 GENERIC_NOP2 GENERIC_NOP3 GENERIC_NOP4 GENERIC_NOP5 GENERIC_NOP6

	GENERIC_NOP7 GENERIC_NOP8

    "\t.previous");

extern const unsigned char intelnops[];

static const unsigned char *const intel_nops[ASM_NOP_MAX+1] = {

static const unsigned char *const __initconst_or_module

intel_nops[ASM_NOP_MAX+1] = {

	NULL,

	intelnops,

	intelnops + 1,
@@ -87,12 +89,13 @@ static const unsigned char *const intel_nops[ASM_NOP_MAX+1] = { 
#endif



#ifdef K8_NOP1

asm("\t.section .rodata, \"a\"\nk8nops: "

asm("\t" __stringify(__INITRODATA_OR_MODULE) "\nk8nops: "

	K8_NOP1 K8_NOP2 K8_NOP3 K8_NOP4 K8_NOP5 K8_NOP6

	K8_NOP7 K8_NOP8

    "\t.previous");

extern const unsigned char k8nops[];

static const unsigned char *const k8_nops[ASM_NOP_MAX+1] = {

static const unsigned char *const __initconst_or_module

k8_nops[ASM_NOP_MAX+1] = {

	NULL,

	k8nops,

	k8nops + 1,
@@ -105,13 +108,14 @@ static const unsigned char *const k8_nops[ASM_NOP_MAX+1] = { 
};

#endif



#ifdef K7_NOP1

asm("\t.section .rodata, \"a\"\nk7nops: "

#if defined(K7_NOP1) && !defined(CONFIG_X86_64)

asm("\t" __stringify(__INITRODATA_OR_MODULE) "\nk7nops: "

	K7_NOP1 K7_NOP2 K7_NOP3 K7_NOP4 K7_NOP5 K7_NOP6

	K7_NOP7 K7_NOP8

    "\t.previous");

extern const unsigned char k7nops[];

static const unsigned char *const k7_nops[ASM_NOP_MAX+1] = {

static const unsigned char *const __initconst_or_module

k7_nops[ASM_NOP_MAX+1] = {

	NULL,

	k7nops,

	k7nops + 1,
@@ -125,12 +129,13 @@ static const unsigned char *const k7_nops[ASM_NOP_MAX+1] = { 
#endif



#ifdef P6_NOP1

asm("\t.section .rodata, \"a\"\np6nops: "

asm("\t" __stringify(__INITRODATA_OR_MODULE) "\np6nops: "

	P6_NOP1 P6_NOP2 P6_NOP3 P6_NOP4 P6_NOP5 P6_NOP6

	P6_NOP7 P6_NOP8

    "\t.previous");

extern const unsigned char p6nops[];

static const unsigned char *const p6_nops[ASM_NOP_MAX+1] = {

static const unsigned char *const __initconst_or_module

p6_nops[ASM_NOP_MAX+1] = {

	NULL,

	p6nops,

	p6nops + 1,
@@ -146,7 +151,7 @@ static const unsigned char *const p6_nops[ASM_NOP_MAX+1] = { 
#ifdef CONFIG_X86_64



extern char __vsyscall_0;

const unsigned char *const *find_nop_table(void)

static const unsigned char *const *__init_or_module find_nop_table(void)

{

	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&

	    boot_cpu_has(X86_FEATURE_NOPL))
@@ -157,7 +162,7 @@ const unsigned char *const *find_nop_table(void) 


#else /* CONFIG_X86_64 */



const unsigned char *const *find_nop_table(void)

static const unsigned char *const *__init_or_module find_nop_table(void)

{

	if (boot_cpu_has(X86_FEATURE_K8))

		return k8_nops;
@@ -172,7 +177,7 @@ const unsigned char *const *find_nop_table(void) 
#endif /* CONFIG_X86_64 */



/* Use this to add nops to a buffer, then text_poke the whole buffer. */

void add_nops(void *insns, unsigned int len)

static void __init_or_module add_nops(void *insns, unsigned int len)

{

	const unsigned char *const *noptable = find_nop_table();
@@ -185,10 +190,10 @@ void add_nops(void *insns, unsigned int len) 
		len -= noplen;

	}

}

EXPORT_SYMBOL_GPL(add_nops);



extern struct alt_instr __alt_instructions[], __alt_instructions_end[];

extern u8 *__smp_locks[], *__smp_locks_end[];

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



/* Replace instructions with better alternatives for this CPU type.

   This runs before SMP is initialized to avoid SMP problems with
@@ -196,7 +201,8 @@ extern u8 *__smp_locks[], *__smp_locks_end[]; 
   APs have less capabilities than the boot processor are not handled.

   Tough. Make sure you disable such features by hand. */



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

void __init_or_module apply_alternatives(struct alt_instr *start,

					 struct alt_instr *end)

{

	struct alt_instr *a;

	char insnbuf[MAX_PATCH_LEN];
@@ -279,7 +285,8 @@ static LIST_HEAD(smp_alt_modules); 
static DEFINE_MUTEX(smp_alt);

static int smp_mode = 1;	/* protected by smp_alt */



void alternatives_smp_module_add(struct module *mod, char *name,

void __init_or_module alternatives_smp_module_add(struct module *mod,

						  char *name,

						  void *locks, void *locks_end,

						  void *text,  void *text_end)

{
@@ -317,7 +324,7 @@ void alternatives_smp_module_add(struct module *mod, char *name, 
	mutex_unlock(&smp_alt);

}



void alternatives_smp_module_del(struct module *mod)

void __init_or_module alternatives_smp_module_del(struct module *mod)

{

	struct smp_alt_module *item;
@@ -386,7 +393,7 @@ void alternatives_smp_switch(int smp) 
#endif



#ifdef CONFIG_PARAVIRT

void apply_paravirt(struct paravirt_patch_site *start,

void __init_or_module apply_paravirt(struct paravirt_patch_site *start,

				     struct paravirt_patch_site *end)

{

	struct paravirt_patch_site *p;
@@ -485,7 +492,8 @@ void __init alternative_instructions(void) 
 * instructions. And on the local CPU you need to be protected again NMI or MCE

 * handlers seeing an inconsistent instruction while you patch.

 */

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

static void *__init_or_module text_poke_early(void *addr, const void *opcode,

					      size_t len)

{

	unsigned long flags;

	local_irq_save(flags);

include/linux/init.h

+10 −2
Original line number Diff line number Diff line
@@ -103,8 +103,8 @@ 
#define __INIT		.section	".init.text","ax"

#define __FINIT		.previous



#define __INITDATA	.section	".init.data","aw"

#define __INITRODATA	.section	".init.rodata","a"

#define __INITDATA	.section	".init.data","aw",%progbits

#define __INITRODATA	.section	".init.rodata","a",%progbits

#define __FINITDATA	.previous



#define __DEVINIT        .section	".devinit.text", "ax"
@@ -305,9 +305,17 @@ void __init parse_early_options(char *cmdline); 
#ifdef CONFIG_MODULES

#define __init_or_module

#define __initdata_or_module

#define __initconst_or_module

#define __INIT_OR_MODULE	.text

#define __INITDATA_OR_MODULE	.data

#define __INITRODATA_OR_MODULE	.section ".rodata","a",%progbits

#else

#define __init_or_module __init

#define __initdata_or_module __initdata

#define __initconst_or_module __initconst

#define __INIT_OR_MODULE __INIT

#define __INITDATA_OR_MODULE __INITDATA

#define __INITRODATA_OR_MODULE __INITRODATA

#endif /*CONFIG_MODULES*/



/* Functions marked as __devexit may be discarded at kernel link time, depending