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Commit 8ec4d41f authored by Gerd Hoffmann's avatar Gerd Hoffmann Committed by Linus Torvalds
Browse files

[PATCH] SMP alternatives: skip with UP kernels 



Hide the magic in alternative.h and provide some dummy inline functions
for the UP case (gcc should manage to optimize away these calls).  No
changes in module.c.

Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 27b678dd

arch/i386/kernel/alternative.c

+6 −0
Original line number Diff line number Diff line
@@ -168,6 +168,8 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end) 
	}

}



#ifdef CONFIG_SMP



static void alternatives_smp_save(struct alt_instr *start, struct alt_instr *end)

{

	struct alt_instr *a;
@@ -328,6 +330,8 @@ void alternatives_smp_switch(int smp) 
	spin_unlock_irqrestore(&smp_alt, flags);

}



#endif



void __init alternative_instructions(void)

{

	if (no_replacement) {
@@ -349,6 +353,7 @@ void __init alternative_instructions(void) 
	smp_alt_once = 1;

#endif



#ifdef CONFIG_SMP

	if (smp_alt_once) {

		if (1 == num_possible_cpus()) {

			printk(KERN_INFO "SMP alternatives: switching to UP code\n");
@@ -370,4 +375,5 @@ void __init alternative_instructions(void) 
					    _text, _etext);

		alternatives_smp_switch(0);

	}

#endif

}

include/asm-i386/alternative.h

+8 −0
Original line number Diff line number Diff line
@@ -19,11 +19,19 @@ struct alt_instr { 
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *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_smp_switch(int smp);

#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_smp_switch(int smp) {}

#endif



#endif

include/asm-x86_64/alternative.h

+9 −0
Original line number Diff line number Diff line
@@ -17,11 +17,20 @@ struct alt_instr { 
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *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_smp_switch(int smp);

#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_smp_switch(int smp) {}

#endif



#endif