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[PATCH] SMP alternatives: skip with UP kernels

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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: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Gerd Hoffmann 2006-07-01 04:36:18 -07:00 committed by Linus Torvalds
parent 27b678dd04
commit 8ec4d41f88
3 changed files with 23 additions and 0 deletions
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6
arch/i386/kernel/alternative.c
View file

@ -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
}

8
include/asm-i386/alternative.h
View file

@ -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

9
include/asm-x86_64/alternative.h
View file

@ -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