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x86/jump_label: add arch_jump_label_transform_static()
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This allows jump-label entries to be cheaply updated on code which is
not yet live.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
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Jeremy Fitzhardinge committed Oct 25, 2011
1 parent 61f4218 commit e71a5be
Showing 1 changed file with 17 additions and 3 deletions.
20 changes: 17 additions & 3 deletions arch/x86/kernel/jump_label.c
Original file line number Diff line number Diff line change
Expand Up @@ -24,8 +24,9 @@ union jump_code_union {
} __attribute__((packed));
};

void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
static void __jump_label_transform(struct jump_entry *entry,
enum jump_label_type type,
void *(*poker)(void *, const void *, size_t))
{
union jump_code_union code;

Expand All @@ -35,11 +36,24 @@ void arch_jump_label_transform(struct jump_entry *entry,
(entry->code + JUMP_LABEL_NOP_SIZE);
} else
memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE);

(*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
}

void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
{
get_online_cpus();
mutex_lock(&text_mutex);
text_poke_smp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
__jump_label_transform(entry, type, text_poke_smp);
mutex_unlock(&text_mutex);
put_online_cpus();
}

void arch_jump_label_transform_static(struct jump_entry *entry,
enum jump_label_type type)
{
__jump_label_transform(entry, type, text_poke_early);
}

#endif

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