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https://github.com/fail0verflow/switch-linux.git
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20284aa77c
When updating a newly loaded module, the code is definitely not yet executing on any processor, so it can be updated with no need for any heavyweight synchronization. This patch adds arch_jump_label_static() which is implemented as arch_jump_label_transform() by default, but architectures can override it if it avoids, say, a call to stop_machine(). 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>
103 lines
2.2 KiB
C
103 lines
2.2 KiB
C
#ifndef _LINUX_JUMP_LABEL_H
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#define _LINUX_JUMP_LABEL_H
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#include <linux/types.h>
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#include <linux/compiler.h>
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#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
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struct jump_label_key {
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atomic_t enabled;
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struct jump_entry *entries;
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#ifdef CONFIG_MODULES
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struct jump_label_mod *next;
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#endif
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};
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# include <asm/jump_label.h>
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# define HAVE_JUMP_LABEL
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#endif
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enum jump_label_type {
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JUMP_LABEL_DISABLE = 0,
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JUMP_LABEL_ENABLE,
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};
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struct module;
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#ifdef HAVE_JUMP_LABEL
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#ifdef CONFIG_MODULES
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#define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL, NULL}
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#else
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#define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL}
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#endif
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static __always_inline bool static_branch(struct jump_label_key *key)
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{
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return arch_static_branch(key);
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}
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extern struct jump_entry __start___jump_table[];
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extern struct jump_entry __stop___jump_table[];
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extern void jump_label_lock(void);
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extern void jump_label_unlock(void);
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extern void arch_jump_label_transform(struct jump_entry *entry,
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enum jump_label_type type);
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extern void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type);
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extern int jump_label_text_reserved(void *start, void *end);
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extern void jump_label_inc(struct jump_label_key *key);
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extern void jump_label_dec(struct jump_label_key *key);
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extern bool jump_label_enabled(struct jump_label_key *key);
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extern void jump_label_apply_nops(struct module *mod);
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#else
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#include <linux/atomic.h>
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#define JUMP_LABEL_INIT {ATOMIC_INIT(0)}
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struct jump_label_key {
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atomic_t enabled;
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};
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static __always_inline bool static_branch(struct jump_label_key *key)
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{
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if (unlikely(atomic_read(&key->enabled)))
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return true;
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return false;
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}
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static inline void jump_label_inc(struct jump_label_key *key)
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{
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atomic_inc(&key->enabled);
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}
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static inline void jump_label_dec(struct jump_label_key *key)
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{
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atomic_dec(&key->enabled);
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}
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static inline int jump_label_text_reserved(void *start, void *end)
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{
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return 0;
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}
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static inline void jump_label_lock(void) {}
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static inline void jump_label_unlock(void) {}
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static inline bool jump_label_enabled(struct jump_label_key *key)
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{
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return !!atomic_read(&key->enabled);
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}
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static inline int jump_label_apply_nops(struct module *mod)
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{
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return 0;
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}
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#endif
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#endif
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