fed1939c64
When a mcount pointer is recorded into a table, it is used to add or remove calls to mcount (replacing them with nops). If the code is removed via removing a module, the pointers still exist. At modifying the code a check is always made to make sure the code being replaced is the code expected. In-other-words, the code being replaced is compared to what it is expected to be before being replaced. There is a very small chance that the code being replaced just happens to look like code that calls mcount (very small since the call to mcount is relative). To remove this chance, this patch adds ftrace_release to allow module unloading to remove the pointers to mcount within the module. Another change for init calls is made to not trace calls marked with __init. The tracing can not be started until after init is done anyway. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
177 lines
5.2 KiB
C
177 lines
5.2 KiB
C
#ifndef _LINUX_FTRACE_H
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#define _LINUX_FTRACE_H
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#ifdef CONFIG_FTRACE
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#include <linux/linkage.h>
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#include <linux/fs.h>
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extern int ftrace_enabled;
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extern int
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ftrace_enable_sysctl(struct ctl_table *table, int write,
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struct file *filp, void __user *buffer, size_t *lenp,
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loff_t *ppos);
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typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
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struct ftrace_ops {
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ftrace_func_t func;
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struct ftrace_ops *next;
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};
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/*
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* The ftrace_ops must be a static and should also
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* be read_mostly. These functions do modify read_mostly variables
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* so use them sparely. Never free an ftrace_op or modify the
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* next pointer after it has been registered. Even after unregistering
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* it, the next pointer may still be used internally.
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*/
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int register_ftrace_function(struct ftrace_ops *ops);
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int unregister_ftrace_function(struct ftrace_ops *ops);
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void clear_ftrace_function(void);
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extern void ftrace_stub(unsigned long a0, unsigned long a1);
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#else /* !CONFIG_FTRACE */
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# define register_ftrace_function(ops) do { } while (0)
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# define unregister_ftrace_function(ops) do { } while (0)
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# define clear_ftrace_function(ops) do { } while (0)
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#endif /* CONFIG_FTRACE */
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#ifdef CONFIG_DYNAMIC_FTRACE
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# define FTRACE_HASHBITS 10
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# define FTRACE_HASHSIZE (1<<FTRACE_HASHBITS)
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enum {
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FTRACE_FL_FREE = (1 << 0),
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FTRACE_FL_FAILED = (1 << 1),
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FTRACE_FL_FILTER = (1 << 2),
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FTRACE_FL_ENABLED = (1 << 3),
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FTRACE_FL_NOTRACE = (1 << 4),
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FTRACE_FL_CONVERTED = (1 << 5),
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FTRACE_FL_FROZEN = (1 << 6),
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};
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struct dyn_ftrace {
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struct hlist_node node;
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unsigned long ip; /* address of mcount call-site */
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unsigned long flags;
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};
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int ftrace_force_update(void);
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void ftrace_set_filter(unsigned char *buf, int len, int reset);
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/* defined in arch */
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extern int ftrace_ip_converted(unsigned long ip);
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extern unsigned char *ftrace_nop_replace(void);
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extern unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr);
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extern int ftrace_dyn_arch_init(void *data);
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extern int ftrace_mcount_set(unsigned long *data);
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extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
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unsigned char *new_code);
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extern int ftrace_update_ftrace_func(ftrace_func_t func);
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extern void ftrace_caller(void);
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extern void ftrace_call(void);
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extern void mcount_call(void);
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extern int skip_trace(unsigned long ip);
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void ftrace_disable_daemon(void);
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void ftrace_enable_daemon(void);
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#else
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# define skip_trace(ip) ({ 0; })
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# define ftrace_force_update() ({ 0; })
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# define ftrace_set_filter(buf, len, reset) do { } while (0)
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# define ftrace_disable_daemon() do { } while (0)
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# define ftrace_enable_daemon() do { } while (0)
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#endif /* CONFIG_DYNAMIC_FTRACE */
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/* totally disable ftrace - can not re-enable after this */
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void ftrace_kill(void);
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void ftrace_kill_atomic(void);
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static inline void tracer_disable(void)
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{
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#ifdef CONFIG_FTRACE
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ftrace_enabled = 0;
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#endif
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}
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/* Ftrace disable/restore without lock. Some synchronization mechanism
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* must be used to prevent ftrace_enabled to be changed between
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* disable/restore. */
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static inline int __ftrace_enabled_save(void)
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{
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#ifdef CONFIG_FTRACE
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int saved_ftrace_enabled = ftrace_enabled;
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ftrace_enabled = 0;
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return saved_ftrace_enabled;
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#else
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return 0;
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#endif
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}
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static inline void __ftrace_enabled_restore(int enabled)
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{
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#ifdef CONFIG_FTRACE
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ftrace_enabled = enabled;
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#endif
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}
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#ifdef CONFIG_FRAME_POINTER
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/* TODO: need to fix this for ARM */
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# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
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# define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
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# define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
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# define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
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# define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
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# define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
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# define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
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#else
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# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
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# define CALLER_ADDR1 0UL
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# define CALLER_ADDR2 0UL
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# define CALLER_ADDR3 0UL
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# define CALLER_ADDR4 0UL
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# define CALLER_ADDR5 0UL
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# define CALLER_ADDR6 0UL
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#endif
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#ifdef CONFIG_IRQSOFF_TRACER
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extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
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extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
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#else
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# define time_hardirqs_on(a0, a1) do { } while (0)
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# define time_hardirqs_off(a0, a1) do { } while (0)
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#endif
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#ifdef CONFIG_PREEMPT_TRACER
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extern void trace_preempt_on(unsigned long a0, unsigned long a1);
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extern void trace_preempt_off(unsigned long a0, unsigned long a1);
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#else
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# define trace_preempt_on(a0, a1) do { } while (0)
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# define trace_preempt_off(a0, a1) do { } while (0)
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#endif
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#ifdef CONFIG_TRACING
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extern void
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ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
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#else
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static inline void
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ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
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#endif
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#ifdef CONFIG_FTRACE_MCOUNT_RECORD
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extern void ftrace_init(void);
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extern void ftrace_init_module(unsigned long *start, unsigned long *end);
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extern void ftrace_release(void *start, unsigned long size);
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#else
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static inline void ftrace_init(void) { }
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static inline void
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ftrace_init_module(unsigned long *start, unsigned long *end) { }
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static inline void ftrace_release(void *start, unsigned long size) { }
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#endif
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#endif /* _LINUX_FTRACE_H */
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