From 2f5f6ad9390c1ebbf738d130dbfe80b60eaa167e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 8 Aug 2011 16:57:47 -0400 Subject: ftrace: Pass ftrace_ops as third parameter to function trace callback Currently the function trace callback receives only the ip and parent_ip of the function that it traced. It would be more powerful to also return the ops that registered the function as well. This allows the same function to act differently depending on what ftrace_ops registered it. Link: http://lkml.kernel.org/r/20120612225424.267254552@goodmis.org Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 55e6d63d46d0..2d5964119885 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -18,6 +18,15 @@ #include +/* + * If the arch supports passing the variable contents of + * function_trace_op as the third parameter back from the + * mcount call, then the arch should define this as 1. + */ +#ifndef ARCH_SUPPORTS_FTRACE_OPS +#define ARCH_SUPPORTS_FTRACE_OPS 0 +#endif + struct module; struct ftrace_hash; @@ -29,7 +38,10 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); -typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip); +struct ftrace_ops; + +typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op); /* * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are @@ -163,7 +175,7 @@ static inline int ftrace_function_local_disabled(struct ftrace_ops *ops) return *this_cpu_ptr(ops->disabled); } -extern void ftrace_stub(unsigned long a0, unsigned long a1); +extern void ftrace_stub(unsigned long a0, unsigned long a1, struct ftrace_ops *op); #else /* !CONFIG_FUNCTION_TRACER */ /* -- cgit v1.2.3 From ccf3672d530170c98c734dfc5db07d64bcbad2ad Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 5 Jun 2012 09:44:25 -0400 Subject: ftrace: Consolidate arch dependent functions with 'list' function As the function tracer starts to get more features, the support for theses features will spread out throughout the different architectures over time. These features boil down to what each arch does in the mcount trampoline (the ftrace_caller). Currently there's two features that are not the same throughout the archs. 1) Support to stop function tracing before the callback 2) passing of the ftrace ops Both of these require placing an indirect function to support the features if the mcount trampoline does not. On a side note, for all architectures, when more than one callback is registered to the function tracer, an intermediate 'list' function is called by the mcount trampoline to iterate through the callbacks that are registered. Instead of making a separate function for each of these features, and requiring several indirect calls, just use the single 'list' function as the intermediate, to handle all cases. If an arch does not support the 'stop function tracing' or the passing of ftrace ops, just force it to use the list function that will handle the features required. This makes the code cleaner and simpler and removes a lot of #ifdefs in the code. Link: http://lkml.kernel.org/r/20120612225424.495625483@goodmis.org Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 2d5964119885..3651fdc3bec9 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -27,6 +27,19 @@ #define ARCH_SUPPORTS_FTRACE_OPS 0 #endif +/* + * If the arch's mcount caller does not support all of ftrace's + * features, then it must call an indirect function that + * does. Or at least does enough to prevent any unwelcomed side effects. + */ +#if !defined(CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST) || \ + !ARCH_SUPPORTS_FTRACE_OPS +# define FTRACE_FORCE_LIST_FUNC 1 +#else +# define FTRACE_FORCE_LIST_FUNC 0 +#endif + + struct module; struct ftrace_hash; -- cgit v1.2.3 From a1e2e31d175a1349274eba3465d17616c6725f8c Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 9 Aug 2011 12:50:46 -0400 Subject: ftrace: Return pt_regs to function trace callback Return as the 4th paramater to the function tracer callback the pt_regs. Later patches that implement regs passing for the architectures will require having the ftrace_ops set the SAVE_REGS flag, which will tell the arch to take the time to pass a full set of pt_regs to the ftrace_ops callback function. If the arch does not support it then it should pass NULL. If an arch can pass full regs, then it should define: ARCH_SUPPORTS_FTRACE_SAVE_REGS to 1 Link: http://lkml.kernel.org/r/20120702201821.019966811@goodmis.org Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 3651fdc3bec9..e4202881fb00 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -54,7 +55,7 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, struct ftrace_ops; typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op); + struct ftrace_ops *op, struct pt_regs *regs); /* * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are @@ -188,7 +189,8 @@ static inline int ftrace_function_local_disabled(struct ftrace_ops *ops) return *this_cpu_ptr(ops->disabled); } -extern void ftrace_stub(unsigned long a0, unsigned long a1, struct ftrace_ops *op); +extern void ftrace_stub(unsigned long a0, unsigned long a1, + struct ftrace_ops *op, struct pt_regs *regs); #else /* !CONFIG_FUNCTION_TRACER */ /* -- cgit v1.2.3 From 08f6fba503111e0336f2b4d6915a4a18f9b60e51 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 30 Apr 2012 16:20:23 -0400 Subject: ftrace/x86: Add separate function to save regs Add a way to have different functions calling different trampolines. If a ftrace_ops wants regs saved on the return, then have only the functions with ops registered to save regs. Functions registered by other ops would not be affected, unless the functions overlap. If one ftrace_ops registered functions A, B and C and another ops registered fucntions to save regs on A, and D, then only functions A and D would be saving regs. Function B and C would work as normal. Although A is registered by both ops: normal and saves regs; this is fine as saving the regs is needed to satisfy one of the ops that calls it but the regs are ignored by the other ops function. x86_64 implements the full regs saving, and i386 just passes a NULL for regs to satisfy the ftrace_ops passing. Where an arch must supply both regs and ftrace_ops parameters, even if regs is just NULL. It is OK for an arch to pass NULL regs. All function trace users that require regs passing must add the flag FTRACE_OPS_FL_SAVE_REGS when registering the ftrace_ops. If the arch does not support saving regs then the ftrace_ops will fail to register. The flag FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED may be set that will prevent the ftrace_ops from failing to register. In this case, the handler may either check if regs is not NULL or check if ARCH_SUPPORTS_FTRACE_SAVE_REGS. If the arch supports passing regs it will set this macro and pass regs for ops that request them. All other archs will just pass NULL. Link: Link: http://lkml.kernel.org/r/20120711195745.107705970@goodmis.org Cc: Alexander van Heukelum Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 107 +++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 100 insertions(+), 7 deletions(-) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index e4202881fb00..ab39990cc43f 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -71,12 +71,28 @@ typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, * could be controled by following calls: * ftrace_function_local_enable * ftrace_function_local_disable + * SAVE_REGS - The ftrace_ops wants regs saved at each function called + * and passed to the callback. If this flag is set, but the + * architecture does not support passing regs + * (ARCH_SUPPORTS_FTRACE_SAVE_REGS is not defined), then the + * ftrace_ops will fail to register, unless the next flag + * is set. + * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the + * handler can handle an arch that does not save regs + * (the handler tests if regs == NULL), then it can set + * this flag instead. It will not fail registering the ftrace_ops + * but, the regs field will be NULL if the arch does not support + * passing regs to the handler. + * Note, if this flag is set, the SAVE_REGS flag will automatically + * get set upon registering the ftrace_ops, if the arch supports it. */ enum { - FTRACE_OPS_FL_ENABLED = 1 << 0, - FTRACE_OPS_FL_GLOBAL = 1 << 1, - FTRACE_OPS_FL_DYNAMIC = 1 << 2, - FTRACE_OPS_FL_CONTROL = 1 << 3, + FTRACE_OPS_FL_ENABLED = 1 << 0, + FTRACE_OPS_FL_GLOBAL = 1 << 1, + FTRACE_OPS_FL_DYNAMIC = 1 << 2, + FTRACE_OPS_FL_CONTROL = 1 << 3, + FTRACE_OPS_FL_SAVE_REGS = 1 << 4, + FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = 1 << 5, }; struct ftrace_ops { @@ -254,12 +270,31 @@ extern void unregister_ftrace_function_probe_all(char *glob); extern int ftrace_text_reserved(void *start, void *end); +/* + * The dyn_ftrace record's flags field is split into two parts. + * the first part which is '0-FTRACE_REF_MAX' is a counter of + * the number of callbacks that have registered the function that + * the dyn_ftrace descriptor represents. + * + * The second part is a mask: + * ENABLED - the function is being traced + * REGS - the record wants the function to save regs + * REGS_EN - the function is set up to save regs. + * + * When a new ftrace_ops is registered and wants a function to save + * pt_regs, the rec->flag REGS is set. When the function has been + * set up to save regs, the REG_EN flag is set. Once a function + * starts saving regs it will do so until all ftrace_ops are removed + * from tracing that function. + */ enum { - FTRACE_FL_ENABLED = (1 << 30), + FTRACE_FL_ENABLED = (1UL << 29), + FTRACE_FL_REGS = (1UL << 30), + FTRACE_FL_REGS_EN = (1UL << 31) }; -#define FTRACE_FL_MASK (0x3UL << 30) -#define FTRACE_REF_MAX ((1 << 30) - 1) +#define FTRACE_FL_MASK (0x7UL << 29) +#define FTRACE_REF_MAX ((1UL << 29) - 1) struct dyn_ftrace { union { @@ -290,9 +325,23 @@ enum { FTRACE_STOP_FUNC_RET = (1 << 4), }; +/* + * The FTRACE_UPDATE_* enum is used to pass information back + * from the ftrace_update_record() and ftrace_test_record() + * functions. These are called by the code update routines + * to find out what is to be done for a given function. + * + * IGNORE - The function is already what we want it to be + * MAKE_CALL - Start tracing the function + * MODIFY_CALL - Stop saving regs for the function + * MODIFY_CALL_REGS - Start saving regs for the function + * MAKE_NOP - Stop tracing the function + */ enum { FTRACE_UPDATE_IGNORE, FTRACE_UPDATE_MAKE_CALL, + FTRACE_UPDATE_MODIFY_CALL, + FTRACE_UPDATE_MODIFY_CALL_REGS, FTRACE_UPDATE_MAKE_NOP, }; @@ -344,7 +393,9 @@ extern int ftrace_dyn_arch_init(void *data); extern void ftrace_replace_code(int enable); extern int ftrace_update_ftrace_func(ftrace_func_t func); extern void ftrace_caller(void); +extern void ftrace_regs_caller(void); extern void ftrace_call(void); +extern void ftrace_regs_call(void); extern void mcount_call(void); void ftrace_modify_all_code(int command); @@ -352,6 +403,15 @@ void ftrace_modify_all_code(int command); #ifndef FTRACE_ADDR #define FTRACE_ADDR ((unsigned long)ftrace_caller) #endif + +#ifndef FTRACE_REGS_ADDR +#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS +# define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) +#else +# define FTRACE_REGS_ADDR FTRACE_ADDR +#endif +#endif + #ifdef CONFIG_FUNCTION_GRAPH_TRACER extern void ftrace_graph_caller(void); extern int ftrace_enable_ftrace_graph_caller(void); @@ -407,6 +467,39 @@ extern int ftrace_make_nop(struct module *mod, */ extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); +#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS +/** + * ftrace_modify_call - convert from one addr to another (no nop) + * @rec: the mcount call site record + * @old_addr: the address expected to be currently called to + * @addr: the address to change to + * + * This is a very sensitive operation and great care needs + * to be taken by the arch. The operation should carefully + * read the location, check to see if what is read is indeed + * what we expect it to be, and then on success of the compare, + * it should write to the location. + * + * The code segment at @rec->ip should be a caller to @old_addr + * + * Return must be: + * 0 on success + * -EFAULT on error reading the location + * -EINVAL on a failed compare of the contents + * -EPERM on error writing to the location + * Any other value will be considered a failure. + */ +extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr); +#else +/* Should never be called */ +static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr) +{ + return -EINVAL; +} +#endif + /* May be defined in arch */ extern int ftrace_arch_read_dyn_info(char *buf, int size); -- cgit v1.2.3 From 4740974a6844156c14d741b0080b59d275679a23 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 20 Jul 2012 11:04:44 -0400 Subject: ftrace: Add default recursion protection for function tracing As more users of the function tracer utility are being added, they do not always add the necessary recursion protection. To protect from function recursion due to tracing, if the callback ftrace_ops does not specifically specify that it protects against recursion (by setting the FTRACE_OPS_FL_RECURSION_SAFE flag), the list operation will be called by the mcount trampoline which adds recursion protection. If the flag is set, then the function will be called directly with no extra protection. Note, the list operation is called if more than one function callback is registered, or if the arch does not support all of the function tracer features. Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index ab39990cc43f..65a14e47a0db 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -85,6 +85,10 @@ typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, * passing regs to the handler. * Note, if this flag is set, the SAVE_REGS flag will automatically * get set upon registering the ftrace_ops, if the arch supports it. + * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure + * that the call back has its own recursion protection. If it does + * not set this, then the ftrace infrastructure will add recursion + * protection for the caller. */ enum { FTRACE_OPS_FL_ENABLED = 1 << 0, @@ -93,6 +97,7 @@ enum { FTRACE_OPS_FL_CONTROL = 1 << 3, FTRACE_OPS_FL_SAVE_REGS = 1 << 4, FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = 1 << 5, + FTRACE_OPS_FL_RECURSION_SAFE = 1 << 6, }; struct ftrace_ops { -- cgit v1.2.3 From ea701f11da44b44907af226fe5a5f57d2f26eeb2 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 20 Jul 2012 13:08:05 -0400 Subject: ftrace: Add selftest to test function trace recursion protection Add selftests to test the function tracing recursion protection actually does work. It also tests if a ftrace_ops states it will perform its own protection. Although, even if the ftrace_ops states it will protect itself, the ftrace infrastructure may still provide protection if the arch does not support all features or another ftrace_ops is registered. Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 65a14e47a0db..9962e954a633 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -220,6 +220,10 @@ extern void ftrace_stub(unsigned long a0, unsigned long a1, */ #define register_ftrace_function(ops) ({ 0; }) #define unregister_ftrace_function(ops) ({ 0; }) +static inline int ftrace_nr_registered_ops(void) +{ + return 0; +} static inline void clear_ftrace_function(void) { } static inline void ftrace_kill(void) { } static inline void ftrace_stop(void) { } @@ -275,6 +279,8 @@ extern void unregister_ftrace_function_probe_all(char *glob); extern int ftrace_text_reserved(void *start, void *end); +extern int ftrace_nr_registered_ops(void); + /* * The dyn_ftrace record's flags field is split into two parts. * the first part which is '0-FTRACE_REF_MAX' is a counter of -- cgit v1.2.3 From 647664eaf4033501739ac1f42dd52ce8c9266ccc Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 5 Jun 2012 19:28:08 +0900 Subject: ftrace: add ftrace_set_filter_ip() for address based filter Add a new filter update interface ftrace_set_filter_ip() to set ftrace filter by ip address, not only glob pattern. Link: http://lkml.kernel.org/r/20120605102808.27845.67952.stgit@localhost.localdomain Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Ananth N Mavinakayanahalli Cc: "Frank Ch. Eigler" Cc: Andrew Morton Cc: Frederic Weisbecker Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 9962e954a633..3e711122f66c 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -317,6 +317,8 @@ struct dyn_ftrace { }; int ftrace_force_update(void); +int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, + int remove, int reset); int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, int len, int reset); int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, @@ -544,6 +546,7 @@ static inline int ftrace_text_reserved(void *start, void *end) */ #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; }) #define ftrace_set_early_filter(ops, buf, enable) do { } while (0) +#define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; }) #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; }) #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; }) #define ftrace_free_filter(ops) do { } while (0) -- cgit v1.2.3 From 4dc936769e8a6382a4cc12375e8a4daa2b829fda Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 6 Jun 2012 13:45:31 -0400 Subject: ftrace: Make ftrace_location() a nop on !DYNAMIC_FTRACE When CONFIG_DYNAMIC_FTRACE is not set, ftrace_location() is not defined. If a user (like kprobes) references this function, it will break the compile when CONFIG_DYNAMIC_FTRACE is not set. Add ftrace_location() as a nop (return 0) when DYNAMIC_FTRACE is not defined. Link: http://lkml.kernel.org/r/20120612225426.961092717@goodmis.org Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 3e711122f66c..a52f2f4fe030 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -520,7 +520,7 @@ extern int skip_trace(unsigned long ip); extern void ftrace_disable_daemon(void); extern void ftrace_enable_daemon(void); -#else +#else /* CONFIG_DYNAMIC_FTRACE */ static inline int skip_trace(unsigned long ip) { return 0; } static inline int ftrace_force_update(void) { return 0; } static inline void ftrace_disable_daemon(void) { } @@ -538,6 +538,10 @@ static inline int ftrace_text_reserved(void *start, void *end) { return 0; } +static inline unsigned long ftrace_location(unsigned long ip) +{ + return 0; +} /* * Again users of functions that have ftrace_ops may not -- cgit v1.2.3