From cf2cb0b27116883c23761e974acba5f3bd719d21 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 7 May 2014 12:42:28 -0400 Subject: ftrace: Use macros for numbers in ftrace rec shift bits As new flags will be added to the ftrace dynamic record, and since the flags field is also a counter, converting the numbers used to do the shifting and masking into a set of macros where we only need to deal with the max bit count of the counter and the number of bits for the flags will prevent mistakes in the future. Dealing with only two numbers is much easier than updating all the macros that deal with shifting and masking. Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 404a686a3644..e4e7df422021 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -322,8 +322,11 @@ enum { FTRACE_FL_REGS_EN = (1UL << 31) }; -#define FTRACE_FL_MASK (0x7UL << 29) -#define FTRACE_REF_MAX ((1UL << 29) - 1) +#define FTRACE_REF_MAX_SHIFT 29 +#define FTRACE_FL_BITS 3 +#define FTRACE_FL_MASKED_BITS ((1UL << FTRACE_FL_BITS) - 1) +#define FTRACE_FL_MASK (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT) +#define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) struct dyn_ftrace { unsigned long ip; /* address of mcount call-site */ -- cgit v1.2.3 From 0376bde11be5b87c9fd7d6813ac5fd7e1798b1bf Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 7 May 2014 13:46:45 -0400 Subject: ftrace: Add ftrace_rec_counter() macro to simplify the code The ftrace dynamic record has a flags element that also has a counter. Instead of hard coding "rec->flags & ~FTRACE_FL_MASK" all over the place. Use a macro instead. Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 2 ++ kernel/trace/ftrace.c | 12 ++++++------ 2 files changed, 8 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index e4e7df422021..e5baa6b2c93f 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -328,6 +328,8 @@ enum { #define FTRACE_FL_MASK (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT) #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) +#define ftrace_rec_count(rec) ((rec)->flags & ~FTRACE_FL_MASK) + struct dyn_ftrace { unsigned long ip; /* address of mcount call-site */ unsigned long flags; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index b867c647e5bc..a58d840305c3 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1592,7 +1592,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (inc) { rec->flags++; - if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX)) + if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) return; /* * If any ops wants regs saved for this function @@ -1601,7 +1601,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) rec->flags |= FTRACE_FL_REGS; } else { - if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0)) + if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0)) return; rec->flags--; /* @@ -1610,7 +1610,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, * still any ops for this record that wants regs. * If not, we can stop recording them. */ - if ((rec->flags & ~FTRACE_FL_MASK) > 0 && + if (ftrace_rec_count(rec) > 0 && rec->flags & FTRACE_FL_REGS && ops->flags & FTRACE_OPS_FL_SAVE_REGS) { if (!test_rec_ops_needs_regs(rec)) @@ -1700,7 +1700,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) * If we are disabling calls, then disable all records that * are enabled. */ - if (enable && (rec->flags & ~FTRACE_FL_MASK)) + if (enable && ftrace_rec_count(rec)) flag = FTRACE_FL_ENABLED; /* @@ -1746,7 +1746,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) if (update) { /* If there's no more users, clear all flags */ - if (!(rec->flags & ~FTRACE_FL_MASK)) + if (!ftrace_rec_count(rec)) rec->flags = 0; else /* Just disable the record (keep REGS state) */ @@ -2685,7 +2685,7 @@ static int t_show(struct seq_file *m, void *v) seq_printf(m, "%ps", (void *)rec->ip); if (iter->flags & FTRACE_ITER_ENABLED) seq_printf(m, " (%ld)%s", - rec->flags & ~FTRACE_FL_MASK, + ftrace_rec_count(rec), rec->flags & FTRACE_FL_REGS ? " R" : ""); seq_printf(m, "\n"); -- cgit v1.2.3 From 79922b8009c074e30d3a97f5a24519f11814ad03 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 6 May 2014 21:56:17 -0400 Subject: ftrace: Optimize function graph to be called directly Function graph tracing is a bit different than the function tracers, as it is processed after either the ftrace_caller or ftrace_regs_caller and we only have one place to modify the jump to ftrace_graph_caller, the jump needs to happen after the restore of registeres. The function graph tracer is dependent on the function tracer, where even if the function graph tracing is going on by itself, the save and restore of registers is still done for function tracing regardless of if function tracing is happening, before it calls the function graph code. If there's no function tracing happening, it is possible to just call the function graph tracer directly, and avoid the wasted effort to save and restore regs for function tracing. This requires adding new flags to the dyn_ftrace records: FTRACE_FL_TRAMP FTRACE_FL_TRAMP_EN The first is set if the count for the record is one, and the ftrace_ops associated to that record has its own trampoline. That way the mcount code can call that trampoline directly. In the future, trampolines can be added to arbitrary ftrace_ops, where you can have two or more ftrace_ops registered to ftrace (like kprobes and perf) and if they are not tracing the same functions, then instead of doing a loop to check all registered ftrace_ops against their hashes, just call the ftrace_ops trampoline directly, which would call the registered ftrace_ops function directly. Without this patch perf showed: 0.05% hackbench [kernel.kallsyms] [k] ftrace_caller 0.05% hackbench [kernel.kallsyms] [k] arch_local_irq_save 0.05% hackbench [kernel.kallsyms] [k] native_sched_clock 0.04% hackbench [kernel.kallsyms] [k] __buffer_unlock_commit 0.04% hackbench [kernel.kallsyms] [k] preempt_trace 0.04% hackbench [kernel.kallsyms] [k] prepare_ftrace_return 0.04% hackbench [kernel.kallsyms] [k] __this_cpu_preempt_check 0.04% hackbench [kernel.kallsyms] [k] ftrace_graph_caller See that the ftrace_caller took up more time than the ftrace_graph_caller did. With this patch: 0.05% hackbench [kernel.kallsyms] [k] __buffer_unlock_commit 0.04% hackbench [kernel.kallsyms] [k] call_filter_check_discard 0.04% hackbench [kernel.kallsyms] [k] ftrace_graph_caller 0.04% hackbench [kernel.kallsyms] [k] sched_clock The ftrace_caller is no where to be found and ftrace_graph_caller still takes up the same percentage. Signed-off-by: Steven Rostedt --- arch/x86/kernel/mcount_64.S | 5 + include/linux/ftrace.h | 19 +++- kernel/trace/ftrace.c | 242 ++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 254 insertions(+), 12 deletions(-) (limited to 'include') diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S index c050a0153168..6b4e3c3b3d74 100644 --- a/arch/x86/kernel/mcount_64.S +++ b/arch/x86/kernel/mcount_64.S @@ -182,6 +182,10 @@ END(function_hook) ENTRY(ftrace_graph_caller) MCOUNT_SAVE_FRAME + /* Check if tracing was disabled (quick check) */ + cmpl $0, function_trace_stop + jne fgraph_skip + #ifdef CC_USING_FENTRY leaq SS+16(%rsp), %rdi movq $0, %rdx /* No framepointers needed */ @@ -194,6 +198,7 @@ ENTRY(ftrace_graph_caller) call prepare_ftrace_return +fgraph_skip: MCOUNT_RESTORE_FRAME retq diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index e5baa6b2c93f..11e18fd58b1a 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -118,12 +118,15 @@ struct ftrace_ops { ftrace_func_t func; struct ftrace_ops *next; unsigned long flags; - int __percpu *disabled; void *private; + int __percpu *disabled; #ifdef CONFIG_DYNAMIC_FTRACE + int trampolines; struct ftrace_hash *notrace_hash; struct ftrace_hash *filter_hash; + struct ftrace_hash *tramp_hash; struct mutex regex_lock; + unsigned long trampoline; #endif }; @@ -317,13 +320,15 @@ extern int ftrace_nr_registered_ops(void); * from tracing that function. */ enum { - FTRACE_FL_ENABLED = (1UL << 29), + FTRACE_FL_ENABLED = (1UL << 31), FTRACE_FL_REGS = (1UL << 30), - FTRACE_FL_REGS_EN = (1UL << 31) + FTRACE_FL_REGS_EN = (1UL << 29), + FTRACE_FL_TRAMP = (1UL << 28), + FTRACE_FL_TRAMP_EN = (1UL << 27), }; -#define FTRACE_REF_MAX_SHIFT 29 -#define FTRACE_FL_BITS 3 +#define FTRACE_REF_MAX_SHIFT 27 +#define FTRACE_FL_BITS 5 #define FTRACE_FL_MASKED_BITS ((1UL << FTRACE_FL_BITS) - 1) #define FTRACE_FL_MASK (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT) #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) @@ -436,6 +441,10 @@ void ftrace_modify_all_code(int command); #define FTRACE_ADDR ((unsigned long)ftrace_caller) #endif +#ifndef FTRACE_GRAPH_ADDR +#define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller) +#endif + #ifndef FTRACE_REGS_ADDR #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a58d840305c3..5d15eb8146a7 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1042,6 +1042,8 @@ static struct pid * const ftrace_swapper_pid = &init_struct_pid; #ifdef CONFIG_DYNAMIC_FTRACE +static struct ftrace_ops *removed_ops; + #ifndef CONFIG_FTRACE_MCOUNT_RECORD # error Dynamic ftrace depends on MCOUNT_RECORD #endif @@ -1512,6 +1514,33 @@ static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec) return keep_regs; } +static void ftrace_remove_tramp(struct ftrace_ops *ops, + struct dyn_ftrace *rec) +{ + struct ftrace_func_entry *entry; + + entry = ftrace_lookup_ip(ops->tramp_hash, rec->ip); + if (!entry) + return; + + /* + * The tramp_hash entry will be removed at time + * of update. + */ + ops->trampolines--; + rec->flags &= ~FTRACE_FL_TRAMP; +} + +static void ftrace_clear_tramps(struct dyn_ftrace *rec) +{ + struct ftrace_ops *op; + + do_for_each_ftrace_op(op, ftrace_ops_list) { + if (op->trampolines) + ftrace_remove_tramp(op, rec); + } while_for_each_ftrace_op(op); +} + static void __ftrace_hash_rec_update(struct ftrace_ops *ops, int filter_hash, bool inc) @@ -1594,6 +1623,28 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, rec->flags++; if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) return; + + /* + * If there's only a single callback registered to a + * function, and the ops has a trampoline registered + * for it, then we can call it directly. + */ + if (ftrace_rec_count(rec) == 1 && ops->trampoline) { + rec->flags |= FTRACE_FL_TRAMP; + ops->trampolines++; + } else { + /* + * If we are adding another function callback + * to this function, and the previous had a + * trampoline used, then we need to go back to + * the default trampoline. + */ + rec->flags &= ~FTRACE_FL_TRAMP; + + /* remove trampolines from any ops for this rec */ + ftrace_clear_tramps(rec); + } + /* * If any ops wants regs saved for this function * then all ops will get saved regs. @@ -1604,6 +1655,10 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0)) return; rec->flags--; + + if (ops->trampoline && !ftrace_rec_count(rec)) + ftrace_remove_tramp(ops, rec); + /* * If the rec had REGS enabled and the ops that is * being removed had REGS set, then see if there is @@ -1616,6 +1671,11 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (!test_rec_ops_needs_regs(rec)) rec->flags &= ~FTRACE_FL_REGS; } + + /* + * flags will be cleared in ftrace_check_record() + * if rec count is zero. + */ } count++; /* Shortcut, if we handled all records, we are done. */ @@ -1704,13 +1764,19 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) flag = FTRACE_FL_ENABLED; /* - * If enabling and the REGS flag does not match the REGS_EN, then - * do not ignore this record. Set flags to fail the compare against - * ENABLED. + * If enabling and the REGS flag does not match the REGS_EN, or + * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore + * this record. Set flags to fail the compare against ENABLED. */ - if (flag && - (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN))) - flag |= FTRACE_FL_REGS; + if (flag) { + if (!(rec->flags & FTRACE_FL_REGS) != + !(rec->flags & FTRACE_FL_REGS_EN)) + flag |= FTRACE_FL_REGS; + + if (!(rec->flags & FTRACE_FL_TRAMP) != + !(rec->flags & FTRACE_FL_TRAMP_EN)) + flag |= FTRACE_FL_TRAMP; + } /* If the state of this record hasn't changed, then do nothing */ if ((rec->flags & FTRACE_FL_ENABLED) == flag) @@ -1728,6 +1794,12 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) else rec->flags &= ~FTRACE_FL_REGS_EN; } + if (flag & FTRACE_FL_TRAMP) { + if (rec->flags & FTRACE_FL_TRAMP) + rec->flags |= FTRACE_FL_TRAMP_EN; + else + rec->flags &= ~FTRACE_FL_TRAMP_EN; + } } /* @@ -1736,7 +1808,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) * Otherwise, * return UPDATE_MODIFY_CALL to tell the caller to convert * from the save regs, to a non-save regs function or - * vice versa. + * vice versa, or from a trampoline call. */ if (flag & FTRACE_FL_ENABLED) return FTRACE_UPDATE_MAKE_CALL; @@ -1783,6 +1855,43 @@ int ftrace_test_record(struct dyn_ftrace *rec, int enable) return ftrace_check_record(rec, enable, 0); } +static struct ftrace_ops * +ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec) +{ + struct ftrace_ops *op; + + /* Removed ops need to be tested first */ + if (removed_ops && removed_ops->tramp_hash) { + if (ftrace_lookup_ip(removed_ops->tramp_hash, rec->ip)) + return removed_ops; + } + + do_for_each_ftrace_op(op, ftrace_ops_list) { + if (!op->tramp_hash) + continue; + + if (ftrace_lookup_ip(op->tramp_hash, rec->ip)) + return op; + + } while_for_each_ftrace_op(op); + + return NULL; +} + +static struct ftrace_ops * +ftrace_find_tramp_ops_new(struct dyn_ftrace *rec) +{ + struct ftrace_ops *op; + + do_for_each_ftrace_op(op, ftrace_ops_list) { + /* pass rec in as regs to have non-NULL val */ + if (ftrace_ops_test(op, rec->ip, rec)) + return op; + } while_for_each_ftrace_op(op); + + return NULL; +} + /** * ftrace_get_addr_new - Get the call address to set to * @rec: The ftrace record descriptor @@ -1795,6 +1904,20 @@ int ftrace_test_record(struct dyn_ftrace *rec, int enable) */ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) { + struct ftrace_ops *ops; + + /* Trampolines take precedence over regs */ + if (rec->flags & FTRACE_FL_TRAMP) { + ops = ftrace_find_tramp_ops_new(rec); + if (FTRACE_WARN_ON(!ops || !ops->trampoline)) { + pr_warning("Bad trampoline accounting at: %p (%pS)\n", + (void *)rec->ip, (void *)rec->ip); + /* Ftrace is shutting down, return anything */ + return (unsigned long)FTRACE_ADDR; + } + return ops->trampoline; + } + if (rec->flags & FTRACE_FL_REGS) return (unsigned long)FTRACE_REGS_ADDR; else @@ -1813,6 +1936,20 @@ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) */ unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec) { + struct ftrace_ops *ops; + + /* Trampolines take precedence over regs */ + if (rec->flags & FTRACE_FL_TRAMP_EN) { + ops = ftrace_find_tramp_ops_curr(rec); + if (FTRACE_WARN_ON(!ops)) { + pr_warning("Bad trampoline accounting at: %p (%pS)\n", + (void *)rec->ip, (void *)rec->ip); + /* Ftrace is shutting down, return anything */ + return (unsigned long)FTRACE_ADDR; + } + return ops->trampoline; + } + if (rec->flags & FTRACE_FL_REGS_EN) return (unsigned long)FTRACE_REGS_ADDR; else @@ -2055,6 +2192,78 @@ void __weak arch_ftrace_update_code(int command) ftrace_run_stop_machine(command); } +static int ftrace_save_ops_tramp_hash(struct ftrace_ops *ops) +{ + struct ftrace_page *pg; + struct dyn_ftrace *rec; + int size, bits; + int ret; + + size = ops->trampolines; + bits = 0; + /* + * Make the hash size about 1/2 the # found + */ + for (size /= 2; size; size >>= 1) + bits++; + + ops->tramp_hash = alloc_ftrace_hash(bits); + /* + * TODO: a failed allocation is going to screw up + * the accounting of what needs to be modified + * and not. For now, we kill ftrace if we fail + * to allocate here. But there are ways around this, + * but that will take a little more work. + */ + if (!ops->tramp_hash) + return -ENOMEM; + + do_for_each_ftrace_rec(pg, rec) { + if (ftrace_rec_count(rec) == 1 && + ftrace_ops_test(ops, rec->ip, rec)) { + + /* This record had better have a trampoline */ + if (FTRACE_WARN_ON(!(rec->flags & FTRACE_FL_TRAMP_EN))) + return -1; + + ret = add_hash_entry(ops->tramp_hash, rec->ip); + if (ret < 0) + return ret; + } + } while_for_each_ftrace_rec(); + + return 0; +} + +static int ftrace_save_tramp_hashes(void) +{ + struct ftrace_ops *op; + int ret; + + /* + * Now that any trampoline is being used, we need to save the + * hashes for the ops that have them. This allows the mapping + * back from the record to the ops that has the trampoline to + * know what code is being replaced. Modifying code must always + * verify what it is changing. + */ + do_for_each_ftrace_op(op, ftrace_ops_list) { + + /* The tramp_hash is recreated each time. */ + free_ftrace_hash(op->tramp_hash); + op->tramp_hash = NULL; + + if (op->trampolines) { + ret = ftrace_save_ops_tramp_hash(op); + if (ret) + return ret; + } + + } while_for_each_ftrace_op(op); + + return 0; +} + static void ftrace_run_update_code(int command) { int ret; @@ -2081,6 +2290,9 @@ static void ftrace_run_update_code(int command) ret = ftrace_arch_code_modify_post_process(); FTRACE_WARN_ON(ret); + + ret = ftrace_save_tramp_hashes(); + FTRACE_WARN_ON(ret); } static ftrace_func_t saved_ftrace_func; @@ -2171,8 +2383,16 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) return 0; } + /* + * If the ops uses a trampoline, then it needs to be + * tested first on update. + */ + removed_ops = ops; + ftrace_run_update_code(command); + removed_ops = NULL; + /* * Dynamic ops may be freed, we must make sure that all * callers are done before leaving this function. @@ -5116,6 +5336,11 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, /* Function graph doesn't use the .func field of global_ops */ global_ops.flags |= FTRACE_OPS_FL_STUB; +#ifdef CONFIG_DYNAMIC_FTRACE + /* Optimize function graph calling (if implemented by arch) */ + global_ops.trampoline = FTRACE_GRAPH_ADDR; +#endif + ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET); out: @@ -5136,6 +5361,9 @@ void unregister_ftrace_graph(void) __ftrace_graph_entry = ftrace_graph_entry_stub; ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET); global_ops.flags &= ~FTRACE_OPS_FL_STUB; +#ifdef CONFIG_DYNAMIC_FTRACE + global_ops.trampoline = 0; +#endif unregister_pm_notifier(&ftrace_suspend_notifier); unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); -- cgit v1.2.3 From 12306276fabcb746a14979e96f43a13c724dec49 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 20 Jun 2014 13:38:54 -0400 Subject: tracing: Move the trace_seq_* functions into its own trace_seq.c file The trace_seq_*() functions are a nice utility that allows users to manipulate buffers with printf() like formats. It has its own trace_seq.h header in include/linux and should be in its own file. Being tied with trace_output.c is rather awkward. Signed-off-by: Steven Rostedt --- include/linux/trace_seq.h | 2 + kernel/trace/Makefile | 1 + kernel/trace/trace.c | 24 ---- kernel/trace/trace_output.c | 268 --------------------------------------- kernel/trace/trace_output.h | 3 - kernel/trace/trace_seq.c | 303 ++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 306 insertions(+), 295 deletions(-) create mode 100644 kernel/trace/trace_seq.c (limited to 'include') diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 136116924d8d..66ea365acf01 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -25,6 +25,8 @@ trace_seq_init(struct trace_seq *s) s->full = 0; } +#define MAX_MEMHEX_BYTES 8 + /* * Currently only defined when tracing is enabled. */ diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 2611613f14f1..67d6369ddf83 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -28,6 +28,7 @@ obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o obj-$(CONFIG_TRACING) += trace.o obj-$(CONFIG_TRACING) += trace_output.o +obj-$(CONFIG_TRACING) += trace_seq.o obj-$(CONFIG_TRACING) += trace_stat.o obj-$(CONFIG_TRACING) += trace_printk.o obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 384ede311717..eeb233cbac4f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -923,30 +923,6 @@ out: return ret; } -ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) -{ - int len; - int ret; - - if (!cnt) - return 0; - - if (s->len <= s->readpos) - return -EBUSY; - - len = s->len - s->readpos; - if (cnt > len) - cnt = len; - ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt); - if (ret == cnt) - return -EFAULT; - - cnt -= ret; - - s->readpos += cnt; - return cnt; -} - static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt) { int len; diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index f3dad80c20b2..b8930f79a04b 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -20,23 +20,6 @@ static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly; static int next_event_type = __TRACE_LAST_TYPE + 1; -int trace_print_seq(struct seq_file *m, struct trace_seq *s) -{ - int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; - int ret; - - ret = seq_write(m, s->buffer, len); - - /* - * Only reset this buffer if we successfully wrote to the - * seq_file buffer. - */ - if (!ret) - trace_seq_init(s); - - return ret; -} - enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; @@ -85,257 +68,6 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter) return TRACE_TYPE_HANDLED; } -/** - * trace_seq_printf - sequence printing of trace information - * @s: trace sequence descriptor - * @fmt: printf format string - * - * It returns 0 if the trace oversizes the buffer's free - * space, 1 otherwise. - * - * The tracer may use either sequence operations or its own - * copy to user routines. To simplify formating of a trace - * trace_seq_printf is used to store strings into a special - * buffer (@s). Then the output may be either used by - * the sequencer or pulled into another buffer. - */ -int -trace_seq_printf(struct trace_seq *s, const char *fmt, ...) -{ - int len = (PAGE_SIZE - 1) - s->len; - va_list ap; - int ret; - - if (s->full || !len) - return 0; - - va_start(ap, fmt); - ret = vsnprintf(s->buffer + s->len, len, fmt, ap); - va_end(ap); - - /* If we can't write it all, don't bother writing anything */ - if (ret >= len) { - s->full = 1; - return 0; - } - - s->len += ret; - - return 1; -} -EXPORT_SYMBOL_GPL(trace_seq_printf); - -/** - * trace_seq_bitmask - put a list of longs as a bitmask print output - * @s: trace sequence descriptor - * @maskp: points to an array of unsigned longs that represent a bitmask - * @nmaskbits: The number of bits that are valid in @maskp - * - * It returns 0 if the trace oversizes the buffer's free - * space, 1 otherwise. - * - * Writes a ASCII representation of a bitmask string into @s. - */ -int -trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, - int nmaskbits) -{ - int len = (PAGE_SIZE - 1) - s->len; - int ret; - - if (s->full || !len) - return 0; - - ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits); - s->len += ret; - - return 1; -} -EXPORT_SYMBOL_GPL(trace_seq_bitmask); - -/** - * trace_seq_vprintf - sequence printing of trace information - * @s: trace sequence descriptor - * @fmt: printf format string - * - * The tracer may use either sequence operations or its own - * copy to user routines. To simplify formating of a trace - * trace_seq_printf is used to store strings into a special - * buffer (@s). Then the output may be either used by - * the sequencer or pulled into another buffer. - */ -int -trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) -{ - int len = (PAGE_SIZE - 1) - s->len; - int ret; - - if (s->full || !len) - return 0; - - ret = vsnprintf(s->buffer + s->len, len, fmt, args); - - /* If we can't write it all, don't bother writing anything */ - if (ret >= len) { - s->full = 1; - return 0; - } - - s->len += ret; - - return len; -} -EXPORT_SYMBOL_GPL(trace_seq_vprintf); - -int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) -{ - int len = (PAGE_SIZE - 1) - s->len; - int ret; - - if (s->full || !len) - return 0; - - ret = bstr_printf(s->buffer + s->len, len, fmt, binary); - - /* If we can't write it all, don't bother writing anything */ - if (ret >= len) { - s->full = 1; - return 0; - } - - s->len += ret; - - return len; -} - -/** - * trace_seq_puts - trace sequence printing of simple string - * @s: trace sequence descriptor - * @str: simple string to record - * - * The tracer may use either the sequence operations or its own - * copy to user routines. This function records a simple string - * into a special buffer (@s) for later retrieval by a sequencer - * or other mechanism. - */ -int trace_seq_puts(struct trace_seq *s, const char *str) -{ - int len = strlen(str); - - if (s->full) - return 0; - - if (len > ((PAGE_SIZE - 1) - s->len)) { - s->full = 1; - return 0; - } - - memcpy(s->buffer + s->len, str, len); - s->len += len; - - return len; -} - -int trace_seq_putc(struct trace_seq *s, unsigned char c) -{ - if (s->full) - return 0; - - if (s->len >= (PAGE_SIZE - 1)) { - s->full = 1; - return 0; - } - - s->buffer[s->len++] = c; - - return 1; -} -EXPORT_SYMBOL(trace_seq_putc); - -int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) -{ - if (s->full) - return 0; - - if (len > ((PAGE_SIZE - 1) - s->len)) { - s->full = 1; - return 0; - } - - memcpy(s->buffer + s->len, mem, len); - s->len += len; - - return len; -} - -int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len) -{ - unsigned char hex[HEX_CHARS]; - const unsigned char *data = mem; - int i, j; - - if (s->full) - return 0; - -#ifdef __BIG_ENDIAN - for (i = 0, j = 0; i < len; i++) { -#else - for (i = len-1, j = 0; i >= 0; i--) { -#endif - hex[j++] = hex_asc_hi(data[i]); - hex[j++] = hex_asc_lo(data[i]); - } - hex[j++] = ' '; - - return trace_seq_putmem(s, hex, j); -} - -void *trace_seq_reserve(struct trace_seq *s, size_t len) -{ - void *ret; - - if (s->full) - return NULL; - - if (len > ((PAGE_SIZE - 1) - s->len)) { - s->full = 1; - return NULL; - } - - ret = s->buffer + s->len; - s->len += len; - - return ret; -} - -int trace_seq_path(struct trace_seq *s, const struct path *path) -{ - unsigned char *p; - - if (s->full) - return 0; - - if (s->len >= (PAGE_SIZE - 1)) { - s->full = 1; - return 0; - } - - p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len); - if (!IS_ERR(p)) { - p = mangle_path(s->buffer + s->len, p, "\n"); - if (p) { - s->len = p - s->buffer; - return 1; - } - } else { - s->buffer[s->len++] = '?'; - return 1; - } - - s->full = 1; - return 0; -} - const char * ftrace_print_flags_seq(struct trace_seq *p, const char *delim, unsigned long flags, diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h index 127a9d8c8357..bf7daf2237ed 100644 --- a/kernel/trace/trace_output.h +++ b/kernel/trace/trace_output.h @@ -35,9 +35,6 @@ trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry); extern int __unregister_ftrace_event(struct trace_event *event); extern struct rw_semaphore trace_event_sem; -#define MAX_MEMHEX_BYTES 8 -#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) - #define SEQ_PUT_FIELD_RET(s, x) \ do { \ if (!trace_seq_putmem(s, &(x), sizeof(x))) \ diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c new file mode 100644 index 000000000000..5ba99c6cf834 --- /dev/null +++ b/kernel/trace/trace_seq.c @@ -0,0 +1,303 @@ +/* + * trace_seq.c + * + * Copyright (C) 2008-2014 Red Hat Inc, Steven Rostedt + * + */ +#include +#include +#include + +int trace_print_seq(struct seq_file *m, struct trace_seq *s) +{ + int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; + int ret; + + ret = seq_write(m, s->buffer, len); + + /* + * Only reset this buffer if we successfully wrote to the + * seq_file buffer. + */ + if (!ret) + trace_seq_init(s); + + return ret; +} + +/** + * trace_seq_printf - sequence printing of trace information + * @s: trace sequence descriptor + * @fmt: printf format string + * + * It returns 0 if the trace oversizes the buffer's free + * space, 1 otherwise. + * + * The tracer may use either sequence operations or its own + * copy to user routines. To simplify formating of a trace + * trace_seq_printf is used to store strings into a special + * buffer (@s). Then the output may be either used by + * the sequencer or pulled into another buffer. + */ +int +trace_seq_printf(struct trace_seq *s, const char *fmt, ...) +{ + int len = (PAGE_SIZE - 1) - s->len; + va_list ap; + int ret; + + if (s->full || !len) + return 0; + + va_start(ap, fmt); + ret = vsnprintf(s->buffer + s->len, len, fmt, ap); + va_end(ap); + + /* If we can't write it all, don't bother writing anything */ + if (ret >= len) { + s->full = 1; + return 0; + } + + s->len += ret; + + return 1; +} +EXPORT_SYMBOL_GPL(trace_seq_printf); + +/** + * trace_seq_bitmask - put a list of longs as a bitmask print output + * @s: trace sequence descriptor + * @maskp: points to an array of unsigned longs that represent a bitmask + * @nmaskbits: The number of bits that are valid in @maskp + * + * It returns 0 if the trace oversizes the buffer's free + * space, 1 otherwise. + * + * Writes a ASCII representation of a bitmask string into @s. + */ +int +trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, + int nmaskbits) +{ + int len = (PAGE_SIZE - 1) - s->len; + int ret; + + if (s->full || !len) + return 0; + + ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits); + s->len += ret; + + return 1; +} +EXPORT_SYMBOL_GPL(trace_seq_bitmask); + +/** + * trace_seq_vprintf - sequence printing of trace information + * @s: trace sequence descriptor + * @fmt: printf format string + * + * The tracer may use either sequence operations or its own + * copy to user routines. To simplify formating of a trace + * trace_seq_printf is used to store strings into a special + * buffer (@s). Then the output may be either used by + * the sequencer or pulled into another buffer. + */ +int +trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) +{ + int len = (PAGE_SIZE - 1) - s->len; + int ret; + + if (s->full || !len) + return 0; + + ret = vsnprintf(s->buffer + s->len, len, fmt, args); + + /* If we can't write it all, don't bother writing anything */ + if (ret >= len) { + s->full = 1; + return 0; + } + + s->len += ret; + + return len; +} +EXPORT_SYMBOL_GPL(trace_seq_vprintf); + +int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) +{ + int len = (PAGE_SIZE - 1) - s->len; + int ret; + + if (s->full || !len) + return 0; + + ret = bstr_printf(s->buffer + s->len, len, fmt, binary); + + /* If we can't write it all, don't bother writing anything */ + if (ret >= len) { + s->full = 1; + return 0; + } + + s->len += ret; + + return len; +} + +/** + * trace_seq_puts - trace sequence printing of simple string + * @s: trace sequence descriptor + * @str: simple string to record + * + * The tracer may use either the sequence operations or its own + * copy to user routines. This function records a simple string + * into a special buffer (@s) for later retrieval by a sequencer + * or other mechanism. + */ +int trace_seq_puts(struct trace_seq *s, const char *str) +{ + int len = strlen(str); + + if (s->full) + return 0; + + if (len > ((PAGE_SIZE - 1) - s->len)) { + s->full = 1; + return 0; + } + + memcpy(s->buffer + s->len, str, len); + s->len += len; + + return len; +} + +int trace_seq_putc(struct trace_seq *s, unsigned char c) +{ + if (s->full) + return 0; + + if (s->len >= (PAGE_SIZE - 1)) { + s->full = 1; + return 0; + } + + s->buffer[s->len++] = c; + + return 1; +} +EXPORT_SYMBOL(trace_seq_putc); + +int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) +{ + if (s->full) + return 0; + + if (len > ((PAGE_SIZE - 1) - s->len)) { + s->full = 1; + return 0; + } + + memcpy(s->buffer + s->len, mem, len); + s->len += len; + + return len; +} + +#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) + +int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len) +{ + unsigned char hex[HEX_CHARS]; + const unsigned char *data = mem; + int i, j; + + if (s->full) + return 0; + +#ifdef __BIG_ENDIAN + for (i = 0, j = 0; i < len; i++) { +#else + for (i = len-1, j = 0; i >= 0; i--) { +#endif + hex[j++] = hex_asc_hi(data[i]); + hex[j++] = hex_asc_lo(data[i]); + } + hex[j++] = ' '; + + return trace_seq_putmem(s, hex, j); +} + +void *trace_seq_reserve(struct trace_seq *s, size_t len) +{ + void *ret; + + if (s->full) + return NULL; + + if (len > ((PAGE_SIZE - 1) - s->len)) { + s->full = 1; + return NULL; + } + + ret = s->buffer + s->len; + s->len += len; + + return ret; +} + +int trace_seq_path(struct trace_seq *s, const struct path *path) +{ + unsigned char *p; + + if (s->full) + return 0; + + if (s->len >= (PAGE_SIZE - 1)) { + s->full = 1; + return 0; + } + + p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len); + if (!IS_ERR(p)) { + p = mangle_path(s->buffer + s->len, p, "\n"); + if (p) { + s->len = p - s->buffer; + return 1; + } + } else { + s->buffer[s->len++] = '?'; + return 1; + } + + s->full = 1; + return 0; +} + +ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) +{ + int len; + int ret; + + if (!cnt) + return 0; + + if (s->len <= s->readpos) + return -EBUSY; + + len = s->len - s->readpos; + if (cnt > len) + cnt = len; + ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt); + if (ret == cnt) + return -EFAULT; + + cnt -= ret; + + s->readpos += cnt; + return cnt; +} -- cgit v1.2.3 From 36aabfff50b6a03bcfd2c3cfbd7b83eb0a9ce0c1 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 20 Jun 2014 17:38:01 -0400 Subject: tracing: Clean up trace_seq.c For using trace_seq_*() functions in NMI context, I posted a patch to move it to the lib/ directory. This caused Andrew Morton to take a look at the code. He went through and gave a lot of comments about missing kernel doc, inconsistent types for the save variable, mix match of EXPORT_SYMBOL_GPL() and EXPORT_SYMBOL() as well as missing EXPORT_SYMBOL*()s. There were a few comments about the way variables were being compared (int vs uint). All these were good review comments and should be implemented regardless of if trace_seq.c should be moved to lib/ or not. Signed-off-by: Steven Rostedt --- include/linux/trace_seq.h | 20 ++--- kernel/trace/trace_seq.c | 207 +++++++++++++++++++++++++++++++++++++++------- 2 files changed, 185 insertions(+), 42 deletions(-) (limited to 'include') diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 66ea365acf01..1f05317f51c4 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -38,14 +38,14 @@ int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args); extern int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary); extern int trace_print_seq(struct seq_file *m, struct trace_seq *s); -extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, - size_t cnt); +extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, + int cnt); extern int trace_seq_puts(struct trace_seq *s, const char *str); extern int trace_seq_putc(struct trace_seq *s, unsigned char c); -extern int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len); +extern int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len); extern int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, - size_t len); -extern void *trace_seq_reserve(struct trace_seq *s, size_t len); + unsigned int len); +extern void *trace_seq_reserve(struct trace_seq *s, unsigned int len); extern int trace_seq_path(struct trace_seq *s, const struct path *path); extern int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, @@ -73,8 +73,8 @@ static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s) { return 0; } -static inline ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, - size_t cnt) +static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, + int cnt) { return 0; } @@ -87,16 +87,16 @@ static inline int trace_seq_putc(struct trace_seq *s, unsigned char c) return 0; } static inline int -trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) +trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) { return 0; } static inline int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, - size_t len) + unsigned int len) { return 0; } -static inline void *trace_seq_reserve(struct trace_seq *s, size_t len) +static inline void *trace_seq_reserve(struct trace_seq *s, unsigned int len) { return NULL; } diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 5ba99c6cf834..0fabca773e51 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -3,21 +3,55 @@ * * Copyright (C) 2008-2014 Red Hat Inc, Steven Rostedt * + * The trace_seq is a handy tool that allows you to pass a descriptor around + * to a buffer that other functions can write to. It is similar to the + * seq_file functionality but has some differences. + * + * To use it, the trace_seq must be initialized with trace_seq_init(). + * This will set up the counters within the descriptor. You can call + * trace_seq_init() more than once to reset the trace_seq to start + * from scratch. + * + * The buffer size is currently PAGE_SIZE, although it may become dynamic + * in the future. + * + * A write to the buffer will either succed or fail. That is, unlike + * sprintf() there will not be a partial write (well it may write into + * the buffer but it wont update the pointers). This allows users to + * try to write something into the trace_seq buffer and if it fails + * they can flush it and try again. + * */ #include #include #include +/* How much buffer is left on the trace_seq? */ +#define TRACE_SEQ_BUF_LEFT(s) ((PAGE_SIZE - 1) - (s)->len) + +/* How much buffer is written? */ +#define TRACE_SEQ_BUF_USED(s) min((s)->len, (unsigned int)(PAGE_SIZE - 1)) + +/** + * trace_print_seq - move the contents of trace_seq into a seq_file + * @m: the seq_file descriptor that is the destination + * @s: the trace_seq descriptor that is the source. + * + * Returns 0 on success and non zero on error. If it succeeds to + * write to the seq_file it will reset the trace_seq, otherwise + * it does not modify the trace_seq to let the caller try again. + */ int trace_print_seq(struct seq_file *m, struct trace_seq *s) { - int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; + unsigned int len = TRACE_SEQ_BUF_USED(s); int ret; ret = seq_write(m, s->buffer, len); /* * Only reset this buffer if we successfully wrote to the - * seq_file buffer. + * seq_file buffer. This lets the caller try again or + * do something else with the contents. */ if (!ret) trace_seq_init(s); @@ -30,19 +64,20 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s) * @s: trace sequence descriptor * @fmt: printf format string * - * It returns 0 if the trace oversizes the buffer's free - * space, 1 otherwise. - * * The tracer may use either sequence operations or its own * copy to user routines. To simplify formating of a trace - * trace_seq_printf is used to store strings into a special + * trace_seq_printf() is used to store strings into a special * buffer (@s). Then the output may be either used by * the sequencer or pulled into another buffer. + * + * Returns 1 if we successfully written all the contents to + * the buffer. + * Returns 0 if we the length to write is bigger than the + * reserved buffer space. In this case, nothing gets written. */ -int -trace_seq_printf(struct trace_seq *s, const char *fmt, ...) +int trace_seq_printf(struct trace_seq *s, const char *fmt, ...) { - int len = (PAGE_SIZE - 1) - s->len; + unsigned int len = TRACE_SEQ_BUF_LEFT(s); va_list ap; int ret; @@ -66,21 +101,22 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...) EXPORT_SYMBOL_GPL(trace_seq_printf); /** - * trace_seq_bitmask - put a list of longs as a bitmask print output + * trace_seq_bitmask - write a bitmask array in its ASCII representation * @s: trace sequence descriptor * @maskp: points to an array of unsigned longs that represent a bitmask * @nmaskbits: The number of bits that are valid in @maskp * - * It returns 0 if the trace oversizes the buffer's free - * space, 1 otherwise. - * * Writes a ASCII representation of a bitmask string into @s. + * + * Returns 1 if we successfully written all the contents to + * the buffer. + * Returns 0 if we the length to write is bigger than the + * reserved buffer space. In this case, nothing gets written. */ -int -trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, - int nmaskbits) +int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, + int nmaskbits) { - int len = (PAGE_SIZE - 1) - s->len; + unsigned int len = TRACE_SEQ_BUF_LEFT(s); int ret; if (s->full || !len) @@ -103,11 +139,12 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask); * trace_seq_printf is used to store strings into a special * buffer (@s). Then the output may be either used by * the sequencer or pulled into another buffer. + * + * Returns how much it wrote to the buffer. */ -int -trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) +int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) { - int len = (PAGE_SIZE - 1) - s->len; + unsigned int len = TRACE_SEQ_BUF_LEFT(s); int ret; if (s->full || !len) @@ -127,9 +164,26 @@ trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) } EXPORT_SYMBOL_GPL(trace_seq_vprintf); +/** + * trace_seq_bprintf - Write the printf string from binary arguments + * @s: trace sequence descriptor + * @fmt: The format string for the @binary arguments + * @binary: The binary arguments for @fmt. + * + * When recording in a fast path, a printf may be recorded with just + * saving the format and the arguments as they were passed to the + * function, instead of wasting cycles converting the arguments into + * ASCII characters. Instead, the arguments are saved in a 32 bit + * word array that is defined by the format string constraints. + * + * This function will take the format and the binary array and finish + * the conversion into the ASCII string within the buffer. + * + * Returns how much it wrote to the buffer. + */ int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) { - int len = (PAGE_SIZE - 1) - s->len; + unsigned int len = TRACE_SEQ_BUF_LEFT(s); int ret; if (s->full || !len) @@ -147,6 +201,7 @@ int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) return len; } +EXPORT_SYMBOL_GPL(trace_seq_bprintf); /** * trace_seq_puts - trace sequence printing of simple string @@ -157,15 +212,17 @@ int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) * copy to user routines. This function records a simple string * into a special buffer (@s) for later retrieval by a sequencer * or other mechanism. + * + * Returns how much it wrote to the buffer. */ int trace_seq_puts(struct trace_seq *s, const char *str) { - int len = strlen(str); + unsigned int len = strlen(str); if (s->full) return 0; - if (len > ((PAGE_SIZE - 1) - s->len)) { + if (len > TRACE_SEQ_BUF_LEFT(s)) { s->full = 1; return 0; } @@ -175,13 +232,26 @@ int trace_seq_puts(struct trace_seq *s, const char *str) return len; } +EXPORT_SYMBOL_GPL(trace_seq_puts); +/** + * trace_seq_putc - trace sequence printing of simple character + * @s: trace sequence descriptor + * @c: simple character to record + * + * The tracer may use either the sequence operations or its own + * copy to user routines. This function records a simple charater + * into a special buffer (@s) for later retrieval by a sequencer + * or other mechanism. + * + * Returns how much it wrote to the buffer. + */ int trace_seq_putc(struct trace_seq *s, unsigned char c) { if (s->full) return 0; - if (s->len >= (PAGE_SIZE - 1)) { + if (TRACE_SEQ_BUF_LEFT(s) < 1) { s->full = 1; return 0; } @@ -190,14 +260,26 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c) return 1; } -EXPORT_SYMBOL(trace_seq_putc); +EXPORT_SYMBOL_GPL(trace_seq_putc); -int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) +/** + * trace_seq_putmem - write raw data into the trace_seq buffer + * @s: trace sequence descriptor + * @mem: The raw memory to copy into the buffer + * @len: The length of the raw memory to copy (in bytes) + * + * There may be cases where raw memory needs to be written into the + * buffer and a strcpy() would not work. Using this function allows + * for such cases. + * + * Returns how much it wrote to the buffer. + */ +int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) { if (s->full) return 0; - if (len > ((PAGE_SIZE - 1) - s->len)) { + if (len > TRACE_SEQ_BUF_LEFT(s)) { s->full = 1; return 0; } @@ -207,10 +289,24 @@ int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) return len; } +EXPORT_SYMBOL_GPL(trace_seq_putmem); #define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) -int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len) +/** + * trace_seq_putmem_hex - write raw memory into the buffer in ASCII hex + * @s: trace sequence descriptor + * @mem: The raw memory to write its hex ASCII representation of + * @len: The length of the raw memory to copy (in bytes) + * + * This is similar to trace_seq_putmem() except instead of just copying the + * raw memory into the buffer it writes its ASCII representation of it + * in hex characters. + * + * Returns how much it wrote to the buffer. + */ +int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, + unsigned int len) { unsigned char hex[HEX_CHARS]; const unsigned char *data = mem; @@ -231,15 +327,27 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len) return trace_seq_putmem(s, hex, j); } +EXPORT_SYMBOL_GPL(trace_seq_putmem_hex); -void *trace_seq_reserve(struct trace_seq *s, size_t len) +/** + * trace_seq_reserve - reserve space on the sequence buffer + * @s: trace sequence descriptor + * @len: The amount to reserver. + * + * If for some reason there is a need to save some space on the + * buffer to fill in later, this function is used for that purpose. + * The given length will be reserved and the pointer to that + * location on the buffer is returned, unless there is not enough + * buffer left to hold the given length then NULL is returned. + */ +void *trace_seq_reserve(struct trace_seq *s, unsigned int len) { void *ret; if (s->full) return NULL; - if (len > ((PAGE_SIZE - 1) - s->len)) { + if (len > TRACE_SEQ_BUF_LEFT(s)) { s->full = 1; return NULL; } @@ -249,7 +357,20 @@ void *trace_seq_reserve(struct trace_seq *s, size_t len) return ret; } +EXPORT_SYMBOL_GPL(trace_seq_reserve); +/** + * trace_seq_path - copy a path into the sequence buffer + * @s: trace sequence descriptor + * @path: path to write into the sequence buffer. + * + * Write a path name into the sequence buffer. + * + * Returns 1 if we successfully written all the contents to + * the buffer. + * Returns 0 if we the length to write is bigger than the + * reserved buffer space. In this case, nothing gets written. + */ int trace_seq_path(struct trace_seq *s, const struct path *path) { unsigned char *p; @@ -257,7 +378,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path) if (s->full) return 0; - if (s->len >= (PAGE_SIZE - 1)) { + if (TRACE_SEQ_BUF_LEFT(s) < 1) { s->full = 1; return 0; } @@ -277,8 +398,29 @@ int trace_seq_path(struct trace_seq *s, const struct path *path) s->full = 1; return 0; } +EXPORT_SYMBOL_GPL(trace_seq_path); -ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) +/** + * trace_seq_to_user - copy the squence buffer to user space + * @s: trace sequence descriptor + * @ubuf: The userspace memory location to copy to + * @cnt: The amount to copy + * + * Copies the sequence buffer into the userspace memory pointed to + * by @ubuf. It starts from the last read position (@s->readpos) + * and writes up to @cnt characters or till it reaches the end of + * the content in the buffer (@s->len), which ever comes first. + * + * On success, it returns a positive number of the number of bytes + * it copied. + * + * On failure it returns -EBUSY if all of the content in the + * sequence has been already read, which includes nothing in the + * sequenc (@s->len == @s->readpos). + * + * Returns -EFAULT if the copy to userspace fails. + */ +int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt) { int len; int ret; @@ -301,3 +443,4 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) s->readpos += cnt; return cnt; } +EXPORT_SYMBOL_GPL(trace_seq_to_user); -- cgit v1.2.3 From 6d2289f3faa71dcc5bba15c7aeba4f31c185b6df Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 20 Jun 2014 23:31:26 -0400 Subject: tracing: Make trace_seq_putmem_hex() more robust Currently trace_seq_putmem_hex() can only take as a parameter a pointer to something that is 8 bytes or less, otherwise it will overflow the buffer. This is protected by a macro that encompasses the call to trace_seq_putmem_hex() that has a BUILD_BUG_ON() for the variable before it is passed in. This is not very robust and if trace_seq_putmem_hex() ever gets used outside that macro it will cause issues. Instead of only being able to produce a hex output of memory that is for a single word, change it to be more robust and allow any size input. Signed-off-by: Steven Rostedt --- include/linux/trace_seq.h | 2 -- kernel/trace/trace_output.h | 1 - kernel/trace/trace_seq.c | 26 +++++++++++++++++++------- 3 files changed, 19 insertions(+), 10 deletions(-) (limited to 'include') diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 1f05317f51c4..8283762ab7ef 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -25,8 +25,6 @@ trace_seq_init(struct trace_seq *s) s->full = 0; } -#define MAX_MEMHEX_BYTES 8 - /* * Currently only defined when tracing is enabled. */ diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h index bf7daf2237ed..80b25b585a70 100644 --- a/kernel/trace/trace_output.h +++ b/kernel/trace/trace_output.h @@ -43,7 +43,6 @@ do { \ #define SEQ_PUT_HEX_FIELD_RET(s, x) \ do { \ - BUILD_BUG_ON(sizeof(x) > MAX_MEMHEX_BYTES); \ if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \ return TRACE_TYPE_PARTIAL_LINE; \ } while (0) diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 0fabca773e51..88c0f80f0a1f 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -291,6 +291,7 @@ int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) } EXPORT_SYMBOL_GPL(trace_seq_putmem); +#define MAX_MEMHEX_BYTES 8U #define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) /** @@ -310,22 +311,33 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, { unsigned char hex[HEX_CHARS]; const unsigned char *data = mem; + unsigned int start_len; int i, j; + int cnt = 0; if (s->full) return 0; + while (len) { + start_len = min(len, HEX_CHARS - 1); #ifdef __BIG_ENDIAN - for (i = 0, j = 0; i < len; i++) { + for (i = 0, j = 0; i < start_len; i++) { #else - for (i = len-1, j = 0; i >= 0; i--) { + for (i = start_len-1, j = 0; i >= 0; i--) { #endif - hex[j++] = hex_asc_hi(data[i]); - hex[j++] = hex_asc_lo(data[i]); - } - hex[j++] = ' '; + hex[j++] = hex_asc_hi(data[i]); + hex[j++] = hex_asc_lo(data[i]); + } + if (WARN_ON_ONCE(j == 0 || j/2 > len)) + break; + + /* j increments twice per loop */ + len -= j / 2; + hex[j++] = ' '; - return trace_seq_putmem(s, hex, j); + cnt += trace_seq_putmem(s, hex, j); + } + return cnt; } EXPORT_SYMBOL_GPL(trace_seq_putmem_hex); -- cgit v1.2.3 From 9096032fbcdcdb80b76f1046346499e20417988e Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 23 Jun 2014 16:42:07 -0400 Subject: tracing: Remove trace_seq_reserve() trace_seq_reserve() has no users in the kernel, it just wastes space. Remove it. Cc: Eduard - Gabriel Munteanu Signed-off-by: Steven Rostedt --- include/linux/trace_seq.h | 5 ----- kernel/trace/trace_seq.c | 30 ------------------------------ 2 files changed, 35 deletions(-) (limited to 'include') diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 8283762ab7ef..dd85753e1bb0 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -43,7 +43,6 @@ extern int trace_seq_putc(struct trace_seq *s, unsigned char c); extern int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len); extern int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, unsigned int len); -extern void *trace_seq_reserve(struct trace_seq *s, unsigned int len); extern int trace_seq_path(struct trace_seq *s, const struct path *path); extern int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, @@ -94,10 +93,6 @@ static inline int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, { return 0; } -static inline void *trace_seq_reserve(struct trace_seq *s, unsigned int len) -{ - return NULL; -} static inline int trace_seq_path(struct trace_seq *s, const struct path *path) { return 0; diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 88c0f80f0a1f..1f24ed99dca2 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -341,36 +341,6 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, } EXPORT_SYMBOL_GPL(trace_seq_putmem_hex); -/** - * trace_seq_reserve - reserve space on the sequence buffer - * @s: trace sequence descriptor - * @len: The amount to reserver. - * - * If for some reason there is a need to save some space on the - * buffer to fill in later, this function is used for that purpose. - * The given length will be reserved and the pointer to that - * location on the buffer is returned, unless there is not enough - * buffer left to hold the given length then NULL is returned. - */ -void *trace_seq_reserve(struct trace_seq *s, unsigned int len) -{ - void *ret; - - if (s->full) - return NULL; - - if (len > TRACE_SEQ_BUF_LEFT(s)) { - s->full = 1; - return NULL; - } - - ret = s->buffer + s->len; - s->len += len; - - return ret; -} -EXPORT_SYMBOL_GPL(trace_seq_reserve); - /** * trace_seq_path - copy a path into the sequence buffer * @s: trace sequence descriptor -- cgit v1.2.3 From 7b039cb4c5a90d8ea576b17e096f7334457aeb57 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Thu, 26 Jun 2014 09:42:41 -0400 Subject: tracing: Add trace_seq_buffer_ptr() helper function There's several locations in the kernel that open code the calculation of the next location in the trace_seq buffer. This is usually done with p->buffer + p->len Instead of having this open coded, supply a helper function in the header to do it for them. This function is called trace_seq_buffer_ptr(). Link: http://lkml.kernel.org/p/20140626220129.452783019@goodmis.org Acked-by: Paolo Bonzini Signed-off-by: Steven Rostedt --- arch/x86/kvm/mmutrace.h | 2 +- drivers/scsi/scsi_trace.c | 16 ++++++++-------- include/linux/trace_seq.h | 15 +++++++++++++++ kernel/trace/trace_output.c | 14 +++++++------- 4 files changed, 31 insertions(+), 16 deletions(-) (limited to 'include') diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h index 9d2e0ffcb190..2e5652b62fd6 100644 --- a/arch/x86/kvm/mmutrace.h +++ b/arch/x86/kvm/mmutrace.h @@ -22,7 +22,7 @@ __entry->unsync = sp->unsync; #define KVM_MMU_PAGE_PRINTK() ({ \ - const char *ret = p->buffer + p->len; \ + const char *ret = trace_seq_buffer_ptr(p); \ static const char *access_str[] = { \ "---", "--x", "w--", "w-x", "-u-", "-ux", "wu-", "wux" \ }; \ diff --git a/drivers/scsi/scsi_trace.c b/drivers/scsi/scsi_trace.c index 2bea4f0b684a..503594e5f76d 100644 --- a/drivers/scsi/scsi_trace.c +++ b/drivers/scsi/scsi_trace.c @@ -28,7 +28,7 @@ scsi_trace_misc(struct trace_seq *, unsigned char *, int); static const char * scsi_trace_rw6(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); sector_t lba = 0, txlen = 0; lba |= ((cdb[1] & 0x1F) << 16); @@ -46,7 +46,7 @@ scsi_trace_rw6(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_rw10(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); sector_t lba = 0, txlen = 0; lba |= (cdb[2] << 24); @@ -71,7 +71,7 @@ scsi_trace_rw10(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_rw12(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); sector_t lba = 0, txlen = 0; lba |= (cdb[2] << 24); @@ -94,7 +94,7 @@ scsi_trace_rw12(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_rw16(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); sector_t lba = 0, txlen = 0; lba |= ((u64)cdb[2] << 56); @@ -125,7 +125,7 @@ scsi_trace_rw16(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_rw32(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len, *cmd; + const char *ret = trace_seq_buffer_ptr(p), *cmd; sector_t lba = 0, txlen = 0; u32 ei_lbrt = 0; @@ -180,7 +180,7 @@ out: static const char * scsi_trace_unmap(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); unsigned int regions = cdb[7] << 8 | cdb[8]; trace_seq_printf(p, "regions=%u", (regions - 8) / 16); @@ -192,7 +192,7 @@ scsi_trace_unmap(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_service_action_in(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len, *cmd; + const char *ret = trace_seq_buffer_ptr(p), *cmd; sector_t lba = 0; u32 alloc_len = 0; @@ -247,7 +247,7 @@ scsi_trace_varlen(struct trace_seq *p, unsigned char *cdb, int len) static const char * scsi_trace_misc(struct trace_seq *p, unsigned char *cdb, int len) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); trace_seq_printf(p, "-"); trace_seq_putc(p, 0); diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index dd85753e1bb0..ea6c9dea79e3 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -25,6 +25,21 @@ trace_seq_init(struct trace_seq *s) s->full = 0; } +/** + * trace_seq_buffer_ptr - return pointer to next location in buffer + * @s: trace sequence descriptor + * + * Returns the pointer to the buffer where the next write to + * the buffer will happen. This is useful to save the location + * that is about to be written to and then return the result + * of that write. + */ +static inline unsigned char * +trace_seq_buffer_ptr(struct trace_seq *s) +{ + return s->buffer + s->len; +} + /* * Currently only defined when tracing is enabled. */ diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index b8930f79a04b..c6977d5a9b12 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -75,7 +75,7 @@ ftrace_print_flags_seq(struct trace_seq *p, const char *delim, { unsigned long mask; const char *str; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); int i, first = 1; for (i = 0; flag_array[i].name && flags; i++) { @@ -111,7 +111,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val, const struct trace_print_flags *symbol_array) { int i; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); for (i = 0; symbol_array[i].name; i++) { @@ -122,7 +122,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val, break; } - if (ret == (const char *)(p->buffer + p->len)) + if (ret == (const char *)(trace_seq_buffer_ptr(p))) trace_seq_printf(p, "0x%lx", val); trace_seq_putc(p, 0); @@ -137,7 +137,7 @@ ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val, const struct trace_print_flags_u64 *symbol_array) { int i; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); for (i = 0; symbol_array[i].name; i++) { @@ -148,7 +148,7 @@ ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val, break; } - if (ret == (const char *)(p->buffer + p->len)) + if (ret == (const char *)(trace_seq_buffer_ptr(p))) trace_seq_printf(p, "0x%llx", val); trace_seq_putc(p, 0); @@ -162,7 +162,7 @@ const char * ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr, unsigned int bitmask_size) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8); trace_seq_putc(p, 0); @@ -175,7 +175,7 @@ const char * ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len) { int i; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); for (i = 0; i < buf_len; i++) trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]); -- cgit v1.2.3 From 646d7043adf3d92de5d3db1244a82a12628303de Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 11 Jul 2014 14:39:10 -0400 Subject: ftrace: Allow archs to specify if they need a separate function graph trampoline Currently if an arch supports function graph tracing, the core code will just assign the function graph trampoline to the function graph addr that gets called. But as the old method for function graph tracing always calls the function trampoline first and that calls the function graph trampoline, some archs may have the function graph trampoline dependent on operations that were done in the function trampoline. This causes function graph tracer to break on those archs. Instead of having the default be to set the function graph ftrace_ops to the function graph trampoline, have it instead just set it to zero which will keep it from jumping to a trampoline that is not set up to be jumped directly too. Link: http://lkml.kernel.org/r/53BED155.9040607@nvidia.com Reported-by: Tuomas Tynkkynen Tested-by: Tuomas Tynkkynen Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 10 ++++++++++ kernel/trace/ftrace.c | 6 ++++-- 2 files changed, 14 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 11e18fd58b1a..4807a39e7ae1 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -453,6 +453,16 @@ void ftrace_modify_all_code(int command); #endif #endif +/* + * If an arch would like functions that are only traced + * by the function graph tracer to jump directly to its own + * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR + * to be that address to jump to. + */ +#ifndef FTRACE_GRAPH_TRAMP_ADDR +#define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0) +#endif + #ifdef CONFIG_FUNCTION_GRAPH_TRACER extern void ftrace_graph_caller(void); extern int ftrace_enable_ftrace_graph_caller(void); diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 45aac1a742c5..1776153ea6e0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5366,7 +5366,8 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, #ifdef CONFIG_DYNAMIC_FTRACE /* Optimize function graph calling (if implemented by arch) */ - global_ops.trampoline = FTRACE_GRAPH_ADDR; + if (FTRACE_GRAPH_TRAMP_ADDR != 0) + global_ops.trampoline = FTRACE_GRAPH_TRAMP_ADDR; #endif ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET); @@ -5390,7 +5391,8 @@ void unregister_ftrace_graph(void) ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET); global_ops.flags &= ~FTRACE_OPS_FL_STUB; #ifdef CONFIG_DYNAMIC_FTRACE - global_ops.trampoline = 0; + if (FTRACE_GRAPH_TRAMP_ADDR != 0) + global_ops.trampoline = 0; #endif unregister_pm_notifier(&ftrace_suspend_notifier); unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); -- cgit v1.2.3 From 1b2f121c1418249e56048d816754b479b3cb6fb3 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 25 Jun 2014 10:39:46 -0400 Subject: ftrace-graph: Remove dependency of ftrace_stop() from ftrace_graph_stop() ftrace_stop() is going away as it disables parts of function tracing that affects users that should not be affected. But ftrace_graph_stop() is built on ftrace_stop(). Here's another example of killing all of function tracing because something went wrong with function graph tracing. Instead of disabling all users of function tracing on function graph error, disable only function graph tracing. A new function is created called ftrace_graph_is_dead(). This is called in strategic paths to prevent function graph from doing more harm and allowing at least a warning to be printed before the system crashes. NOTE: ftrace_stop() is still used until all the archs are converted over to use ftrace_graph_is_dead(). After that, ftrace_stop() will be removed. Reviewed-by: Masami Hiramatsu Cc: Frederic Weisbecker Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 1 + kernel/trace/ftrace.c | 5 ----- kernel/trace/trace_functions_graph.c | 35 +++++++++++++++++++++++++++++++++++ 3 files changed, 36 insertions(+), 5 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 4807a39e7ae1..18fb2c4a3f7f 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -760,6 +760,7 @@ extern char __irqentry_text_end[]; extern int register_ftrace_graph(trace_func_graph_ret_t retfunc, trace_func_graph_ent_t entryfunc); +extern bool ftrace_graph_is_dead(void); extern void ftrace_graph_stop(void); /* The current handlers in use */ diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1776153ea6e0..8063280fd53d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5473,9 +5473,4 @@ void ftrace_graph_exit_task(struct task_struct *t) kfree(ret_stack); } - -void ftrace_graph_stop(void) -{ - ftrace_stop(); -} #endif diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 4de3e57f723c..3604690be70b 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -15,6 +15,38 @@ #include "trace.h" #include "trace_output.h" +static bool kill_ftrace_graph; + +/** + * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called + * + * ftrace_graph_stop() is called when a severe error is detected in + * the function graph tracing. This function is called by the critical + * paths of function graph to keep those paths from doing any more harm. + */ +bool ftrace_graph_is_dead(void) +{ + return kill_ftrace_graph; +} + +/** + * ftrace_graph_stop - set to permanently disable function graph tracincg + * + * In case of an error int function graph tracing, this is called + * to try to keep function graph tracing from causing any more harm. + * Usually this is pretty severe and this is called to try to at least + * get a warning out to the user. + */ +void ftrace_graph_stop(void) +{ + kill_ftrace_graph = true; + /* + * ftrace_stop() will be removed when all archs are updated to + * use ftrace_graph_is_dead() + */ + ftrace_stop(); +} + /* When set, irq functions will be ignored */ static int ftrace_graph_skip_irqs; @@ -92,6 +124,9 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, unsigned long long calltime; int index; + if (unlikely(ftrace_graph_is_dead())) + return -EBUSY; + if (!current->ret_stack) return -EBUSY; -- cgit v1.2.3 From 0ef1b9e0cfd98f91b2341d581ea9424eb4ba3aa7 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 25 Jun 2014 11:25:19 -0400 Subject: ftrace: Remove ftrace_start/stop() There are no more kernel users of ftrace_stop() and ftrace_start(). Remove them. Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 28 ---------------------------- 1 file changed, 28 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 18fb2c4a3f7f..b7333794554f 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -143,32 +143,6 @@ enum ftrace_tracing_type_t { /* Current tracing type, default is FTRACE_TYPE_ENTER */ extern enum ftrace_tracing_type_t ftrace_tracing_type; -/** - * ftrace_stop - stop function tracer. - * - * A quick way to stop the function tracer. Note this an on off switch, - * it is not something that is recursive like preempt_disable. - * This does not disable the calling of mcount, it only stops the - * calling of functions from mcount. - */ -static inline void ftrace_stop(void) -{ - function_trace_stop = 1; -} - -/** - * ftrace_start - start the function tracer. - * - * This function is the inverse of ftrace_stop. This does not enable - * the function tracing if the function tracer is disabled. This only - * sets the function tracer flag to continue calling the functions - * from mcount. - */ -static inline void ftrace_start(void) -{ - function_trace_stop = 0; -} - /* * The ftrace_ops must be a static and should also * be read_mostly. These functions do modify read_mostly variables @@ -245,8 +219,6 @@ static inline int ftrace_nr_registered_ops(void) } static inline void clear_ftrace_function(void) { } static inline void ftrace_kill(void) { } -static inline void ftrace_stop(void) { } -static inline void ftrace_start(void) { } #endif /* CONFIG_FUNCTION_TRACER */ #ifdef CONFIG_STACK_TRACER -- cgit v1.2.3 From 7544256aa20356e506b0d179f9b6abc661847e2f Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 25 Jun 2014 13:26:59 -0400 Subject: ftrace: Remove check for HAVE_FUNCTION_TRACE_MCOUNT_TEST function_trace_stop is no longer used to disable function tracing. This means that archs are no longer limited if it does not support checking this variable in the mcount trampoline. No need to use the list_func for archs that do not support this obsolete method. Acked-by: James Hogan Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- Documentation/trace/ftrace-design.txt | 26 -------------------------- include/linux/ftrace.h | 3 +-- 2 files changed, 1 insertion(+), 28 deletions(-) (limited to 'include') diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt index 3f669b9e8852..dd5f916b351d 100644 --- a/Documentation/trace/ftrace-design.txt +++ b/Documentation/trace/ftrace-design.txt @@ -102,30 +102,6 @@ extern void mcount(void); EXPORT_SYMBOL(mcount); -HAVE_FUNCTION_TRACE_MCOUNT_TEST -------------------------------- - -This is an optional optimization for the normal case when tracing is turned off -in the system. If you do not enable this Kconfig option, the common ftrace -code will take care of doing the checking for you. - -To support this feature, you only need to check the function_trace_stop -variable in the mcount function. If it is non-zero, there is no tracing to be -done at all, so you can return. - -This additional pseudo code would simply be: -void mcount(void) -{ - /* save any bare state needed in order to do initial checking */ - -+ if (function_trace_stop) -+ return; - - extern void (*ftrace_trace_function)(unsigned long, unsigned long); - if (ftrace_trace_function != ftrace_stub) -... - - HAVE_FUNCTION_GRAPH_TRACER -------------------------- @@ -328,8 +304,6 @@ void mcount(void) void ftrace_caller(void) { - /* implement HAVE_FUNCTION_TRACE_MCOUNT_TEST if you desire */ - /* save all state needed by the ABI (see paragraph above) */ unsigned long frompc = ...; diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index b7333794554f..c800906235e1 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -33,8 +33,7 @@ * 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 +#if !ARCH_SUPPORTS_FTRACE_OPS # define FTRACE_FORCE_LIST_FUNC 1 #else # define FTRACE_FORCE_LIST_FUNC 0 -- cgit v1.2.3 From 3a636388bae8390d23f31e061c0c6fdc14525786 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Thu, 26 Jun 2014 11:24:52 -0400 Subject: tracing: Remove function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST All users of function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST have been removed. We can safely remove them from the kernel. Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 2 -- kernel/trace/Kconfig | 5 ----- kernel/trace/ftrace.c | 3 --- 3 files changed, 10 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index c800906235e1..7a5b7b97e539 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -129,8 +129,6 @@ struct ftrace_ops { #endif }; -extern int function_trace_stop; - /* * Type of the current tracing. */ diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index d4409356f40d..a5da09c899dd 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -29,11 +29,6 @@ config HAVE_FUNCTION_GRAPH_FP_TEST help See Documentation/trace/ftrace-design.txt -config HAVE_FUNCTION_TRACE_MCOUNT_TEST - bool - help - See Documentation/trace/ftrace-design.txt - config HAVE_DYNAMIC_FTRACE bool help diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 70abf97d6e84..4c61f28a08e0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -80,9 +80,6 @@ static struct ftrace_ops ftrace_list_end __read_mostly = { int ftrace_enabled __read_mostly; static int last_ftrace_enabled; -/* Quick disabling of function tracer. */ -int function_trace_stop __read_mostly; - /* Current function tracing op */ struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end; /* What to set function_trace_op to */ -- cgit v1.2.3 From 0162d621ddf3bd02bf7de324dcf002d9c84c5059 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 23 Jul 2014 15:03:00 -0400 Subject: ftrace: Rename ftrace_ops field from trampolines to nr_trampolines Having two fields within the same struct that is off by one character can be confusing and error prone. Rename the counter "trampolines" to "nr_trampolines" to explicitly show it is a counter and not to be confused by the "trampoline" field. Suggested-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 2 +- kernel/trace/ftrace.c | 10 +++++----- 2 files changed, 6 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 7a5b7b97e539..6bb5e3f2a3b4 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -120,7 +120,7 @@ struct ftrace_ops { void *private; int __percpu *disabled; #ifdef CONFIG_DYNAMIC_FTRACE - int trampolines; + int nr_trampolines; struct ftrace_hash *notrace_hash; struct ftrace_hash *filter_hash; struct ftrace_hash *tramp_hash; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 762806026561..eda69c9f78d0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1513,7 +1513,7 @@ static void ftrace_remove_tramp(struct ftrace_ops *ops, * The tramp_hash entry will be removed at time * of update. */ - ops->trampolines--; + ops->nr_trampolines--; rec->flags &= ~FTRACE_FL_TRAMP; } @@ -1522,7 +1522,7 @@ static void ftrace_clear_tramps(struct dyn_ftrace *rec) struct ftrace_ops *op; do_for_each_ftrace_op(op, ftrace_ops_list) { - if (op->trampolines) + if (op->nr_trampolines) ftrace_remove_tramp(op, rec); } while_for_each_ftrace_op(op); } @@ -1617,7 +1617,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, */ if (ftrace_rec_count(rec) == 1 && ops->trampoline) { rec->flags |= FTRACE_FL_TRAMP; - ops->trampolines++; + ops->nr_trampolines++; } else { /* * If we are adding another function callback @@ -2185,7 +2185,7 @@ static int ftrace_save_ops_tramp_hash(struct ftrace_ops *ops) int size, bits; int ret; - size = ops->trampolines; + size = ops->nr_trampolines; bits = 0; /* * Make the hash size about 1/2 the # found @@ -2239,7 +2239,7 @@ static int ftrace_save_tramp_hashes(void) free_ftrace_hash(op->tramp_hash); op->tramp_hash = NULL; - if (op->trampolines) { + if (op->nr_trampolines) { ret = ftrace_save_ops_tramp_hash(op); if (ret) return ret; -- cgit v1.2.3