Merge tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/…

…git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Restructure of lockdep and latency tracers

   This is the biggest change. Joel Fernandes restructured the hooks
   from irqs and preemption disabling and enabling. He got rid of a lot
   of the preprocessor #ifdef mess that they caused.

   He turned both lockdep and the latency tracers to use trace events
   inserted in the preempt/irqs disabling paths. But unfortunately,
   these started to cause issues in corner cases. Thus, parts of the
   code was reverted back to where lockdep and the latency tracers just
   get called directly (without using the trace events). But because the
   original change cleaned up the code very nicely we kept that, as well
   as the trace events for preempt and irqs disabling, but they are
   limited to not being called in NMIs.

 - Have trace events use SRCU for "rcu idle" calls. This was required
   for the preempt/irqs off trace events. But it also had to not allow
   them to be called in NMI context. Waiting till Paul makes an NMI safe
   SRCU API.

 - New notrace SRCU API to allow trace events to use SRCU.

 - Addition of mcount-nop option support

 - SPDX headers replacing GPL templates.

 - Various other fixes and clean ups.

 - Some fixes are marked for stable, but were not fully tested before
   the merge window opened.

* tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
  tracing: Fix SPDX format headers to use C++ style comments
  tracing: Add SPDX License format tags to tracing files
  tracing: Add SPDX License format to bpf_trace.c
  blktrace: Add SPDX License format header
  s390/ftrace: Add -mfentry and -mnop-mcount support
  tracing: Add -mcount-nop option support
  tracing: Avoid calling cc-option -mrecord-mcount for every Makefile
  tracing: Handle CC_FLAGS_FTRACE more accurately
  Uprobe: Additional argument arch_uprobe to uprobe_write_opcode()
  Uprobes: Simplify uprobe_register() body
  tracepoints: Free early tracepoints after RCU is initialized
  uprobes: Use synchronize_rcu() not synchronize_sched()
  tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()
  ftrace: Remove unused pointer ftrace_swapper_pid
  tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage"
  tracing/irqsoff: Handle preempt_count for different configs
  tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage"
  tracing: irqsoff: Account for additional preempt_disable
  trace: Use rcu_dereference_raw for hooks from trace-event subsystem
  tracing/kprobes: Fix within_notrace_func() to check only notrace functions
  ...

Makefile

@@ -754,12 +754,28 @@ ifdef CONFIG_FUNCTION_TRACER
 ifndef CC_FLAGS_FTRACE
 CC_FLAGS_FTRACE := -pg
 endif
-export CC_FLAGS_FTRACE
+ifdef CONFIG_FTRACE_MCOUNT_RECORD
+  # gcc 5 supports generating the mcount tables directly
+  ifeq ($(call cc-option-yn,-mrecord-mcount),y)
+    CC_FLAGS_FTRACE	+= -mrecord-mcount
+    export CC_USING_RECORD_MCOUNT := 1
+  endif
+  ifdef CONFIG_HAVE_NOP_MCOUNT
+    ifeq ($(call cc-option-yn, -mnop-mcount),y)
+      CC_FLAGS_FTRACE	+= -mnop-mcount
+      CC_FLAGS_USING	+= -DCC_USING_NOP_MCOUNT
+    endif
+  endif
+endif
 ifdef CONFIG_HAVE_FENTRY
-CC_USING_FENTRY	:= $(call cc-option, -mfentry -DCC_USING_FENTRY)
+  ifeq ($(call cc-option-yn, -mfentry),y)
+    CC_FLAGS_FTRACE	+= -mfentry
+    CC_FLAGS_USING	+= -DCC_USING_FENTRY
+  endif
 endif
-KBUILD_CFLAGS	+= $(CC_FLAGS_FTRACE) $(CC_USING_FENTRY)
-KBUILD_AFLAGS	+= $(CC_USING_FENTRY)
+export CC_FLAGS_FTRACE
+KBUILD_CFLAGS	+= $(CC_FLAGS_FTRACE) $(CC_FLAGS_USING)
+KBUILD_AFLAGS	+= $(CC_FLAGS_USING)
 ifdef CONFIG_DYNAMIC_FTRACE
 	ifdef CONFIG_HAVE_C_RECORDMCOUNT
 		BUILD_C_RECORDMCOUNT := y

arch/arm/probes/uprobes/core.c

@@ -32,7 +32,7 @@ bool is_swbp_insn(uprobe_opcode_t *insn)
 int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	     unsigned long vaddr)
 {
-	return uprobe_write_opcode(mm, vaddr,
+	return uprobe_write_opcode(auprobe, mm, vaddr,
 		   __opcode_to_mem_arm(auprobe->bpinsn));
 }
 

arch/mips/kernel/uprobes.c

@@ -224,7 +224,7 @@ unsigned long arch_uretprobe_hijack_return_addr(
 int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	unsigned long vaddr)
 {
-	return uprobe_write_opcode(mm, vaddr, UPROBE_SWBP_INSN);
+	return uprobe_write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN);
 }
 
 void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,

arch/s390/Kconfig

@@ -135,6 +135,7 @@ config S390
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
+	select HAVE_FENTRY
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
@@ -157,6 +158,7 @@ config S390
 	select HAVE_MEMBLOCK_NODE_MAP
 	select HAVE_MEMBLOCK_PHYS_MAP
 	select HAVE_MOD_ARCH_SPECIFIC
+	select HAVE_NOP_MCOUNT
 	select HAVE_OPROFILE
 	select HAVE_PERF_EVENTS
 	select HAVE_REGS_AND_STACK_ACCESS_API

arch/s390/Makefile

@@ -96,13 +96,15 @@ ifdef CONFIG_EXPOLINE
 endif
 
 ifdef CONFIG_FUNCTION_TRACER
-# make use of hotpatch feature if the compiler supports it
-cc_hotpatch	:= -mhotpatch=0,3
-ifeq ($(call cc-option-yn,$(cc_hotpatch)),y)
-CC_FLAGS_FTRACE := $(cc_hotpatch)
-KBUILD_AFLAGS	+= -DCC_USING_HOTPATCH
-KBUILD_CFLAGS	+= -DCC_USING_HOTPATCH
-endif
+  ifeq ($(call cc-option-yn,-mfentry -mnop-mcount),n)
+    # make use of hotpatch feature if the compiler supports it
+    cc_hotpatch	:= -mhotpatch=0,3
+    ifeq ($(call cc-option-yn,$(cc_hotpatch)),y)
+      CC_FLAGS_FTRACE := $(cc_hotpatch)
+      KBUILD_AFLAGS	+= -DCC_USING_HOTPATCH
+      KBUILD_CFLAGS	+= -DCC_USING_HOTPATCH
+    endif
+  endif
 endif
 
 # Test CFI features of binutils

arch/s390/include/asm/ftrace.h

@@ -4,7 +4,7 @@
 
 #define ARCH_SUPPORTS_FTRACE_OPS 1
 
-#ifdef CC_USING_HOTPATCH
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
 #define MCOUNT_INSN_SIZE	6
 #else
 #define MCOUNT_INSN_SIZE	24
@@ -42,7 +42,7 @@ struct ftrace_insn {
 static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
 {
 #ifdef CONFIG_FUNCTION_TRACER
-#ifdef CC_USING_HOTPATCH
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
 	/* brcl 0,0 */
 	insn->opc = 0xc004;
 	insn->disp = 0;
@@ -57,7 +57,7 @@ static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
 static inline int is_ftrace_nop(struct ftrace_insn *insn)
 {
 #ifdef CONFIG_FUNCTION_TRACER
-#ifdef CC_USING_HOTPATCH
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
 	if (insn->disp == 0)
 		return 1;
 #else

arch/s390/kernel/ftrace.c

@@ -61,7 +61,7 @@ unsigned long ftrace_plt;
 
 static inline void ftrace_generate_orig_insn(struct ftrace_insn *insn)
 {
-#ifdef CC_USING_HOTPATCH
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
 	/* brcl 0,0 */
 	insn->opc = 0xc004;
 	insn->disp = 0;

arch/s390/kernel/mcount.S

@@ -35,7 +35,7 @@ ENTRY(ftrace_caller)
 	.globl	ftrace_regs_caller
 	.set	ftrace_regs_caller,ftrace_caller
 	lgr	%r1,%r15
-#ifndef CC_USING_HOTPATCH
+#if !(defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT))
 	aghi	%r0,MCOUNT_RETURN_FIXUP
 #endif
 	aghi	%r15,-STACK_FRAME_SIZE

fs/tracefs/inode.c

@@ -53,7 +53,7 @@ static const struct file_operations tracefs_file_operations = {
 static struct tracefs_dir_ops {
 	int (*mkdir)(const char *name);
 	int (*rmdir)(const char *name);
-} tracefs_ops;
+} tracefs_ops __ro_after_init;
 
 static char *get_dname(struct dentry *dentry)
 {
@@ -478,7 +478,8 @@ struct dentry *tracefs_create_dir(const char *name, struct dentry *parent)
  *
  * Returns the dentry of the instances directory.
  */
-struct dentry *tracefs_create_instance_dir(const char *name, struct dentry *parent,
+__init struct dentry *tracefs_create_instance_dir(const char *name,
+					  struct dentry *parent,
 					  int (*mkdir)(const char *name),
 					  int (*rmdir)(const char *name))
 {

include/linux/ftrace.h

@@ -234,10 +234,6 @@ 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 ftrace_kill(void) { }
 static inline void ftrace_free_init_mem(void) { }
 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
@@ -328,8 +324,6 @@ struct seq_file;
 
 extern int ftrace_text_reserved(const void *start, const void *end);
 
-extern int ftrace_nr_registered_ops(void);
-
 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
 
 bool is_ftrace_trampoline(unsigned long addr);
@@ -707,16 +701,7 @@ static inline unsigned long get_lock_parent_ip(void)
 	return CALLER_ADDR2;
 }
 
-#ifdef CONFIG_IRQSOFF_TRACER
-  extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
-  extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
-#else
-  static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
-  static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
-#endif
-
-#if defined(CONFIG_PREEMPT_TRACER) || \
-	(defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
+#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 #else

include/linux/irqflags.h

@@ -15,9 +15,20 @@
 #include <linux/typecheck.h>
 #include <asm/irqflags.h>
 
-#ifdef CONFIG_TRACE_IRQFLAGS
+/* Currently trace_softirqs_on/off is used only by lockdep */
+#ifdef CONFIG_PROVE_LOCKING
   extern void trace_softirqs_on(unsigned long ip);
   extern void trace_softirqs_off(unsigned long ip);
+  extern void lockdep_hardirqs_on(unsigned long ip);
+  extern void lockdep_hardirqs_off(unsigned long ip);
+#else
+  static inline void trace_softirqs_on(unsigned long ip) { }
+  static inline void trace_softirqs_off(unsigned long ip) { }
+  static inline void lockdep_hardirqs_on(unsigned long ip) { }
+  static inline void lockdep_hardirqs_off(unsigned long ip) { }
+#endif
+
+#ifdef CONFIG_TRACE_IRQFLAGS
   extern void trace_hardirqs_on(void);
   extern void trace_hardirqs_off(void);
 # define trace_hardirq_context(p)	((p)->hardirq_context)
@@ -43,8 +54,6 @@ do {						\
 #else
 # define trace_hardirqs_on()		do { } while (0)
 # define trace_hardirqs_off()		do { } while (0)
-# define trace_softirqs_on(ip)		do { } while (0)
-# define trace_softirqs_off(ip)		do { } while (0)
 # define trace_hardirq_context(p)	0
 # define trace_softirq_context(p)	0
 # define trace_hardirqs_enabled(p)	0

include/linux/lockdep.h

@@ -266,7 +266,7 @@ struct held_lock {
 /*
  * Initialization, self-test and debugging-output methods:
  */
-extern void lockdep_info(void);
+extern void lockdep_init(void);
 extern void lockdep_reset(void);
 extern void lockdep_reset_lock(struct lockdep_map *lock);
 extern void lockdep_free_key_range(void *start, unsigned long size);
@@ -406,7 +406,7 @@ static inline void lockdep_on(void)
 # define lock_downgrade(l, i)			do { } while (0)
 # define lock_set_class(l, n, k, s, i)		do { } while (0)
 # define lock_set_subclass(l, s, i)		do { } while (0)
-# define lockdep_info()				do { } while (0)
+# define lockdep_init()				do { } while (0)
 # define lockdep_init_map(lock, name, key, sub) \
 		do { (void)(name); (void)(key); } while (0)
 # define lockdep_set_class(lock, key)		do { (void)(key); } while (0)
@@ -532,7 +532,7 @@ do {								\
 
 #endif /* CONFIG_LOCKDEP */
 
-#ifdef CONFIG_TRACE_IRQFLAGS
+#ifdef CONFIG_PROVE_LOCKING
 extern void print_irqtrace_events(struct task_struct *curr);
 #else
 static inline void print_irqtrace_events(struct task_struct *curr)

include/linux/preempt.h

@@ -150,7 +150,7 @@
  */
 #define in_atomic_preempt_off() (preempt_count() != PREEMPT_DISABLE_OFFSET)
 
-#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
+#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
 extern void preempt_count_add(int val);
 extern void preempt_count_sub(int val);
 #define preempt_count_dec_and_test() \

include/linux/ring_buffer.h

@@ -164,8 +164,8 @@ void ring_buffer_record_disable(struct ring_buffer *buffer);
 void ring_buffer_record_enable(struct ring_buffer *buffer);
 void ring_buffer_record_off(struct ring_buffer *buffer);
 void ring_buffer_record_on(struct ring_buffer *buffer);
-int ring_buffer_record_is_on(struct ring_buffer *buffer);
-int ring_buffer_record_is_set_on(struct ring_buffer *buffer);
+bool ring_buffer_record_is_on(struct ring_buffer *buffer);
+bool ring_buffer_record_is_set_on(struct ring_buffer *buffer);
 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
 

include/linux/srcu.h

@@ -169,6 +169,11 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
  */
 #define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)
 
+/**
+ * srcu_dereference_notrace - no tracing and no lockdep calls from here
+ */
+#define srcu_dereference_notrace(p, sp) srcu_dereference_check((p), (sp), 1)
+
 /**
  * srcu_read_lock - register a new reader for an SRCU-protected structure.
  * @sp: srcu_struct in which to register the new reader.

include/linux/tracepoint.h

@@ -15,6 +15,7 @@
  */
 
 #include <linux/smp.h>
+#include <linux/srcu.h>
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/cpumask.h>
@@ -33,6 +34,8 @@ struct trace_eval_map {
 
 #define TRACEPOINT_DEFAULT_PRIO	10
 
+extern struct srcu_struct tracepoint_srcu;
+
 extern int
 tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
 extern int
@@ -75,10 +78,16 @@ int unregister_tracepoint_module_notifier(struct notifier_block *nb)
  * probe unregistration and the end of module exit to make sure there is no
  * caller executing a probe when it is freed.
  */
+#ifdef CONFIG_TRACEPOINTS
 static inline void tracepoint_synchronize_unregister(void)
 {
+	synchronize_srcu(&tracepoint_srcu);
 	synchronize_sched();
 }
+#else
+static inline void tracepoint_synchronize_unregister(void)
+{ }
+#endif
 
 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 extern int syscall_regfunc(void);
@@ -129,28 +138,43 @@ extern void syscall_unregfunc(void);
  * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
  * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto".
  */
-#define __DO_TRACE(tp, proto, args, cond, rcucheck)			\
+#define __DO_TRACE(tp, proto, args, cond, rcuidle)			\
 	do {								\
 		struct tracepoint_func *it_func_ptr;			\
 		void *it_func;						\
 		void *__data;						\
+		int __maybe_unused idx = 0;				\
 									\
 		if (!(cond))						\
 			return;						\
-		if (rcucheck)						\
-			rcu_irq_enter_irqson();				\
-		rcu_read_lock_sched_notrace();				\
-		it_func_ptr = rcu_dereference_sched((tp)->funcs);	\
+									\
+		/* srcu can't be used from NMI */			\
+		WARN_ON_ONCE(rcuidle && in_nmi());			\
+									\
+		/* keep srcu and sched-rcu usage consistent */		\
+		preempt_disable_notrace();				\
+									\
+		/*							\
+		 * For rcuidle callers, use srcu since sched-rcu	\
+		 * doesn't work from the idle path.			\
+		 */							\
+		if (rcuidle)						\
+			idx = srcu_read_lock_notrace(&tracepoint_srcu);	\
+									\
+		it_func_ptr = rcu_dereference_raw((tp)->funcs);		\
+									\
 		if (it_func_ptr) {					\
 			do {						\
 				it_func = (it_func_ptr)->func;		\
 				__data = (it_func_ptr)->data;		\
 				((void(*)(proto))(it_func))(args);	\
 			} while ((++it_func_ptr)->func);		\
 		}							\
-		rcu_read_unlock_sched_notrace();			\
-		if (rcucheck)						\
-			rcu_irq_exit_irqson();				\
+									\
+		if (rcuidle)						\
+			srcu_read_unlock_notrace(&tracepoint_srcu, idx);\
+									\
+		preempt_enable_notrace();				\
 	} while (0)
 
 #ifndef MODULE

include/linux/uprobes.h

@@ -121,7 +121,7 @@ extern bool is_swbp_insn(uprobe_opcode_t *insn);
 extern bool is_trap_insn(uprobe_opcode_t *insn);
 extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs);
 extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);
-extern int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t);
+extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t);
 extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
 extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool);
 extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);