Merge tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - kprobes: Restructured stack unwinder to show properly on x86 when a
   stack dump happens from a kretprobe callback.

 - Fix to bootconfig parsing

 - Have tracefs allow owner and group permissions by default (only
   denying others). There's been pressure to allow non root to tracefs
   in a controlled fashion, and using groups is probably the safest.

 - Bootconfig memory managament updates.

 - Bootconfig clean up to have the tools directory be less dependent on
   changes in the kernel tree.

 - Allow perf to be traced by function tracer.

 - Rewrite of function graph tracer to be a callback from the function
   tracer instead of having its own trampoline (this change will happen
   on an arch by arch basis, and currently only x86_64 implements it).

 - Allow multiple direct trampolines (bpf hooks to functions) be batched
   together in one synchronization.

 - Allow histogram triggers to add variables that can perform
   calculations against the event's fields.

 - Use the linker to determine architecture callbacks from the ftrace
   trampoline to allow for proper parameter prototypes and prevent
   warnings from the compiler.

 - Extend histogram triggers to key off of variables.

 - Have trace recursion use bit magic to determine preempt context over
   if branches.

 - Have trace recursion disable preemption as all use cases do anyway.

 - Added testing for verification of tracing utilities.

 - Various small clean ups and fixes.

* tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (101 commits)
  tracing/histogram: Fix semicolon.cocci warnings
  tracing/histogram: Fix documentation inline emphasis warning
  tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together
  tracing: Show size of requested perf buffer
  bootconfig: Initialize ret in xbc_parse_tree()
  ftrace: do CPU checking after preemption disabled
  ftrace: disable preemption when recursion locked
  tracing/histogram: Document expression arithmetic and constants
  tracing/histogram: Optimize division by a power of 2
  tracing/histogram: Covert expr to const if both operands are constants
  tracing/histogram: Simplify handling of .sym-offset in expressions
  tracing: Fix operator precedence for hist triggers expression
  tracing: Add division and multiplication support for hist triggers
  tracing: Add support for creating hist trigger variables from literal
  selftests/ftrace: Stop tracing while reading the trace file by default
  MAINTAINERS: Update KPROBES and TRACING entries
  test_kprobes: Move it from kernel/ to lib/
  docs, kprobes: Remove invalid URL and add new reference
  samples/kretprobes: Fix return value if register_kretprobe() failed
  lib/bootconfig: Fix the xbc_get_info kerneldoc
  ...

1 files changed, 71 insertions, 42 deletions

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index e4f3bfe08757..e974caf39d3e 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -3,7 +3,6 @@
 #define _LINUX_KPROBES_H
 /*
  *  Kernel Probes (KProbes)
- *  include/linux/kprobes.h
  *
  * Copyright (C) IBM Corporation, 2002, 2004
  *
@@ -39,7 +38,7 @@
 #define KPROBE_REENTER		0x00000004
 #define KPROBE_HIT_SSDONE	0x00000008
 
-#else /* CONFIG_KPROBES */
+#else /* !CONFIG_KPROBES */
 #include <asm-generic/kprobes.h>
 typedef int kprobe_opcode_t;
 struct arch_specific_insn {
@@ -105,25 +104,25 @@ struct kprobe {
 #define KPROBE_FLAG_FTRACE	8 /* probe is using ftrace */
 
 /* Has this kprobe gone ? */
-static inline int kprobe_gone(struct kprobe *p)
+static inline bool kprobe_gone(struct kprobe *p)
 {
 	return p->flags & KPROBE_FLAG_GONE;
 }
 
 /* Is this kprobe disabled ? */
-static inline int kprobe_disabled(struct kprobe *p)
+static inline bool kprobe_disabled(struct kprobe *p)
 {
 	return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
 }
 
 /* Is this kprobe really running optimized path ? */
-static inline int kprobe_optimized(struct kprobe *p)
+static inline bool kprobe_optimized(struct kprobe *p)
 {
 	return p->flags & KPROBE_FLAG_OPTIMIZED;
 }
 
 /* Is this kprobe uses ftrace ? */
-static inline int kprobe_ftrace(struct kprobe *p)
+static inline bool kprobe_ftrace(struct kprobe *p)
 {
 	return p->flags & KPROBE_FLAG_FTRACE;
 }
@@ -181,14 +180,6 @@ struct kprobe_blacklist_entry {
 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
-/*
- * For #ifdef avoidance:
- */
-static inline int kprobes_built_in(void)
-{
-	return 1;
-}
-
 extern void kprobe_busy_begin(void);
 extern void kprobe_busy_end(void);
 
@@ -197,15 +188,26 @@ extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 				   struct pt_regs *regs);
 extern int arch_trampoline_kprobe(struct kprobe *p);
 
+void arch_kretprobe_fixup_return(struct pt_regs *regs,
+				 kprobe_opcode_t *correct_ret_addr);
+
+void __kretprobe_trampoline(void);
+/*
+ * Since some architecture uses structured function pointer,
+ * use dereference_function_descriptor() to get real function address.
+ */
+static nokprobe_inline void *kretprobe_trampoline_addr(void)
+{
+	return dereference_kernel_function_descriptor(__kretprobe_trampoline);
+}
+
 /* If the trampoline handler called from a kprobe, use this version */
 unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
-				void *trampoline_address,
-				void *frame_pointer);
+					     void *frame_pointer);
 
 static nokprobe_inline
 unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
-				void *trampoline_address,
-				void *frame_pointer)
+					   void *frame_pointer)
 {
 	unsigned long ret;
 	/*
@@ -214,7 +216,7 @@ unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
 	 * be running at this point.
 	 */
 	kprobe_busy_begin();
-	ret = __kretprobe_trampoline_handler(regs, trampoline_address, frame_pointer);
+	ret = __kretprobe_trampoline_handler(regs, frame_pointer);
 	kprobe_busy_end();
 
 	return ret;
@@ -228,7 +230,7 @@ static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance
 	return READ_ONCE(ri->rph->rp);
 }
 
-#else /* CONFIG_KRETPROBES */
+#else /* !CONFIG_KRETPROBES */
 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 					struct pt_regs *regs)
 {
@@ -239,11 +241,15 @@ static inline int arch_trampoline_kprobe(struct kprobe *p)
 }
 #endif /* CONFIG_KRETPROBES */
 
+/* Markers of '_kprobe_blacklist' section */
+extern unsigned long __start_kprobe_blacklist[];
+extern unsigned long __stop_kprobe_blacklist[];
+
 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 
 #ifdef CONFIG_KPROBES_SANITY_TEST
 extern int init_test_probes(void);
-#else
+#else /* !CONFIG_KPROBES_SANITY_TEST */
 static inline int init_test_probes(void)
 {
 	return 0;
@@ -303,7 +309,7 @@ static inline bool is_kprobe_##__name##_slot(unsigned long addr)	\
 #define KPROBE_OPTINSN_PAGE_SYM		"kprobe_optinsn_page"
 int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
 			     unsigned long *value, char *type, char *sym);
-#else /* __ARCH_WANT_KPROBES_INSN_SLOT */
+#else /* !__ARCH_WANT_KPROBES_INSN_SLOT */
 #define DEFINE_INSN_CACHE_OPS(__name)					\
 static inline bool is_kprobe_##__name##_slot(unsigned long addr)	\
 {									\
@@ -334,7 +340,7 @@ extern void arch_unoptimize_kprobes(struct list_head *oplist,
 				    struct list_head *done_list);
 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
-					unsigned long addr);
+					kprobe_opcode_t *addr);
 
 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 
@@ -345,18 +351,22 @@ extern int sysctl_kprobes_optimization;
 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 					     int write, void *buffer,
 					     size_t *length, loff_t *ppos);
-#endif
+#endif /* CONFIG_SYSCTL */
 extern void wait_for_kprobe_optimizer(void);
-#else
+#else /* !CONFIG_OPTPROBES */
 static inline void wait_for_kprobe_optimizer(void) { }
 #endif /* CONFIG_OPTPROBES */
+
 #ifdef CONFIG_KPROBES_ON_FTRACE
 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 				  struct ftrace_ops *ops, struct ftrace_regs *fregs);
 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
-#endif
-
-int arch_check_ftrace_location(struct kprobe *p);
+#else
+static inline int arch_prepare_kprobe_ftrace(struct kprobe *p)
+{
+	return -EINVAL;
+}
+#endif /* CONFIG_KPROBES_ON_FTRACE */
 
 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 struct kprobe *get_kprobe(void *addr);
@@ -364,7 +374,7 @@ struct kprobe *get_kprobe(void *addr);
 /* kprobe_running() will just return the current_kprobe on this CPU */
 static inline struct kprobe *kprobe_running(void)
 {
-	return (__this_cpu_read(current_kprobe));
+	return __this_cpu_read(current_kprobe);
 }
 
 static inline void reset_current_kprobe(void)
@@ -382,7 +392,6 @@ int register_kprobe(struct kprobe *p);
 void unregister_kprobe(struct kprobe *p);
 int register_kprobes(struct kprobe **kps, int num);
 void unregister_kprobes(struct kprobe **kps, int num);
-unsigned long arch_deref_entry_point(void *);
 
 int register_kretprobe(struct kretprobe *rp);
 void unregister_kretprobe(struct kretprobe *rp);
@@ -410,10 +419,6 @@ int arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
 			    char *type, char *sym);
 #else /* !CONFIG_KPROBES: */
 
-static inline int kprobes_built_in(void)
-{
-	return 0;
-}
 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
 	return 0;
@@ -428,11 +433,11 @@ static inline struct kprobe *kprobe_running(void)
 }
 static inline int register_kprobe(struct kprobe *p)
 {
-	return -ENOSYS;
+	return -EOPNOTSUPP;
 }
 static inline int register_kprobes(struct kprobe **kps, int num)
 {
-	return -ENOSYS;
+	return -EOPNOTSUPP;
 }
 static inline void unregister_kprobe(struct kprobe *p)
 {
@@ -442,11 +447,11 @@ static inline void unregister_kprobes(struct kprobe **kps, int num)
 }
 static inline int register_kretprobe(struct kretprobe *rp)
 {
-	return -ENOSYS;
+	return -EOPNOTSUPP;
 }
 static inline int register_kretprobes(struct kretprobe **rps, int num)
 {
-	return -ENOSYS;
+	return -EOPNOTSUPP;
 }
 static inline void unregister_kretprobe(struct kretprobe *rp)
 {
@@ -462,11 +467,11 @@ static inline void kprobe_free_init_mem(void)
 }
 static inline int disable_kprobe(struct kprobe *kp)
 {
-	return -ENOSYS;
+	return -EOPNOTSUPP;
 }
 static inline int enable_kprobe(struct kprobe *kp)
 {
-	return -ENOSYS;
+	return -EOPNOTSUPP;
 }
 
 static inline bool within_kprobe_blacklist(unsigned long addr)
@@ -479,6 +484,7 @@ static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
 	return -ERANGE;
 }
 #endif /* CONFIG_KPROBES */
+
 static inline int disable_kretprobe(struct kretprobe *rp)
 {
 	return disable_kprobe(&rp->kp);
@@ -493,19 +499,42 @@ static inline bool is_kprobe_insn_slot(unsigned long addr)
 {
 	return false;
 }
-#endif
+#endif /* !CONFIG_KPROBES */
+
 #ifndef CONFIG_OPTPROBES
 static inline bool is_kprobe_optinsn_slot(unsigned long addr)
 {
 	return false;
 }
+#endif /* !CONFIG_OPTPROBES */
+
+#ifdef CONFIG_KRETPROBES
+static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
+{
+	return (void *)addr == kretprobe_trampoline_addr();
+}
+
+unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
+				      struct llist_node **cur);
+#else
+static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
+{
+	return false;
+}
+
+static nokprobe_inline
+unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
+				      struct llist_node **cur)
+{
+	return 0;
+}
 #endif
 
 /* Returns true if kprobes handled the fault */
 static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
 					      unsigned int trap)
 {
-	if (!kprobes_built_in())
+	if (!IS_ENABLED(CONFIG_KPROBES))
 		return false;
 	if (user_mode(regs))
 		return false;