[tip:core/stacktrace] x86/stacktrace: Use common infrastructure

[tip-bot for Thomas Gleixner]

Commit-ID:  3599fe12a125fa7118da2bcc5033d7741fb5f3a1
Gitweb:     https://git.kernel.org/tip/3599fe12a125fa7118da2bcc5033d7741fb5f3a1
Author:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 25 Apr 2019 11:45:22 +0200
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Mon, 29 Apr 2019 12:37:57 +0200

x86/stacktrace: Use common infrastructure

Replace the stack_trace_save*() functions with the new arch_stack_walk()
interfaces.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: kasan-dev@xxxxxxxxxxxxxxxx
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: David Sterba <dsterba@xxxxxxxx>
Cc: Chris Mason <clm@xxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
Cc: linux-btrfs@xxxxxxxxxxxxxxx
Cc: dm-devel@xxxxxxxxxx
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: Alasdair Kergon <agk@xxxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Cc: Miroslav Benes <mbenes@xxxxxxx>
Link: https://lkml.kernel.org/r/20190425094803.816485461@xxxxxxxxxxxxx

---
 arch/x86/Kconfig             |   1 +
 arch/x86/kernel/stacktrace.c | 116 +++++++------------------------------------
 2 files changed, 20 insertions(+), 97 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5ad92419be19..b5978e35a8a8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -74,6 +74,7 @@ config X86
 	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_MIGHT_HAVE_PC_SERIO
+	select ARCH_STACKWALK
 	select ARCH_SUPPORTS_ACPI
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index b2f706f1e0b7..2abf27d7df6b 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -12,75 +12,31 @@
 #include <asm/stacktrace.h>
 #include <asm/unwind.h>
 
-static int save_stack_address(struct stack_trace *trace, unsigned long addr,
-			      bool nosched)
-{
-	if (nosched && in_sched_functions(addr))
-		return 0;
-
-	if (trace->skip > 0) {
-		trace->skip--;
-		return 0;
-	}
-
-	if (trace->nr_entries >= trace->max_entries)
-		return -1;
-
-	trace->entries[trace->nr_entries++] = addr;
-	return 0;
-}
-
-static void noinline __save_stack_trace(struct stack_trace *trace,
-			       struct task_struct *task, struct pt_regs *regs,
-			       bool nosched)
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+		     struct task_struct *task, struct pt_regs *regs)
 {
 	struct unwind_state state;
 	unsigned long addr;
 
-	if (regs)
-		save_stack_address(trace, regs->ip, nosched);
+	if (regs && !consume_entry(cookie, regs->ip, false))
+		return;
 
 	for (unwind_start(&state, task, regs, NULL); !unwind_done(&state);
 	     unwind_next_frame(&state)) {
 		addr = unwind_get_return_address(&state);
-		if (!addr || save_stack_address(trace, addr, nosched))
+		if (!addr || !consume_entry(cookie, addr, false))
 			break;
 	}
 }
 
 /*
- * Save stack-backtrace addresses into a stack_trace buffer.
+ * This function returns an error if it detects any unreliable features of the
+ * stack.  Otherwise it guarantees that the stack trace is reliable.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
  */
-void save_stack_trace(struct stack_trace *trace)
-{
-	trace->skip++;
-	__save_stack_trace(trace, current, NULL, false);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace);
-
-void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
-{
-	__save_stack_trace(trace, current, regs, false);
-}
-
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
-{
-	if (!try_get_task_stack(tsk))
-		return;
-
-	if (tsk == current)
-		trace->skip++;
-	__save_stack_trace(trace, tsk, NULL, true);
-
-	put_task_stack(tsk);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
-
-#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
-
-static int __always_inline
-__save_stack_trace_reliable(struct stack_trace *trace,
-			    struct task_struct *task)
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+			     void *cookie, struct task_struct *task)
 {
 	struct unwind_state state;
 	struct pt_regs *regs;
@@ -117,7 +73,7 @@ __save_stack_trace_reliable(struct stack_trace *trace,
 		if (!addr)
 			return -EINVAL;
 
-		if (save_stack_address(trace, addr, false))
+		if (!consume_entry(cookie, addr, false))
 			return -EINVAL;
 	}
 
@@ -132,32 +88,6 @@ __save_stack_trace_reliable(struct stack_trace *trace,
 	return 0;
 }
 
-/*
- * This function returns an error if it detects any unreliable features of the
- * stack.  Otherwise it guarantees that the stack trace is reliable.
- *
- * If the task is not 'current', the caller *must* ensure the task is inactive.
- */
-int save_stack_trace_tsk_reliable(struct task_struct *tsk,
-				  struct stack_trace *trace)
-{
-	int ret;
-
-	/*
-	 * If the task doesn't have a stack (e.g., a zombie), the stack is
-	 * "reliably" empty.
-	 */
-	if (!try_get_task_stack(tsk))
-		return 0;
-
-	ret = __save_stack_trace_reliable(trace, tsk);
-
-	put_task_stack(tsk);
-
-	return ret;
-}
-#endif /* CONFIG_HAVE_RELIABLE_STACKTRACE */
-
 /* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
 
 struct stack_frame_user {
@@ -182,15 +112,15 @@ copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
 	return ret;
 }
 
-static inline void __save_stack_trace_user(struct stack_trace *trace)
+void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
+			  const struct pt_regs *regs)
 {
-	const struct pt_regs *regs = task_pt_regs(current);
 	const void __user *fp = (const void __user *)regs->bp;
 
-	if (trace->nr_entries < trace->max_entries)
-		trace->entries[trace->nr_entries++] = regs->ip;
+	if (!consume_entry(cookie, regs->ip, false))
+		return;
 
-	while (trace->nr_entries < trace->max_entries) {
+	while (1) {
 		struct stack_frame_user frame;
 
 		frame.next_fp = NULL;
@@ -200,8 +130,8 @@ static inline void __save_stack_trace_user(struct stack_trace *trace)
 		if ((unsigned long)fp < regs->sp)
 			break;
 		if (frame.ret_addr) {
-			trace->entries[trace->nr_entries++] =
-				frame.ret_addr;
+			if (!consume_entry(cookie, frame.ret_addr, false))
+				return;
 		}
 		if (fp == frame.next_fp)
 			break;
@@ -209,11 +139,3 @@ static inline void __save_stack_trace_user(struct stack_trace *trace)
 	}
 }
 
-void save_stack_trace_user(struct stack_trace *trace)
-{
-	/*
-	 * Trace user stack if we are not a kernel thread
-	 */
-	if (current->mm)
-		__save_stack_trace_user(trace);
-}