x86/dumpstack: Remove dump_trace() and related callbacks

All previous users of dump_trace() have been converted to use the new
unwind interfaces, so we can remove it and the related
print_context_stack() and print_context_stack_bp() callback functions.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/5b97da3572b40b5a4d8e185cf2429308d0987a13.1474045023.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/stacktrace.h

@@ -45,42 +45,6 @@ static inline bool on_stack(struct stack_info *info, void *addr, size_t len)
 
 extern int kstack_depth_to_print;
 
-struct thread_info;
-struct stacktrace_ops;
-
-typedef unsigned long (*walk_stack_t)(struct task_struct *task,
-				      unsigned long *stack,
-				      unsigned long bp,
-				      const struct stacktrace_ops *ops,
-				      void *data,
-				      struct stack_info *info,
-				      int *graph);
-
-extern unsigned long
-print_context_stack(struct task_struct *task,
-		    unsigned long *stack, unsigned long bp,
-		    const struct stacktrace_ops *ops, void *data,
-		    struct stack_info *info, int *graph);
-
-extern unsigned long
-print_context_stack_bp(struct task_struct *task,
-		       unsigned long *stack, unsigned long bp,
-		       const struct stacktrace_ops *ops, void *data,
-		       struct stack_info *info, int *graph);
-
-/* Generic stack tracer with callbacks */
-
-struct stacktrace_ops {
-	int (*address)(void *data, unsigned long address, int reliable);
-	/* On negative return stop dumping */
-	int (*stack)(void *data, const char *name);
-	walk_stack_t	walk_stack;
-};
-
-void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
-		unsigned long *stack, unsigned long bp,
-		const struct stacktrace_ops *ops, void *data);
-
 #ifdef CONFIG_X86_32
 #define STACKSLOTS_PER_LINE 8
 #else

arch/x86/kernel/dumpstack.c

@@ -56,92 +56,6 @@ void printk_address(unsigned long address)
 	pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address);
 }
 
-/*
- * x86-64 can have up to three kernel stacks:
- * process stack
- * interrupt stack
- * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
- */
-
-unsigned long
-print_context_stack(struct task_struct *task,
-		unsigned long *stack, unsigned long bp,
-		const struct stacktrace_ops *ops, void *data,
-		struct stack_info *info, int *graph)
-{
-	struct stack_frame *frame = (struct stack_frame *)bp;
-
-	/*
-	 * If we overflowed the stack into a guard page, jump back to the
-	 * bottom of the usable stack.
-	 */
-	if ((unsigned long)task_stack_page(task) - (unsigned long)stack <
-	    PAGE_SIZE)
-		stack = (unsigned long *)task_stack_page(task);
-
-	while (on_stack(info, stack, sizeof(*stack))) {
-		unsigned long addr = *stack;
-
-		if (__kernel_text_address(addr)) {
-			unsigned long real_addr;
-			int reliable = 0;
-
-			if ((unsigned long) stack == bp + sizeof(long)) {
-				reliable = 1;
-				frame = frame->next_frame;
-				bp = (unsigned long) frame;
-			}
-
-			/*
-			 * When function graph tracing is enabled for a
-			 * function, its return address on the stack is
-			 * replaced with the address of an ftrace handler
-			 * (return_to_handler).  In that case, before printing
-			 * the "real" address, we want to print the handler
-			 * address as an "unreliable" hint that function graph
-			 * tracing was involved.
-			 */
-			real_addr = ftrace_graph_ret_addr(task, graph, addr,
-							  stack);
-			if (real_addr != addr)
-				ops->address(data, addr, 0);
-
-			ops->address(data, real_addr, reliable);
-		}
-		stack++;
-	}
-	return bp;
-}
-EXPORT_SYMBOL_GPL(print_context_stack);
-
-unsigned long
-print_context_stack_bp(struct task_struct *task,
-		       unsigned long *stack, unsigned long bp,
-		       const struct stacktrace_ops *ops, void *data,
-		       struct stack_info *info, int *graph)
-{
-	struct stack_frame *frame = (struct stack_frame *)bp;
-	unsigned long *retp = &frame->return_address;
-
-	while (on_stack(info, stack, sizeof(*stack) * 2)) {
-		unsigned long addr = *retp;
-		unsigned long real_addr;
-
-		if (!__kernel_text_address(addr))
-			break;
-
-		real_addr = ftrace_graph_ret_addr(task, graph, addr, retp);
-		if (ops->address(data, real_addr, 1))
-			break;
-
-		frame = frame->next_frame;
-		retp = &frame->return_address;
-	}
-
-	return (unsigned long)frame;
-}
-EXPORT_SYMBOL_GPL(print_context_stack_bp);
-
 void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 			unsigned long *stack, char *log_lvl)
 {

arch/x86/kernel/dumpstack_32.c

@@ -121,41 +121,6 @@ unknown:
 	return -EINVAL;
 }
 
-void dump_trace(struct task_struct *task, struct pt_regs *regs,
-		unsigned long *stack, unsigned long bp,
-		const struct stacktrace_ops *ops, void *data)
-{
-	unsigned long visit_mask = 0;
-	int graph = 0;
-
-	task = task ? : current;
-	stack = stack ? : get_stack_pointer(task, regs);
-	bp = bp ? : (unsigned long)get_frame_pointer(task, regs);
-
-	for (;;) {
-		const char *begin_str, *end_str;
-		struct stack_info info;
-
-		if (get_stack_info(stack, task, &info, &visit_mask))
-			break;
-
-		stack_type_str(info.type, &begin_str, &end_str);
-
-		if (begin_str && ops->stack(data, begin_str) < 0)
-			break;
-
-		bp = ops->walk_stack(task, stack, bp, ops, data, &info, &graph);
-
-		if (end_str && ops->stack(data, end_str) < 0)
-			break;
-
-		stack = info.next_sp;
-
-		touch_nmi_watchdog();
-	}
-}
-EXPORT_SYMBOL(dump_trace);
-
 void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 			unsigned long *sp, char *log_lvl)
 {

arch/x86/kernel/dumpstack_64.c

@@ -140,75 +140,6 @@ unknown:
 	return -EINVAL;
 }
 
-/*
- * x86-64 can have up to three kernel stacks:
- * process stack
- * interrupt stack
- * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
- */
-
-void dump_trace(struct task_struct *task, struct pt_regs *regs,
-		unsigned long *stack, unsigned long bp,
-		const struct stacktrace_ops *ops, void *data)
-{
-	unsigned long visit_mask = 0;
-	struct stack_info info;
-	int graph = 0;
-	int done = 0;
-
-	task = task ? : current;
-	stack = stack ? : get_stack_pointer(task, regs);
-	bp = bp ? : (unsigned long)get_frame_pointer(task, regs);
-
-	/*
-	 * Print function call entries in all stacks, starting at the
-	 * current stack address. If the stacks consist of nested
-	 * exceptions
-	 */
-	while (!done) {
-		const char *begin_str, *end_str;
-
-		get_stack_info(stack, task, &info, &visit_mask);
-
-		/* Default finish unless specified to continue */
-		done = 1;
-
-		switch (info.type) {
-
-		/* Break out early if we are on the thread stack */
-		case STACK_TYPE_TASK:
-			break;
-
-		case STACK_TYPE_IRQ:
-		case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
-
-			stack_type_str(info.type, &begin_str, &end_str);
-
-			if (ops->stack(data, begin_str) < 0)
-				break;
-
-			bp = ops->walk_stack(task, stack, bp, ops,
-					     data, &info, &graph);
-
-			ops->stack(data, end_str);
-
-			stack = info.next_sp;
-			done = 0;
-			break;
-
-		default:
-			ops->stack(data, "UNK");
-			break;
-		}
-	}
-
-	/*
-	 * This handles the process stack:
-	 */
-	bp = ops->walk_stack(task, stack, bp, ops, data, &info, &graph);
-}
-EXPORT_SYMBOL(dump_trace);
-
 void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 			unsigned long *sp, char *log_lvl)
 {