arch/csky/kernel/stacktrace.c

Source file repositories/reference/linux-study-clean/arch/csky/kernel/stacktrace.c

File Facts

System
Linux kernel
Corpus path
arch/csky/kernel/stacktrace.c
Extension
.c
Size
3540 bytes
Lines
157
Domain
Architecture Layer
Bucket
arch/csky
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct stackframe {
	unsigned long fp;
	unsigned long ra;
};

void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
			     bool (*fn)(unsigned long, void *), void *arg)
{
	unsigned long fp, sp, pc;

	if (regs) {
		fp = frame_pointer(regs);
		sp = user_stack_pointer(regs);
		pc = instruction_pointer(regs);
	} else if (task == NULL || task == current) {
		const register unsigned long current_fp __asm__ ("r8");
		fp = current_fp;
		sp = current_stack_pointer;
		pc = (unsigned long)walk_stackframe;
	} else {
		/* task blocked in __switch_to */
		fp = thread_saved_fp(task);
		sp = thread_saved_sp(task);
		pc = thread_saved_lr(task);
	}

	for (;;) {
		unsigned long low, high;
		struct stackframe *frame;

		if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
			break;

		/* Validate frame pointer */
		low = sp;
		high = ALIGN(sp, THREAD_SIZE);
		if (unlikely(fp < low || fp > high || fp & 0x3))
			break;
		/* Unwind stack frame */
		frame = (struct stackframe *)fp;
		sp = fp;
		fp = frame->fp;
		pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
					   (unsigned long *)(fp - 8));
	}
}

#else /* !CONFIG_FRAME_POINTER */

static void notrace walk_stackframe(struct task_struct *task,
	struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
{
	unsigned long sp, pc;
	unsigned long *ksp;

	if (regs) {
		sp = user_stack_pointer(regs);
		pc = instruction_pointer(regs);
	} else if (task == NULL || task == current) {
		sp = current_stack_pointer;
		pc = (unsigned long)walk_stackframe;
	} else {
		/* task blocked in __switch_to */
		sp = thread_saved_sp(task);
		pc = thread_saved_lr(task);
	}

	if (unlikely(sp & 0x3))
		return;

	ksp = (unsigned long *)sp;
	while (!kstack_end(ksp)) {
		if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
			break;
		pc = (*ksp++) - 0x4;
	}
}
#endif /* CONFIG_FRAME_POINTER */

static bool print_trace_address(unsigned long pc, void *arg)
{
	print_ip_sym((const char *)arg, pc);
	return false;
}

void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
{
	pr_cont("Call Trace:\n");
	walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);
}

Annotation

Implementation Notes