s390/dumpstack: implement and use return_address() (56063306) · Commits · 戴 / test

Implement return_address() and use it instead of __builtin_return_address(n). __builtin_return_address(n) is not guaranteed to work for n > 0, therefore implement a private return_address() function which walks the stack frames and returns the proper return address. This way we get also rid of a compile warning which gcc 6.1 emits and look like all other architectures. Signed-off-by:

Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by:

Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/ftrace.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -12,7 +12,9 @@

		#ifndef __ASSEMBLY__

		#define ftrace_return_address(n) __builtin_return_address(n)
		unsigned long return_address(int depth);

		#define ftrace_return_address(n) return_address(n)

		void _mcount(void);
		void ftrace_caller(void);

arch/s390/kernel/dumpstack.c

+24 −0

Original line number	Diff line number	Diff line
		@@ -89,6 +89,30 @@ void dump_trace(dump_trace_func_t func, void data, struct task_struct task,
		}
		EXPORT_SYMBOL_GPL(dump_trace);

		struct return_address_data {
		unsigned long address;
		int depth;
		};

		static int __return_address(void *data, unsigned long address)
		{
		struct return_address_data *rd = data;

		if (rd->depth--)
		return 0;
		rd->address = address;
		return 1;
		}

		unsigned long return_address(int depth)
		{
		struct return_address_data rd = { .depth = depth + 2 };

		dump_trace(__return_address, &rd, NULL, current_stack_pointer());
		return rd.address;
		}
		EXPORT_SYMBOL_GPL(return_address);

		static int show_address(void *data, unsigned long address)
		{
		printk("([<%016lx>] %pSR)\n", address, (void *)address);

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