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s390/dumpstack: implement and use return_address() 

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>
This commit is contained in:
Heiko Carstens 2016-05-02 14:38:29 +02:00 committed by Martin Schwidefsky
parent e18eb2d1eb
commit 5606330627
2 changed files with 27 additions and 1 deletions
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4
arch/s390/include/asm/ftrace.h
View File

@ -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);

24
arch/s390/kernel/dumpstack.c
View File

@ -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);