Commit ebd912ff authored by Heiko Carstens's avatar Heiko Carstens Committed by Alexander Gordeev
Browse files

s390/stacktrace: Merge perf_callchain_user() and arch_stack_walk_user() 



The two functions perf_callchain_user() and arch_stack_walk_user() are
nearly identical. Reduce code duplication and add a common helper which can
be called by both functions.

Fixes: aa44433a ("s390: add USER_STACKTRACE support")
Reviewed-by: default avatarJens Remus <jremus@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent 185445c7

arch/s390/include/asm/stacktrace.h

+7 −0
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
#ifndef _ASM_S390_STACKTRACE_H

#define _ASM_S390_STACKTRACE_H



#include <linux/stacktrace.h>

#include <linux/uaccess.h>

#include <linux/ptrace.h>
@@ -12,6 +13,12 @@ struct stack_frame_user { 
	unsigned long empty2[4];

};



struct perf_callchain_entry_ctx;



void arch_stack_walk_user_common(stack_trace_consume_fn consume_entry, void *cookie,

				 struct perf_callchain_entry_ctx *entry,

				 const struct pt_regs *regs, bool perf);



enum stack_type {

	STACK_TYPE_UNKNOWN,

	STACK_TYPE_TASK,

arch/s390/kernel/perf_event.c

+1 −33
Original line number Diff line number Diff line
@@ -218,39 +218,7 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, 
void perf_callchain_user(struct perf_callchain_entry_ctx *entry,

			 struct pt_regs *regs)

{

	struct stack_frame_user __user *sf;

	unsigned long ip, sp;

	bool first = true;



	if (is_compat_task())

		return;

	perf_callchain_store(entry, instruction_pointer(regs));

	sf = (void __user *)user_stack_pointer(regs);

	pagefault_disable();

	while (entry->nr < entry->max_stack) {

		if (__get_user(sp, &sf->back_chain))

			break;

		if (__get_user(ip, &sf->gprs[8]))

			break;

		if (ip & 0x1) {

			/*

			 * If the instruction address is invalid, and this

			 * is the first stack frame, assume r14 has not

			 * been written to the stack yet. Otherwise exit.

			 */

			if (first && !(regs->gprs[14] & 0x1))

				ip = regs->gprs[14];

			else

				break;

		}

		perf_callchain_store(entry, ip);

		/* Sanity check: ABI requires SP to be aligned 8 bytes. */

		if (!sp || sp & 0x7)

			break;

		sf = (void __user *)sp;

		first = false;

	}

	pagefault_enable();

	arch_stack_walk_user_common(NULL, NULL, entry, regs, true);

}



/* Perf definitions for PMU event attributes in sysfs */

arch/s390/kernel/stacktrace.c

+28 −5
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 *  Copyright IBM Corp. 2006

 */



#include <linux/perf_event.h>

#include <linux/stacktrace.h>

#include <linux/uaccess.h>

#include <linux/compat.h>
@@ -62,8 +63,23 @@ int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, 
	return 0;

}



void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,

			  const struct pt_regs *regs)

static inline bool store_ip(stack_trace_consume_fn consume_entry, void *cookie,

			    struct perf_callchain_entry_ctx *entry, bool perf,

			    unsigned long ip)

{

#ifdef CONFIG_PERF_EVENTS

	if (perf) {

		if (perf_callchain_store(entry, ip))

			return false;

		return true;

	}

#endif

	return consume_entry(cookie, ip);

}



void arch_stack_walk_user_common(stack_trace_consume_fn consume_entry, void *cookie,

				 struct perf_callchain_entry_ctx *entry,

				 const struct pt_regs *regs, bool perf)

{

	struct stack_frame_user __user *sf;

	unsigned long ip, sp;
@@ -71,7 +87,8 @@ void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie, 


	if (is_compat_task())

		return;

	if (!consume_entry(cookie, instruction_pointer(regs)))

	ip = instruction_pointer(regs);

	if (!store_ip(consume_entry, cookie, entry, perf, ip))

		return;

	sf = (void __user *)user_stack_pointer(regs);

	pagefault_disable();
@@ -91,8 +108,8 @@ void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie, 
			else

				break;

		}

		if (!consume_entry(cookie, ip))

			break;

		if (!store_ip(consume_entry, cookie, entry, perf, ip))

			return;

		/* Sanity check: ABI requires SP to be aligned 8 bytes. */

		if (!sp || sp & 0x7)

			break;
@@ -102,6 +119,12 @@ void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie, 
	pagefault_enable();

}



void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,

			  const struct pt_regs *regs)

{

	arch_stack_walk_user_common(consume_entry, cookie, NULL, regs, false);

}



unsigned long return_address(unsigned int n)

{

	struct unwind_state state;