[PATCH 6.9 131/374] s390/stacktrace: Merge perf_callchain_user() and arch_stack_walk_user()

Greg Kroah-Hartman
2024-06-06T14:09:22Z

From: Heiko Carstens <hca@linux.ibm.com>

[ Upstream commit ebd912ff9919a10609511383d94942362234c077 ]

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: aa44433ac4ee ("s390: add USER_STACKTRACE support")
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/include/asm/stacktrace.h | 7 ++++++
arch/s390/kernel/perf_event.c | 34 +-----------------------------
arch/s390/kernel/stacktrace.c | 33 ++++++++++++++++++++++++-----
3 files changed, 36 insertions(+), 38 deletions(-)

diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
index 433fde85b14ea..4aefbe32265d8 100644
--- a/arch/s390/include/asm/stacktrace.h
+++ b/arch/s390/include/asm/stacktrace.h
@@ -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,
diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c
index dfa77da2fd2ec..5fff629b1a898 100644
--- a/arch/s390/kernel/perf_event.c
+++ b/arch/s390/kernel/perf_event.c
@@ -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 */
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 7c294da45bf52..e580d4cd2729a 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -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;
--
2.43.0