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: 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>

diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
index 433fde85b14ea902308cdf5bf83583c7305473b1..4aefbe32265d8f31b64308350ea3b2b9d8a4d96c 100644 (file)
--- 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 dfa77da2fd2ec5413b6358c853f5a8532d250419..5fff629b1a89806649fcf53483bb9be211bace1c 100644 (file)
--- 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 7c294da45bf524e9891d8c3e83ab71f9b0115e50..e580d4cd2729afa0f53c8cace5fc844f17d5e2d6 100644 (file)
--- 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;