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From: Miroslav Benes <mbenes@suse.cz>
To: heiko.carstens@de.ibm.com, gor@linux.ibm.com,
	borntraeger@de.ibm.com, jpoimboe@redhat.com,
	joe.lawrence@redhat.com
Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
	jikos@kernel.org, pmladek@suse.com, nstange@suse.de,
	live-patching@vger.kernel.org, Miroslav Benes <mbenes@suse.cz>
Subject: [PATCH v3 1/4] s390/unwind: drop unnecessary code around calling ftrace_graph_ret_addr()
Date: Wed,  6 Nov 2019 10:55:58 +0100
Message-ID: <20191106095601.29986-2-mbenes@suse.cz> (raw)
In-Reply-To: <20191106095601.29986-1-mbenes@suse.cz>

The current code around calling ftrace_graph_ret_addr() is ifdeffed and
also tests if ftrace redirection is present on stack.
ftrace_graph_ret_addr() however performs the test internally and there
is a version for !CONFIG_FUNCTION_GRAPH_TRACER as well. The unnecessary
code can thus be dropped.

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
---
 arch/s390/kernel/unwind_bc.c | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c
index a8204f952315..5a78deacb972 100644
--- a/arch/s390/kernel/unwind_bc.c
+++ b/arch/s390/kernel/unwind_bc.c
@@ -85,12 +85,8 @@ bool unwind_next_frame(struct unwind_state *state)
 		}
 	}
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	/* Decode any ftrace redirection */
-	if (ip == (unsigned long) return_to_handler)
-		ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
-					   ip, (void *) sp);
-#endif
+	ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+				   ip, (void *) sp);
 
 	/* Update unwind state */
 	state->sp = sp;
@@ -147,12 +143,8 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
 		reuse_sp = false;
 	}
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	/* Decode any ftrace redirection */
-	if (ip == (unsigned long) return_to_handler)
-		ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
-					   ip, NULL);
-#endif
+	ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+				   ip, NULL);
 
 	/* Update unwind state */
 	state->sp = sp;
-- 
2.23.0


  reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-06  9:55 [PATCH v3 0/4] s390/livepatch: Implement reliable stack tracing for the consistency model Miroslav Benes
2019-11-06  9:55 ` Miroslav Benes [this message]
2019-11-06  9:55 ` [PATCH v3 2/4] s390/unwind: split unwind_next_frame() to several functions Miroslav Benes
2019-11-06  9:56 ` [PATCH v3 3/4] s390/unwind: prepare the unwinding interface for reliable stack traces Miroslav Benes
2019-11-06  9:56 ` [PATCH v3 4/4] s390/livepatch: Implement reliable stack tracing for the consistency model Miroslav Benes

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