From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
"David S. Miller" <davem@davemloft.net>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Jonathan Corbet <corbet@lwn.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>
Subject: [PATCH v7 2/3] ftrace: introduce FTRACE_IP_EXTENSION
Date: Wed, 25 Dec 2019 09:42:52 +0000 [thread overview]
Message-ID: <20191225172836.7f381759@xhacker.debian> (raw)
In-Reply-To: <20191225172625.69811b3e@xhacker.debian>
On some architectures, the DYNAMIC_FTRACE_WITH_REGS is implemented by
gcc's -fpatchable-function-entry option. Take arm64 for example, arm64
makes use of GCC -fpatchable-function-entry=2 option to insert two
nops. When the function is traced, the first nop will be modified to
the LR saver, then the second nop to "bl <ftrace-entry>". we need to
update ftrace_location() to recognise these two instructions as being
part of ftrace. To do this, we introduce FTRACE_IP_EXTENSION to let
ftrace_location search IP, IP + FTRACE_IP_EXTENSION range.
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
include/linux/ftrace.h | 4 ++++
kernel/trace/ftrace.c | 2 +-
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 7247d35c3d16..05a03b2a2f39 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -20,6 +20,10 @@
#include <asm/ftrace.h>
+#ifndef FTRACE_IP_EXTENSION
+#define FTRACE_IP_EXTENSION 0
+#endif
+
/*
* If the arch supports passing the variable contents of
* function_trace_op as the third parameter back from the
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 74439ab5c2b6..a8cfea502369 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1590,7 +1590,7 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end)
*/
unsigned long ftrace_location(unsigned long ip)
{
- return ftrace_location_range(ip, ip);
+ return ftrace_location_range(ip, ip + FTRACE_IP_EXTENSION);
}
/**
--
2.24.1
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next prev parent reply other threads:[~2019-12-25 9:43 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-25 9:40 [PATCH v7 0/3] arm64: implement KPROBES_ON_FTRACE Jisheng Zhang
2019-12-25 9:42 ` [PATCH v7 1/3] kprobes/ftrace: Use ftrace_location() when [dis]arming probes Jisheng Zhang
2019-12-25 9:46 ` Jisheng Zhang
2019-12-25 9:42 ` Jisheng Zhang [this message]
2019-12-26 2:45 ` [PATCH v7 2/3] ftrace: introduce FTRACE_IP_EXTENSION Masami Hiramatsu
2020-01-08 0:05 ` Steven Rostedt
2019-12-25 9:44 ` [PATCH v7 3/3] arm64: implement KPROBES_ON_FTRACE Jisheng Zhang
2019-12-26 2:57 ` Masami Hiramatsu
2019-12-26 3:18 ` Jisheng Zhang
2019-12-26 4:25 ` Jisheng Zhang
2019-12-26 9:26 ` Masami Hiramatsu
2020-07-21 13:24 ` Masami Hiramatsu
2020-07-24 7:06 ` Jisheng Zhang
2020-07-24 16:54 ` Masami Hiramatsu
2020-02-28 15:31 ` Mark Rutland
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