From: Huang Pei <huangpei@loongson.cn>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>, ambrosehua@gmail.com
Cc: Bibo Mao <maobibo@loongson.cn>,
linux-mips@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org, Jiaxun Yang <jiaxun.yang@flygoat.com>,
Paul Burton <paulburton@kernel.org>,
Li Xuefeng <lixuefeng@loongson.cn>,
Yang Tiezhu <yangtiezhu@loongson.cn>,
Gao Juxin <gaojuxin@loongson.cn>,
Huacai Chen <chenhuacai@loongson.cn>,
Jinyang He <hejinyang@loongson.cn>,
"Maciej W . Rozycki" <macro@orcam.me.uk>,
Steven Rostedt <rostedt@goodmis.org>,
Jisheng Zhang <Jisheng.Zhang@synaptics.com>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH 5/6] ftrace: introduce FTRACE_IP_EXTENSION
Date: Sat, 13 Mar 2021 14:41:48 +0800 [thread overview]
Message-ID: <20210313064149.29276-6-huangpei@loongson.cn> (raw)
In-Reply-To: <20210313064149.29276-1-huangpei@loongson.cn>
From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
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 1bd3a0356ae4..c1e1fbde8a04 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 9c1bba8cc51b..a6f0e3db2479 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1583,7 +1583,7 @@ 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);
}
/**
--
2.17.1
next prev parent reply other threads:[~2021-03-13 6:42 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-13 6:41 [RFC PATCH V2]: add DYNAMC_FTRACE_WITH_REGS and Huang Pei
2021-03-13 6:41 ` [PATCH 1/6] MIPS: replace -pg with CC_FLAGS_FTRACE Huang Pei
2021-03-25 19:38 ` Steven Rostedt
2021-03-26 1:48 ` Huang Pei
2021-03-13 6:41 ` [PATCH 2/6] MIPS: move FTRACE_SYSCALLS from ftrace.c into syscall.c Huang Pei
2021-03-25 19:38 ` Steven Rostedt
2021-03-26 14:01 ` Huang Pei
2021-03-13 6:41 ` [PATCH 3/6] MIPS: prepare for new ftrace implementation Huang Pei
2021-03-25 19:39 ` Steven Rostedt
2021-03-13 6:41 ` [PATCH 4/6] kprobes/ftrace: Use ftrace_location() when [dis]arming probes Huang Pei
2021-03-25 19:44 ` Steven Rostedt
2021-03-26 14:12 ` Huang Pei
2021-03-26 14:23 ` Steven Rostedt
2021-03-13 6:41 ` Huang Pei [this message]
2021-03-13 9:26 ` [PATCH 5/6] ftrace: introduce FTRACE_IP_EXTENSION Sergei Shtylyov
2021-03-13 6:41 ` [PATCH 6/6] MIPS: add DYNAMIC_FTRACE_WITH_REGS and KPROBES_ON_FTACE Huang Pei
2021-03-13 21:37 ` kernel test robot
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