[tip:perf/core] x86/kprobes: Move trampoline code into RODATA

tip-bot for Masami Hiramatsu
2019-02-13T09:01:13Z

Commit-ID: 877b145f0f4723133f934be402b8dfc769eb971f
Gitweb: https://git.kernel.org/tip/877b145f0f4723133f934be402b8dfc769eb971f
Author: Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Wed, 13 Feb 2019 01:11:47 +0900
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 13 Feb 2019 08:16:39 +0100

x86/kprobes: Move trampoline code into RODATA

Move optprobe trampoline code into RODATA since it is
not executed, but copied and modified to be used on
a trampoline buffer.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/154998790744.31052.3016106262944915510.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/kprobes/opt.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 544bd41a514c..f14262952015 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -97,6 +97,7 @@ static void synthesize_set_arg1(kprobe_opcode_t *addr, unsigned long val)
}

asm (
+ ".pushsection .rodata\n"
"optprobe_template_func:\n"
".global optprobe_template_entry\n"
"optprobe_template_entry:\n"
@@ -136,16 +137,10 @@ asm (
#endif
".global optprobe_template_end\n"
"optprobe_template_end:\n"
- ".type optprobe_template_func, @function\n"
- ".size optprobe_template_func, .-optprobe_template_func\n");
+ ".popsection\n");

void optprobe_template_func(void);
STACK_FRAME_NON_STANDARD(optprobe_template_func);
-NOKPROBE_SYMBOL(optprobe_template_func);
-NOKPROBE_SYMBOL(optprobe_template_entry);
-NOKPROBE_SYMBOL(optprobe_template_val);
-NOKPROBE_SYMBOL(optprobe_template_call);
-NOKPROBE_SYMBOL(optprobe_template_end);

#define TMPL_MOVE_IDX \
((long)optprobe_template_val - (long)optprobe_template_entry)