linux-kernel - [PATCH v1 tip/master 0/3] kprobes/x86: retpoline: Fix kprobes for retpoline

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Message-Id: <151627684798.24682.2979775081582774869.stgit@devbox>
Date:   Thu, 18 Jan 2018 21:00:48 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Ingo Molnar <mingo@...nel.org>, David Woodhouse <dwmw@...zon.co.uk>
Cc:     Masami Hiramatsu <mhiramat@...nel.org>,
        linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...ux-foundation.org>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H . Peter Anvin" <hpa@...or.com>
Subject: [PATCH v1 tip/master 0/3] kprobes/x86: retpoline: Fix kprobes for retpoline

Hi,

This is a series of patches to fix kprobes issues on the
kernel with CONFIG_RETPOLINE=y.

- [1/3]: This introduces __x86_indirect_thunk_* boundary
	 symbols so that kprobes easily identify those functions.
- [2/3]: Mark __x86_indirect_thunk_* as blacklisted function
	 for kprobes, since it can be called from other
	 blacklisted functions.
- [3/3]: Check jmp instructions in the probe target function
	 whether it jumps into the __x86_indirect_thunk_*,
	 because it is equal to an indirect jump instruction.

Side effect: [1/3] will move __x86_indirect_thunk_* functions
in kernel text area. Of course those functions were in the
.text area, but placed in right after _etext. This just moves
it right before the _etext.

Thank you,

---

Masami Hiramatsu (3):
      retpoline: Introduce start/end markers of indirect thunk
      kprobes/x86: Blacklist indirect thunk functions for kprobes
      kprobes/x86: Disable optimizing on the function jumps to indirect thunk


 arch/x86/include/asm/nospec-branch.h |    3 +++
 arch/x86/kernel/kprobes/opt.c        |   23 +++++++++++++++++++++-
 arch/x86/kernel/vmlinux.lds.S        |   35 ++++++++++++++++++++++++++++++++++
 arch/x86/lib/retpoline.S             |    3 ++-
 4 files changed, 62 insertions(+), 2 deletions(-)

--
Masami Hiramatsu (Linaro) <mhiramat@...nel.org>