Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932376AbbFOTId (ORCPT ); Mon, 15 Jun 2015 15:08:33 -0400 Received: from mail-qc0-f175.google.com ([209.85.216.175]:34603 "EHLO mail-qc0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756166AbbFOTHM (ORCPT ); Mon, 15 Jun 2015 15:07:12 -0400 From: David Long To: Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Russell King Cc: sandeepa.s.prabhu@gmail.com, William Cohen , Steve Capper , "Jon Medhurst (Tixy)" , Masami Hiramatsu , Ananth N Mavinakayanahalli , Anil S Keshavamurthy , , Mark Brown , linux-kernel@vger.kernel.org Subject: [PATCH v7 0/7] arm64: Add kernel probes (kprobes) support Date: Mon, 15 Jun 2015 15:07:02 -0400 Message-Id: <1434395229-6654-1-git-send-email-dave.long@linaro.org> X-Mailer: git-send-email 1.8.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6086 Lines: 137 From: "David A. Long" This patchset is heavily based on Sandeepa Prabhu's ARM v8 kprobes patches, first seen in October 2013. This version attempts to address concerns raised by reviewers and also fixes problems discovered during testing. This patchset adds support for kernel probes(kprobes), jump probes(jprobes) and return probes(kretprobes) support for ARM64. The kprobes mechanism makes use of software breakpoint and single stepping support available in the ARM v8 kernel. The is patch depends on: [PATCH 1/2] Move the pt_regs_offset struct definition from arch to common include file [PATCH 2/2] Consolidate redundant register/stack access code Changes since v2 include: 1) Removal of NOP padding in kprobe XOL slots. Slots are now exactly one instruction long. 2) Disabling of interrupts during execution in single-step mode. 3) Fixing of numerous problems in instruction simulation code (mostly thanks to Will Cohen). 4) Support for the HAVE_REGS_AND_STACK_ACCESS_API feature is added, to allow access to kprobes through debugfs. 5) kprobes is *not* enabled in defconfig. 6) Numerous complaints from checkpatch have been cleaned up, although a couple remain as removing the function pointer typedefs results in ugly code. Changes since v3 include: 1) Remove table-driven instruction parsing and replace with an if statement calling out to old and new instruction test functions in insn.c. 2) I removed the addition of orig_x0 to ptrace.h. 3) Reorder the patches. 4) Replace the previous interrupt disabling (from Will Cohen) with an improved solution (from Steve Capper). Changes since v4 include: 1) Added insn.c functions to detect exception instructions and DAIF read/write instructions, and use them to reject probing same. 2) Changed adr detect function to also recognize adrp. Reject both. 3) Added missing __kprobes for some new functions. 4) Added call to kprobes_fault_handler from mm do_page_fault. 5) Reject all non-simulated branch/ret instructions, not just those that use an immediate offset. 6) Moved software breakpoint definitions into debug-monitors.h. 7) Removed "!XIP_KERNEL" from Kconfig. 8) changed kprobes_condition_check_t and kprobes_prepare_t to probes_*, for future sharing with uprobes. 9) Removed bogus call to kprobes_restore_local_irqflag() from trampoline_probe_handler(). Changes since v5 include: 1) Replaced installation of breakpoint hook with direct call from the handlers in debug-monitors.c, as requested. 2) Reject probing of instructions that read the interrupt mask, in addition to instructions that set it. 3) Cleaned up comments describing usage of Debug Mask. 4) Added KPROBE_REENTER case in reenter_kprobe. 5) Corrected the ifdef'd definitions for notify_page_fault() to be consistent when KPROBES is not configed. 6) Changed "cpsr" to "pstate" for HAVE_REGS_AND_STACK_ACCESS_API feature. 7) Added back in missing new files in previous patch. 8) Changed two instances of pr_warning() to pr_warn(). Note that there seems to be at least a potential issue with kprobes on multiple (possibly all) platforms having to do with use of kfree inside of the kretprobes trampoline handler. This has manifested occasionally in systemtap testing on arm64. There does not appear to be an simple solution to the problem. Changes since v6 include: 1) New trampoline code from Will Cohen fixes the occasional failure seen when processing kretprobes by replacing the software breakpoint with assembly code to implement the return to the original execution stream. 2) Changed ip0, ip1, fp, and lr to plain numbered registers for purposes of recognizing them as an ascii string in the stack/reg access code. 3) Removed orig_x0. 4) Moved ARM_x* defines from arch/arm64/include/uapi/asm/ptrace.h to arch/arm64/kernel/ptrace.c. David A. Long (2): arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature arm64: Add more test functions to insn.c Sandeepa Prabhu (4): arm64: Kprobes with single stepping support arm64: kprobes instruction simulation support arm64: Add kernel return probes support (kretprobes) kprobes: Add arm64 case in kprobe example module William Cohen (1): arm64: Add trampoline code for kretprobes arch/arm64/Kconfig | 3 + arch/arm64/include/asm/debug-monitors.h | 5 + arch/arm64/include/asm/insn.h | 18 + arch/arm64/include/asm/kprobes.h | 63 +++ arch/arm64/include/asm/probes.h | 50 +++ arch/arm64/include/asm/ptrace.h | 28 +- arch/arm64/kernel/Makefile | 3 + arch/arm64/kernel/debug-monitors.c | 35 +- arch/arm64/kernel/insn.c | 28 ++ arch/arm64/kernel/kprobes-arm64.c | 166 ++++++++ arch/arm64/kernel/kprobes-arm64.h | 71 ++++ arch/arm64/kernel/kprobes.c | 665 +++++++++++++++++++++++++++++++ arch/arm64/kernel/kprobes.h | 24 ++ arch/arm64/kernel/probes-condn-check.c | 122 ++++++ arch/arm64/kernel/probes-simulate-insn.c | 174 ++++++++ arch/arm64/kernel/probes-simulate-insn.h | 33 ++ arch/arm64/kernel/ptrace.c | 77 ++++ arch/arm64/kernel/vmlinux.lds.S | 1 + arch/arm64/mm/fault.c | 25 ++ samples/kprobes/kprobe_example.c | 8 + 20 files changed, 1588 insertions(+), 11 deletions(-) create mode 100644 arch/arm64/include/asm/kprobes.h create mode 100644 arch/arm64/include/asm/probes.h create mode 100644 arch/arm64/kernel/kprobes-arm64.c create mode 100644 arch/arm64/kernel/kprobes-arm64.h create mode 100644 arch/arm64/kernel/kprobes.c create mode 100644 arch/arm64/kernel/kprobes.h create mode 100644 arch/arm64/kernel/probes-condn-check.c create mode 100644 arch/arm64/kernel/probes-simulate-insn.c create mode 100644 arch/arm64/kernel/probes-simulate-insn.h -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/