From mboxrd@z Thu Jan 1 00:00:00 1970 From: guoren@kernel.org Subject: [PATCH 06/13] csky: Add support for function error injection Date: Sat, 1 Aug 2020 01:14:06 +0000 Message-ID: <1596244453-98575-7-git-send-email-guoren@kernel.org> References: <1596244453-98575-1-git-send-email-guoren@kernel.org> Return-path: Received: from mail.kernel.org ([198.145.29.99]:43640 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728234AbgHABOt (ORCPT ); Fri, 31 Jul 2020 21:14:49 -0400 In-Reply-To: <1596244453-98575-1-git-send-email-guoren@kernel.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: guoren@kernel.org, arnd@arndb.de Cc: linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org, linux-arch@vger.kernel.org, Guo Ren From: Guo Ren Inspired by the commit 42d038c4fb00 ("arm64: Add support for function error injection"), this patch supports function error injection for csky. This patch mainly support two functions: one is regs_set_return_value() which is used to overwrite the return value; the another function is override_function_with_return() which is to override the probed function returning and jump to its caller. Test log: cd /sys/kernel/debug/fail_function/ echo sys_clone > inject echo 100 > probability echo 1 > interval ls / [ 108.644163] FAULT_INJECTION: forcing a failure. [ 108.644163] name fail_function, interval 1, probability 100, space 0, times 1 [ 108.647799] CPU: 0 PID: 104 Comm: sh Not tainted 5.8.0-rc5+ #46 [ 108.648384] Call Trace: [ 108.649339] [<8005eed4>] walk_stackframe+0x0/0xf0 [ 108.649679] [<8005f16a>] show_stack+0x32/0x5c [ 108.649927] [<8040f9d2>] dump_stack+0x6e/0x9c [ 108.650271] [<80406f7e>] should_fail+0x15e/0x1ac [ 108.650720] [<80118ba8>] fei_kprobe_handler+0x28/0x5c [ 108.651519] [<80754110>] kprobe_breakpoint_handler+0x144/0x1cc [ 108.652289] [<8005d6da>] trap_c+0x8e/0x110 [ 108.652816] [<8005ce8c>] csky_trap+0x5c/0x70 -sh: can't fork: Invalid argument Signed-off-by: Guo Ren Cc: Arnd Bergmann --- arch/csky/Kconfig | 1 + arch/csky/include/asm/ptrace.h | 6 ++++++ arch/csky/lib/Makefile | 1 + arch/csky/lib/error-inject.c | 10 ++++++++++ 4 files changed, 18 insertions(+) create mode 100644 arch/csky/lib/error-inject.c diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index 822362d..c51f64c 100644 --- a/arch/csky/Kconfig +++ b/arch/csky/Kconfig @@ -45,6 +45,7 @@ config CSKY select HAVE_DYNAMIC_FTRACE_WITH_REGS select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_GRAPH_TRACER + select HAVE_FUNCTION_ERROR_INJECTION select HAVE_FTRACE_MCOUNT_RECORD select HAVE_KERNEL_GZIP select HAVE_KERNEL_LZO diff --git a/arch/csky/include/asm/ptrace.h b/arch/csky/include/asm/ptrace.h index bcfb707..82da5e0 100644 --- a/arch/csky/include/asm/ptrace.h +++ b/arch/csky/include/asm/ptrace.h @@ -52,6 +52,12 @@ static inline unsigned long regs_return_value(struct pt_regs *regs) return regs->a0; } +static inline void regs_set_return_value(struct pt_regs *regs, + unsigned long val) +{ + regs->a0 = val; +} + /* Valid only for Kernel mode traps. */ static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) { diff --git a/arch/csky/lib/Makefile b/arch/csky/lib/Makefile index 078e2d5..7fbdbb2 100644 --- a/arch/csky/lib/Makefile +++ b/arch/csky/lib/Makefile @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only lib-y := usercopy.o delay.o +obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o diff --git a/arch/csky/lib/error-inject.c b/arch/csky/lib/error-inject.c new file mode 100644 index 00000000..c15fb36 --- /dev/null +++ b/arch/csky/lib/error-inject.c @@ -0,0 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +void override_function_with_return(struct pt_regs *regs) +{ + instruction_pointer_set(regs, regs->lr); +} +NOKPROBE_SYMBOL(override_function_with_return); -- 2.7.4