From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934137AbeE2Mgx (ORCPT ); Tue, 29 May 2018 08:36:53 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:54938 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933778AbeE2Mg3 (ORCPT ); Tue, 29 May 2018 08:36:29 -0400 From: "Naveen N. Rao" To: Ingo Molnar , Michael Ellerman , Masami Hiramatsu , Josef Bacik Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] error-injection: Simplify arch specific helpers Date: Tue, 29 May 2018 18:06:02 +0530 X-Mailer: git-send-email 2.17.0 In-Reply-To: References: In-Reply-To: References: X-TM-AS-GCONF: 00 x-cbid: 18052912-0040-0000-0000-0000045E87CE X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18052912-0041-0000-0000-00002102F8E8 Message-Id: <8f4883f08feaf6e040255015af2da7bbc7741e41.1527596631.git.naveen.n.rao@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-05-29_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1805290144 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We already have an arch-independent way to set the instruction pointer with instruction_pointer_set(). Using this allows us to get rid of the need for override_function_with_return() that each architecture has to implement. Furthermore, just_return_func() only has to encode arch-specific assembly instructions to return from a function. Introduce a macro ARCH_FUNC_RET to provide the arch-specific instruction and move over just_return_func() to generic code. With these changes, architectures that already support kprobes, only just need to ensure they provide regs_set_return_value(), GET_IP() (for instruction_pointer_set()), and ARCH_FUNC_RET to support error injection. Signed-off-by: Naveen N. Rao --- arch/x86/include/asm/error-injection.h | 6 +----- arch/x86/lib/Makefile | 1 - arch/x86/lib/error-inject.c | 20 -------------------- include/asm-generic/error-injection.h | 6 ++++++ include/linux/error-injection.h | 1 + kernel/fail_function.c | 2 +- kernel/trace/bpf_trace.c | 2 +- lib/error-inject.c | 8 ++++++++ 8 files changed, 18 insertions(+), 28 deletions(-) delete mode 100644 arch/x86/lib/error-inject.c diff --git a/arch/x86/include/asm/error-injection.h b/arch/x86/include/asm/error-injection.h index 47b7a1296245..f3f22e237b86 100644 --- a/arch/x86/include/asm/error-injection.h +++ b/arch/x86/include/asm/error-injection.h @@ -2,12 +2,8 @@ #ifndef _ASM_ERROR_INJECTION_H #define _ASM_ERROR_INJECTION_H -#include -#include -#include #include -asmlinkage void just_return_func(void); -void override_function_with_return(struct pt_regs *regs); +#define ARCH_FUNC_RET "ret" #endif /* _ASM_ERROR_INJECTION_H */ diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 25a972c61b0a..f23934bbaf4e 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -26,7 +26,6 @@ lib-y += memcpy_$(BITS).o lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o -lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o lib-$(CONFIG_RETPOLINE) += retpoline.o obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o diff --git a/arch/x86/lib/error-inject.c b/arch/x86/lib/error-inject.c deleted file mode 100644 index 3cdf06128d13..000000000000 --- a/arch/x86/lib/error-inject.c +++ /dev/null @@ -1,20 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 - -#include -#include - -asmlinkage void just_return_func(void); - -asm( - ".type just_return_func, @function\n" - ".globl just_return_func\n" - "just_return_func:\n" - " ret\n" - ".size just_return_func, .-just_return_func\n" -); - -void override_function_with_return(struct pt_regs *regs) -{ - regs->ip = (unsigned long)&just_return_func; -} -NOKPROBE_SYMBOL(override_function_with_return); diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h index 296c65442f00..8ac152cc204a 100644 --- a/include/asm-generic/error-injection.h +++ b/include/asm-generic/error-injection.h @@ -3,6 +3,9 @@ #define _ASM_GENERIC_ERROR_INJECTION_H #if defined(__KERNEL__) && !defined(__ASSEMBLY__) +#include +#include + enum { EI_ETYPE_NONE, /* Dummy value for undefined case */ EI_ETYPE_NULL, /* Return NULL if failure */ @@ -27,6 +30,9 @@ static struct error_injection_entry __used \ .addr = (unsigned long)fname, \ .etype = EI_ETYPE_##_etype, \ }; + +asmlinkage void just_return_func(void); + #else #define ALLOW_ERROR_INJECTION(fname, _etype) #endif diff --git a/include/linux/error-injection.h b/include/linux/error-injection.h index 280c61ecbf20..f4a0b23423d2 100644 --- a/include/linux/error-injection.h +++ b/include/linux/error-injection.h @@ -4,6 +4,7 @@ #ifdef CONFIG_FUNCTION_ERROR_INJECTION +#include #include extern bool within_error_injection_list(unsigned long addr); diff --git a/kernel/fail_function.c b/kernel/fail_function.c index 1d5632d8bbcc..0ae2ca4a29e8 100644 --- a/kernel/fail_function.c +++ b/kernel/fail_function.c @@ -183,7 +183,7 @@ static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) if (should_fail(&fei_fault_attr, 1)) { regs_set_return_value(regs, attr->retval); - override_function_with_return(regs); + instruction_pointer_set(regs, (unsigned long)&just_return_func); /* Kprobe specific fixup */ reset_current_kprobe(); preempt_enable_no_resched(); diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 56ba0f2a01db..23f1f4ffda6c 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -84,7 +84,7 @@ EXPORT_SYMBOL_GPL(trace_call_bpf); BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) { regs_set_return_value(regs, rc); - override_function_with_return(regs); + instruction_pointer_set(regs, (unsigned long)&just_return_func); return 0; } diff --git a/lib/error-inject.c b/lib/error-inject.c index c0d4600f4896..7fdc92b5babc 100644 --- a/lib/error-inject.c +++ b/lib/error-inject.c @@ -20,6 +20,14 @@ struct ei_entry { void *priv; }; +asm( + ".type just_return_func, @function\n" + ".globl just_return_func\n" + "just_return_func:\n" + ARCH_FUNC_RET "\n" + ".size just_return_func, .-just_return_func\n" +); + bool within_error_injection_list(unsigned long addr) { struct ei_entry *ent; -- 2.17.0