From patchwork Wed Sep 7 09:33:10 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anju T Sudhakar X-Patchwork-Id: 666859 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3sTdd8125Gz9s4n for ; Wed, 7 Sep 2016 19:36:12 +1000 (AEST) Received: from ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3sTdd75t08zDsVX for ; Wed, 7 Sep 2016 19:36:11 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3sTdZ21fp7zDrvR for ; Wed, 7 Sep 2016 19:33:30 +1000 (AEST) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u879WSiP043840 for ; Wed, 7 Sep 2016 05:33:28 -0400 Received: from e23smtp08.au.ibm.com (e23smtp08.au.ibm.com [202.81.31.141]) by mx0a-001b2d01.pphosted.com with ESMTP id 25a2xyn2hw-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 07 Sep 2016 05:33:28 -0400 Received: from localhost by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 7 Sep 2016 19:33:23 +1000 X-IBM-Helo: d23dlp03.au.ibm.com X-IBM-MailFrom: anju@linux.vnet.ibm.com X-IBM-RcptTo: linuxppc-dev@lists.ozlabs.org Received: from d23relay07.au.ibm.com (d23relay07.au.ibm.com [9.190.26.37]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id BA9313578053 for ; Wed, 7 Sep 2016 19:33:22 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay07.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u879XMkj3735928 for ; Wed, 7 Sep 2016 19:33:22 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u879XLa3009788 for ; Wed, 7 Sep 2016 19:33:22 +1000 Received: from xenial-xerus.in.ibm.com (xenial-xerus.in.ibm.com [9.124.31.45]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u879XEeA009360; Wed, 7 Sep 2016 19:33:19 +1000 From: Anju T Sudhakar To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH 1/3] arch/powerpc : Add detour buffer support for optprobes Date: Wed, 7 Sep 2016 15:03:10 +0530 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1473240792-10596-1-git-send-email-anju@linux.vnet.ibm.com> References: <1473240792-10596-1-git-send-email-anju@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16090709-0048-0000-0000-000001B64F34 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16090709-0049-0000-0000-0000467E8A72 Message-Id: <1473240792-10596-2-git-send-email-anju@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-09-07_06:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1609070148 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ananth@in.ibm.com, mahesh@linux.vnet.ibm.com, Anju T Sudhakar , paulus@samba.org, mhiramat@kernel.org, naveen.n.rao@linux.vnet.ibm.com, hemant@linux.vnet.ibm.com, srikar@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Detour buffer contains instructions to create an in memory pt_regs. After the execution of prehandler a call is made for instruction emulation. The NIP is decided after the probed instruction is executed. Hence a branch instruction is created to the NIP returned by emulate_step(). Instruction slot for detour buffer is allocated from the reserved area. For the time being 64KB is reserved in memory for this purpose. Signed-off-by: Anju T Sudhakar --- arch/powerpc/include/asm/kprobes.h | 24 +++++++ arch/powerpc/kernel/optprobes_head.S | 119 +++++++++++++++++++++++++++++++++++ 2 files changed, 143 insertions(+) create mode 100644 arch/powerpc/kernel/optprobes_head.S diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/asm/kprobes.h index 2c9759bd..2109ce03 100644 --- a/arch/powerpc/include/asm/kprobes.h +++ b/arch/powerpc/include/asm/kprobes.h @@ -38,7 +38,25 @@ struct pt_regs; struct kprobe; typedef ppc_opcode_t kprobe_opcode_t; + +extern kprobe_opcode_t optinsn_slot; +/* Optinsn template address */ +extern kprobe_opcode_t optprobe_template_entry[]; +extern kprobe_opcode_t optprobe_template_call_handler[]; +extern kprobe_opcode_t optprobe_template_call_emulate[]; +extern kprobe_opcode_t optprobe_template_ret[]; +extern kprobe_opcode_t optprobe_template_insn[]; +extern kprobe_opcode_t optprobe_template_kp_addr[]; +extern kprobe_opcode_t optprobe_template_op_address1[]; +extern kprobe_opcode_t optprobe_template_end[]; + #define MAX_INSN_SIZE 1 +#define MAX_OPTIMIZED_LENGTH 4 +#define MAX_OPTINSN_SIZE \ + (((unsigned long)&optprobe_template_end - \ + (unsigned long)&optprobe_template_entry) / \ + sizeof(kprobe_opcode_t)) +#define RELATIVEJUMP_SIZE 4 #ifdef PPC64_ELF_ABI_v2 /* PPC64 ABIv2 needs local entry point */ @@ -124,6 +142,12 @@ struct kprobe_ctlblk { struct prev_kprobe prev_kprobe; }; +struct arch_optimized_insn { + kprobe_opcode_t copied_insn[1]; + /* detour buffer */ + kprobe_opcode_t *insn; +}; + extern int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data); extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr); diff --git a/arch/powerpc/kernel/optprobes_head.S b/arch/powerpc/kernel/optprobes_head.S new file mode 100644 index 0000000..73db1df --- /dev/null +++ b/arch/powerpc/kernel/optprobes_head.S @@ -0,0 +1,119 @@ +/* + * Code to prepare detour buffer for optprobes in Kernel. + * + * Copyright 2016, Anju T, IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include +#include +#include + +#define OPT_SLOT_SIZE 65536 + +.balign 2 +.global optinsn_slot +optinsn_slot: + /* Reserve an area to allocate slots for detour buffer */ + .space OPT_SLOT_SIZE + +/* Create an in-memory pt_regs */ +.global optprobe_template_entry +optprobe_template_entry: + stdu r1,-INT_FRAME_SIZE(r1) + SAVE_GPR(0,r1) + /* Save the previous SP into stack */ + addi r0,r1,INT_FRAME_SIZE + std r0,GPR1(r1) + SAVE_10GPRS(2,r1) + SAVE_10GPRS(12,r1) + SAVE_10GPRS(22,r1) + /* Save SPRS */ + mfmsr r5 + std r5,_MSR(r1) + li r5,0 + std r5,ORIG_GPR3(r1) + std r5,_TRAP(r1) + std r5,RESULT(r1) + mfctr r5 + std r5,_CTR(r1) + mflr r5 + std r5,_LINK(r1) + mfspr r5,SPRN_XER + std r5,_XER(r1) + mfcr r5 + std r5,_CCR(r1) + lbz r5,PACASOFTIRQEN(r13) + std r5,SOFTE(r1) + mfdar r5 + std r5,_DAR(r1) + mfdsisr r5 + std r5,_DSISR(r1) + +/* Save p->addr into stack */ +.global optprobe_template_kp_addr +optprobe_template_kp_addr: + nop + nop + nop + nop + nop + std r3,_NIP(r1) + +/* Pass parameters for optimized_callback */ +.global optprobe_template_op_address1 +optprobe_template_op_address1: + nop + nop + nop + nop + nop + addi r4,r1,STACK_FRAME_OVERHEAD + +/* Branch to optimized_callback() */ +.global optprobe_template_call_handler +optprobe_template_call_handler: + nop + /* Pass parameters for instruction emulation */ + addi r3,r1,STACK_FRAME_OVERHEAD +.global optprobe_template_insn +optprobe_template_insn: + nop + nop + +/* Branch to instruction emulation */ +.global optprobe_template_call_emulate +optprobe_template_call_emulate: + nop + /* Restore the registers */ + ld r5,_MSR(r1) + mtmsr r5 + ld r5,_CTR(r1) + mtctr r5 + ld r5,_LINK(r1) + mtlr r5 + ld r5,_XER(r1) + mtxer r5 + ld r5,_CCR(r1) + mtcr r5 + ld r5,_DAR(r1) + mtdar r5 + ld r5,_DSISR(r1) + mtdsisr r5 + REST_GPR(0,r1) + REST_10GPRS(2,r1) + REST_10GPRS(12,r1) + REST_10GPRS(22,r1) + /* Restore the previous SP */ + addi r1,r1,INT_FRAME_SIZE + +/* Jump back to the normal workflow from trampoline */ +.global optprobe_template_ret +optprobe_template_ret: + nop +.global optprobe_template_end +optprobe_template_end: