From patchwork Thu May 19 15:10:38 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: 624097 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 3r9ZMl1ZG6z9ssM for ; Fri, 20 May 2016 01:13:39 +1000 (AEST) Received: from ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3r9ZMl0hYCzDqVv for ; Fri, 20 May 2016 01:13:39 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from e18.ny.us.ibm.com (e18.ny.us.ibm.com [129.33.205.208]) (using TLSv1.2 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3r9ZJc55H2zDqCc for ; Fri, 20 May 2016 01:10:56 +1000 (AEST) Received: from localhost by e18.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Thu, 19 May 2016 11:10:51 -0400 X-IBM-Helo: d01dlp02.pok.ibm.com X-IBM-MailFrom: anju@linux.vnet.ibm.com X-IBM-RcptTo: mpe@ellerman.id.au; benh@kernel.crashing.org; mhiramat@kernel.org; linuxppc-dev@lists.ozlabs.org; paulus@samba.org; linux-kernel@vger.kernel.org Received: from b01cxnp22035.gho.pok.ibm.com (b01cxnp22035.gho.pok.ibm.com [9.57.198.25]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id 04DF56E803C; Thu, 19 May 2016 11:10:35 -0400 (EDT) Received: from b01ledav004.gho.pok.ibm.com (b01ledav004.gho.pok.ibm.com [9.57.199.109]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u4JFApCH39256262; Thu, 19 May 2016 15:10:51 GMT Received: from b01ledav004.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 17629112034; Thu, 19 May 2016 11:10:51 -0400 (EDT) Received: from localhost.in.ibm.com (unknown [9.79.210.80]) by b01ledav004.gho.pok.ibm.com (Postfix) with ESMTP id 55C54112057; Thu, 19 May 2016 11:10:47 -0400 (EDT) From: Anju T To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [RFC PATCH v2 1/3] arch/powerpc : Add detour buffer support for optprobes Date: Thu, 19 May 2016 20:40:38 +0530 Message-Id: <1463670640-25701-2-git-send-email-anju@linux.vnet.ibm.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1463670640-25701-1-git-send-email-anju@linux.vnet.ibm.com> References: <1463670640-25701-1-git-send-email-anju@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16051915-0045-0000-0000-0000043BB7D8 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused 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@linux.vnet.ibm.com, paulus@samba.org, mhiramat@kernel.org, naveen.n.rao@linux.vnet.ibm.com, hemant@linux.vnet.ibm.com, srikar@linux.vnet.ibm.com MIME-Version: 1.0 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 --- arch/powerpc/include/asm/kprobes.h | 25 ++++++++ arch/powerpc/kernel/optprobes_head.S | 108 +++++++++++++++++++++++++++++++++++ 2 files changed, 133 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 039b583..3e4c998 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_branch[]; +extern kprobe_opcode_t optprobe_template_ret[]; +extern kprobe_opcode_t optprobe_template_insn[]; +extern kprobe_opcode_t optprobe_template_op_address1[]; +extern kprobe_opcode_t optprobe_template_op_address2[]; +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) +#define RELATIVEJUMP_SIZE 4 #ifdef CONFIG_PPC64 #if defined(_CALL_ELF) && _CALL_ELF == 2 @@ -129,5 +147,12 @@ struct kprobe_ctlblk { 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); + +struct arch_optimized_insn { + kprobe_opcode_t copied_insn[1]; + /* detour buffer */ + kprobe_opcode_t *insn; +}; + #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_KPROBES_H */ diff --git a/arch/powerpc/kernel/optprobes_head.S b/arch/powerpc/kernel/optprobes_head.S new file mode 100644 index 0000000..ce32aec --- /dev/null +++ b/arch/powerpc/kernel/optprobes_head.S @@ -0,0 +1,108 @@ +/* + * 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 + +.global optinsn_slot +optinsn_slot: + /* Reserve an area to allocate slots for detour buffer */ + .space 65536 +.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 0,GPR1(r1) + SAVE_2GPRS(2,r1) + SAVE_8GPRS(4,r1) + SAVE_10GPRS(12,r1) + SAVE_10GPRS(22,r1) + /* Save SPRS */ + mfcfar r5 + std r5,_NIP(r1) + mfmsr r5 + std r5,_MSR(r1) + mfctr r5 + std r5,_CTR(r1) + mflr r5 + std r5,_LINK(r1) + mfspr r5,SPRN_XER + std r5,_XER(r1) + li r5,0 + std r5,_TRAP(r1) + mfdar r5 + std r5,_DAR(r1) + mfdsisr r5 + std r5,_DSISR(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 the prehandler */ +.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 +.global optprobe_template_op_address2 +optprobe_template_op_address2: + nop + nop + nop + nop + nop + addi r4,r1,STACK_FRAME_OVERHEAD + /* Branch to create_return_branch() function */ +.global optprobe_template_ret_branch +optprobe_template_ret_branch: + 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,_DAR(r1) + mtdar r5 + ld r5,_DSISR(r1) + mtdsisr r5 + REST_GPR(0,r1) + REST_2GPRS(2,r1) + REST_8GPRS(4,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: