From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755853Ab3LDRvM (ORCPT ); Wed, 4 Dec 2013 12:51:12 -0500 Received: from mail-lb0-f169.google.com ([209.85.217.169]:46472 "EHLO mail-lb0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752632Ab3LDRvH (ORCPT ); Wed, 4 Dec 2013 12:51:07 -0500 Message-ID: <529F6B88.2050005@linaro.org> Date: Wed, 04 Dec 2013 19:51:04 +0200 From: Taras Kondratiuk User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.1 MIME-Version: 1.0 To: David Long , linux-arm-kernel@lists.infradead.org, Russell King CC: Rabin Vincent , "Jon Medhurst (Tixy)" , Oleg Nesterov , Srikar Dronamraju , Ingo Molnar , Masami Hiramatsu , Ananth N Mavinakayanahalli , Anil S Keshavamurthy , davem@davemloft.net, Peter Zijlstra , Paul Mackerras , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, Linaro Networking Subject: Re: [PATCH v3 00/15] uprobes: Add uprobes support for ARM References: <1385520814-10663-1-git-send-email-dave.long@linaro.org> In-Reply-To: <1385520814-10663-1-git-send-email-dave.long@linaro.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/27/2013 04:53 AM, David Long wrote: > From: "David A. Long" > > This patch series adds basic uprobes support to ARM. It is based on patches > developed earlier by Rabin Vincent. That approach of adding hooks into > the kprobes instruction parsing code was not well received. This approach > separates the ARM instruction parsing code in kprobes out into a separate set > of functions which can be used by both kprobes and uprobes. Both kprobes and > uprobes then provide their own semantic action tables to process the results of > the parsing. > > The following are noteworthy changes made for v3: > > 1) The ARM uprobes functionality no longer depends on kprobes. As > a side effect of this there are no longer any changes to the common > kprobes include file (or any other common kprobes files). > 2) A couple large patches have been broken down into more smaller > patches. > 3) A problem with uretprobes has been fixed. > 4) The kprobes-test module has been made more useable for thumb tests. > 5) The argument list to the "action" functions has been shrunk. > 6) Alignment with a few recent patches that were made to common > uprobes code specifically to support this patchset. > > This patchset is based on v3.13-rc1 Hi Dave I've tested this series in big-endian mode. There is an issue within __create_xol_area() function. It writes UPROBE_SWBP_INSN directly to memory, but UPROBE_SWBP_INSN stores canonical opcode, which leads to a wrong instruction endianness if CPU runs in BE. I think the easies way to fix it without touching generic uprobes code is to store opcode in native endianness in UPROBE_SWBP_INSN, and use another macro for canonical form in ARM specific code. Please check a diff below. With this diff plus addressed comment for patch 14/15 plus fixed Ben's BE kprobes series I have uprobes working on LE and BE. diff --git a/arch/arm/include/asm/uprobes.h b/arch/arm/include/asm/uprobes.h index e5acaa3..5313418 100644 --- a/arch/arm/include/asm/uprobes.h +++ b/arch/arm/include/asm/uprobes.h @@ -2,14 +2,16 @@ #define _ASM_UPROBES_H #include +#include typedef u32 uprobe_opcode_t; #define MAX_UINSN_BYTES 4 #define UPROBE_XOL_SLOT_BYTES 64 -#define UPROBE_SWBP_INSN 0xe7f001f9 -#define UPROBE_SS_INSN 0xe7f001fa +#define UPROBE_SWBP_ARM_INSN 0xe7f001f9 +#define UPROBE_SS_ARM_INSN 0xe7f001fa +#define UPROBE_SWBP_INSN __opcode_to_mem_arm(UPROBE_SWBP_ARM_INSN) #define UPROBE_SWBP_INSN_SIZE 4 struct arch_uprobe_task { diff --git a/arch/arm/kernel/uprobes.c b/arch/arm/kernel/uprobes.c index d9873ef..ae18549 100644 --- a/arch/arm/kernel/uprobes.c +++ b/arch/arm/kernel/uprobes.c @@ -22,7 +22,7 @@ bool is_swbp_insn(uprobe_opcode_t *insn) { return (__mem_to_opcode_arm(*insn) & 0x0fffffff) == - (UPROBE_SWBP_INSN & 0x0fffffff); + (UPROBE_SWBP_ARM_INSN & 0x0fffffff); } int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, @@ -83,7 +83,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, insn = __mem_to_opcode_arm(*(unsigned int *)auprobe->insn); auprobe->ixol[0] = __opcode_to_mem_arm(insn); - auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_INSN); + auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_ARM_INSN); ret = arm_probes_decode_insn(insn, &auprobe->asi, false, uprobes_probes_actions); @@ -100,7 +100,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, break; } - bpinsn = UPROBE_SWBP_INSN & 0x0fffffff; + bpinsn = UPROBE_SWBP_ARM_INSN & 0x0fffffff; if (insn >= 0xe0000000) bpinsn |= 0xe0000000; /* Unconditional instruction */ else @@ -158,9 +158,9 @@ static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr) local_irq_save(flags); instr &= 0x0fffffff; - if (instr == (UPROBE_SWBP_INSN & 0x0fffffff)) + if (instr == (UPROBE_SWBP_ARM_INSN & 0x0fffffff)) uprobe_pre_sstep_notifier(regs); - else if (instr == (UPROBE_SS_INSN & 0x0fffffff)) + else if (instr == (UPROBE_SS_ARM_INSN & 0x0fffffff)) uprobe_post_sstep_notifier(regs); local_irq_restore(flags); @@ -174,7 +174,7 @@ unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) static struct undef_hook uprobes_arm_break_hook = { .instr_mask = 0x0fffffff, - .instr_val = (UPROBE_SWBP_INSN & 0x0fffffff), + .instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff), .cpsr_mask = MODE_MASK, .cpsr_val = USR_MODE, .fn = uprobe_trap_handler, @@ -182,7 +182,7 @@ static struct undef_hook uprobes_arm_break_hook = { static struct undef_hook uprobes_arm_ss_hook = { .instr_mask = 0x0fffffff, - .instr_val = (UPROBE_SS_INSN & 0x0fffffff), + .instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff), .cpsr_mask = MODE_MASK, .cpsr_val = USR_MODE, .fn = uprobe_trap_handler, -- Taras Kondratiuk