From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1F56C0044D for ; Mon, 16 Mar 2020 14:40:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B82202051A for ; Mon, 16 Mar 2020 14:40:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="HUf43cOY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731621AbgCPOkE (ORCPT ); Mon, 16 Mar 2020 10:40:04 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:38644 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731572AbgCPOkE (ORCPT ); Mon, 16 Mar 2020 10:40:04 -0400 Received: by mail-pg1-f193.google.com with SMTP id x7so9874458pgh.5 for ; Mon, 16 Mar 2020 07:40:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=WRycM3kvderYb9CwKZ+TYqaJ73yGSs7D+hHRot+jXvM=; b=HUf43cOYSl5Ax/fWaclU2KwFUT7Mwg2q8rOdMnZbO0gqt1/k9zjUFcbUU50Scy+R/X Tw+jrhgXncye3ZiyrJwiSk2N4oAeJKe6UCargnOwPyszZfdP44T34vJnHkuPpOQVGDbT W7rBvsVCb8BB8yO7zAuwz3cY5InPNGnmp1OBCU6fDgUj7nF172DR+CXJ7Q/+Emo059Ko KlesoY9hqusjR0Z0KiAjQoHQQu0mxWHaxSYH92FF0UC4vKSqhIbSp0RP78haFToleRlb sk9RtZfFOrrGWNZ6igKDqKw1QFdlqh7k1pKnIMeJoyiCAqwy3tNiy133z3mS926LSXMV v7bQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=WRycM3kvderYb9CwKZ+TYqaJ73yGSs7D+hHRot+jXvM=; b=e6iYLqd9Yr9n6tfvQgzMPjF0beZID4cYIMwvwWzXPBGs5tXsRPxqzHctSmh9M5JkaD qpSsQmaXW+IG+6h+9gZmCLg1Q8PTd345jRZLxzbhIdN3XDLd2dek67bMA5iyOsKJhmaH xEPKIEDp/THvPDl2erg6usoqyIETje/YfzYrjQknZuJmjc9p8YF4e6qVAcRKzMnCQ7Js /XY17WonwdBcIkHLJcNLN/+fDFC7NJ5w59BfAPQAmGFldZWTnhTdtlxWFWNAIjhs7fRr i+w9uz6X6gER/942JAhN28SMfu93hReWxZ75zGlOGFZtwxJh1/MV7a7N/d+/g7x4aL10 N7Bw== X-Gm-Message-State: ANhLgQ2DsEA0dxGsHyQyuO9S7N61dCX70u9LYxodvpfnrF4riqnydX6l pg/0x1n69NdtibbCAgsylYSHXS40cOI7ZQ== X-Google-Smtp-Source: ADFU+vvNGndmDLdbuAl2FMjLfkFtwyASEmyqaj7ZVt3NTnGfj55nVCmperlLspPTEWNVPpNkQ+pljg== X-Received: by 2002:a63:1862:: with SMTP id 34mr164092pgy.191.1584369600556; Mon, 16 Mar 2020 07:40:00 -0700 (PDT) Received: from Mindolluin.aristanetworks.com ([2a02:8084:e84:2480:228:f8ff:fe6f:83a8]) by smtp.gmail.com with ESMTPSA id i2sm81524pjs.21.2020.03.16.07.39.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Mar 2020 07:39:59 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov <0x7f454c46@gmail.com>, Dmitry Safonov , Andrew Morton , Greg Kroah-Hartman , Ingo Molnar , Jiri Slaby , Petr Mladek , Sergey Senozhatsky , Steven Rostedt , Tetsuo Handa , Russell King , Will Deacon , linux-arm-kernel@lists.infradead.org, clang-built-linux@googlegroups.com Subject: [PATCHv2 04/50] arm/asm: Add loglvl to c_backtrace() Date: Mon, 16 Mar 2020 14:38:30 +0000 Message-Id: <20200316143916.195608-5-dima@arista.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200316143916.195608-1-dima@arista.com> References: <20200316143916.195608-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user). Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred. Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers. Add log level argument to c_backtrace() as a preparation for introducing show_stack_loglvl(). Cc: Russell King Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Cc: clang-built-linux@googlegroups.com [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Signed-off-by: Dmitry Safonov --- arch/arm/include/asm/bug.h | 3 ++- arch/arm/include/asm/traps.h | 3 ++- arch/arm/kernel/traps.c | 9 +++++---- arch/arm/kernel/unwind.c | 2 +- arch/arm/lib/backtrace-clang.S | 9 +++++++-- arch/arm/lib/backtrace.S | 14 ++++++++++---- 6 files changed, 27 insertions(+), 13 deletions(-) diff --git a/arch/arm/include/asm/bug.h b/arch/arm/include/asm/bug.h index deef4d0cb3b5..673c7dd75ab9 100644 --- a/arch/arm/include/asm/bug.h +++ b/arch/arm/include/asm/bug.h @@ -82,7 +82,8 @@ void hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *), int sig, int code, const char *name); -extern asmlinkage void c_backtrace(unsigned long fp, int pmode); +extern asmlinkage void c_backtrace(unsigned long fp, int pmode, + const char *loglvl); struct mm_struct; void show_pte(const char *lvl, struct mm_struct *mm, unsigned long addr); diff --git a/arch/arm/include/asm/traps.h b/arch/arm/include/asm/traps.h index 172b08ff3760..987fefb0a4db 100644 --- a/arch/arm/include/asm/traps.h +++ b/arch/arm/include/asm/traps.h @@ -29,7 +29,8 @@ static inline int __in_irqentry_text(unsigned long ptr) } extern void __init early_trap_init(void *); -extern void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame); +extern void dump_backtrace_entry(unsigned long where, unsigned long from, + unsigned long frame, const char *loglvl); extern void ptrace_break(struct pt_regs *regs); extern void *vectors_page; diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 1e70e7227f0f..2030611f22b8 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -62,7 +62,8 @@ __setup("user_debug=", user_debug_setup); static void dump_mem(const char *, const char *, unsigned long, unsigned long); -void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) +void dump_backtrace_entry(unsigned long where, unsigned long from, + unsigned long frame, const char *loglvl) { unsigned long end = frame + 4 + sizeof(struct pt_regs); @@ -76,7 +77,7 @@ void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long dump_mem("", "Exception stack", frame + 4, end); } -void dump_backtrace_stm(u32 *stack, u32 instruction) +void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl) { char str[80], *p; unsigned int x; @@ -238,7 +239,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) pr_cont("\n"); if (ok) - c_backtrace(fp, mode); + c_backtrace(fp, mode, NULL); } #endif @@ -666,7 +667,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs) dump_instr("", regs); if (user_mode(regs)) { __show_regs(regs); - c_backtrace(frame_pointer(regs), processor_mode(regs)); + c_backtrace(frame_pointer(regs), processor_mode(regs), NULL); } } #endif diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c index 4574e6aea0a5..0a65005e10f0 100644 --- a/arch/arm/kernel/unwind.c +++ b/arch/arm/kernel/unwind.c @@ -493,7 +493,7 @@ void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk) urc = unwind_frame(&frame); if (urc < 0) break; - dump_backtrace_entry(where, frame.pc, frame.sp - 4); + dump_backtrace_entry(where, frame.pc, frame.sp - 4, NULL); } } diff --git a/arch/arm/lib/backtrace-clang.S b/arch/arm/lib/backtrace-clang.S index 2ff375144b55..6174c45f53a5 100644 --- a/arch/arm/lib/backtrace-clang.S +++ b/arch/arm/lib/backtrace-clang.S @@ -17,6 +17,7 @@ #define sv_pc r6 #define mask r7 #define sv_lr r8 +#define loglvl r9 ENTRY(c_backtrace) @@ -99,6 +100,7 @@ ENDPROC(c_backtrace) @ to ensure 8 byte alignment movs frame, r0 @ if frame pointer is zero beq no_frame @ we have no stack frames + mov loglvl, r2 tst r1, #0x10 @ 26 or 32-bit mode? moveq mask, #0xfc000003 movne mask, #0 @ mask for 32-bit @@ -167,6 +169,7 @@ finished_setup: mov r1, sv_lr mov r2, frame bic r1, r1, mask @ mask PC/LR for the mode + mov r3, loglvl bl dump_backtrace_entry /* @@ -183,6 +186,7 @@ finished_setup: ldr r0, [frame] @ locals are stored in @ the preceding frame subeq r0, r0, #4 + mov r2, loglvl bleq dump_backtrace_stm @ dump saved registers /* @@ -196,7 +200,8 @@ finished_setup: bhi for_each_frame 1006: adr r0, .Lbad - mov r1, frame + mov r1, loglvl + mov r2, frame bl printk no_frame: ldmfd sp!, {r4 - r9, fp, pc} ENDPROC(c_backtrace) @@ -209,7 +214,7 @@ ENDPROC(c_backtrace) .long 1005b, 1006b .popsection -.Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n" +.Lbad: .asciz "%sBacktrace aborted due to bad frame pointer <%p>\n" .align .Lopcode: .word 0xe92d4800 >> 11 @ stmfd sp!, {... fp, lr} .word 0x0b000000 @ bl if these bits are set diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S index 582925238d65..872f658638d9 100644 --- a/arch/arm/lib/backtrace.S +++ b/arch/arm/lib/backtrace.S @@ -18,6 +18,7 @@ #define sv_pc r6 #define mask r7 #define offset r8 +#define loglvl r9 ENTRY(c_backtrace) @@ -25,9 +26,10 @@ ENTRY(c_backtrace) ret lr ENDPROC(c_backtrace) #else - stmfd sp!, {r4 - r8, lr} @ Save an extra register so we have a location... + stmfd sp!, {r4 - r9, lr} @ Save an extra register so we have a location... movs frame, r0 @ if frame pointer is zero beq no_frame @ we have no stack frames + mov loglvl, r2 tst r1, #0x10 @ 26 or 32-bit mode? ARM( moveq mask, #0xfc000003 ) @@ -73,6 +75,7 @@ for_each_frame: tst frame, mask @ Check for address exceptions ldr r1, [frame, #-4] @ get saved lr mov r2, frame bic r1, r1, mask @ mask PC/LR for the mode + mov r3, loglvl bl dump_backtrace_entry ldr r1, [sv_pc, #-4] @ if stmfd sp!, {args} exists, @@ -80,12 +83,14 @@ for_each_frame: tst frame, mask @ Check for address exceptions teq r3, r1, lsr #11 ldreq r0, [frame, #-8] @ get sp subeq r0, r0, #4 @ point at the last arg + mov r2, loglvl bleq dump_backtrace_stm @ dump saved registers 1004: ldr r1, [sv_pc, #0] @ if stmfd sp!, {..., fp, ip, lr, pc} ldr r3, .Ldsi @ instruction exists, teq r3, r1, lsr #11 subeq r0, frame, #16 + mov r2, loglvl bleq dump_backtrace_stm @ dump saved registers teq sv_fp, #0 @ zero saved fp means @@ -96,9 +101,10 @@ for_each_frame: tst frame, mask @ Check for address exceptions bhi for_each_frame 1006: adr r0, .Lbad - mov r1, frame + mov r1, loglvl + mov r2, frame bl printk -no_frame: ldmfd sp!, {r4 - r8, pc} +no_frame: ldmfd sp!, {r4 - r9, pc} ENDPROC(c_backtrace) .pushsection __ex_table,"a" @@ -109,7 +115,7 @@ ENDPROC(c_backtrace) .long 1004b, 1006b .popsection -.Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n" +.Lbad: .asciz "%sBacktrace aborted due to bad frame pointer <%p>\n" .align .Ldsi: .word 0xe92dd800 >> 11 @ stmfd sp!, {... fp, ip, lr, pc} .word 0xe92d0000 >> 11 @ stmfd sp!, {} -- 2.25.1