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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 83118C433DF for ; Tue, 9 Jun 2020 04:30:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 31ED0207F9 for ; Tue, 9 Jun 2020 04:30:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="elB/+T7R" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 31ED0207F9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D88B56B0007; Tue, 9 Jun 2020 00:30:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D13BE6B000A; Tue, 9 Jun 2020 00:30:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C03816B000C; Tue, 9 Jun 2020 00:30:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0105.hostedemail.com [216.40.44.105]) by kanga.kvack.org (Postfix) with ESMTP id A5C056B0007 for ; Tue, 9 Jun 2020 00:30:09 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 5174D804D143 for ; Tue, 9 Jun 2020 04:30:09 +0000 (UTC) X-FDA: 76908396138.20.place26_431384a26dbf Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 2CA96180C07AB for ; Tue, 9 Jun 2020 04:30:09 +0000 (UTC) X-HE-Tag: place26_431384a26dbf X-Filterd-Recvd-Size: 9207 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Tue, 9 Jun 2020 04:30:08 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9092320810; Tue, 9 Jun 2020 04:30:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591677007; bh=1QVhbvlppbo0ng/+UAFA0kT8hNdFPa/BE3FSAwlVt00=; h=Date:From:To:Subject:In-Reply-To:From; b=elB/+T7RMoFYCULhBzXywE4crwe7rEuVA3R7Slq9ZEoT0gP31mlb9s6PsrLbOUStX t9DEPGgHaItX5bhS5ccLZqgBoeOox+EaxlEIiTNO/eGJmbuRRDSxdN8h7Hbi4KGMiA IgLoQPK0i+KBTKfElbmc8GQMcxIEx8+uPlpEnx10= Date: Mon, 08 Jun 2020 21:30:07 -0700 From: Andrew Morton To: akpm@linux-foundation.org, dima@arista.com, linux-mm@kvack.org, linux@armlinux.org.uk, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, will@kernel.org Subject: [patch 04/93] arm/asm: add loglvl to c_backtrace() Message-ID: <20200609043007.KcV14EbSN%akpm@linux-foundation.org> In-Reply-To: <20200608212922.5b7fa74ca3f4e2444441b7f9@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 2CA96180C07AB X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Dmitry Safonov Subject: arm/asm: add loglvl to c_backtrace() 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(). [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Link: http://lkml.kernel.org/r/20200418201944.482088-5-dima@arista.com Signed-off-by: Dmitry Safonov Cc: Russell King Cc: Will Deacon Signed-off-by: Andrew Morton --- 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(-) --- a/arch/arm/include/asm/bug.h~arm-asm-add-loglvl-to-c_backtrace +++ a/arch/arm/include/asm/bug.h @@ -82,7 +82,8 @@ void hook_ifault_code(int nr, int (*fn)( 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); --- a/arch/arm/include/asm/traps.h~arm-asm-add-loglvl-to-c_backtrace +++ a/arch/arm/include/asm/traps.h @@ -29,7 +29,8 @@ static inline int __in_irqentry_text(uns } 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; --- a/arch/arm/kernel/traps.c~arm-asm-add-loglvl-to-c_backtrace +++ a/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 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_reg 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, struc 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 --- a/arch/arm/kernel/unwind.c~arm-asm-add-loglvl-to-c_backtrace +++ a/arch/arm/kernel/unwind.c @@ -493,7 +493,7 @@ void unwind_backtrace(struct pt_regs *re 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); } } --- a/arch/arm/lib/backtrace-clang.S~arm-asm-add-loglvl-to-c_backtrace +++ a/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 --- a/arch/arm/lib/backtrace.S~arm-asm-add-loglvl-to-c_backtrace +++ a/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 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 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 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!, {} _