From patchwork Tue Mar 30 15:35:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 1460140 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=qQDflIkA; dkim=fail reason="signature verification failed" header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=DAWOFKfB; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4F8tpX5nzsz9sWk for ; Wed, 31 Mar 2021 02:36:36 +1100 (AEDT) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4F8tpX4rC9z3cHf for ; Wed, 31 Mar 2021 02:36:36 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=qQDflIkA; dkim=fail reason="signature verification failed" header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=DAWOFKfB; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linutronix.de (client-ip=2a0a:51c0:0:12e:550::1; helo=galois.linutronix.de; envelope-from=john.ogness@linutronix.de; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=qQDflIkA; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=DAWOFKfB; dkim-atps=neutral Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4F8tn84Fgwz3bpP for ; Wed, 31 Mar 2021 02:35:23 +1100 (AEDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1617118514; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=YPYdY00O6y5AyCUxqpuYCSP5+y//XPdG6L9507cj5Ic=; b=qQDflIkAz51LrvGLUrPwJwlERwWmT6hRYLbUtz0Trgd18/qLrOCW3YJxVb2jNAurM81TyI 3AsXxivkW9AuZRb35RUNhV/DFicFLJm/ny52MZHlxV7nYaB82D7yRtI4eJOR3/A6GZI+4W Oj90Fp+qLdueXya9Nqaj7zUEgUAq3I566RihuuDiupy7dG0M1LBtHXzJHIUGFj2fBotjoc m2sdVo64AJACocszlTWXWkB3zjWrA7HaH4WgN9u85YOkFnQ/JYc9BcjSaehTMGu0Tieka6 Qum9ld/CWbuBmTjG8QIJS2kuF/+SwuV/YneE4CHchkQF8b8DmaCwDpcuT+u3QQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1617118514; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=YPYdY00O6y5AyCUxqpuYCSP5+y//XPdG6L9507cj5Ic=; b=DAWOFKfBAuSGqLOlxY962SnoWviQuD0AGtEm319HtzpL33OlIzgLcrRMou9nKTPDT+oWj6 VfRxVIoORXq20wCQ== To: Petr Mladek Subject: [PATCH printk v2 0/5] printk: remove safe buffers Date: Tue, 30 Mar 2021 17:35:07 +0200 Message-Id: <20210330153512.1182-1-john.ogness@linutronix.de> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sergey Senozhatsky , Alexey Kardashevskiy , Alexei Starovoitov , David Howells , Paul Mackerras , Tiezhu Yang , Will Deacon , Rafael Aquini , Marc Zyngier , "Aneesh Kumar K.V" , Masahiro Yamada , Russell King , Peter Zijlstra , Yue Hu , Ingo Molnar , Geert Uytterhoeven , Jordan Niethe , Valentin Schneider , Kees Cook , "Paul E. McKenney" , Anshuman Khandual , Alistair Popple , Frederic Weisbecker , "Guilherme G. Piccoli" , Nicholas Piggin , Nathan Chancellor , Nick Terrell , Steven Rostedt , Andy Lutomirski , Leonardo Bras , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Johannes Weiner , Sergey Senozhatsky , Eric Biederman , Andrew Morton , linuxppc-dev@lists.ozlabs.org, Mike Rapoport Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi, Here is v2 of a series to remove the safe buffers. v1 can be found here [0]. The safe buffers are no longer needed because messages can be stored directly into the log buffer from any context. However, the safe buffers also provided a form of recursion protection. For that reason, explicit recursion protection is also implemented for this series. And finally, with the removal of the safe buffers, there is no need for extra NMI enter/exit tracking. So this is also removed (which includes removing config option CONFIG_PRINTK_NMI). This series is based on the printk-rework branch of printk/linux.git: commit acebb5597ff1 ("kernel/printk.c: Fixed mundane typos") Changes since v1: - remove the printk nmi enter/exit tracking - remove CONFIG_PRINTK_NMI config option - use in_nmi() to detect NMI context - remove unused printk_safe_enter/exit macros - after switching to the dynamic buffer, copy over NMI records that may have arrived during the switch window - use local_irq_*() instead of printk_safe_*() for console spinning - use separate variables rather than arrays for the per-cpu recursion tracking - make @syslog_lock a mutex instead of a spin_lock - close the wait-read window for SYSLOG_ACTION_READ - adjust various comments and commit messages as requested John Ogness [0] https://lore.kernel.org/lkml/20210316233326.10778-1-john.ogness@linutronix.de John Ogness (5): printk: track/limit recursion printk: remove safe buffers printk: remove NMI tracking printk: convert @syslog_lock to mutex printk: syslog: close window between wait and read arch/arm/kernel/smp.c | 2 - arch/powerpc/kernel/traps.c | 1 - arch/powerpc/kernel/watchdog.c | 5 - arch/powerpc/kexec/crash.c | 3 - include/linux/hardirq.h | 2 - include/linux/printk.h | 22 -- init/Kconfig | 5 - kernel/kexec_core.c | 1 - kernel/panic.c | 3 - kernel/printk/internal.h | 23 --- kernel/printk/printk.c | 281 +++++++++++++++---------- kernel/printk/printk_safe.c | 362 +-------------------------------- kernel/trace/trace.c | 2 - lib/nmi_backtrace.c | 6 - 14 files changed, 171 insertions(+), 547 deletions(-)