From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-564561-1519835525-2-12030858093000368530 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519835524; b=snnTIYc5clr9zFeMaMAAM5dZIg4zmoFFtnowIxs53O9imY1 pFwjuPTt+ticibm7bss7op2kaWuXjuzBA+Wxh6ATOsAG7O4m0rJBR+ssFIhmZ6gf Yx0LeL/XxoH+IYbVnCWWtFXe1N7B5n/LwZVjqsT5K6m0fuzSrFVj4rvs8VQZ5Ag+ 2qbMYQqcaoCdJknjiY+AGbPMjoCvaR/t9qA6O0OPuw2dtdjh6wry9mOwmVEixGIQ lLmLjgWDVjE+6In20FbX+WgEuWvAyDIkH6WK99ji8vHaMQMFov3+d19ow6CwbQrB X/pQw90BgVa5p1X76qZG/ygu34lBIv0F82gWMAA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1519835524; bh=ZKRNdQ7NGDJHH9ciw47 2GfNUG+B0yG6FSlrNMgota3M=; b=MokdfXsVKdOHsySqJaxLqo2nX7sl1lY7w5e 6fUC85gwH3Cze2VpOzdFozh2vD1j9/HGGL1d1bor2lHlW3UByw4xKGBvLCT9wT/Q FuNkNf1532e1kApSkOVlq92z4unZfJrU0G18q/XKxcww9U7wN4rVfdoxgNSNzp6r kxxNX11ngTUX0OQXty3I7cfhvixyGZgTBpSR9Pix8fm/HruIDXoLI5Vdv0uel7Xk I/1A6p6Gly+TMllTNdZw6AM3+UADq2tCbyMW8luNBTeuDFWEWtUOXS2c4kZfBFUD behtEdEMj9R0PLlSrl86srYCw9pVDMEG0XlKIDi4ALnlx1J/uWA== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932760AbeB1QOy (ORCPT ); Wed, 28 Feb 2018 11:14:54 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35129 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933021AbeB1QOw (ORCPT ); Wed, 28 Feb 2018 11:14:52 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Ralf Baechle" , "Ezequiel Garcia" , "Markos Chandras" , "Paul Martin" , "Maciej W. Rozycki" , linux-mips@linux-mips.org, "James Hogan" Date: Wed, 28 Feb 2018 15:20:18 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 101/254] MIPS: Fix a preemption issue with thread's FPU defaults In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.16.55-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "Maciej W. Rozycki" commit 03dce595270f22d59a6f37e9170287c1afd94bc2 upstream. Fix "BUG: using smp_processor_id() in preemptible" reported in accesses to thread's FPU defaults: the value to initialise FSCR to at program startup, the FCSR r/w mask and the contents of FIR in full FPU emulation, removing a regression introduced with 9b26616c [MIPS: Respect the ISA level in FCSR handling] and f6843626 [MIPS: math-emu: Set FIR feature flags for full emulation]. Use `boot_cpu_data' to obtain the data from, following the approach that `cpu_has_*' macros take and avoiding the call to `smp_processor_id' made in the reference to `current_cpu_data'. The contents of FSCR have to be consistent across processors in an SMP system, the settings there must not change as a thread is migrated across processors. And the contents of FIR are guaranteed to be consistent in FPU emulation, by definition. Signed-off-by: Maciej W. Rozycki Tested-by: Ezequiel Garcia Tested-by: Paul Martin Cc: Markos Chandras Cc: James Hogan Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/10030/ Signed-off-by: Ralf Baechle [bwh: Backported to 3.16: - Drop change in cop1_cfc() - Adjust context] Signed-off-by: Ben Hutchings --- --- a/arch/mips/include/asm/elf.h +++ b/arch/mips/include/asm/elf.h @@ -277,7 +277,7 @@ do { \ \ current->thread.abi = &mips_abi; \ \ - current->thread.fpu.fcr31 = current_cpu_data.fpu_csr31; \ + current->thread.fpu.fcr31 = boot_cpu_data.fpu_csr31; \ } while (0) #endif /* CONFIG_32BIT */ @@ -337,7 +337,7 @@ do { \ else \ current->thread.abi = &mips_abi; \ \ - current->thread.fpu.fcr31 = current_cpu_data.fpu_csr31; \ + current->thread.fpu.fcr31 = boot_cpu_data.fpu_csr31; \ \ p = personality(current->personality); \ if (p != PER_LINUX32 && p != PER_LINUX) \ --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -177,7 +177,7 @@ int ptrace_setfpregs(struct task_struct __get_user(value, data + 64); fcr31 = child->thread.fpu.fcr31; - mask = current_cpu_data.fpu_msk31; + mask = boot_cpu_data.fpu_msk31; child->thread.fpu.fcr31 = (value & ~mask) | (fcr31 & mask); /* FIR may not be written. */ --- a/arch/mips/math-emu/cp1emu.c +++ b/arch/mips/math-emu/cp1emu.c @@ -934,7 +934,7 @@ emul: * Preserve read-only bits, * and convert to ieee library modes */ - mask = current_cpu_data.fpu_msk31; + mask = boot_cpu_data.fpu_msk31; ctx->fcr31 = (value & ~(mask | FPU_CSR_RM)) | (ctx->fcr31 & mask) | modeindex(value);