From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f52.google.com (mail-oi0-f52.google.com [209.85.218.52]) by kanga.kvack.org (Postfix) with ESMTP id 46F716B006E for ; Fri, 29 May 2015 19:18:50 -0400 (EDT) Received: by oihd6 with SMTP id d6so67567140oih.2 for ; Fri, 29 May 2015 16:18:50 -0700 (PDT) Received: from g9t5008.houston.hp.com (g9t5008.houston.hp.com. [15.240.92.66]) by mx.google.com with ESMTPS id f4si4406205oeu.54.2015.05.29.16.18.49 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 29 May 2015 16:18:49 -0700 (PDT) From: Toshi Kani Subject: [PATCH v11 1/12] x86, mm, pat: Cleanup init flags in pat_init() Date: Fri, 29 May 2015 16:58:59 -0600 Message-Id: <1432940350-1802-2-git-send-email-toshi.kani@hp.com> In-Reply-To: <1432940350-1802-1-git-send-email-toshi.kani@hp.com> References: <1432940350-1802-1-git-send-email-toshi.kani@hp.com> Sender: owner-linux-mm@kvack.org List-ID: To: bp@alien8.de, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org, arnd@arndb.de Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-nvdimm@lists.01.org, jgross@suse.com, stefan.bader@canonical.com, luto@amacapital.net, hmh@hmh.eng.br, yigal@plexistor.com, konrad.wilk@oracle.com, Elliott@hp.com, mcgrof@suse.com, hch@lst.de, Toshi Kani From: Toshi Kani pat_init() uses two flags, 'boot_cpu' and 'boot_pat_state', for tracking the boot CPU's initialization status. 'boot_pat_state' is also overloaded to carry the boot PAT value. This patch cleans this up by replacing them with a new single flag, 'boot_cpu_done', to track the boot CPU's initialization status. 'boot_pat_state' is only used to carry the boot PAT value as a result. Suggested-by: Thomas Gleixner Signed-off-by: Toshi Kani --- arch/x86/mm/pat.c | 40 +++++++++++++++++++--------------------- 1 file changed, 19 insertions(+), 21 deletions(-) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index a1c9654..e1ec6a7 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -197,24 +197,29 @@ void pat_init_cache_modes(void) void pat_init(void) { u64 pat; - bool boot_cpu = !boot_pat_state; + static bool boot_cpu_done; if (!pat_enabled()) return; - if (!cpu_has_pat) { - if (!boot_pat_state) { + if (!boot_cpu_done) { + if (!cpu_has_pat) { pat_disable("PAT not supported by CPU."); return; - } else { - /* - * If this happens we are on a secondary CPU, but - * switched to PAT on the boot CPU. We have no way to - * undo PAT. - */ - pr_err("x86/PAT: PAT enabled, but not supported by secondary CPU\n"); - BUG(); } + + rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); + if (!boot_pat_state) { + pat_disable("PAT read returns always zero, disabled."); + return; + } + } else if (!cpu_has_pat) { + /* + * If this happens we are on a secondary CPU, but + * switched to PAT on the boot CPU. We have no way to + * undo PAT. + */ + panic("PAT enabled, but not supported by secondary CPU\n"); } /* Set PWT to Write-Combining. All other bits stay the same */ @@ -233,19 +238,12 @@ void pat_init(void) pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) | PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC); - /* Boot CPU check */ - if (!boot_pat_state) { - rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); - if (!boot_pat_state) { - pat_disable("PAT read returns always zero, disabled."); - return; - } - } - wrmsrl(MSR_IA32_CR_PAT, pat); - if (boot_cpu) + if (!boot_cpu_done) { pat_init_cache_modes(); + boot_cpu_done = true; + } } #undef PAT -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org