From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELskv96aLu1rKVuoTVe8xB38rK8d91Xf7DsxNvCdlf15baYrqgFBwrodN5MyOaN9KkT1cDk3 ARC-Seal: i=1; a=rsa-sha256; t=1520245584; cv=none; d=google.com; s=arc-20160816; b=wm3thkx6zF1xwqkiwTsb1NwB7Tjg50KuTcOc1ApVaVPJdqA2SwlC6tsf0nWh4/MGIV I4kNBgLjdw4HmxC6JbEfaLPqgYuTJIFVMGkO5XzweTtBWCLSZOeO3AHhvTwpd+0q8Yf8 G0upe7AAEwUiu3x5+nCTJb/pQImwj6LkOGcVaqFiq3uRWkYGiju6AKUpit0ZtBYKUPSH ggs4cW5UlNGYVhlA/6F2R/yxUsoTpqxn5gpDlat73lB2DcfzTAtnMBSoGFbEXR9iV45I LeSGeaB5kP6tqUWbVo+NOc8uqvGpw13RIEX3L8pa3jEdrHFyRoR8ccucihWII3flDl9U wKWw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:arc-authentication-results; bh=Bb0yXFnnfWeJuIId9R35QPqjkYX4kDq1nzrBg7fvyCM=; b=PFUM9vnyiOpbSh71yMCZAsTwWIuDN2sG4pXxGdNnOlWF+gr+x00AfHbmCTIC2HV2vC kKlalBzJXnZF++wBcMFtnNwpfkTv1xUpXHpMhWFJ+SGKVwa7cJqx/HrHydi14tcMX2aG T2doXW9lw0jPTKSCmYPHHAxJfrPuqFKlvusZzRSAZtXbSblnb/Fn+kl3gx3N3QUlecO0 IU61PVEXGwTmjzli76KXO41KffRFuzFxRkUjaopGmvXQExn08bIApi+QYqb56ZDi3a6S X/Oi6cSldCUPXNIgIx/LVFxnML3fX+ljCSuHPpIxIDIxM0fz2FgmbPXu1R0iHL9PUu0P AxUw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=hsmbDYuS; spf=pass (google.com: domain of joro@8bytes.org designates 81.169.241.247 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org Authentication-Results: mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=hsmbDYuS; spf=pass (google.com: domain of joro@8bytes.org designates 81.169.241.247 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org From: Joerg Roedel To: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Andy Lutomirski , Dave Hansen , Josh Poimboeuf , Juergen Gross , Peter Zijlstra , Borislav Petkov , Jiri Kosina , Boris Ostrovsky , Brian Gerst , David Laight , Denys Vlasenko , Eduardo Valentin , Greg KH , Will Deacon , aliguori@amazon.com, daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com, Andrea Arcangeli , Waiman Long , Pavel Machek , jroedel@suse.de, joro@8bytes.org Subject: [PATCH 34/34] x86/mm/pti: Add Warning when booting on a PCIE capable CPU Date: Mon, 5 Mar 2018 11:26:03 +0100 Message-Id: <1520245563-8444-35-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1520245563-8444-1-git-send-email-joro@8bytes.org> References: <1520245563-8444-1-git-send-email-joro@8bytes.org> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594093033976694451?= X-GMAIL-MSGID: =?utf-8?q?1594093033976694451?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Joerg Roedel Warn the user in case the performance can be significantly improved by switching to a 64-bit kernel. Suggested-by: Andy Lutomirski Signed-off-by: Joerg Roedel --- arch/x86/mm/pti.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 3ffd923..8f5aa0d 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -385,6 +385,22 @@ void __init pti_init(void) pr_info("enabled\n"); +#ifdef CONFIG_X86_32 + if (boot_cpu_has(X86_FEATURE_PCID)) { + /* Use printk to work around pr_fmt() */ + printk(KERN_WARNING "\n"); + printk(KERN_WARNING "************************************************************\n"); + printk(KERN_WARNING "** WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! **\n"); + printk(KERN_WARNING "** **\n"); + printk(KERN_WARNING "** You are using 32-bit PTI on a 64-bit PCID-capable CPU. **\n"); + printk(KERN_WARNING "** Your performance will increase dramatically if you **\n"); + printk(KERN_WARNING "** switch to a 64-bit kernel! **\n"); + printk(KERN_WARNING "** **\n"); + printk(KERN_WARNING "** WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! **\n"); + printk(KERN_WARNING "************************************************************\n"); + } +#endif + pti_clone_user_shared(); pti_clone_entry_text(); pti_setup_espfix64(); -- 2.7.4