From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754664AbdKJTdz (ORCPT ); Fri, 10 Nov 2017 14:33:55 -0500 Received: from mga05.intel.com ([192.55.52.43]:10120 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753721AbdKJTcM (ORCPT ); Fri, 10 Nov 2017 14:32:12 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,375,1505804400"; d="scan'208";a="1302062" Subject: [PATCH 25/30] x86, kaiser: add debugfs file to turn KAISER on/off at runtime To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, dave.hansen@linux.intel.com, moritz.lipp@iaik.tugraz.at, daniel.gruss@iaik.tugraz.at, michael.schwarz@iaik.tugraz.at, richard.fellner@student.tugraz.at, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, x86@kernel.org From: Dave Hansen Date: Fri, 10 Nov 2017 11:31:53 -0800 References: <20171110193058.BECA7D88@viggo.jf.intel.com> In-Reply-To: <20171110193058.BECA7D88@viggo.jf.intel.com> Message-Id: <20171110193153.D45596C9@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen This will be used in a few patches. Right now, it's not wired up to do anything useful. Signed-off-by: Dave Hansen Cc: Moritz Lipp Cc: Daniel Gruss Cc: Michael Schwarz Cc: Richard Fellner Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Kees Cook Cc: Hugh Dickins Cc: x86@kernel.org --- b/arch/x86/mm/kaiser.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff -puN arch/x86/mm/kaiser.c~kaiser-dynamic-debugfs arch/x86/mm/kaiser.c --- a/arch/x86/mm/kaiser.c~kaiser-dynamic-debugfs 2017-11-10 11:22:18.900244925 -0800 +++ b/arch/x86/mm/kaiser.c 2017-11-10 11:22:18.904244925 -0800 @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -457,3 +458,50 @@ void kaiser_remove_mapping(unsigned long */ __native_flush_tlb_global(); } + +int kaiser_enabled = 1; +static ssize_t kaiser_enabled_read_file(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos) +{ + char buf[32]; + unsigned int len; + + len = sprintf(buf, "%d\n", kaiser_enabled); + return simple_read_from_buffer(user_buf, count, ppos, buf, len); +} + +static ssize_t kaiser_enabled_write_file(struct file *file, + const char __user *user_buf, size_t count, loff_t *ppos) +{ + char buf[32]; + ssize_t len; + unsigned int enable; + + len = min(count, sizeof(buf) - 1); + if (copy_from_user(buf, user_buf, len)) + return -EFAULT; + + buf[len] = '\0'; + if (kstrtoint(buf, 0, &enable)) + return -EINVAL; + + if (enable > 1) + return -EINVAL; + + WRITE_ONCE(kaiser_enabled, enable); + return count; +} + +static const struct file_operations fops_kaiser_enabled = { + .read = kaiser_enabled_read_file, + .write = kaiser_enabled_write_file, + .llseek = default_llseek, +}; + +static int __init create_kaiser_enabled(void) +{ + debugfs_create_file("kaiser-enabled", S_IRUSR | S_IWUSR, + arch_debugfs_dir, NULL, &fops_kaiser_enabled); + return 0; +} +late_initcall(create_kaiser_enabled); _