From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933906Ab1JaSeX (ORCPT ); Mon, 31 Oct 2011 14:34:23 -0400 Received: from mga02.intel.com ([134.134.136.20]:54577 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932711Ab1JaSeW (ORCPT ); Mon, 31 Oct 2011 14:34:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,352,1309762800"; d="scan'208";a="69708458" From: To: linux-kernel@vger.kernel.org Cc: "Arjan van de Ven" Subject: [PATCH] Stop mce-inject writing to mce_chrdev_ops Date: Mon, 31 Oct 2011 11:34:21 -0700 Message-Id: <4eaeea2d17118d40b4@agluck-desktop.sc.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Arjan would like to make struct file_operations const, but mce-inject directly writes to the mce_chrdev_ops to install its write handler. In an ideal world mce-inject would have its own character device, but we have a sizable legacy of test scripts that hardwire "/dev/mcelog", so it would be painful to switch to a separate device now. Instead, this patch switches to a stub function in the mce code, with a registration helper that mce-inject can call when it is loaded. Note that this would also allow for a sane process to allow mce-inject to be unloaded again (with an unregister function, and appropriate module_{get,put}() calls), but that is left for potential future patches. Signed-off-by: Tony Luck --- diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h index c9321f3..22cc0eb 100644 --- a/arch/x86/include/asm/mce.h +++ b/arch/x86/include/asm/mce.h @@ -201,7 +201,10 @@ int mce_notify_irq(void); void mce_notify_process(void); DECLARE_PER_CPU(struct mce, injectm); -extern struct file_operations mce_chrdev_ops; + +extern void register_mce_write_hook(ssize_t (*)(struct file *filp, + const char __user *ubuf, + size_t usize, loff_t *off)); /* * Exception handler diff --git a/arch/x86/kernel/cpu/mcheck/mce-inject.c b/arch/x86/kernel/cpu/mcheck/mce-inject.c index 0ed633c..a18c2c8 100644 --- a/arch/x86/kernel/cpu/mcheck/mce-inject.c +++ b/arch/x86/kernel/cpu/mcheck/mce-inject.c @@ -215,7 +215,7 @@ static int inject_init(void) if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL)) return -ENOMEM; printk(KERN_INFO "Machine check injector initialized\n"); - mce_chrdev_ops.write = mce_write; + register_mce_write_hook(mce_write); register_die_notifier(&mce_raise_nb); return 0; } diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 08363b0..e24468d 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -1628,16 +1628,35 @@ static long mce_chrdev_ioctl(struct file *f, unsigned int cmd, } } +static ssize_t (*mce_write)(struct file *filp, const char __user *ubuf, + size_t usize, loff_t *off); + +void register_mce_write_hook(ssize_t (*fn)(struct file *filp, const char __user *ubuf, + size_t usize, loff_t *off)) +{ + mce_write = fn; +} +EXPORT_SYMBOL_GPL(register_mce_write_hook); + +ssize_t mce_chrdev_write(struct file *filp, const char __user *ubuf, + size_t usize, loff_t *off) +{ + if (mce_write) + return mce_write(filp, ubuf, usize, off); + else + return -ENODEV; +} + /* Modified in mce-inject.c, so not static or const */ struct file_operations mce_chrdev_ops = { .open = mce_chrdev_open, .release = mce_chrdev_release, .read = mce_chrdev_read, + .write = mce_chrdev_write, .poll = mce_chrdev_poll, .unlocked_ioctl = mce_chrdev_ioctl, .llseek = no_llseek, }; -EXPORT_SYMBOL_GPL(mce_chrdev_ops); static struct miscdevice mce_chrdev_device = { MISC_MCELOG_MINOR,