/* * Copyright (C) 2008 Red Hat, Inc., Eric Paris * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; see the file COPYING. If not, write to * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include #include #include #include #include "fsnotify.h" #include /* * Final freeing of a group */ static void fsnotify_final_destroy_group(struct fsnotify_group *group) { if (group->ops->free_group_priv) group->ops->free_group_priv(group); kfree(group); } /* * Stop queueing new events for this group. Once this function returns * fsnotify_add_event() will not add any new events to the group's queue. */ void fsnotify_group_stop_queueing(struct fsnotify_group *group) { spin_lock(&group->notification_lock); group->shutdown = true; spin_unlock(&group->notification_lock); } /* * Trying to get rid of a group. Remove all marks, flush all events and release * the group reference. * Note that another thread calling fsnotify_clear_marks_by_group() may still * hold a ref to the group. */ void fsnotify_destroy_group(struct fsnotify_group *group) { /* * Stop queueing new events. The code below is careful enough to not * require this but fanotify needs to stop queuing events even before * fsnotify_destroy_group() is called and this makes the other callers * of fsnotify_destroy_group() to see the same behavior. */ fsnotify_group_stop_queueing(group); /* clear all inode marks for this group, attach them to destroy_list */ fsnotify_detach_group_marks(group); /* * Wait for fsnotify_mark_srcu period to end and free all marks in * destroy_list */ fsnotify_mark_destroy_list(); /* * Since we have waited for fsnotify_mark_srcu in * fsnotify_mark_destroy_list() there can be no outstanding event * notification against this group. So clearing the notification queue * of all events is reliable now. */ fsnotify_flush_notify(group); /* * Destroy overflow event (we cannot use fsnotify_destroy_event() as * that deliberately ignores overflow events. */ if (group->overflow_event) group->ops->free_event(group->overflow_event); fsnotify_put_group(group); } /* * Get reference to a group. */ void fsnotify_get_group(struct fsnotify_group *group) { atomic_inc(&group->refcnt); } /* * Drop a reference to a group. Free it if it's through. */ void fsnotify_put_group(struct fsnotify_group *group) { if (atomic_dec_and_test(&group->refcnt)) fsnotify_final_destroy_group(group); } /* * Create a new fsnotify_group and hold a reference for the group returned. */ struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops) { struct fsnotify_group *group; group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL); if (!group) return ERR_PTR(-ENOMEM); /* set to 0 when there a no external references to this group */ atomic_set(&group->refcnt, 1); atomic_set(&group->num_marks, 0); spin_lock_init(&group->notification_lock); INIT_LIST_HEAD(&group->notification_list); init_waitqueue_head(&group->notification_waitq); group->max_events = UINT_MAX; mutex_init(&group->mark_mutex); INIT_LIST_HEAD(&group->marks_list); group->ops = ops; return group; } int fsnotify_fasync(int fd, struct file *file, int on) { struct fsnotify_group *group = file->private_data; return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO; } .submit();'>mode:
authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-02-01 17:45:02 +0000
committerIngo Molnar <mingo@kernel.org>2017-02-01 21:17:49 +0100
commitc8f325a59cfc718d13a50fbc746ed9b415c25e92 (patch)
treed53fbdac9d0781e39a13b2ac6b2bd258cf3b4140 /net/sched/act_meta_skbtcindex.c
parentbf29bddf0417a4783da3b24e8c9e017ac649326f (diff)
efi/fdt: Avoid FDT manipulation after ExitBootServices()
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(), after which unaligned accesses to RAM are no longer supported. Commit: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") fixed an issue in the memory map handling of the stub FDT code, but inadvertently created an issue with such firmware, by moving some of the FDT manipulation to after the invocation of ExitBootServices(). Given that the stub's libfdt implementation uses the ordinary, accelerated string functions, which rely on hardware handling of unaligned accesses, manipulating the FDT with the MMU off may result in alignment faults. So fix the situation by moving the update_fdt_memmap() call into the callback function invoked by efi_exit_boot_services() right before it calls the ExitBootServices() UEFI service (which is arguably a better place for it anyway) Note that disabling the MMU in ExitBootServices() is not compliant with the UEFI spec, and carries great risk due to the fact that switching from cached to uncached memory accesses halfway through compiler generated code (i.e., involving a stack) can never be done in a way that is architecturally safe. Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Riku Voipio <riku.voipio@linaro.org> Cc: <stable@vger.kernel.org> Cc: mark.rutland@arm.com Cc: linux-efi@vger.kernel.org Cc: matt@codeblueprint.co.uk Cc: leif.lindholm@linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'net/sched/act_meta_skbtcindex.c')