Revision aa76042a016474775ccd187c068669148c30c3bb authored by James Hogan on 27 May 2016, 21:25:23 UTC, committed by Ralf Baechle on 28 May 2016, 10:35:11 UTC
The Hardware page Table Walker (HTW) is being misconfigured on 64-bit
kernels. The PWSize.PS (pointer size) bit determines whether pointers
within directories are loaded as 32-bit or 64-bit addresses, but was
never being set to 1 for 64-bit kernels where the unsigned long in pgd_t
is 64-bits wide.
This actually reduces rather than improves performance when the HTW is
enabled on P6600 since the HTW is initiated lots, but walks are all
aborted due I think to bad intermediate pointers.
Since we were already taking the width of the PTEs into account by
setting PWSize.PTEW, which is the left shift applied to the page table
index *in addition to* the native pointer size, we also need to reduce
PTEW by 1 when PS=1. This is done by calculating PTEW based on the
relative size of pte_t compared to pgd_t.
Finally in order for the HTW to be used when PS=1, the appropriate
XK/XS/XU bits corresponding to the different 64-bit segments need to be
set in PWCtl. We enable only XU for now to enable walking for XUSeg.
Supporting walking for XKSeg would be a bit more involved so is left for
a future patch. It would either require the use of a per-CPU top level
base directory if supported by the HTW (a bit like pgd_current but with
a second entry pointing at swapper_pg_dir), or the HTW would prepend bit
63 of the address to the global directory index which doesn't really
match how we split user and kernel page directories.
Fixes: cab25bc7537b ("MIPS: Extend hardware table walking support to MIPS64")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13364/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
1 parent 6446e6c
v9fs_vfs.h
/*
* V9FS VFS extensions.
*
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* 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; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#ifndef FS_9P_V9FS_VFS_H
#define FS_9P_V9FS_VFS_H
/* plan9 semantics are that created files are implicitly opened.
* But linux semantics are that you call create, then open.
* the plan9 approach is superior as it provides an atomic
* open.
* we track the create fid here. When the file is opened, if fidopen is
* non-zero, we use the fid and can skip some steps.
* there may be a better way to do this, but I don't know it.
* one BAD way is to clunk the fid on create, then open it again:
* you lose the atomicity of file open
*/
/* special case:
* unlink calls remove, which is an implicit clunk. So we have to track
* that kind of thing so that we don't try to clunk a dead fid.
*/
#define P9_LOCK_TIMEOUT (30*HZ)
extern struct file_system_type v9fs_fs_type;
extern const struct address_space_operations v9fs_addr_operations;
extern const struct file_operations v9fs_file_operations;
extern const struct file_operations v9fs_file_operations_dotl;
extern const struct file_operations v9fs_dir_operations;
extern const struct file_operations v9fs_dir_operations_dotl;
extern const struct dentry_operations v9fs_dentry_operations;
extern const struct dentry_operations v9fs_cached_dentry_operations;
extern const struct file_operations v9fs_cached_file_operations;
extern const struct file_operations v9fs_cached_file_operations_dotl;
extern const struct file_operations v9fs_mmap_file_operations;
extern const struct file_operations v9fs_mmap_file_operations_dotl;
extern struct kmem_cache *v9fs_inode_cache;
struct inode *v9fs_alloc_inode(struct super_block *sb);
void v9fs_destroy_inode(struct inode *inode);
struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t);
int v9fs_init_inode(struct v9fs_session_info *v9ses,
struct inode *inode, umode_t mode, dev_t);
void v9fs_evict_inode(struct inode *inode);
ino_t v9fs_qid2ino(struct p9_qid *qid);
void v9fs_stat2inode(struct p9_wstat *, struct inode *, struct super_block *);
void v9fs_stat2inode_dotl(struct p9_stat_dotl *, struct inode *);
int v9fs_dir_release(struct inode *inode, struct file *filp);
int v9fs_file_open(struct inode *inode, struct file *file);
void v9fs_inode2stat(struct inode *inode, struct p9_wstat *stat);
int v9fs_uflags2omode(int uflags, int extended);
void v9fs_blank_wstat(struct p9_wstat *wstat);
int v9fs_vfs_setattr_dotl(struct dentry *, struct iattr *);
int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
int datasync);
int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode);
int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode);
static inline void v9fs_invalidate_inode_attr(struct inode *inode)
{
struct v9fs_inode *v9inode;
v9inode = V9FS_I(inode);
v9inode->cache_validity |= V9FS_INO_INVALID_ATTR;
return;
}
int v9fs_open_to_dotl_flags(int flags);
#endif
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