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>
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bad_inode.c
/*
* linux/fs/bad_inode.c
*
* Copyright (C) 1997, Stephen Tweedie
*
* Provide stub functions for unreadable inodes
*
* Fabian Frederick : August 2003 - All file operations assigned to EIO
*/
#include <linux/fs.h>
#include <linux/export.h>
#include <linux/stat.h>
#include <linux/time.h>
#include <linux/namei.h>
#include <linux/poll.h>
static int bad_file_open(struct inode *inode, struct file *filp)
{
return -EIO;
}
static const struct file_operations bad_file_ops =
{
.open = bad_file_open,
};
static int bad_inode_create (struct inode *dir, struct dentry *dentry,
umode_t mode, bool excl)
{
return -EIO;
}
static struct dentry *bad_inode_lookup(struct inode *dir,
struct dentry *dentry, unsigned int flags)
{
return ERR_PTR(-EIO);
}
static int bad_inode_link (struct dentry *old_dentry, struct inode *dir,
struct dentry *dentry)
{
return -EIO;
}
static int bad_inode_unlink(struct inode *dir, struct dentry *dentry)
{
return -EIO;
}
static int bad_inode_symlink (struct inode *dir, struct dentry *dentry,
const char *symname)
{
return -EIO;
}
static int bad_inode_mkdir(struct inode *dir, struct dentry *dentry,
umode_t mode)
{
return -EIO;
}
static int bad_inode_rmdir (struct inode *dir, struct dentry *dentry)
{
return -EIO;
}
static int bad_inode_mknod (struct inode *dir, struct dentry *dentry,
umode_t mode, dev_t rdev)
{
return -EIO;
}
static int bad_inode_rename2(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags)
{
return -EIO;
}
static int bad_inode_readlink(struct dentry *dentry, char __user *buffer,
int buflen)
{
return -EIO;
}
static int bad_inode_permission(struct inode *inode, int mask)
{
return -EIO;
}
static int bad_inode_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
return -EIO;
}
static int bad_inode_setattr(struct dentry *direntry, struct iattr *attrs)
{
return -EIO;
}
static int bad_inode_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
return -EIO;
}
static ssize_t bad_inode_getxattr(struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
return -EIO;
}
static ssize_t bad_inode_listxattr(struct dentry *dentry, char *buffer,
size_t buffer_size)
{
return -EIO;
}
static int bad_inode_removexattr(struct dentry *dentry, const char *name)
{
return -EIO;
}
static const struct inode_operations bad_inode_ops =
{
.create = bad_inode_create,
.lookup = bad_inode_lookup,
.link = bad_inode_link,
.unlink = bad_inode_unlink,
.symlink = bad_inode_symlink,
.mkdir = bad_inode_mkdir,
.rmdir = bad_inode_rmdir,
.mknod = bad_inode_mknod,
.rename2 = bad_inode_rename2,
.readlink = bad_inode_readlink,
/* follow_link must be no-op, otherwise unmounting this inode
won't work */
/* put_link returns void */
/* truncate returns void */
.permission = bad_inode_permission,
.getattr = bad_inode_getattr,
.setattr = bad_inode_setattr,
.setxattr = bad_inode_setxattr,
.getxattr = bad_inode_getxattr,
.listxattr = bad_inode_listxattr,
.removexattr = bad_inode_removexattr,
};
/*
* When a filesystem is unable to read an inode due to an I/O error in
* its read_inode() function, it can call make_bad_inode() to return a
* set of stubs which will return EIO errors as required.
*
* We only need to do limited initialisation: all other fields are
* preinitialised to zero automatically.
*/
/**
* make_bad_inode - mark an inode bad due to an I/O error
* @inode: Inode to mark bad
*
* When an inode cannot be read due to a media or remote network
* failure this function makes the inode "bad" and causes I/O operations
* on it to fail from this point on.
*/
void make_bad_inode(struct inode *inode)
{
remove_inode_hash(inode);
inode->i_mode = S_IFREG;
inode->i_atime = inode->i_mtime = inode->i_ctime =
current_fs_time(inode->i_sb);
inode->i_op = &bad_inode_ops;
inode->i_fop = &bad_file_ops;
}
EXPORT_SYMBOL(make_bad_inode);
/*
* This tests whether an inode has been flagged as bad. The test uses
* &bad_inode_ops to cover the case of invalidated inodes as well as
* those created by make_bad_inode() above.
*/
/**
* is_bad_inode - is an inode errored
* @inode: inode to test
*
* Returns true if the inode in question has been marked as bad.
*/
bool is_bad_inode(struct inode *inode)
{
return (inode->i_op == &bad_inode_ops);
}
EXPORT_SYMBOL(is_bad_inode);
/**
* iget_failed - Mark an under-construction inode as dead and release it
* @inode: The inode to discard
*
* Mark an under-construction inode as dead and release it.
*/
void iget_failed(struct inode *inode)
{
make_bad_inode(inode);
unlock_new_inode(inode);
iput(inode);
}
EXPORT_SYMBOL(iget_failed);
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