Page table entries are made invalid by writing a zero into the the PTE
slot in a page table. This creates a race condition with the TLB
modify handlers when they are updating the PTE.
CPU0 CPU1
Test for _PAGE_PRESENT
. set to not _PAGE_PRESENT (zero)
Set to _PAGE_VALID
So now the page not present value (zero) is suddenly valid and user
space programs have access to physical page zero.
We close the race by putting the test for _PAGE_PRESENT and setting of
_PAGE_VALID into an atomic LL/SC section. This requires more registers
than just K0 and K1 in the handlers, so we need to save some registers
to a save area and then restore them when we are done.
The save area is an array of cacheline aligned structures that should
not suffer cache line bouncing as they are CPU private.
[ralf@linux-mips.org: Fix !defined(CONFIG_MIPS_PGD_C0_CONTEXT) build error.]
Signed-off-by: David Daney <david.daney@cavium.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2577/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This can be used from either 32-bit or 64-bit code to generate logical
right shifts of any constant amount.
Signed-off-by: David Daney <david.daney@cavium.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2576/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Enable cpu_has_clo_clz only when CONFIG_CPU_MIPS32 or CONFIG_CPU_MIPS64
is selected. This will optimize fls() and __fls() to use CLZ insn, and
eventually ffs() and __ffs() as well.
Malta and MIPSSim are development platforms, and need to take care of
various processor configurations, release rivisions and so on, even
across different MIPS ISAs. For such platforms we have to be careful,
for instance, with turning on cpu_has_mips{32,64}r[12] features.
As for CLZ, all MIPS32/64 processors support it, regardless of release
revisions.
Signed-off-by: Shinya Kuribayashi <skuribay@pobox.com>
To: David VomLehn <dvomlehn@cisco.com>
To: macro@linux-mips.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1453/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This will optimize fls() and __fls() to use CLZ throughout the kernel,
and any other optimizations that depend on constant cpu_has_* values
will also be used.
Signed-off-by: David VomLehn <dvomlehn@cisco.com>
Signed-off-by: Shinya Kuribayashi <skuribay@pobox.com>
To: David VomLehn <dvomlehn@cisco.com>
To: macro@linux-mips.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1452/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
fixrange_init() allocates page tables for all addresses higher than
FIXADDR_TOP. On processors that override the default FIXADDR_TOP
address of 0xfffe_0000, this can consume up to 4 pages (1 page per 4MB)
for pgd's that are never used.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1980/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Memory maps and addressing quirks are normally defined in <spaces.h>.
There are already three targets that need to override FIXADDR_TOP, and
others exist. This will be a cleaner approach than adding lots of
ifdefs in fixmap.h .
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1573/
Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
On processors with deep write buffers, it is likely that many cycles
will pass between a CACHE instruction and the time the data actually
gets written out to DRAM. Add a SYNC instruction to ensure that the
buffers get emptied before the flush functions return.
Actual problem seen in the wild:
1) dma_alloc_coherent() allocates cached memory
2) memset() is called to clear the new pages
3) dma_cache_wback_inv() is called to flush the zero data out to memory
4) dma_alloc_coherent() returns an uncached (kseg1) pointer to the
freshly allocated pages
5) Caller writes data through the kseg1 pointer
6) Buffered writeback data finally gets flushed out to DRAM
7) Part of caller's data is inexplicably zeroed out
This patch adds SYNC between steps 3 and 4, which fixed the problem.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork:
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
pfn_valid() compares the PFN to max_mapnr:
__pfn >= min_low_pfn && __pfn < max_mapnr;
On HIGHMEM kernels, highend_pfn is used to set the value of max_mapnr.
Unfortunately, highend_pfn is left at zero if the system does not
actually have enough RAM to reach into the HIGHMEM range. This causes
pfn_valid() to always return false, and when debug checks are enabled
the kernel will fail catastrophically:
Memory: 22432k/32768k available (2249k kernel code, 10336k reserved, 653k data, 1352k init, 0k highmem)
NR_IRQS:128
kfree_debugcheck: out of range ptr 81c02900h.
Kernel bug detected[#1]:
Cpu 0
$ 0 : 00000000 10008400 00000034 00000000
$ 4 : 8003e160 802a0000 8003e160 00000000
$ 8 : 00000000 0000003e 00000747 00000747
...
On such a configuration, max_low_pfn should be used to set max_mapnr.
This was seen on 2.6.34.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1992/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch introduced topdown mmap support in user process address
space allocation policy.
Recently, we ran some large applications that use mmap heavily and
lead to OOM due to inflexible mmap allocation policy on MIPS32.
Since most other major archs supported it for years, it is reasonable
to follow the trend and reduce the pain of porting applications.
Due to cache aliasing concern, arch_get_unmapped_area_topdown() and
other helper functions are implemented in arch/mips/kernel/syscall.c.
Signed-off-by: Jian Peng <jipeng2005@gmail.com>
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2389/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The address limit is already set in flush_old_exec() via set_fs(USER_DS)
so this assignment is redundant.
[ralf@linux-mips.org: also see dac853ae89 for
further explanation.]
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/2466/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Fix few issues in the Netlogic code:
- Use handle_percpu_irq to handle per-cpu interrupts
- Remove unused function nlm_common_ipi_handler()
- Call scheduler_ipi() on SMP_RESCHEDULE_YOURSELF
- Enable interrupts in nlm_smp_finish()
Signed-off-by: Jayachandran C <jayachandranc@netlogicmicro.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2460/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Commit d6d5d5c4a (MIPS: Sibyte: Convert to new irq_chip functions)
removed the mask function which breaks irq_shutdown(). Restore it.
Reported-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2460/
Tested-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Since 6be63bbbda (lmo) rsp.
af3a1f6f48 (kernel.org) the Malta code does
no longer probe for presence of GCMP if CMP is not configured. This means
that the variable gcmp_present well be left at its default value of -1
which normally is meant to indicate that GCMP has not yet been mmapped.
This non-zero value is now interpreted as GCMP being present resulting
in a write attempt to a GCMP register resulting in a crash.
Reported and a build fix on top of my fix by Rob Landley <rob@landley.net>.
Reported-by: Rob Landley <rob@landley.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/2413/
Renumbering was necessary because I had already wired up setns(2) in the
linux-mips.org tree in commit c3fce54644cabbb90700cc3acc040718a377f609
[MIPS: Wire up new sendmmsg syscall.] but the same syscall numbers were
used by 7b21fddd08 [ns: Wire up the setns
system call] resulting in a conflict.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Commit ee6114202e48dc282c6d04741e9c5d7171eb8bb8 (lmo) rsp.
1685f3b158 (kernel.org) ["MIPS: SMTC: Move
declaration of smtc_init_secondary to <asm/smtc.h>."] didn't quite do
that - it rather lost the declaration of smtc_init_secondary resulting in
a build error.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
I'm running a workload which triggers a lot of swap in a machine with 4
nodes. After I kill the workload, I found a kswapd livelock. Sometimes
kswapd3 or kswapd2 are keeping running and I can't access filesystem,
but most memory is free.
This looks like a regression since commit 08951e5459 ("mm: vmscan:
correct check for kswapd sleeping in sleeping_prematurely").
Node 2 and 3 have only ZONE_NORMAL, but balance_pgdat() will return 0
for classzone_idx. The reason is end_zone in balance_pgdat() is 0 by
default, if all zones have watermark ok, end_zone will keep 0.
Later sleeping_prematurely() always returns true. Because this is an
order 3 wakeup, and if classzone_idx is 0, both balanced_pages and
present_pages in pgdat_balanced() are 0. We add a special case here.
If a zone has no page, we think it's balanced. This fixes the livelock.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Assume that /sys/kernel/debug/dummy64 is debugfs file created by
debugfs_create_x64().
# cd /sys/kernel/debug
# echo 0x1234567812345678 > dummy64
# cat dummy64
0x0000000012345678
# echo 0x80000000 > dummy64
# cat dummy64
0xffffffff80000000
A value larger than INT_MAX cannot be written to the debugfs file created
by debugfs_create_u64 or debugfs_create_x64 on 32bit machine. Because
simple_attr_write() uses simple_strtol() for the conversion.
To fix this, use simple_strtoll() instead.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
vfs: fix race in rcu lookup of pruned dentry
Fix cifs_get_root()
[ Edited the last commit to get rid of a 'unused variable "seq"'
warning due to Al editing the patch. - Linus ]
Don't update *inode in __follow_mount_rcu() until we'd verified that
there is mountpoint there. Kudos to Hugh Dickins for catching that
one in the first place and eventually figuring out the solution (and
catching a braino in the earlier version of patch).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
open(2) must always include one of O_RDONLY, O_WRONLY, or O_RDWR. No need
for any O_APPEND special case.
Passing O_WRONLY|O_RDWR is undefined according to the man page, but the
Linux VFS interprets this as O_RDWR, so we'll do the same.
This fixes open(2) with flags O_RDWR|O_APPEND, which was incorrectly being
translated to readonly.
Reported-by: Fyodor Ustinov <ufm@ufm.su>
Signed-off-by: Sage Weil <sage@newdream.net>
Video input mux settings for tvp7002 and imager inputs were swapped.
Comment was correct.
Tested on EVM with tvp7002 input.
Signed-off-by: Jon Povey <jon.povey@racelogic.co.uk>
Acked-by: Manjunath Hadli <manjunath.hadli@ti.com>
Cc: stable@kernel.org
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
pppoe: Must flush connections when MAC address changes too.
include/linux/sdla.h: remove the prototype of sdla()
tulip: dmfe: Remove old log spamming pr_debugs
`make headers_check` complains that
linux-2.6/usr/include/linux/sdla.h:116: userspace cannot reference
function or variable defined in the kernel
this is due to that there is no such a kernel function,
void sdla(void *cfg_info, char *dev, struct frad_conf *conf, int quiet);
I don't know why we have it in a kernel header, so remove it.
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add missing ->i_mutex, convert to lookup_one_len() instead of
(broken) open-coded analog, cope with getting something like
a//b as relative pathname. Simplify the hell out of it, while
we are there...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Commit 726b65ad44 ("tulip: Convert uses of KERN_DEBUG") enabled
some old previously inactive uses of pr_debug converted by
commit dde7c8ef16 ("tulip/dmfe.c: Use dev_<level> and pr_<level>").
Remove these pr_debugs.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While compiling it with Fedora 15, I noticed this issue:
inlined from ‘si4713_write_econtrol_string’ at drivers/media/radio/si4713-i2c.c:1065:24:
arch/x86/include/asm/uaccess_32.h:211:26: error: call to ‘copy_from_user_overflow’ declared with attribute error: copy_from_user() buffer size is not provably correct
Cc: stable@kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
Acked-by: Eduardo Valentin <edubezval@gmail.com>
Reviewed-by: Eugene Teo <eugeneteo@kernel.sg>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
... and it's getting it wrong, too - missing ->d_revalidate() calls when
it's dealing with filesystem (procfs) that has non-trivial ->d_revalidate()...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
