This is unnecessary since it is already protected by
spin_lock_irq{save, restore} in clock.c.
Signed-off-by: Neric miao <eric.miao@marvell.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: Neric miao <eric.miao@marvell.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

"cat /dev/mem" may cause kernel Oops for boards with PHYS_OFFSET != 0
because character device is mapped to addresses starting from zero
and there is no protection against such situation.
Patch just add this.
Signed-off-by: NAlexandre Rusev <arusev@ru.mvista.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Convert debug-only (and removed) MODULE_PARM() to module_param().
Compiles cleanly (with DEBUG=1).
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

On Wed, Feb 20, 2008 at 11:50:33AM +0100, Guennadi Liakhovetski wrote:
> arch/arm/kernel/atags.c uses for some reason the
> KEXEC_BOOT_PARAMS_SIZE macro, which is only defined if CONFIG_KEXEC
> is set. So, either this macro should be defined always, or another
> macro should be used, or ATAGS_PROC should depend on KEXEC.

As the procfs export of ATAGS is not meant as a stable, general purpose
ABI it shouldn't be an independent, general configuration option.

This patch make ATAGS_PROC depend on KEXEC
Signed-off-by: NUli Luckas <u.luckas@road.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fix 32-on-64 pvops kernel:

we don't want userspace using syscall/sysenter, even if the hypervisor
supports it, so mask it out from CPUID.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

revert the BTS ptrace extension for now.

based on general objections from Roland McGrath:

    http://lkml.org/lkml/2008/2/21/323

we'll let the BTS functionality cook some more and re-enable
it in v2.6.26. We'll leave the dead code around to help the
development of this code.

(X86_BTS is not defined at the moment)
Signed-off-by: NIngo Molnar <mingo@elte.hu>

avoid over-eager large page splitup.

When the target area needs to be split or is split already (ioremap)
then the current code enforces the split of large mappings in the alias
regions even if we could avoid it.

Use a separate variable processed in the cpa_data structure to carry
the number of pages which have been processed instead of reusing the
numpages variable. This keeps numpages intact and gives the alias code
a chance to keep large mappings intact.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

delay the removal of this symbol export by one more kernel release,
giving external modules such as VirtualBox a chance to stop using it.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Jan Beulich noticed it during code review that if a driver's ioremap()
fails (say due to -ENOMEM) then we might leak the struct vm_area.

Free it properly.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Priit Laes discovered that the sed command processing nm output was
sensitive to locale settings.  This was addressed in commit
03994f01 by using [:alnum:] in place of
[a-zA-Z0-9].

But that solution too is locale-dependent and may not always match
the identifiers it needs to.  The better fix is just to run sed et al
with a fixed locale setting in all builds.
Signed-off-by: NRoland McGrath <roland@redhat.com>
CC: Priit Laes <plaes@plaes.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

a recent fix:

  commit ce28b986
  Author: Thomas Gleixner <tglx@linutronix.de>
  Date:   Wed Feb 20 23:57:30 2008 +0100

    x86: fix vsyscall wreckage

removed the broken /kernel/vsyscall64 handler completely.
This triggers the following debug check:

  sysctl table check failed: /kernel/vsyscall64  No proc_handler

Restore the sane part of the proc handler.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix a kernel bug (vmware boot problem) reported by Tomasz Grobelny,
which occurs with certain .config variants and gccs.

The x86 TLS cleanup in commit efd1ca52
made the sys_set_thread_area and sys_get_thread_area functions ripe for
tail call optimization.  If the compiler chooses to use it for them, it
can clobber the user trap frame because these are asmlinkage functions.
Reported-by: NTomasz Grobelny <tomasz@grobelny.oswiecenia.net>
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Because of the new futex validation init handler, we have
to accept faults in init section text as well as the normal
kernel text.

Thanks to Tom Callaway for the bug report.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Iff the parent has TIF_DEBUG set, _and_ clone_flags includes
CLONE_PTRACE we should set the TIF_DEBUG flag for the child and
increment the ocd refcount. Otherwise, the TIF_DEBUG flag must be
unset.

Currently, the child inherits TIF_DEBUG from the parent before
copy_thread is called, so TIF_DEBUG may be already be set before we
determine whether the child is supposed to inherit debugging
capabilities from the parent or not. This means that ocd_enable()
won't increment the refcount, because TIF_DEBUG is already set, and
that TIF_DEBUG will be set for processes that aren't being debugged.

This leads to a refcounting asymmetry, which may show up as

------------[ cut here ]------------
Badness at arch/avr32/kernel/ocd.c:73
PC is at ocd_disable+0x34/0x60
LR is at put_lock_stats+0xa/0x20

as reported by David Brownell. Happens when strace'ing a process that
forks a new child process, e.g. "strace mount -tjffs2 mtd1 /mnt", and
subsequently killing the child process (e.g. "umount /mnt".)
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>

Some parts of the kernel now do things like do *_user() accesses while
set_fs(KERNEL_DS) that fault on purpose.

See, for example, the code added by changeset
a0c1e907 ("futex: runtime enable pi
and robust functionality").

That trips up the ASI sanity checking we make in do_kernel_fault().

Just remove it for now.  Maybe we can add it back later with an added
conditional which looks at the current get_fs() value.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In commit e6bafba5, a bug was fixed that
involved converting !x & y to !(x & y).  The code below shows the same
pattern, and thus should perhaps be fixed in the same way.

This is not tested and clearly changes the semantics, so it is only
something to consider.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@ expression E1,E2; @@
(
  !E1 & !E2
|
- !E1 & E2
+ !(E1 & E2)
)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

 > Diffing dmesg between git7 and git8 doesn't sched any light since
 > git8 also removed the printouts of the x86 caps as they were being
 > initialised and updated. I'm currently adding those printouts back
 > in the hope of seeing where and when the caps get broken.

That turned out to be very illuminating:

 --- dmesg-2.6.24-git7	2008-02-24 18:01:25.295851000 +0100
 +++ dmesg-2.6.24-git8	2008-02-24 18:01:25.530358000 +0100
 ...
 CPU: After generic identify, caps: 00000003 00000000 00000000 00000000 00000000 00000000 00000000 00000000

 CPU: After all inits, caps: 00000003 00000000 00000000 00000000 00000000 00000000 00000000 00000000
+CPU: After applying cleared_cpu_caps, caps: 00000013 00000000 00000000 00000000 00000000 00000000 00000000 00000000

Notice how the TSC cap bit goes from Off to On.

(The first two lines are printout loops from -git7 forward-ported
to -git8, the third line is the same printout loop added just after
the xor-with-cleared_cpu_caps[] loop.)

Here's how the breakage occurs:
1. arch/x86/kernel/tsc_32.c:tsc_init() sees !cpu_has_tsc,
   so bails and calls setup_clear_cpu_cap(X86_FEATURE_TSC).
2. include/asm-x86/cpufeature.h:setup_clear_cpu_cap(bit) clears
   the bit in boot_cpu_data and sets it in cleared_cpu_caps
3. arch/x86/kernel/cpu/common.c:identify_cpu() XORs all caps
   in with cleared_cpu_caps
   HOWEVER, at this point c->x86_capability correctly has TSC
   Off, cleared_cpu_caps has TSC On, so the XOR incorrectly
   sets TSC to On in c->x86_capability, with disastrous results.

The real bug is that clearing bits with XOR only works if the
bits are known to be 1 prior to the XOR, and that's not true here.

A simple fix is to convert the XOR to AND-NOT instead. The following
patch does that, and allows my 486 to boot 2.6.25-rc kernels again.

[ mingo@elte.hu: fixed a similar bug in setup_64.c as well. ]

The breakage was introduced via commit 7d851c8d.
Signed-off-by: NMikael Pettersson <mikpe@it.uu.se>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

For some locales regex range [a-zA-Z] does not work as it is supposed to.
so we have to use [:alnum:] and [:xdigit:] to make it work as intended.

[1] http://en.wikipedia.org/wiki/Estonian_alphabetSigned-off-by: NIngo Molnar <mingo@elte.hu>

Currently, c_idle is declared in the stack, and thus, have no static address.

Peter Zijlstra points out this simple solution, in which c_idle.work
is initializated separatedly. Note that the INIT_WORK macro has a static
declaration of a key inside.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Acked-by: NPeter Zijlstra <pzijlstr@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Currently, there is no way for print_stack_trace() to determine whether
a given stack trace entry was deemed reliable or not, simply because
save_stack_trace() does not record this information. (Perhaps needless
to say, this makes the saved stack traces A LOT harder to read, and
probably with no other benefits, since debugging features that use
save_stack_trace() most likely also require frame pointers, etc.)

This patch reverts to the old behaviour of only recording the reliable trace
entries for saved stack traces.
Signed-off-by: NVegard Nossum <vegardno@ifi.uio.no>
Acked-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

There doesn't seem to be any reason for swapper_pg_pmd being global.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Inside a KVM virtual machine the MTRRs are usually blank. This confuses Linux
and causes a warning message at boot. This patch removes that warning message
when running Linux as a KVM guest.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

pointed out by pageexec@freemail.hu:

> what happens here is that gcc treats the argument area as owned by the
> callee, not the caller and is allowed to do certain tricks. for ssp it
> will make a copy of the struct passed by value into the local variable
> area and pass *its* address down, and it won't copy it back into the
> original instance stored in the argument area.
>
> so once sys_execve returns, the pt_regs passed by value hasn't at all
> changed and its default content will cause a nice double fault (FWIW,
> this part took me the longest to debug, being down with cold didn't
> help it either ;).

To fix this we pass in pt_regs by pointer.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

based on a report from Arne Georg Gleditsch about user-space apps
misbehaving after toggling /proc/sys/kernel/vsyscall64, a review
of the code revealed that the "NOP patching" done there is
fundamentally unsafe for a number of reasons:

1) the patching code runs without synchronizing other CPUs

2) it inserts NOPs even if there is no clock source which provides vread

3) when the clock source changes to one without vread we run in
   exactly the same problem as in #2

4) if nobody toggles the proc entry from 1 to 0 and to 1 again, then
   the syscall is not patched out

as a result it is possible to break user-space via this patching.
The only safe thing for now is to remove the patching.

This code was broken since v2.6.21.
Reported-by: NArne Georg Gleditsch <arne.gleditsch@dolphinics.no>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The KERNEL_TEXT_SIZE constant was mis-named, as we not only map the kernel
text but data, bss and init sections as well.

That name led me on the wrong path with the KERNEL_TEXT_SIZE regression,
because i knew how big of _text_ my images have and i knew about the 40 MB
"text" limit so i wrongly thought to be on the safe side of the 40 MB limit
with my 29 MB of text, while the total image size was slightly above 40 MB.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

recently the 64-bit allyesconfig bzImage kernel started spontaneously
rebooting during early bootup.

after a few fun hours spent with early init debugging, it turns out
that we've got this rather annoying limit on the size of the kernel
image:

      #define KERNEL_TEXT_SIZE  (40*1024*1024)

which limit my vmlinux just happened to pass:

       text           data       bss        dec       hex   filename
   29703744        4222751   8646224c   42572719   2899baf   vmlinux

40 MB is 42572719 bytes, so my vmlinux was just 1.5% above this limit :-/

So it happily crashed right in head_64.S, which - as we all know - is
the most debuggable code in the whole architecture ;-)

So increase the limit to allow an up to 128MB kernel image to be mapped.
(should anyone be that crazy or lazy)

We have a full 4K of pagetable (level2_kernel_pgt) allocated for these
mappings already, so there's no RAM overhead and the limit was rather
pointless and arbitrary.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

so far no one complained about that.
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

notsc is ignored in 32-bit kernels if CONFIG_X86_TSC is on.. which is
bad, fix it.
Signed-off-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix mtrr kernel-doc warning:
Warning(linux-2.6.24-git12//arch/x86/kernel/cpu/mtrr/main.c:677): No description found for parameter 'end_pfn'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The proper way to terminate the e820 chain is with %ebx == 0 on the
last legitimate memory block.  However, several BIOSes don't do that
and instead return error (CF = 1) when trying to read off the end of
the list.  For this error return, %eax doesn't necessarily return the
SMAP signature -- correctly so, since %ah should contain an error code
in this case.

To deal with some particularly broken BIOSes, we clear the entire e820
chain if the SMAP signature is missing in the middle, indicating a
plain insane e820 implementation.  However, we need to make the test
for CF = 1 before the SMAP check.

This fixes at least one HP laptop (nc6400) for which none of the
memory-probing methods (e820, e801, 88) functioned fully according to
spec.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

P6_NOPs are definitely not supported on some VIA CPUs, and possibly
(unverified) on AMD K7s.  It is also the only thing that prevents a
686 kernel from running on Transmeta TM3x00/5x00 (Crusoe) series.

The performance benefit over generic NOPs is very small, so when
building for generic consumption, avoid using them.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The P6 family of NOPs are only available on family >= 6 or above, so
enforce that in the boot code.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

We have been promoting Transmeta TM3x00/TM5x00 chips to i686-class
based on the notion that they contain all the user-space visible
features of an i686-class chip.  However, this is not actually true:
they lack the EA-taking long NOPs (0F 1F /0).  Since this is a
userspace-visible incompatibility, downgrade these CPUs to the
manufacturer-defined i586 level.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NPavel Machek <Pavel@suse.cz>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Use PF_MEMALLOC to prevent recursive calls in the DBEUG_PAGEALLOC
case. This makes the code simpler and more robust against allocation
failures.

This fixes the following fallback to non-mmconfig:

   http://lkml.org/lkml/2008/2/20/551
   http://bugzilla.kernel.org/show_bug.cgi?id=10083

Also, for DEBUG_PAGEALLOC=n reduce the pool size to one page.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Hi all,

Beginning from commits close to v2.6.25-rc2, running lguest always oopses
the host kernel. Oops is at [1].

Bisection led to the following commit:

commit 37cc8d7f

    x86/early_ioremap: don't assume we're using swapper_pg_dir

    At the early stages of boot, before the kernel pagetable has been
    fully initialized, a Xen kernel will still be running off the
    Xen-provided pagetables rather than swapper_pg_dir[].  Therefore,
    readback cr3 to determine the base of the pagetable rather than
    assuming swapper_pg_dir[].

 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
 {
-	pgd_t *pgd = &swapper_pg_dir[pgd_index(addr)];
+	/* Don't assume we're using swapper_pg_dir at this point */
+	pgd_t *base = __va(read_cr3());
+	pgd_t *pgd = &base[pgd_index(addr)];
 	pud_t *pud = pud_offset(pgd, addr);
 	pmd_t *pmd = pmd_offset(pud, addr);

Trying to analyze the problem, it seems on the guest side of lguest,
%cr3 has a different value from &swapper_pg-dir (which
is AFAIK fine on a pravirt guest):

Putting some debugging messages in early_ioremap_pmd:

/* Appears 3 times */
[    0.000000] ***************************
[    0.000000] __va(%cr3) = c0000000, &swapper_pg_dir = c02cc000
[    0.000000] ***************************

After 8 hours of debugging and staring on lguest code, I noticed something
strange in paravirt_ops->set_pmd hypercall invocation:

static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
{
	*pmdp = pmdval;
	lazy_hcall(LHCALL_SET_PMD, __pa(pmdp)&PAGE_MASK,
		   (__pa(pmdp)&(PAGE_SIZE-1))/4, 0);
}

The first hcall parameter is global pgdir which looks fine. The second
parameter is the pmd index in the pgdir which is suspectful.

AFAIK, calculating the index of pmd does not need a divisoin over four.
Removing the division made lguest work fine again . Patch is at [2].

I am not sure why the division over four existed in the first place. It
seems bogus, maybe the Xen patch just made the problem appear ?

[2]: The patch:

[PATCH] lguest: fix pgdir pmd index cacluation

Remove an error in index calculation which leads to removing
a not existing shadow page table (leading to a Null dereference).
Signed-off-by: NAhmed S. Darwish <darwish.07@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

[ mingo@elte.hu: merged to Rusty's patch ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Added a declaration to asm-x86/lguest.h and moved the extern arrays there
as well.  As an alternative to including asm/lguest.h directly, an
include could be put in linux/lguest.h
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: "rusty@rustcorp.com.au" <rusty@rustcorp.com.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This header is needed on other architectures as well (namely h8300),
which currently fails to build without this in place. Rather than
duplicating the port definition completely there, just move this to a
common location instead.

This should get h8300 working again for 2.6.25, in addition to the
changes already pushed by Sato-san in -rc2.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>