linux-stable.git/arch, branch v3.4.36

xen/pat: Disable PAT using pat_enabled value.

2013-03-14T18:29:50+00:00

commit c79c49826270b8b0061b2fca840fc3f013c8a78a upstream.

The git commit 8eaffa67b43e99ae581622c5133e20b0f48bcef1
(xen/pat: Disable PAT support for now) explains in details why
we want to disable PAT for right now. However that
change was not enough and we should have also disabled
the pat_enabled value. Otherwise we end up with:

mmap-example:3481 map pfn expected mapping type write-back for
[mem 0x00010000-0x00010fff], got uncached-minus
 ------------[ cut here ]------------
WARNING: at /build/buildd/linux-3.8.0/arch/x86/mm/pat.c:774 untrack_pfn+0xb8/0xd0()
mem 0x00010000-0x00010fff], got uncached-minus
------------[ cut here ]------------
WARNING: at /build/buildd/linux-3.8.0/arch/x86/mm/pat.c:774
untrack_pfn+0xb8/0xd0()
...
Pid: 3481, comm: mmap-example Tainted: GF 3.8.0-6-generic #13-Ubuntu
Call Trace:
 [] warn_slowpath_common+0x7f/0xc0
 [] warn_slowpath_null+0x1a/0x20
 [] untrack_pfn+0xb8/0xd0
 [] unmap_single_vma+0xac/0x100
 [] unmap_vmas+0x49/0x90
 [] exit_mmap+0x98/0x170
 [] mmput+0x64/0x100
 [] dup_mm+0x445/0x660
 [] copy_process.part.22+0xa5f/0x1510
 [] do_fork+0x91/0x350
 [] sys_clone+0x16/0x20
 [] stub_clone+0x69/0x90
 [] ? system_call_fastpath+0x1a/0x1f
---[ end trace 4918cdd0a4c9fea4 ]---

(a similar message shows up if you end up launching 'mcelog')

The call chain is (as analyzed by Liu, Jinsong):
do_fork
  --> copy_process
    --> dup_mm
      --> dup_mmap
       	--> copy_page_range
          --> track_pfn_copy
            --> reserve_pfn_range
              --> line 624: flags != want_flags
It comes from different memory types of page table (_PAGE_CACHE_WB) and MTRR
(_PAGE_CACHE_UC_MINUS).

Stefan Bader dug in this deep and found out that:
"That makes it clearer as this will do

reserve_memtype(...)
--> pat_x_mtrr_type
  --> mtrr_type_lookup
    --> __mtrr_type_lookup

And that can return -1/0xff in case of MTRR not being enabled/initialized. Which
is not the case (given there are no messages for it in dmesg). This is not equal
to MTRR_TYPE_WRBACK and thus becomes _PAGE_CACHE_UC_MINUS.

It looks like the problem starts early in reserve_memtype:

       	if (!pat_enabled) {
                /* This is identical to page table setting without PAT */
                if (new_type) {
                        if (req_type == _PAGE_CACHE_WC)
                                *new_type = _PAGE_CACHE_UC_MINUS;
                        else
                               	*new_type = req_type & _PAGE_CACHE_MASK;
               	}
                return 0;
        }

This would be what we want, that is clearing the PWT and PCD flags from the
supported flags - if pat_enabled is disabled."

This patch does that - disabling PAT.

Reported-by: Sander Eikelenboom 
Reported-and-Tested-by: Konrad Rzeszutek Wilk 
Reported-and-Tested-by: Stefan Bader 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

ARM: 7663/1: perf: fix ARMv7 EVTYPE_MASK to include NSH bit

2013-03-14T18:29:50+00:00

commit f2fe09b055e2549de41fb107b34c60bac4a1b0cf upstream.

Masked out PMXEVTYPER.NSH means that we can't enable profiling at PL2,
regardless of the settings in the HDCR.

This patch fixes the broken mask.

Reported-by: Christoffer Dall 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

xen/pci: We don't do multiple MSI's.

2013-03-14T18:29:41+00:00

commit 884ac2978a295b7df3c4a686d3bff6932bbbb460 upstream.

There is no hypercall to setup multiple MSI per PCI device.
As such with these two new commits:
-  08261d87f7d1b6253ab3223756625a5c74532293
   PCI/MSI: Enable multiple MSIs with pci_enable_msi_block_auto()
- 5ca72c4f7c412c2002363218901eba5516c476b1
   AHCI: Support multiple MSIs

we would call the PHYSDEVOP_map_pirq 'nvec' times with the same
contents of the PCI device. Sander discovered that we would get
the same PIRQ value 'nvec' times and return said values to the
caller. That of course meant that the device was configured only
with one MSI and AHCI would fail with:

ahci 0000:00:11.0: version 3.0
xen: registering gsi 19 triggering 0 polarity 1
xen: --> pirq=19 -> irq=19 (gsi=19)
(XEN) [2013-02-27 19:43:07] IOAPIC[0]: Set PCI routing entry (6-19 -> 0x99 -> IRQ 19 Mode:1 Active:1)
ahci 0000:00:11.0: AHCI 0001.0200 32 slots 4 ports 6 Gbps 0xf impl SATA mode
ahci 0000:00:11.0: flags: 64bit ncq sntf ilck pm led clo pmp pio slum part
ahci: probe of 0000:00:11.0 failed with error -22

That is b/c in ahci_host_activate the second call to
devm_request_threaded_irq  would return -EINVAL as we passed in
(on the second run) an IRQ that was never initialized.

Reported-and-Tested-by: Sander Eikelenboom 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

ARM: fix scheduling while atomic warning in alignment handling code

2013-03-14T18:29:41+00:00

commit b255188f90e2bade1bd11a986dd1ca4861869f4d upstream.

Paolo Pisati reports that IPv6 triggers this warning:

BUG: scheduling while atomic: swapper/0/0/0x40000100
Modules linked in:
[] (unwind_backtrace+0x0/0xf0) from [] (__schedule_bug+0x48/0x5c)
[] (__schedule_bug+0x48/0x5c) from [] (__schedule+0x700/0x740)
[] (__schedule+0x700/0x740) from [] (__cond_resched+0x24/0x34)
[] (__cond_resched+0x24/0x34) from [] (_cond_resched+0x3c/0x44)
[] (_cond_resched+0x3c/0x44) from [] (do_alignment+0x178/0x78c)
[] (do_alignment+0x178/0x78c) from [] (do_DataAbort+0x34/0x98)
[] (do_DataAbort+0x34/0x98) from [] (__dabt_svc+0x40/0x60)
Exception stack(0xc0763d70 to 0xc0763db8)
3d60:                                     e97e805e e97e806e 2c000000 11000000
3d80: ea86bb00 0000002c 00000011 e97e807e c076d2a8 e97e805e e97e806e 0000002c
3da0: 3d000000 c0763dbc c04b98fc c02a8490 00000113 ffffffff
[] (__dabt_svc+0x40/0x60) from [] (__csum_ipv6_magic+0x8/0xc8)

Fix this by using probe_kernel_address() stead of __get_user().

Reported-by: Paolo Pisati 
Tested-by: Paolo Pisati 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: VFP: fix emulation of second VFP instruction

2013-03-14T18:29:41+00:00

commit 5e4ba617c1b584b2e376f31a63bd4e734109318a upstream.

Martin Storsjö reports that the sequence:

        ee312ac1        vsub.f32        s4, s3, s2
        ee702ac0        vsub.f32        s5, s1, s0
        e59f0028        ldr             r0, [pc, #40]
        ee111a90        vmov            r1, s3

on Raspberry Pi (implementor 41 architecture 1 part 20 variant b rev 5)
where s3 is a denormal and s2 is zero results in incorrect behaviour -
the instruction "vsub.f32 s5, s1, s0" is not executed:

        VFP: bounce: trigger ee111a90 fpexc d0000780
        VFP: emulate: INST=0xee312ac1 SCR=0x00000000
        ...

As we can see, the instruction triggering the exception is the "vmov"
instruction, and we emulate the "vsub.f32 s4, s3, s2" but fail to
properly take account of the FPEXC_FP2V flag in FPEXC.  This is because
the test for the second instruction register being valid is bogus, and
will always skip emulation of the second instruction.

Reported-by: Martin Storsjö 
Tested-by: Martin Storsjö 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

x86: Make sure we can boot in the case the BDA contains pure garbage

2013-03-03T22:06:39+00:00

commit 7c10093692ed2e6f318387d96b829320aa0ca64c upstream.

On non-BIOS platforms it is possible that the BIOS data area contains
garbage instead of being zeroed or something equivalent (firmware
people: we are talking of 1.5K here, so please do the sane thing.)

We need on the order of 20-30K of low memory in order to boot, which
may grow up to < 64K in the future.  We probably want to avoid the
lowest of the low memory.  At the same time, it seems extremely
unlikely that a legitimate EBDA would ever reach down to the 128K
(which would require it to be over half a megabyte in size.)  Thus,
pick 128K as the cutoff for "this is insane, ignore."  We may still
end up reserving a bunch of extra memory on the low megabyte, but that
is not really a major issue these days.  In the worst case we lose
512K of RAM.

This code really should be merged with trim_bios_range() in
arch/x86/kernel/setup.c, but that is a bigger patch for a later merge
window.

Reported-by: Darren Hart 
Signed-off-by: H. Peter Anvin 
Cc: Matt Fleming 
Link: http://lkml.kernel.org/n/tip-oebml055yyfm8yxmria09rja@git.kernel.org
Signed-off-by: Greg Kroah-Hartman

x86, efi: Make "noefi" really disable EFI runtime serivces

2013-03-03T22:06:38+00:00

commit fb834c7acc5e140cf4f9e86da93a66de8c0514da upstream.

commit 1de63d60cd5b ("efi: Clear EFI_RUNTIME_SERVICES rather than
EFI_BOOT by "noefi" boot parameter") attempted to make "noefi" true to
its documentation and disable EFI runtime services to prevent the
bricking bug described in commit e0094244e41c ("samsung-laptop:
Disable on EFI hardware"). However, it's not possible to clear
EFI_RUNTIME_SERVICES from an early param function because
EFI_RUNTIME_SERVICES is set in efi_init() *after* parse_early_param().

This resulted in "noefi" effectively becoming a no-op and no longer
providing users with a way to disable EFI, which is bad for those
users that have buggy machines.

Reported-by: Walt Nelson Jr 
Cc: Satoru Takeuchi 
Signed-off-by: Matt Fleming 
Link: http://lkml.kernel.org/r/1361392572-25657-1-git-send-email-matt@console-pimps.org
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

Purge existing TLB entries in set_pte_at and ptep_set_wrprotect

2013-02-28T14:59:05+00:00

commit 7139bc1579901b53db7e898789e916ee2fb52d78 upstream.

This patch goes a long way toward fixing the minifail bug, and
it  significantly improves the stability of SMP machines such as
the rp3440.  When write  protecting a page for COW, we need to
purge the existing translation.  Otherwise, the COW break
doesn't occur as expected because the TLB may still have a stale entry
which allows writes.

[jejb: fix up checkpatch errors]
Signed-off-by: John David Anglin 
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

powerpc/kexec: Disable hard IRQ before kexec

2013-02-28T14:59:04+00:00

commit 8520e443aa56cc157b015205ea53e7b9fc831291 upstream.

Disable hard IRQ before kexec a new kernel image.
Not doing it can result in corrupted data in the memory segments
reserved for the new kernel.

Signed-off-by: Phileas Fogg 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

ARM: 7643/1: sched: correct update_sched_clock()

2013-02-28T14:59:04+00:00

commit 7c4e9ced424be4d36df6a3e3825763e97ee97607 upstream.

If we want load epoch_cyc and epoch_ns atomically,
we should update epoch_cyc_copy first of all.
This notify reader that updating is in progress.

If we update epoch_cyc first like as current implementation,
there is subtle error case.
Look at the below example.


cyc = 9
ns = 900
cyc_copy = 9

== CASE 1 ==
           
                           write cyc = 10
read cyc = 10
read ns = 900
                           write ns = 1000
                           write cyc_copy = 10
read cyc_copy = 10

output = (10, 900)

== CASE 2 ==
           
read cyc = 9
                           write cyc = 10
                           write ns = 1000
read ns = 1000
read cyc_copy = 9
                           write cyc_copy = 10
output = (9, 1000)

If atomic read is ensured, output should be (9, 900) or (10, 1000).
But, output in example case are not.

So, change updating sequence in order to correct this problem.

Signed-off-by: Joonsoo Kim 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman