linux-toradex.git/arch/x86, branch v3.4.99

x86, ioremap: Speed up check for RAM pages

2014-07-17T22:39:50+00:00

commit c81c8a1eeede61e92a15103748c23d100880cc8a upstream.

In __ioremap_caller() (the guts of ioremap), we loop over the range of
pfns being remapped and checks each one individually with page_is_ram().
For large ioremaps, this can be very slow.  For example, we have a
device with a 256 GiB PCI BAR, and ioremapping this BAR can take 20+
seconds -- sometimes long enough to trigger the soft lockup detector!

Internally, page_is_ram() calls walk_system_ram_range() on a single
page.  Instead, we can make a single call to walk_system_ram_range()
from __ioremap_caller(), and do our further checks only for any RAM
pages that we find.  For the common case of MMIO, this saves an enormous
amount of work, since the range being ioremapped doesn't intersect
system RAM at all.

With this change, ioremap on our 256 GiB BAR takes less than 1 second.

Signed-off-by: Roland Dreier 
Link: http://lkml.kernel.org/r/1399054721-1331-1-git-send-email-roland@kernel.org
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

KVM: x86: preserve the high 32-bits of the PAT register

2014-07-09T17:51:20+00:00

commit 7cb060a91c0efc5ff94f83c6df3ed705e143cdb9 upstream.

KVM does not really do much with the PAT, so this went unnoticed for a
long time.  It is exposed however if you try to do rdmsr on the PAT
register.

Reported-by: Valentine Sinitsyn 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

KVM: x86: Increase the number of fixed MTRR regs to 10

2014-07-09T17:51:20+00:00

commit 682367c494869008eb89ef733f196e99415ae862 upstream.

Recent Intel CPUs have 10 variable range MTRRs. Since operating systems
sometime make assumptions on CPUs while they ignore capability MSRs, it is
better for KVM to be consistent with recent CPUs. Reporting more MTRRs than
actually supported has no functional implications.

Signed-off-by: Nadav Amit 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

ptrace,x86: force IRET path after a ptrace_stop()

2014-07-07T01:49:20+00:00

commit b9cd18de4db3c9ffa7e17b0dc0ca99ed5aa4d43a upstream.

The 'sysret' fastpath does not correctly restore even all regular
registers, much less any segment registers or reflags values.  That is
very much part of why it's faster than 'iret'.

Normally that isn't a problem, because the normal ptrace() interface
catches the process using the signal handler infrastructure, which
always returns with an iret.

However, some paths can get caught using ptrace_event() instead of the
signal path, and for those we need to make sure that we aren't going to
return to user space using 'sysret'.  Otherwise the modifications that
may have been done to the register set by the tracer wouldn't
necessarily take effect.

Fix it by forcing IRET path by setting TIF_NOTIFY_RESUME from
arch_ptrace_stop_needed() which is invoked from ptrace_stop().

Signed-off-by: Tejun Heo 
Reported-by: Andy Lutomirski 
Acked-by: Oleg Nesterov 
Suggested-by: Linus Torvalds 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

x86_32, entry: Do syscall exit work on badsys (CVE-2014-4508)

2014-07-01T03:01:34+00:00

commit 554086d85e71f30abe46fc014fea31929a7c6a8a upstream.

The bad syscall nr paths are their own incomprehensible route
through the entry control flow.  Rearrange them to work just like
syscalls that return -ENOSYS.

This fixes an OOPS in the audit code when fast-path auditing is
enabled and sysenter gets a bad syscall nr (CVE-2014-4508).

This has probably been broken since Linux 2.6.27:
af0575bba0 i386 syscall audit fast-path

Cc: Roland McGrath 
Reported-by: Toralf Förster 
Signed-off-by: Andy Lutomirski 
Link: http://lkml.kernel.org/r/e09c499eade6fc321266dd6b54da7beb28d6991c.1403558229.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

x86, x32: Use compat shims for io_{setup,submit}

2014-07-01T03:01:33+00:00

commit 7fd44dacdd803c0bbf38bf478d51d280902bb0f1 upstream.

The io_setup takes a pointer to a context id of type aio_context_t.
This in turn is typed to a __kernel_ulong_t.  We could tweak the
exported headers to define this as a 64bit quantity for specific
ABIs, but since we already have a 32bit compat shim for the x86 ABI,
let's just re-use that logic.  The libaio package is also written to
expect this as a pointer type, so a compat shim would simplify that.

The io_submit func operates on an array of pointers to iocb structs.
Padding out the array to be 64bit aligned is a huge pain, so convert
it over to the existing compat shim too.

We don't convert io_getevents to the compat func as its only purpose
is to handle the timespec struct, and the x32 ABI uses 64bit times.

With this change, the libaio package can now pass its testsuite when
built for the x32 ABI.

Signed-off-by: Mike Frysinger 
Link: http://lkml.kernel.org/r/1399250595-5005-1-git-send-email-vapier@gentoo.org
Cc: H.J. Lu 
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

x86-32, espfix: Remove filter for espfix32 due to race

2014-07-01T03:01:33+00:00

commit 246f2d2ee1d715e1077fc47d61c394569c8ee692 upstream.

It is not safe to use LAR to filter when to go down the espfix path,
because the LDT is per-process (rather than per-thread) and another
thread might change the descriptors behind our back.  Fortunately it
is always *safe* (if a bit slow) to go down the espfix path, and a
32-bit LDT stack segment is extremely rare.

Signed-off-by: H. Peter Anvin 
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

x86/efi: Fix dummy variable buffer allocation

2014-06-07T23:02:10+00:00

commit b8cb62f82103083a6e8fa5470bfe634a2c06514d upstream.

1. Check for allocation failure
2. Clear the buffer contents, as they may actually be written to flash
3. Don't leak the buffer

Compile-tested only.

[ Tested successfully on my buggy ASUS machine - Matt ]

Signed-off-by: Ben Hutchings 
Signed-off-by: Matt Fleming 
Cc: Rui Xiang 
Signed-off-by: Greg Kroah-Hartman

Modify UEFI anti-bricking code

2014-06-07T23:02:10+00:00

commit f8b8404337de4e2466e2e1139ea68b1f8295974f upstream.

This patch reworks the UEFI anti-bricking code, including an effective
reversion of cc5a080c and 31ff2f20. It turns out that calling
QueryVariableInfo() from boot services results in some firmware
implementations jumping to physical addresses even after entering virtual
mode, so until we have 1:1 mappings for UEFI runtime space this isn't
going to work so well.

Reverting these gets us back to the situation where we'd refuse to create
variables on some systems because they classify deleted variables as "used"
until the firmware triggers a garbage collection run, which they won't do
until they reach a lower threshold. This results in it being impossible to
install a bootloader, which is unhelpful.

Feedback from Samsung indicates that the firmware doesn't need more than
5KB of storage space for its own purposes, so that seems like a reasonable
threshold. However, there's still no guarantee that a platform will attempt
garbage collection merely because it drops below this threshold. It seems
that this is often only triggered if an attempt to write generates a
genuine EFI_OUT_OF_RESOURCES error. We can force that by attempting to
create a variable larger than the remaining space. This should fail, but if
it somehow succeeds we can then immediately delete it.

I've tested this on the UEFI machines I have available, but I don't have
a Samsung and so can't verify that it avoids the bricking problem.

Signed-off-by: Matthew Garrett 
Signed-off-by: Lee, Chun-Y  [ dummy variable cleanup ]
Signed-off-by: Matt Fleming 
[bwh: Backported to 3.2: the reverted changes were never applied here]
Signed-off-by: Ben Hutchings 
Cc: Rui Xiang 
Signed-off-by: Greg Kroah-Hartman

x86,efi: Implement efi_no_storage_paranoia parameter

2014-06-07T23:02:10+00:00

commit 8c58bf3eec3b8fc8162fe557e9361891c20758f2 upstream.

Using this parameter one can disable the storage_size/2 check if
he is really sure that the UEFI does sane gc and fulfills the spec.

This parameter is useful if a devices uses more than 50% of the
storage by default.
The Intel DQSW67 desktop board is such a sucker for exmaple.

Signed-off-by: Richard Weinberger 
Signed-off-by: Matt Fleming 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings 
Cc: Rui Xiang 
Signed-off-by: Greg Kroah-Hartman