linux-toradex.git, branch v2.6.35.8

Linux 2.6.35.8

2010-10-29T04:52:43+00:00

mm: Move vma_stack_continue into mm.h

2010-10-29T04:51:47+00:00

commit 39aa3cb3e8250db9188a6f1e3fb62ffa1a717678 upstream.

So it can be used by all that need to check for that.

Signed-off-by: Stefan Bader 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

execve: make responsive to SIGKILL with large arguments

2010-10-29T04:51:47+00:00

commit 9aea5a65aa7a1af9a4236dfaeb0088f1624f9919 upstream.

An execve with a very large total of argument/environment strings
can take a really long time in the execve system call.  It runs
uninterruptibly to count and copy all the strings.  This change
makes it abort the exec quickly if sent a SIGKILL.

Note that this is the conservative change, to interrupt only for
SIGKILL, by using fatal_signal_pending().  It would be perfectly
correct semantics to let any signal interrupt the string-copying in
execve, i.e. use signal_pending() instead of fatal_signal_pending().
We'll save that change for later, since it could have user-visible
consequences, such as having a timer set too quickly make it so that
an execve can never complete, though it always happened to work before.

Signed-off-by: Roland McGrath 
Reviewed-by: KOSAKI Motohiro 
Cc: Chuck Ebbert 
Signed-off-by: Linus Torvalds

execve: improve interactivity with large arguments

2010-10-29T04:51:46+00:00

commit 7993bc1f4663c0db67bb8f0d98e6678145b387cd upstream.

This adds a preemption point during the copying of the argument and
environment strings for execve, in copy_strings().  There is already
a preemption point in the count() loop, so this doesn't add any new
points in the abstract sense.

When the total argument+environment strings are very large, the time
spent copying them can be much more than a normal user time slice.
So this change improves the interactivity of the rest of the system
when one process is doing an execve with very large arguments.

Signed-off-by: Roland McGrath 
Reviewed-by: KOSAKI Motohiro 
Signed-off-by: Linus Torvalds 
Cc: Chuck Ebbert 
Signed-off-by: Greg Kroah-Hartman

setup_arg_pages: diagnose excessive argument size

2010-10-29T04:51:46+00:00

commit 1b528181b2ffa14721fb28ad1bd539fe1732c583 upstream.

The CONFIG_STACK_GROWSDOWN variant of setup_arg_pages() does not
check the size of the argument/environment area on the stack.
When it is unworkably large, shift_arg_pages() hits its BUG_ON.
This is exploitable with a very large RLIMIT_STACK limit, to
create a crash pretty easily.

Check that the initial stack is not too large to make it possible
to map in any executable.  We're not checking that the actual
executable (or intepreter, for binfmt_elf) will fit.  So those
mappings might clobber part of the initial stack mapping.  But
that is just userland lossage that userland made happen, not a
kernel problem.

Signed-off-by: Roland McGrath 
Reviewed-by: KOSAKI Motohiro 
Signed-off-by: Linus Torvalds 
Cc: Chuck Ebbert 
Signed-off-by: Greg Kroah-Hartman

x86, mm: Fix CONFIG_VMSPLIT_1G and 2G_OPT trampoline

2010-10-29T04:51:45+00:00

commit b7d460897739e02f186425b7276e3fdb1595cea7 upstream.

rc2 kernel crashes when booting second cpu on this CONFIG_VMSPLIT_2G_OPT
laptop: whereas cloning from kernel to low mappings pgd range does need
to limit by both KERNEL_PGD_PTRS and KERNEL_PGD_BOUNDARY, cloning kernel
pgd range itself must not be limited by the smaller KERNEL_PGD_BOUNDARY.

Signed-off-by: Hugh Dickins 
LKML-Reference: 
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

x86-32: Fix dummy trampoline-related inline stubs

2010-10-29T04:51:45+00:00

commit 8848a91068c018bc91f597038a0f41462a0f88a4 upstream.

Fix dummy inline stubs for trampoline-related functions when no
trampolines exist (until we get rid of the no-trampoline case
entirely.)

Signed-off-by: H. Peter Anvin 
Cc: Joerg Roedel 
Cc: Borislav Petkov 
LKML-Reference: <4C6C294D.3030404@zytor.com>
Signed-off-by: Greg Kroah-Hartman

x86-32: Separate 1:1 pagetables from swapper_pg_dir

2010-10-29T04:51:45+00:00

commit fd89a137924e0710078c3ae855e7cec1c43cb845 upstream.

This patch fixes machine crashes which occur when heavily exercising the
CPU hotplug codepaths on a 32-bit kernel. These crashes are caused by
AMD Erratum 383 and result in a fatal machine check exception. Here's
the scenario:

1. On 32-bit, the swapper_pg_dir page table is used as the initial page
table for booting a secondary CPU.

2. To make this work, swapper_pg_dir needs a direct mapping of physical
memory in it (the low mappings). By adding those low, large page (2M)
mappings (PAE kernel), we create the necessary conditions for Erratum
383 to occur.

3. Other CPUs which do not participate in the off- and onlining game may
use swapper_pg_dir while the low mappings are present (when leave_mm is
called). For all steps below, the CPU referred to is a CPU that is using
swapper_pg_dir, and not the CPU which is being onlined.

4. The presence of the low mappings in swapper_pg_dir can result
in TLB entries for addresses below __PAGE_OFFSET to be established
speculatively. These TLB entries are marked global and large.

5. When the CPU with such TLB entry switches to another page table, this
TLB entry remains because it is global.

6. The process then generates an access to an address covered by the
above TLB entry but there is a permission mismatch - the TLB entry
covers a large global page not accessible to userspace.

7. Due to this permission mismatch a new 4kb, user TLB entry gets
established. Further, Erratum 383 provides for a small window of time
where both TLB entries are present. This results in an uncorrectable
machine check exception signalling a TLB multimatch which panics the
machine.

There are two ways to fix this issue:

        1. Always do a global TLB flush when a new cr3 is loaded and the
        old page table was swapper_pg_dir. I consider this a hack hard
        to understand and with performance implications

        2. Do not use swapper_pg_dir to boot secondary CPUs like 64-bit
        does.

This patch implements solution 2. It introduces a trampoline_pg_dir
which has the same layout as swapper_pg_dir with low_mappings. This page
table is used as the initial page table of the booting CPU. Later in the
bringup process, it switches to swapper_pg_dir and does a global TLB
flush. This fixes the crashes in our test cases.

-v2: switch to swapper_pg_dir right after entering start_secondary() so
that we are able to access percpu data which might not be mapped in the
trampoline page table.

Signed-off-by: Joerg Roedel 
LKML-Reference: <20100816123833.GB28147@aftab>
Signed-off-by: Borislav Petkov 
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

agp/intel: Fix cache control for Sandybridge

2010-10-29T04:51:44+00:00

commit f8f235e5bbf4e61f3e0886a44afb1dc4cfe8f337 upstream.

Sandybridge GTT has new cache control bits in PTE, which controls
graphics page cache in LLC or LLC/MLC, so we need to extend the mask
function to respect the new bits.

And set cache control to always LLC only by default on Gen6.

Signed-off-by: Zhenyu Wang 
Signed-off-by: Chris Wilson 
Signed-off-by: Greg Kroah-Hartman

x86: detect scattered cpuid features earlier

2010-10-29T04:51:44+00:00

commit 1dedefd1a066a795a87afca9c0236e1a94de9bf6 upstream.

Some extra CPU features such as ARAT is needed in early boot so
that x86_init function pointers can be set up properly.
http://lkml.org/lkml/2010/5/18/519
At start_kernel() level, this patch moves init_scattered_cpuid_features()
from check_bugs() to setup_arch() -> early_cpu_init() which is earlier than
platform specific x86_init layer setup. Suggested by HPA.

Signed-off-by: Jacob Pan 
LKML-Reference: <1274295685-6774-2-git-send-email-jacob.jun.pan@linux.intel.com>
Acked-by: Thomas Gleixner 
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman