Merge branch 'linus' into x86/boot

Merge this into x86/boot so that we can queue up dependent patches.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
x86/reboot: Reduce to a single DMI table for reboot quirks

This commit reduces the X86_32 reboot_dmi_table and the X86_64
pci_reboot_dmi_table into a single table with a single set of
functions (e.g., only 1 call to core_initcall).

The table entries that use set_bios_reboot are grouped together
inside a #define CONFIG_X86_32 block.

Note that there's a single entry that uses set_kbd_reboot, which
used to be available only on X86_32.  This commit moves that
entry outside the X86_32 block because it seems it never should
have been in there.  There's multiple places in reboot.c that
assume KBD is valid regardless of X86_32/X86_64.

Signed-off-by: Michael D Labriola <michael.d.labriola@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Link: http://lkml.kernel.org/n/tip-lv3aliubas2l3aenq8v3uklk@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
x86/reboot: Clean up coding style

This commit simply cleans up the style used in this file to fall
in line with what's specified in CodingStyle.  Mostly comment
changes, with a single removal of unneeded braces.

Note that the comments for all the DMI quirks in
reboot_dmi_table now all line up consistently using tabs instead
of spaces.

Signed-off-by: Michael D Labriola <michael.d.labriola@gmail.com>
Link: http://lkml.kernel.org/n/tip-lde9yy7qsomh0sdqevn7xp56@git.kernel.org
[ Fixed a few small details. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints

Add uprobes support to the core kernel, with x86 support.

This commit adds the kernel facilities, the actual uprobes
user-space ABI and perf probe support comes in later commits.

General design:

Uprobes are maintained in an rb-tree indexed by inode and offset
(the offset here is from the start of the mapping). For a unique
(inode, offset) tuple, there can be at most one uprobe in the
rb-tree.

Since the (inode, offset) tuple identifies a unique uprobe, more
than one user may be interested in the same uprobe. This provides
the ability to connect multiple 'consumers' to the same uprobe.

Each consumer defines a handler and a filter (optional). The
'handler' is run every time the uprobe is hit, if it matches the
'filter' criteria.

The first consumer of a uprobe causes the breakpoint to be
inserted at the specified address and subsequent consumers are
appended to this list.  On subsequent probes, the consumer gets
appended to the existing list of consumers. The breakpoint is
removed when the last consumer unregisters. For all other
unregisterations, the consumer is removed from the list of
consumers.

Given a inode, we get a list of the mms that have mapped the
inode. Do the actual registration if mm maps the page where a
probe needs to be inserted/removed.

We use a temporary list to walk through the vmas that map the
inode.

- The number of maps that map the inode, is not known before we
  walk the rmap and keeps changing.
- extending vm_area_struct wasn't recommended, it's a
  size-critical data structure.
- There can be more than one maps of the inode in the same mm.

We add callbacks to the mmap methods to keep an eye on text vmas
that are of interest to uprobes.  When a vma of interest is mapped,
we insert the breakpoint at the right address.

Uprobe works by replacing the instruction at the address defined
by (inode, offset) with the arch specific breakpoint
instruction. We save a copy of the original instruction at the
uprobed address.

This is needed for:

 a. executing the instruction out-of-line (xol).
 b. instruction analysis for any subsequent fixups.
 c. restoring the instruction back when the uprobe is unregistered.

We insert or delete a breakpoint instruction, and this
breakpoint instruction is assumed to be the smallest instruction
available on the platform. For fixed size instruction platforms
this is trivially true, for variable size instruction platforms
the breakpoint instruction is typically the smallest (often a
single byte).

Writing the instruction is done by COWing the page and changing
the instruction during the copy, this even though most platforms
allow atomic writes of the breakpoint instruction. This also
mirrors the behaviour of a ptrace() memory write to a PRIVATE
file map.

The core worker is derived from KSM's replace_page() logic.

In essence, similar to KSM:

 a. allocate a new page and copy over contents of the page that
    has the uprobed vaddr
 b. modify the copy and insert the breakpoint at the required
    address
 c. switch the original page with the copy containing the
    breakpoint
 d. flush page tables.

replace_page() is being replicated here because of some minor
changes in the type of pages and also because Hugh Dickins had
plans to improve replace_page() for KSM specific work.

Instruction analysis on x86 is based on instruction decoder and
determines if an instruction can be probed and determines the
necessary fixups after singlestep.  Instruction analysis is done
at probe insertion time so that we avoid having to repeat the
same analysis every time a probe is hit.

A lot of code here is due to the improvement/suggestions/inputs
from Peter Zijlstra.

Changelog:

(v10):
 - Add code to clear REX.B prefix as suggested by Denys Vlasenko
   and Masami Hiramatsu.

(v9):
 - Use insn_offset_modrm as suggested by Masami Hiramatsu.

(v7):

 Handle comments from Peter Zijlstra:

 - Dont take reference to inode. (expect inode to uprobe_register to be sane).
 - Use PTR_ERR to set the return value.
 - No need to take reference to inode.
 - use PTR_ERR to return error value.
 - register and uprobe_unregister share code.

(v5):

 - Modified del_consumer as per comments from Peter.
 - Drop reference to inode before dropping reference to uprobe.
 - Use i_size_read(inode) instead of inode->i_size.
 - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called.
 - Includes errno.h as recommended by Stephen Rothwell to fix a build issue
   on sparc defconfig
 - Remove restrictions while unregistering.
 - Earlier code leaked inode references under some conditions while
   registering/unregistering.
 - Continue the vma-rmap walk even if the intermediate vma doesnt
   meet the requirements.
 - Validate the vma found by find_vma before inserting/removing the
   breakpoint
 - Call del_consumer under mutex_lock.
 - Use hash locks.
 - Handle mremap.
 - Introduce find_least_offset_node() instead of close match logic in
   find_uprobe
 - Uprobes no more depends on MM_OWNER; No reference to task_structs
   while inserting/removing a probe.
 - Uses read_mapping_page instead of grab_cache_page so that the pages
   have valid content.
 - pass NULL to get_user_pages for the task parameter.
 - call SetPageUptodate on the new page allocated in write_opcode.
 - fix leaking a reference to the new page under certain conditions.
 - Include Instruction Decoder if Uprobes gets defined.
 - Remove const attributes for instruction prefix arrays.
 - Uses mm_context to know if the application is 32 bit.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Also-written-by: Jim Keniston <jkenisto@us.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linux-mm <linux-mm@kvack.org>
Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com
[ Made various small edits to the commit log ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
uprobes/core: Clean up, refactor and improve the code

Make the uprobes code readable to me:

 - improve the Kconfig text so that a mere mortal gets some idea
   what CONFIG_UPROBES=y is really about

 - do trivial renames to standardize around the uprobes_*() namespace

 - clean up and simplify various code flow details

 - separate basic blocks of functionality

 - line break artifact and white space related removal

 - use standard local varible definition blocks

 - use vertical spacing to make things more readable

 - remove unnecessary volatile

 - restructure comment blocks to make them more uniform and
   more readable in general

Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Link: http://lkml.kernel.org/n/tip-ewbwhb8o6navvllsauu7k07p@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
uprobes: Move to kernel/events/

Consolidate the uprobes code under kernel/events/, where the various
core kernel event handling routines live.

Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Link: http://lkml.kernel.org/n/tip-biuyhhwohxgbp2vzbap5yr8o@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
uprobes/core: Make instruction tables volatile

Some versions of gcc spits a warning about the asm operand for
test_bit and also causes the first long of the instruction table
to be output.

Fix is similar to 7115e3fc on arch/x86/kernel/kprobes.c

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Stone <jistone@redhat.com>
Link: http://lkml.kernel.org/r/20120222091535.15880.12502.sendpatchset@srdronam.in.ibm.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
uprobes/core: Remove uprobe_opcode_sz

uprobe_opcode_sz refers to the smallest instruction size for
that architecture. UPROBES_BKPT_INSN_SIZE refers to the size of
the breakpoint instruction for that architecture.

For now we are assuming that both uprobe_opcode_sz and
UPROBES_BKPT_INSN_SIZE are the same for all archs and hence
removing uprobe_opcode_sz in favour of UPROBES_BKPT_INSN_SIZE.

However if we have to support architectures where the smallest
instruction size is different from the size of breakpoint
instruction, we may have to re-introduce uprobe_opcode_sz.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Stone <jistone@redhat.com>
Link: http://lkml.kernel.org/r/20120222091549.15880.67020.sendpatchset@srdronam.in.ibm.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
uprobes/core: Move insn to arch specific structure

Few cleanups suggested by Ingo Molnar.

- Rename struct uprobe_arch_info to struct arch_uprobe.
- Move insn from struct uprobe to struct arch_uprobe.
- Make arch specific uprobe functions to accept struct arch_uprobe
  instead of  struct uprobe.
- Move struct uprobe to kernel/uprobes.c from include/linux/uprobes.h

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Stone <jistone@redhat.com>
Link: http://lkml.kernel.org/r/20120222091602.15880.40249.sendpatchset@srdronam.in.ibm.com
[ Made various small improvements ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
uprobes: Update copyright notices

Add Peter Zijlstra's copyright to the uprobes code, whose
contributions to the uprobes code are not visible in the Git
history, because they were backmerged.

Also update existing copyright notices to the year 2012.

Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-vjqxst502pc1efz7ah8cyht4@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
i915: Add option to bypass vbt table.

This change enables the use of displays where the vbt table just
contains inappropriate values, but either the vesa defaults or
the video=... modes do something sensible with the attached display.

The problem happens with an embedded board that contains vbt bios
tables that do not match the attached display.  Using this change and
the appropriate kernel boot command line they are able to use an
otherwise completely unusable secondary display on that embedded
board.

Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: Mathias Froehlich <Mathias.Froehlich@web.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: remove ACPI related DRM_ERRORs

They're not really errors (well actually I don't know; I don't
understand _DSM and _MUX well enough to say, but I do know they spam
people's logs and seem to be harmless).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[danvet: The _DSM error got remove in another patch already]
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44250
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: Retry reading the PCH FDI receiver ISR

According to the PRM (Vol3P2), the PCH FDI receiver ISR read for bit lock
should be retried at least once. This patch retries the read 5 times
with a small delay in between reads. I've had reports of display corruption
on resume with "FDI train 1 fail!", so I'm hoping that adding this retry
will mitigate the issue.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
x86/mm: Fix the size calculation of mapping tables

For machines that enable PSE, the first 2/4M memory region still uses
4K pages, so needs more PTEs in this case, but
find_early_table_space() doesn't count this.

This patch fixes it.

The bug was found via code review, no misbehavior of the kernel
was observed.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: <ianfang.cn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-kq6a00qe33h7c7ais2xsywnh@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
block: blk-throttle should be drained regardless of q->elevator

Currently, blk_cleanup_queue() doesn't call elv_drain_elevator() if
q->elevator doesn't exist; however, bio based drivers don't have
elevator initialized but can still use blk-throttle.  This patch moves
q->elevator test inside blk_drain_queue() such that only
elv_drain_elevator() is skipped if !q->elevator.

-v2: loop can have registered queue which has NULL request_fn.  Make
     sure we don't call into __blk_run_queue() in such cases.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Vivek Goyal <vgoyal@redhat.com>

Fold in bug fix from Vivek.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
blkcg: make CONFIG_BLK_CGROUP bool

Block cgroup core can be built as module; however, it isn't too useful
as blk-throttle can only be built-in and cfq-iosched is usually the
default built-in scheduler.  Scheduled blkcg cleanup requires calling
into blkcg from block core.  To simplify that, disallow building blkcg
as module by making CONFIG_BLK_CGROUP bool.

If building blkcg core as module really matters, which I doubt, we can
revisit it after blkcg API cleanup.

-v2: Vivek pointed out that IOSCHED_CFQ was incorrectly updated to
     depend on BLK_CGROUP.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
cfq: don't register propio policy if !CONFIG_CFQ_GROUP_IOSCHED

cfq has been registering zeroed blkio_poilcy_cfq if CFQ_GROUP_IOSCHED
is disabled.  This fortunately doesn't collide with blk-throtl as
BLKIO_POLICY_PROP is zero but is unnecessary and risky.  Just don't
register it if not enabled.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
elevator: clear auxiliary data earlier during elevator switch

Elevator switch tries hard to keep as much as context until new
elevator is ready so that it can revert to the original state if
initializing the new elevator fails for some reason.  Unfortunately,
with more auxiliary contexts to manage, this makes elevator init and
exit paths too complex and fragile.

This patch makes elevator_switch() unregister the current elevator and
flush icq's before start initializing the new one.  As we still keep
the old elevator itself, the only difference is that we lose icq's on
rare occassions of switching failure, which isn't critical at all.

Note that this makes explicit elevator parameter to
elevator_init_queue() and __elv_register_queue() unnecessary as they
always can use the current elevator.

This patch enables block cgroup cleanups.

-v2: blk_add_trace_msg() prints elevator name from @new_e instead of
     @e->type as the local variable no longer exists.  This caused
     build failure on CONFIG_BLK_DEV_IO_TRACE.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
elevator: make elevator_init_fn() return 0/-errno

elevator_ops->elevator_init_fn() has a weird return value.  It returns
a void * which the caller should assign to q->elevator->elevator_data
and %NULL return denotes init failure.

Update such that it returns integer 0/-errno and sets elevator_data
directly as necessary.

This makes the interface more conventional and eases further cleanup.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: implement blk_queue_bypass_start/end()

Rename and extend elv_queisce_start/end() to
blk_queue_bypass_start/end() which are exported and supports nesting
via @q->bypass_depth.  Also add blk_queue_bypass() to test bypass
state.

This will be further extended and used for blkio_group management.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>