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Yang Zhang d78f266483 KVM: VMX: Register a new IPI for posted interrupt
Posted Interrupt feature requires a special IPI to deliver posted interrupt
to guest. And it should has a high priority so the interrupt will not be
blocked by others.
Normally, the posted interrupt will be consumed by vcpu if target vcpu is
running and transparent to OS. But in some cases, the interrupt will arrive
when target vcpu is scheduled out. And host will see it. So we need to
register a dump handler to handle it.

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-04-16 16:32:39 -03:00
Linus Torvalds 9e2d59ad58 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
Pull signal handling cleanups from Al Viro:
 "This is the first pile; another one will come a bit later and will
  contain SYSCALL_DEFINE-related patches.

   - a bunch of signal-related syscalls (both native and compat)
     unified.

   - a bunch of compat syscalls switched to COMPAT_SYSCALL_DEFINE
     (fixing several potential problems with missing argument
     validation, while we are at it)

   - a lot of now-pointless wrappers killed

   - a couple of architectures (cris and hexagon) forgot to save
     altstack settings into sigframe, even though they used the
     (uninitialized) values in sigreturn; fixed.

   - microblaze fixes for delivery of multiple signals arriving at once

   - saner set of helpers for signal delivery introduced, several
     architectures switched to using those."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (143 commits)
  x86: convert to ksignal
  sparc: convert to ksignal
  arm: switch to struct ksignal * passing
  alpha: pass k_sigaction and siginfo_t using ksignal pointer
  burying unused conditionals
  make do_sigaltstack() static
  arm64: switch to generic old sigaction() (compat-only)
  arm64: switch to generic compat rt_sigaction()
  arm64: switch compat to generic old sigsuspend
  arm64: switch to generic compat rt_sigqueueinfo()
  arm64: switch to generic compat rt_sigpending()
  arm64: switch to generic compat rt_sigprocmask()
  arm64: switch to generic sigaltstack
  sparc: switch to generic old sigsuspend
  sparc: COMPAT_SYSCALL_DEFINE does all sign-extension as well as SYSCALL_DEFINE
  sparc: kill sign-extending wrappers for native syscalls
  kill sparc32_open()
  sparc: switch to use of generic old sigaction
  sparc: switch sys_compat_rt_sigaction() to COMPAT_SYSCALL_DEFINE
  mips: switch to generic sys_fork() and sys_clone()
  ...
2013-02-23 18:50:11 -08:00
K. Y. Srinivasan bc2b0331e0 X86: Handle Hyper-V vmbus interrupts as special hypervisor interrupts
Starting with win8, vmbus interrupts can be delivered on any VCPU in the guest
and furthermore can be concurrently active on multiple VCPUs. Support this
interrupt delivery model by setting up a separate IDT entry for Hyper-V vmbus.
interrupts. I would like to thank Jan Beulich <JBeulich@suse.com> and
Thomas Gleixner <tglx@linutronix.de>, for their help.

In this version of the patch, based on the feedback, I have merged the IDT
vector for Xen and Hyper-V and made the necessary adjustments. Furhermore,
based on Jan's feedback I have added the necessary compilation switches.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1359940959-32168-3-git-send-email-kys@microsoft.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-02-12 16:27:15 -08:00
Al Viro 3fe26fa34d x86: get rid of pt_regs argument in sigreturn variants
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 18:16:24 -05:00
Al Viro b3af11afe0 x86: get rid of pt_regs argument of iopl(2)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 18:16:24 -05:00
Al Viro ea93a6e2e7 amd64: get rid of useless RESTORE_TOP_OF_STACK in stub_execve()
we are not going to return via SYSRET anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 18:16:23 -05:00
Jan Beulich 444723dccc x86-64: Fix unwind annotations in recent NMI changes
While in one case a plain annotation is necessary, in the other
case the stack adjustment can simply be folded into the
immediately preceding RESTORE_ALL, thus getting the correct
annotation for free.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander van Heukelum <heukelum@mailshack.com>
Link: http://lkml.kernel.org/r/51010C9302000078000B9045@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-01-24 10:56:32 +01:00
Linus Torvalds 54d46ea993 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
Pull signal handling cleanups from Al Viro:
 "sigaltstack infrastructure + conversion for x86, alpha and um,
  COMPAT_SYSCALL_DEFINE infrastructure.

  Note that there are several conflicts between "unify
  SS_ONSTACK/SS_DISABLE definitions" and UAPI patches in mainline;
  resolution is trivial - just remove definitions of SS_ONSTACK and
  SS_DISABLED from arch/*/uapi/asm/signal.h; they are all identical and
  include/uapi/linux/signal.h contains the unified variant."

Fixed up conflicts as per Al.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  alpha: switch to generic sigaltstack
  new helpers: __save_altstack/__compat_save_altstack, switch x86 and um to those
  generic compat_sys_sigaltstack()
  introduce generic sys_sigaltstack(), switch x86 and um to it
  new helper: compat_user_stack_pointer()
  new helper: restore_altstack()
  unify SS_ONSTACK/SS_DISABLE definitions
  new helper: current_user_stack_pointer()
  missing user_stack_pointer() instances
  Bury the conditionals from kernel_thread/kernel_execve series
  COMPAT_SYSCALL_DEFINE: infrastructure
2012-12-20 18:05:28 -08:00
Al Viro 9026843952 generic compat_sys_sigaltstack()
Again, conditional on CONFIG_GENERIC_SIGALTSTACK

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-12-19 18:07:41 -05:00
Al Viro 6bf9adfc90 introduce generic sys_sigaltstack(), switch x86 and um to it
Conditional on CONFIG_GENERIC_SIGALTSTACK; architectures that do not
select it are completely unaffected

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-12-19 18:07:40 -05:00
Linus Torvalds 9977d9b379 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
Pull big execve/kernel_thread/fork unification series from Al Viro:
 "All architectures are converted to new model.  Quite a bit of that
  stuff is actually shared with architecture trees; in such cases it's
  literally shared branch pulled by both, not a cherry-pick.

  A lot of ugliness and black magic is gone (-3KLoC total in this one):

   - kernel_thread()/kernel_execve()/sys_execve() redesign.

     We don't do syscalls from kernel anymore for either kernel_thread()
     or kernel_execve():

     kernel_thread() is essentially clone(2) with callback run before we
     return to userland, the callbacks either never return or do
     successful do_execve() before returning.

     kernel_execve() is a wrapper for do_execve() - it doesn't need to
     do transition to user mode anymore.

     As a result kernel_thread() and kernel_execve() are
     arch-independent now - they live in kernel/fork.c and fs/exec.c
     resp.  sys_execve() is also in fs/exec.c and it's completely
     architecture-independent.

   - daemonize() is gone, along with its parts in fs/*.c

   - struct pt_regs * is no longer passed to do_fork/copy_process/
     copy_thread/do_execve/search_binary_handler/->load_binary/do_coredump.

   - sys_fork()/sys_vfork()/sys_clone() unified; some architectures
     still need wrappers (ones with callee-saved registers not saved in
     pt_regs on syscall entry), but the main part of those suckers is in
     kernel/fork.c now."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (113 commits)
  do_coredump(): get rid of pt_regs argument
  print_fatal_signal(): get rid of pt_regs argument
  ptrace_signal(): get rid of unused arguments
  get rid of ptrace_signal_deliver() arguments
  new helper: signal_pt_regs()
  unify default ptrace_signal_deliver
  flagday: kill pt_regs argument of do_fork()
  death to idle_regs()
  don't pass regs to copy_process()
  flagday: don't pass regs to copy_thread()
  bfin: switch to generic vfork, get rid of pointless wrappers
  xtensa: switch to generic clone()
  openrisc: switch to use of generic fork and clone
  unicore32: switch to generic clone(2)
  score: switch to generic fork/vfork/clone
  c6x: sanitize copy_thread(), get rid of clone(2) wrapper, switch to generic clone()
  take sys_fork/sys_vfork/sys_clone prototypes to linux/syscalls.h
  mn10300: switch to generic fork/vfork/clone
  h8300: switch to generic fork/vfork/clone
  tile: switch to generic clone()
  ...

Conflicts:
	arch/microblaze/include/asm/Kbuild
2012-12-12 12:22:13 -08:00
Linus Torvalds 0019fab355 Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm changes from Ingo Molnar:
 "Two fixlets and a cleanup."

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86_32: Return actual stack when requesting sp from regs
  x86: Don't clobber top of pt_regs in nested NMI
  x86/asm: Clean up copy_page_*() comments and code
2012-12-11 19:55:20 -08:00
Ingo Molnar 630e1e0bcd Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Conflicts:
	arch/x86/kernel/ptrace.c

Pull the latest RCU tree from Paul E. McKenney:

"       The major features of this series are:

  1.	A first version of no-callbacks CPUs.  This version prohibits
  	offlining CPU 0, but only when enabled via CONFIG_RCU_NOCB_CPU=y.
  	Relaxing this constraint is in progress, but not yet ready
  	for prime time.  These commits were posted to LKML at
  	https://lkml.org/lkml/2012/10/30/724, and are at branch rcu/nocb.

  2.	Changes to SRCU that allows statically initialized srcu_struct
  	structures.  These commits were posted to LKML at
  	https://lkml.org/lkml/2012/10/30/296, and are at branch rcu/srcu.

  3.	Restructuring of RCU's debugfs output.  These commits were posted
  	to LKML at https://lkml.org/lkml/2012/10/30/341, and are at
  	branch rcu/tracing.

  4.	Additional CPU-hotplug/RCU improvements, posted to LKML at
  	https://lkml.org/lkml/2012/10/30/327, and are at branch rcu/hotplug.
  	Note that the commit eliminating __stop_machine() was judged to
  	be too-high of risk, so is deferred to 3.9.

  5.	Changes to RCU's idle interface, most notably a new module
  	parameter that redirects normal grace-period operations to
  	their expedited equivalents.  These were posted to LKML at
  	https://lkml.org/lkml/2012/10/30/739, and are at branch rcu/idle.

  6.	Additional diagnostics for RCU's CPU stall warning facility,
  	posted to LKML at https://lkml.org/lkml/2012/10/30/315, and
  	are at branch rcu/stall.  The most notable change reduces the
  	default RCU CPU stall-warning time from 60 seconds to 21 seconds,
  	so that it once again happens sooner than the softlockup timeout.

  7.	Documentation updates, which were posted to LKML at
  	https://lkml.org/lkml/2012/10/30/280, and are at branch rcu/doc.
  	A couple of late-breaking changes were posted at
  	https://lkml.org/lkml/2012/11/16/634 and
  	https://lkml.org/lkml/2012/11/16/547.

  8.	Miscellaneous fixes, which were posted to LKML at
  	https://lkml.org/lkml/2012/10/30/309, along with a late-breaking
  	change posted at Fri, 16 Nov 2012 11:26:25 -0800 with message-ID
  	<20121116192625.GA447@linux.vnet.ibm.com>, but which lkml.org
  	seems to have missed.  These are at branch rcu/fixes.

  9.	Finally, a fix for an lockdep-RCU splat was posted to LKML
  	at https://lkml.org/lkml/2012/11/7/486.  This is at rcu/next. "

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-12-03 06:27:05 +01:00
Frederic Weisbecker 91d1aa43d3 context_tracking: New context tracking susbsystem
Create a new subsystem that probes on kernel boundaries
to keep track of the transitions between level contexts
with two basic initial contexts: user or kernel.

This is an abstraction of some RCU code that use such tracking
to implement its userspace extended quiescent state.

We need to pull this up from RCU into this new level of indirection
because this tracking is also going to be used to implement an "on
demand" generic virtual cputime accounting. A necessary step to
shutdown the tick while still accounting the cputime.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
[ paulmck: fix whitespace error and email address. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-11-30 11:40:07 -08:00
Al Viro 1d4b4b2994 x86, um: switch to generic fork/vfork/clone
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-11-28 22:13:44 -05:00
Jan Beulich ee4eb87be2 x86-64: Fix ordering of CFI directives and recent ASM_CLAC additions
While these got added in the right place everywhere else, entry_64.S
is the odd one where they ended up before the initial CFI directive(s).
In order to cover the full code ranges, the CFI directive must be
first, though.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/5093BA1F02000078000A600E@nat28.tlf.novell.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2012-11-20 22:23:57 -08:00
Salman Qazi 28696f434f x86: Don't clobber top of pt_regs in nested NMI
The nested NMI modifies the place (instruction, flags and stack)
that the first NMI will iret to.  However, the copy of registers
modified is exactly the one that is the part of pt_regs in
the first NMI.  This can change the behaviour of the first NMI.

In particular, Google's arch_trigger_all_cpu_backtrace handler
also prints regions of memory surrounding addresses appearing in
registers.  This results in handled exceptions, after which nested NMIs
start coming in.  These nested NMIs change the value of registers
in pt_regs.  This can cause the original NMI handler to produce
incorrect output.

We solve this problem by interchanging the position of the preserved
copy of the iret registers ("saved") and the copy subject to being
trampled by nested NMI ("copied").

Link: http://lkml.kernel.org/r/20121002002919.27236.14388.stgit@dungbeetle.mtv.corp.google.com

Signed-off-by: Salman Qazi <sqazi@google.com>
[ Added a needed CFI_ADJUST_CFA_OFFSET ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-02 11:29:36 -04:00
Konrad Rzeszutek Wilk e05dacd71d Merge commit 'v3.7-rc1' into stable/for-linus-3.7
* commit 'v3.7-rc1': (10892 commits)
  Linux 3.7-rc1
  x86, boot: Explicitly include autoconf.h for hostprogs
  perf: Fix UAPI fallout
  ARM: config: make sure that platforms are ordered by option string
  ARM: config: sort select statements alphanumerically
  UAPI: (Scripted) Disintegrate include/linux/byteorder
  UAPI: (Scripted) Disintegrate include/linux
  UAPI: Unexport linux/blk_types.h
  UAPI: Unexport part of linux/ppp-comp.h
  perf: Handle new rbtree implementation
  procfs: don't need a PATH_MAX allocation to hold a string representation of an int
  vfs: embed struct filename inside of names_cache allocation if possible
  audit: make audit_inode take struct filename
  vfs: make path_openat take a struct filename pointer
  vfs: turn do_path_lookup into wrapper around struct filename variant
  audit: allow audit code to satisfy getname requests from its names_list
  vfs: define struct filename and have getname() return it
  btrfs: Fix compilation with user namespace support enabled
  userns: Fix posix_acl_file_xattr_userns gid conversion
  userns: Properly print bluetooth socket uids
  ...
2012-10-19 15:19:19 -04:00
David Vrabel a349e23d1c xen/x86: don't corrupt %eip when returning from a signal handler
In 32 bit guests, if a userspace process has %eax == -ERESTARTSYS
(-512) or -ERESTARTNOINTR (-513) when it is interrupted by an event
/and/ the process has a pending signal then %eip (and %eax) are
corrupted when returning to the main process after handling the
signal.  The application may then crash with SIGSEGV or a SIGILL or it
may have subtly incorrect behaviour (depending on what instruction it
returned to).

The occurs because handle_signal() is incorrectly thinking that there
is a system call that needs to restarted so it adjusts %eip and %eax
to re-execute the system call instruction (even though user space had
not done a system call).

If %eax == -514 (-ERESTARTNOHAND (-514) or -ERESTART_RESTARTBLOCK
(-516) then handle_signal() only corrupted %eax (by setting it to
-EINTR).  This may cause the application to crash or have incorrect
behaviour.

handle_signal() assumes that regs->orig_ax >= 0 means a system call so
any kernel entry point that is not for a system call must push a
negative value for orig_ax.  For example, for physical interrupts on
bare metal the inverse of the vector is pushed and page_fault() sets
regs->orig_ax to -1, overwriting the hardware provided error code.

xen_hypervisor_callback() was incorrectly pushing 0 for orig_ax
instead of -1.

Classic Xen kernels pushed %eax which works as %eax cannot be both
non-negative and -RESTARTSYS (etc.), but using -1 is consistent with
other non-system call entry points and avoids some of the tests in
handle_signal().

There were similar bugs in xen_failsafe_callback() of both 32 and
64-bit guests. If the fault was corrected and the normal return path
was used then 0 was incorrectly pushed as the value for orig_ax.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Jan Beulich <JBeulich@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Cc: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-10-19 15:17:59 -04:00
Linus Torvalds 4e21fc138b Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
Pull third pile of kernel_execve() patches from Al Viro:
 "The last bits of infrastructure for kernel_thread() et.al., with
  alpha/arm/x86 use of those.  Plus sanitizing the asm glue and
  do_notify_resume() on alpha, fixing the "disabled irq while running
  task_work stuff" breakage there.

  At that point the rest of kernel_thread/kernel_execve/sys_execve work
  can be done independently for different architectures.  The only
  pending bits that do depend on having all architectures converted are
  restrictred to fs/* and kernel/* - that'll obviously have to wait for
  the next cycle.

  I thought we'd have to wait for all of them done before we start
  eliminating the longjump-style insanity in kernel_execve(), but it
  turned out there's a very simple way to do that without flagday-style
  changes."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  alpha: switch to saner kernel_execve() semantics
  arm: switch to saner kernel_execve() semantics
  x86, um: convert to saner kernel_execve() semantics
  infrastructure for saner ret_from_kernel_thread semantics
  make sure that kernel_thread() callbacks call do_exit() themselves
  make sure that we always have a return path from kernel_execve()
  ppc: eeh_event should just use kthread_run()
  don't bother with kernel_thread/kernel_execve for launching linuxrc
  alpha: get rid of switch_stack argument of do_work_pending()
  alpha: don't bother passing switch_stack separately from regs
  alpha: take SIGPENDING/NOTIFY_RESUME loop into signal.c
  alpha: simplify TIF_NEED_RESCHED handling
2012-10-13 10:05:52 +09:00
Al Viro 22e2430d60 x86, um: convert to saner kernel_execve() semantics
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-12 13:35:22 -04:00
Linus Torvalds 42859eea96 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
Pull generic execve() changes from Al Viro:
 "This introduces the generic kernel_thread() and kernel_execve()
  functions, and switches x86, arm, alpha, um and s390 over to them."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (26 commits)
  s390: convert to generic kernel_execve()
  s390: switch to generic kernel_thread()
  s390: fold kernel_thread_helper() into ret_from_fork()
  s390: fold execve_tail() into start_thread(), convert to generic sys_execve()
  um: switch to generic kernel_thread()
  x86, um/x86: switch to generic sys_execve and kernel_execve
  x86: split ret_from_fork
  alpha: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  alpha: switch to generic kernel_thread()
  alpha: switch to generic sys_execve()
  arm: get rid of execve wrapper, switch to generic execve() implementation
  arm: optimized current_pt_regs()
  arm: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  arm: split ret_from_fork, simplify kernel_thread() [based on patch by rmk]
  generic sys_execve()
  generic kernel_execve()
  new helper: current_pt_regs()
  preparation for generic kernel_thread()
  um: kill thread->forking
  um: let signal_delivered() do SIGTRAP on singlestepping into handler
  ...
2012-10-10 12:02:25 +09:00
Linus Torvalds 15385dfe7e Merge branch 'x86-smap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/smap support from Ingo Molnar:
 "This adds support for the SMAP (Supervisor Mode Access Prevention) CPU
  feature on Intel CPUs: a hardware feature that prevents unintended
  user-space data access from kernel privileged code.

  It's turned on automatically when possible.

  This, in combination with SMEP, makes it even harder to exploit kernel
  bugs such as NULL pointer dereferences."

Fix up trivial conflict in arch/x86/kernel/entry_64.S due to newly added
includes right next to each other.

* 'x86-smap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, smep, smap: Make the switching functions one-way
  x86, suspend: On wakeup always initialize cr4 and EFER
  x86-32: Start out eflags and cr4 clean
  x86, smap: Do not abuse the [f][x]rstor_checking() functions for user space
  x86-32, smap: Add STAC/CLAC instructions to 32-bit kernel entry
  x86, smap: Reduce the SMAP overhead for signal handling
  x86, smap: A page fault due to SMAP is an oops
  x86, smap: Turn on Supervisor Mode Access Prevention
  x86, smap: Add STAC and CLAC instructions to control user space access
  x86, uaccess: Merge prototypes for clear_user/__clear_user
  x86, smap: Add a header file with macros for STAC/CLAC
  x86, alternative: Add header guards to <asm/alternative-asm.h>
  x86, alternative: Use .pushsection/.popsection
  x86, smap: Add CR4 bit for SMAP
  x86-32, mm: The WP test should be done on a kernel page
2012-10-01 13:59:17 -07:00
Linus Torvalds da8347969f Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/asm changes from Ingo Molnar:
 "The one change that stands out is the alternatives patching change
  that prevents us from ever patching back instructions from SMP to UP:
  this simplifies things and speeds up CPU hotplug.

  Other than that it's smaller fixes, cleanups and improvements."

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Unspaghettize do_trap()
  x86_64: Work around old GAS bug
  x86: Use REP BSF unconditionally
  x86: Prefer TZCNT over BFS
  x86/64: Adjust types of temporaries used by ffs()/fls()/fls64()
  x86: Drop unnecessary kernel_eflags variable on 64-bit
  x86/smp: Don't ever patch back to UP if we unplug cpus
2012-10-01 10:46:27 -07:00
Linus Torvalds 7e92daaefa Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf update from Ingo Molnar:
 "Lots of changes in this cycle as well, with hundreds of commits from
  over 30 contributors.  Most of the activity was on the tooling side.

  Higher level changes:

   - New 'perf kvm' analysis tool, from Xiao Guangrong.

   - New 'perf trace' system-wide tracing tool

   - uprobes fixes + cleanups from Oleg Nesterov.

   - Lots of patches to make perf build on Android out of box, from
     Irina Tirdea

   - Extend ftrace function tracing utility to be more dynamic for its
     users.  It allows for data passing to the callback functions, as
     well as reading regs as if a breakpoint were to trigger at function
     entry.

     The main goal of this patch series was to allow kprobes to use
     ftrace as an optimized probe point when a probe is placed on an
     ftrace nop.  With lots of help from Masami Hiramatsu, and going
     through lots of iterations, we finally came up with a good
     solution.

   - Add cpumask for uncore pmu, use it in 'stat', from Yan, Zheng.

   - Various tracing updates from Steve Rostedt

   - Clean up and improve 'perf sched' performance by elliminating lots
     of needless calls to libtraceevent.

   - Event group parsing support, from Jiri Olsa

   - UI/gtk refactorings and improvements from Namhyung Kim

   - Add support for non-tracepoint events in perf script python, from
     Feng Tang

   - Add --symbols to 'script', similar to the one in 'report', from
     Feng Tang.

  Infrastructure enhancements and fixes:

   - Convert the trace builtins to use the growing evsel/evlist
     tracepoint infrastructure, removing several open coded constructs
     like switch like series of strcmp to dispatch events, etc.
     Basically what had already been showcased in 'perf sched'.

   - Add evsel constructor for tracepoints, that uses libtraceevent just
     to parse the /format events file, use it in a new 'perf test' to
     make sure the libtraceevent format parsing regressions can be more
     readily caught.

   - Some strange errors were happening in some builds, but not on the
     next, reported by several people, problem was some parser related
     files, generated during the build, didn't had proper make deps, fix
     from Eric Sandeen.

   - Introduce struct and cache information about the environment where
     a perf.data file was captured, from Namhyung Kim.

   - Fix handling of unresolved samples when --symbols is used in
     'report', from Feng Tang.

   - Add union member access support to 'probe', from Hyeoncheol Lee.

   - Fixups to die() removal, from Namhyung Kim.

   - Render fixes for the TUI, from Namhyung Kim.

   - Don't enable annotation in non symbolic view, from Namhyung Kim.

   - Fix pipe mode in 'report', from Namhyung Kim.

   - Move related stats code from stat to util/, will be used by the
     'stat' kvm tool, from Xiao Guangrong.

   - Remove die()/exit() calls from several tools.

   - Resolve vdso callchains, from Jiri Olsa

   - Don't pass const char pointers to basename, so that we can
     unconditionally use libgen.h and thus avoid ifdef BIONIC lines,
     from David Ahern

   - Refactor hist formatting so that it can be reused with the GTK
     browser, From Namhyung Kim

   - Fix build for another rbtree.c change, from Adrian Hunter.

   - Make 'perf diff' command work with evsel hists, from Jiri Olsa.

   - Use the only field_sep var that is set up: symbol_conf.field_sep,
     fix from Jiri Olsa.

   - .gitignore compiled python binaries, from Namhyung Kim.

   - Get rid of die() in more libtraceevent places, from Namhyung Kim.

   - Rename libtraceevent 'private' struct member to 'priv' so that it
     works in C++, from Steven Rostedt

   - Remove lots of exit()/die() calls from tools so that the main perf
     exit routine can take place, from David Ahern

   - Fix x86 build on x86-64, from David Ahern.

   - {int,str,rb}list fixes from Suzuki K Poulose

   - perf.data header fixes from Namhyung Kim

   - Allow user to indicate objdump path, needed in cross environments,
     from Maciek Borzecki

   - Fix hardware cache event name generation, fix from Jiri Olsa

   - Add round trip test for sw, hw and cache event names, catching the
     problem Jiri fixed, after Jiri's patch, the test passes
     successfully.

   - Clean target should do clean for lib/traceevent too, fix from David
     Ahern

   - Check the right variable for allocation failure, fix from Namhyung
     Kim

   - Set up evsel->tp_format regardless of evsel->name being set
     already, fix from Namhyung Kim

   - Oprofile fixes from Robert Richter.

   - Remove perf_event_attr needless version inflation, from Jiri Olsa

   - Introduce libtraceevent strerror like error reporting facility,
     from Namhyung Kim

   - Add pmu mappings to perf.data header and use event names from cmd
     line, from Robert Richter

   - Fix include order for bison/flex-generated C files, from Ben
     Hutchings

   - Build fixes and documentation corrections from David Ahern

   - Assorted cleanups from Robert Richter

   - Let O= makes handle relative paths, from Steven Rostedt

   - perf script python fixes, from Feng Tang.

   - Initial bash completion support, from Frederic Weisbecker

   - Allow building without libelf, from Namhyung Kim.

   - Support DWARF CFI based unwind to have callchains when %bp based
     unwinding is not possible, from Jiri Olsa.

   - Symbol resolution fixes, while fixing support PPC64 files with an
     .opt ELF section was the end goal, several fixes for code that
     handles all architectures and cleanups are included, from Cody
     Schafer.

   - Assorted fixes for Documentation and build in 32 bit, from Robert
     Richter

   - Cache the libtraceevent event_format associated to each evsel
     early, so that we avoid relookups, i.e.  calling pevent_find_event
     repeatedly when processing tracepoint events.

     [ This is to reduce the surface contact with libtraceevents and
        make clear what is that the perf tools needs from that lib: so
        far parsing the common and per event fields.  ]

   - Don't stop the build if the audit libraries are not installed, fix
     from Namhyung Kim.

   - Fix bfd.h/libbfd detection with recent binutils, from Markus
     Trippelsdorf.

   - Improve warning message when libunwind devel packages not present,
     from Jiri Olsa"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (282 commits)
  perf trace: Add aliases for some syscalls
  perf probe: Print an enum type variable in "enum variable-name" format when showing accessible variables
  perf tools: Check libaudit availability for perf-trace builtin
  perf hists: Add missing period_* fields when collapsing a hist entry
  perf trace: New tool
  perf evsel: Export the event_format constructor
  perf evsel: Introduce rawptr() method
  perf tools: Use perf_evsel__newtp in the event parser
  perf evsel: The tracepoint constructor should store sys:name
  perf evlist: Introduce set_filter() method
  perf evlist: Renane set_filters method to apply_filters
  perf test: Add test to check we correctly parse and match syscall open parms
  perf evsel: Handle endianity in intval method
  perf evsel: Know if byte swap is needed
  perf tools: Allow handling a NULL cpu_map as meaning "all cpus"
  perf evsel: Improve tracepoint constructor setup
  tools lib traceevent: Fix error path on pevent_parse_event
  perf test: Fix build failure
  trace: Move trace event enable from fs_initcall to core_initcall
  tracing: Add an option for disabling markers
  ...
2012-10-01 10:28:49 -07:00
Al Viro 6783eaa2e1 x86, um/x86: switch to generic sys_execve and kernel_execve
32bit wrapper is lost on that; 64bit one is *not*, since
we need to arrange for full pt_regs on stack when we call
sys_execve() and we need to load callee-saved ones from
there afterwards.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-30 22:53:32 -04:00
Al Viro 7076aada10 x86: split ret_from_fork
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-30 22:53:31 -04:00
Frederic Weisbecker 0430499ce9 x86: Use the new schedule_user API on userspace preemption
This way we can exit the RCU extended quiescent state before
we schedule a new task from irq/exception exit.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-09-26 15:47:12 +02:00
Tao Guo 1b2b23d857 x86_64: Work around old GAS bug
GAS in binutils(2.16.91) could not parse parentheses within
macro parameters unless fully parenthesized, and this is a
workaround to make old gas work without generating below errors:

 arch/x86/kernel/entry_64.S: Assembler messages:
 arch/x86/kernel/entry_64.S:387: Error: too many positional arguments
 arch/x86/kernel/entry_64.S:389: Error: too many positional arguments
 [...]

Signed-off-by: Tao Guo <glorioustao@gmail.com>
Reluctantly-Acked-by: Jan Beulich <jbeulich@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1348648102-12653-1-git-send-email-glorioustao@gmail.com
[ Jan argues that these old GAS versions are fragile - which is so, but lets give them a chance. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-09-26 13:35:32 +02:00
H. Peter Anvin 63bcff2a30 x86, smap: Add STAC and CLAC instructions to control user space access
When Supervisor Mode Access Prevention (SMAP) is enabled, access to
userspace from the kernel is controlled by the AC flag.  To make the
performance of manipulating that flag acceptable, there are two new
instructions, STAC and CLAC, to set and clear it.

This patch adds those instructions, via alternative(), when the SMAP
feature is enabled.  It also adds X86_EFLAGS_AC unconditionally to the
SYSCALL entry mask; there is simply no reason to make that one
conditional.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1348256595-29119-9-git-send-email-hpa@linux.intel.com
2012-09-21 12:45:27 -07:00
Steven Rostedt 47d5a5f88b ftrace/x86-64: Allow to change RIP in handlers
Allow ftrace handlers to change RIP register (regs->ip)
in handlers. This will allow handlers to call another
function instead of original function.

Link: http://lkml.kernel.org/r/20120905143118.10329.5078.stgit@localhost.localdomain

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-09-13 22:52:10 -04:00
Ian Campbell 6eebdda35e x86: Drop unnecessary kernel_eflags variable on 64-bit
On 64 bit x86 we save the current eflags in cpu_init for use in
ret_from_fork. Strictly speaking reserved bits in EFLAGS should
be read as written but in practise it is unlikely that EFLAGS
could ever be extended in this way and the kernel alread clears
any undefined flags early on.

The equivalent 32 bit code simply hard codes 0x0202 as the new
EFLAGS.

This change makes 64 bit use the same mechanism to setup the
initial EFLAGS on fork. Note that 64 bit resets EFLAGS before
calling schedule_tail() as opposed to 32 bit which calls
schedule_tail() first. Therefore the correct value for EFLAGS
has opposite IF bit.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20120824195847.GA31628@moon
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-09-13 17:32:47 +02:00
Steven Rostedt d57c5d51a3 ftrace/x86: Add support for -mfentry to x86_64
If the kernel is compiled with gcc 4.6.0 which supports -mfentry,
then use that instead of mcount.

With mcount, frame pointers are forced with the -pg option and we
get something like:

<can_vma_merge_before>:
       55                      push   %rbp
       48 89 e5                mov    %rsp,%rbp
       53                      push   %rbx
       41 51                   push   %r9
       e8 fe 6a 39 00          callq  ffffffff81483d00 <mcount>
       31 c0                   xor    %eax,%eax
       48 89 fb                mov    %rdi,%rbx
       48 89 d7                mov    %rdx,%rdi
       48 33 73 30             xor    0x30(%rbx),%rsi
       48 f7 c6 ff ff ff f7    test   $0xfffffffff7ffffff,%rsi

With -mfentry, frame pointers are no longer forced and the call looks
like this:

<can_vma_merge_before>:
       e8 33 af 37 00          callq  ffffffff81461b40 <__fentry__>
       53                      push   %rbx
       48 89 fb                mov    %rdi,%rbx
       31 c0                   xor    %eax,%eax
       48 89 d7                mov    %rdx,%rdi
       41 51                   push   %r9
       48 33 73 30             xor    0x30(%rbx),%rsi
       48 f7 c6 ff ff ff f7    test   $0xfffffffff7ffffff,%rsi

This adds the ftrace hook at the beginning of the function before a
frame is set up, and allows the function callbacks to be able to access
parameters. As kprobes now can use function tracing (at least on x86)
this speeds up the kprobe hooks that are at the beginning of the
function.

Link: http://lkml.kernel.org/r/20120807194100.130477900@goodmis.org

Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-08-23 11:26:36 -04:00
Ingo Molnar bcada3d4b8 perf/core improvements and fixes:
. Fix include order for bison/flex-generated C files, from Ben Hutchings
 
  . Build fixes and documentation corrections from David Ahern
 
  . Group parsing support, from Jiri Olsa
 
  . UI/gtk refactorings and improvements from Namhyung Kim
 
  . NULL deref fix for perf script, from Namhyung Kim
 
  . Assorted cleanups from Robert Richter
 
  . Let O= makes handle relative paths, from Steven Rostedt
 
 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

 * Fix include order for bison/flex-generated C files, from Ben Hutchings

 * Build fixes and documentation corrections from David Ahern

 * Group parsing support, from Jiri Olsa

 * UI/gtk refactorings and improvements from Namhyung Kim

 * NULL deref fix for perf script, from Namhyung Kim

 * Assorted cleanups from Robert Richter

 * Let O= makes handle relative paths, from Steven Rostedt

 * perf script python fixes, from Feng Tang.

 * Improve 'perf lock' error message when the needed tracepoints
   are not present, from David Ahern.

 * Initial bash completion support, from Frederic Weisbecker

 * Allow building without libelf, from Namhyung Kim.

 * Support DWARF CFI based unwind to have callchains when %bp
   based unwinding is not possible, from Jiri Olsa.

 * Symbol resolution fixes, while fixing support PPC64 files with an .opt ELF
   section was the end goal, several fixes for code that handles all
   architectures and cleanups are included, from Cody Schafer.

 * Add a description for the JIT interface, from Andi Kleen.

 * Assorted fixes for Documentation and build in 32 bit, from Robert Richter

 * Add support for non-tracepoint events in perf script python, from Feng Tang

 * Cache the libtraceevent event_format associated to each evsel early, so that we
   avoid relookups, i.e. calling pevent_find_event repeatedly when processing
   tracepoint events.

   [ This is to reduce the surface contact with libtraceevents and make clear what
     is that the perf tools needs from that lib: so far parsing the common and per
     event fields. ]

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-08-21 11:27:00 +02:00
Ingo Molnar 26198c21d1 Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core
Pull ftrace updates from Steve Rostedt:

" This patch series extends ftrace function tracing utility to be
  more dynamic for its users. It allows for data passing to the callback
  functions, as well as reading regs as if a breakpoint were to trigger
  at function entry.

  The main goal of this patch series was to allow kprobes to use ftrace
  as an optimized probe point when a probe is placed on an ftrace nop.
  With lots of help from Masami Hiramatsu, and going through lots of
  iterations, we finally came up with a good solution. "

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-08-21 11:23:40 +02:00
Steven Rostedt 5767cfeaa9 ftrace/x86: Remove function_trace_stop check from graph caller
The graph caller is called by the mcount callers, which already does
the check against the function_trace_stop variable. No reason to
check it again.

Link: http://lkml.kernel.org/r/20120711195745.588538769@goodmis.org

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-07-31 10:29:51 -04:00
Linus Torvalds 4cb38750d4 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/mm changes from Peter Anvin:
 "The big change here is the patchset by Alex Shi to use INVLPG to flush
  only the affected pages when we only need to flush a small page range.

  It also removes the special INVALIDATE_TLB_VECTOR interrupts (32
  vectors!) and replace it with an ordinary IPI function call."

Fix up trivial conflicts in arch/x86/include/asm/apic.h (added code next
to changed line)

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tlb: Fix build warning and crash when building for !SMP
  x86/tlb: do flush_tlb_kernel_range by 'invlpg'
  x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR
  x86/tlb: enable tlb flush range support for x86
  mm/mmu_gather: enable tlb flush range in generic mmu_gather
  x86/tlb: add tlb_flushall_shift knob into debugfs
  x86/tlb: add tlb_flushall_shift for specific CPU
  x86/tlb: fall back to flush all when meet a THP large page
  x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range
  x86/tlb_info: get last level TLB entry number of CPU
  x86: Add read_mostly declaration/definition to variables from smp.h
  x86: Define early read-mostly per-cpu macros
2012-07-26 13:17:17 -07:00
Steven Rostedt 08f6fba503 ftrace/x86: Add separate function to save regs
Add a way to have different functions calling different trampolines.
If a ftrace_ops wants regs saved on the return, then have only the
functions with ops registered to save regs. Functions registered by
other ops would not be affected, unless the functions overlap.

If one ftrace_ops registered functions A, B and C and another ops
registered fucntions to save regs on A, and D, then only functions
A and D would be saving regs. Function B and C would work as normal.
Although A is registered by both ops: normal and saves regs; this is fine
as saving the regs is needed to satisfy one of the ops that calls it
but the regs are ignored by the other ops function.

x86_64 implements the full regs saving, and i386 just passes a NULL
for regs to satisfy the ftrace_ops passing. Where an arch must supply
both regs and ftrace_ops parameters, even if regs is just NULL.

It is OK for an arch to pass NULL regs. All function trace users that
require regs passing must add the flag FTRACE_OPS_FL_SAVE_REGS when
registering the ftrace_ops. If the arch does not support saving regs
then the ftrace_ops will fail to register. The flag
FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED may be set that will prevent the
ftrace_ops from failing to register. In this case, the handler may
either check if regs is not NULL or check if ARCH_SUPPORTS_FTRACE_SAVE_REGS.
If the arch supports passing regs it will set this macro and pass regs
for ops that request them. All other archs will just pass NULL.

Link: Link: http://lkml.kernel.org/r/20120711195745.107705970@goodmis.org

Cc: Alexander van Heukelum <heukelum@fastmail.fm>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-07-19 13:20:03 -04:00
Steven Rostedt 2f5f6ad939 ftrace: Pass ftrace_ops as third parameter to function trace callback
Currently the function trace callback receives only the ip and parent_ip
of the function that it traced. It would be more powerful to also return
the ops that registered the function as well. This allows the same function
to act differently depending on what ftrace_ops registered it.

Link: http://lkml.kernel.org/r/20120612225424.267254552@goodmis.org

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-07-19 13:17:35 -04:00
Alex Shi 52aec3308d x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR
There are 32 INVALIDATE_TLB_VECTOR now in kernel. That is quite big
amount of vector in IDT. But it is still not enough, since modern x86
sever has more cpu number. That still causes heavy lock contention
in TLB flushing.

The patch using generic smp call function to replace it. That saved 32
vector number in IDT, and resolved the lock contention in TLB
flushing on large system.

In the NHM EX machine 4P * 8cores * HT = 64 CPUs, hackbench pthread
has 3% performance increase.

Signed-off-by: Alex Shi <alex.shi@intel.com>
Link: http://lkml.kernel.org/r/1340845344-27557-9-git-send-email-alex.shi@intel.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-06-27 19:29:13 -07:00
Steven Rostedt 7fbb98c5cb x86: Save cr2 in NMI in case NMIs take a page fault
Avi Kivity reported that page faults in NMIs could cause havic if
the NMI preempted another page fault handler:

   The recent changes to NMI allow exceptions to take place in NMI
   handlers, but I think that a #PF (say, due to access to vmalloc space)
   is still problematic.  Consider the sequence

    #PF  (cr2 set by processor)
      NMI
        ...
        #PF (cr2 clobbered)
          do_page_fault()
          IRET
        ...
        IRET
      do_page_fault()
        address = read_cr2()

   The last line reads the overwritten cr2 value.

Originally I wrote a patch to solve this by saving the cr2 on the stack.
Brian Gerst suggested to save it in the r12 register as both r12 and rbx
are saved by the do_nmi handler as required by the C standard. But rbx
is already used for saving if swapgs needs to be run on exit of the NMI
handler.

Link: http://lkml.kernel.org/r/4FBB8C40.6080304@redhat.com
Link: http://lkml.kernel.org/r/1337763411.13348.140.camel@gandalf.stny.rr.com

Reported-by: Avi Kivity <avi@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-07 10:21:21 -04:00
Steven Rostedt 5963e317b1 ftrace/x86: Do not change stacks in DEBUG when calling lockdep
When both DYNAMIC_FTRACE and LOCKDEP are set, the TRACE_IRQS_ON/OFF
will call into the lockdep code. The lockdep code can call lots of
functions that may be traced by ftrace. When ftrace is updating its
code and hits a breakpoint, the breakpoint handler will call into
lockdep. If lockdep happens to call a function that also has a breakpoint
attached, it will jump back into the breakpoint handler resetting
the stack to the debug stack and corrupt the contents currently on
that stack.

The 'do_sym' call that calls do_int3() is protected by modifying the
IST table to point to a different location if another breakpoint is
hit. But the TRACE_IRQS_OFF/ON are outside that protection, and if
a breakpoint is hit from those, the stack will get corrupted, and
the kernel will crash:

[ 1013.243754] BUG: unable to handle kernel NULL pointer dereference at 0000000000000002
[ 1013.272665] IP: [<ffff880145cc0000>] 0xffff880145cbffff
[ 1013.285186] PGD 1401b2067 PUD 14324c067 PMD 0
[ 1013.298832] Oops: 0010 [#1] PREEMPT SMP
[ 1013.310600] CPU 2
[ 1013.317904] Modules linked in: ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables crc32c_intel ghash_clmulni_intel microcode usb_debug serio_raw pcspkr iTCO_wdt i2c_i801 iTCO_vendor_support e1000e nfsd nfs_acl auth_rpcgss lockd sunrpc i915 video i2c_algo_bit drm_kms_helper drm i2c_core [last unloaded: scsi_wait_scan]
[ 1013.401848]
[ 1013.407399] Pid: 112, comm: kworker/2:1 Not tainted 3.4.0+ #30
[ 1013.437943] RIP: 8eb8:[<ffff88014630a000>]  [<ffff88014630a000>] 0xffff880146309fff
[ 1013.459871] RSP: ffffffff8165e919:ffff88014780f408  EFLAGS: 00010046
[ 1013.477909] RAX: 0000000000000001 RBX: ffffffff81104020 RCX: 0000000000000000
[ 1013.499458] RDX: ffff880148008ea8 RSI: ffffffff8131ef40 RDI: ffffffff82203b20
[ 1013.521612] RBP: ffffffff81005751 R08: 0000000000000000 R09: 0000000000000000
[ 1013.543121] R10: ffffffff82cdc318 R11: 0000000000000000 R12: ffff880145cc0000
[ 1013.564614] R13: ffff880148008eb8 R14: 0000000000000002 R15: ffff88014780cb40
[ 1013.586108] FS:  0000000000000000(0000) GS:ffff880148000000(0000) knlGS:0000000000000000
[ 1013.609458] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1013.627420] CR2: 0000000000000002 CR3: 0000000141f10000 CR4: 00000000001407e0
[ 1013.649051] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1013.670724] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 1013.692376] Process kworker/2:1 (pid: 112, threadinfo ffff88013fe0e000, task ffff88014020a6a0)
[ 1013.717028] Stack:
[ 1013.724131]  ffff88014780f570 ffff880145cc0000 0000400000004000 0000000000000000
[ 1013.745918]  cccccccccccccccc ffff88014780cca8 ffffffff811072bb ffffffff81651627
[ 1013.767870]  ffffffff8118f8a7 ffffffff811072bb ffffffff81f2b6c5 ffffffff81f11bdb
[ 1013.790021] Call Trace:
[ 1013.800701] Code: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a <e7> d7 64 81 ff ff ff ff 01 00 00 00 00 00 00 00 65 d9 64 81 ff
[ 1013.861443] RIP  [<ffff88014630a000>] 0xffff880146309fff
[ 1013.884466]  RSP <ffff88014780f408>
[ 1013.901507] CR2: 0000000000000002

The solution was to reuse the NMI functions that change the IDT table to make the debug
stack keep its current stack (in kernel mode) when hitting a breakpoint:

  call debug_stack_set_zero
  TRACE_IRQS_ON
  call debug_stack_reset

If the TRACE_IRQS_ON happens to hit a breakpoint then it will keep the current stack
and not crash the box.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-05-31 23:12:22 -04:00
H. Peter Anvin d7abc0fa99 x86, extable: Remove open-coded exception table entries in arch/x86/kernel/entry_64.S
Remove open-coded exception table entries in arch/x86/kernel/entry_64.S,
and replace them with _ASM_EXTABLE() macros; this will allow us to
change the format and type of the exception table entries.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: David Daney <david.daney@cavium.com>
Link: http://lkml.kernel.org/r/CA%2B55aFyijf43qSu3N9nWHEBwaGbb7T2Oq9A=9EyR=Jtyqfq_cQ@mail.gmail.com
2012-04-20 13:51:38 -07:00
Linus Torvalds a591afc01d Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x32 support for x86-64 from Ingo Molnar:
 "This tree introduces the X32 binary format and execution mode for x86:
  32-bit data space binaries using 64-bit instructions and 64-bit kernel
  syscalls.

  This allows applications whose working set fits into a 32 bits address
  space to make use of 64-bit instructions while using a 32-bit address
  space with shorter pointers, more compressed data structures, etc."

Fix up trivial context conflicts in arch/x86/{Kconfig,vdso/vma.c}

* 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits)
  x32: Fix alignment fail in struct compat_siginfo
  x32: Fix stupid ia32/x32 inversion in the siginfo format
  x32: Add ptrace for x32
  x32: Switch to a 64-bit clock_t
  x32: Provide separate is_ia32_task() and is_x32_task() predicates
  x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls
  x86/x32: Fix the binutils auto-detect
  x32: Warn and disable rather than error if binutils too old
  x32: Only clear TIF_X32 flag once
  x32: Make sure TS_COMPAT is cleared for x32 tasks
  fs: Remove missed ->fds_bits from cessation use of fd_set structs internally
  fs: Fix close_on_exec pointer in alloc_fdtable
  x32: Drop non-__vdso weak symbols from the x32 VDSO
  x32: Fix coding style violations in the x32 VDSO code
  x32: Add x32 VDSO support
  x32: Allow x32 to be configured
  x32: If configured, add x32 system calls to system call tables
  x32: Handle process creation
  x32: Signal-related system calls
  x86: Add #ifdef CONFIG_COMPAT to <asm/sys_ia32.h>
  ...
2012-03-29 18:12:23 -07:00
Linus Torvalds 4c64616bb5 Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/debug changes from Ingo Molnar.

* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Fix section warnings
  x86-64: Fix CFI data for common_interrupt()
  x86: Properly _init-annotate NMI selftest code
  x86/debug: Fix/improve the show_msr=<cpus> debug print out
2012-03-22 09:30:39 -07:00
Ingo Molnar e24b90b282 Merge branch 'tip/x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into x86/asm 2012-02-28 10:28:24 +01:00
Ingo Molnar 458ce2910a Merge branch 'linus' into x86/asm
Sync up the latest NMI fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-28 10:27:36 +01:00
Mark Wielaard 928282e432 x86-64: Fix CFI data for common_interrupt()
Commit eab9e6137f ("x86-64: Fix CFI data for interrupt frames")
introduced a DW_CFA_def_cfa_expression in the SAVE_ARGS_IRQ
macro. To later define the CFA using a simple register+offset
rule both register and offset need to be supplied. Just using
CFI_DEF_CFA_REGISTER leaves the offset undefined. So use
CFI_DEF_CFA with reg+off explicitly at the end of
common_interrupt.

Signed-off-by: Mark Wielaard <mjw@redhat.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/1330079527-30711-1-git-send-email-mjw@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-27 10:46:14 +01:00
Steven Rostedt 79fb4ad63e x86: Fix the NMI nesting comments
Some of the comments for the nesting NMI algorithm were stale and
had some references to some prototypes that were first tried.

I also updated the comments to be a little easier to understand
the flow of the code. It definitely needs the documentation.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-02-24 15:55:13 -05:00
Jan Beulich 69466466ce x86-64: Improve insn scheduling in SAVE_ARGS_IRQ
In one case, use an address register that was computed earlier (and
with a simpler instruction), thus reducing the risk of a stall.

In the second case, eliminate a branch by using a conditional move (as
is already done in call_softirq and xen_do_hypervisor_callback).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/4F4788A50200007800074A26@nat28.tlf.novell.com
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2012-02-24 11:46:28 -08:00