The pcc specification documents an _OSC method that's incompatible with the
one defined as part of the ACPI spec. This shouldn't be a problem as both
are supposed to be guarded with a UUID. Unfortunately approximately nobody
(including HP, who wrote this spec) properly check the UUID on entry to the
_OSC call. Right now this could result in surprising behaviour if the pcc
driver performs an _OSC call on a machine that doesn't implement the pcc
specification. Check whether the PCCH method exists first in order to reduce
this probability.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
When running on VMware's platform, we have seen situations where
the AP's try to calibrate the lpj values and fail to get good calibration
runs becasue of timing issues. As a result delays don't work correctly
on all cpus.
The solutions is to set preset_lpj value based on the current tsc frequency
value. This is similar to what KVM does as well.
Signed-off-by: Alok N Kataria <akataria@vmware.com>
LKML-Reference: <1280790637.14933.29.camel@ank32.eng.vmware.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
It is paramount that we call pci_xen_swiotlb_detect before
pci_swiotlb_detect as both implementations use the 'swiotlb'
and 'swiotlb_force' flags. The pci-xen_swiotlb_detect inhibits
the swiotlb_force and swiotlb flag so that the native SWIOTLB
implementation is not enabled when running under Xen.
[since v1 changed two Cc's to Acked-by]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
[http://lkml.org/lkml/2010/7/27/374]
Cc: Albert Herranz <albert_herranz@yahoo.es>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
[conditional http://lkml.org/lkml/2010/8/2/324]
Cc: x86@kernel.org
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Accomodate the original C1E-aware idle routine to the different times
during boot when the BIOS enables C1E. While at it, remove the synthetic
CPUID flag in favor of a single global setting which denotes C1E status
on the system.
[ hpa: changed c1e_enabled to be a bool; clarified cpu bit 3:21 comment ]
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
LKML-Reference: <20100727165335.GA11630@aftab>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Use a direct per-cpu reference for the GDT instead of using a scratch
register.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1280594903-6341-2-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Use a direct per-cpu reference for the IST instead of using a scratch
register.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1280594903-6341-1-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
The arguments passed to OFW shouldn't be modified; update the 'args'
argument of olpc_ofw to reflect this. This saves us some later
casting away of consts.
Signed-off-by: Andres Salomon <dilinger@queued.net>
LKML-Reference: <20100628220029.1555ac24@debian>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Unconditionally printing EC debug messages was helpful when we were actually
debugging the EC, but during normal operation it can get pretty annoying.
Using pr_debug allows us finer-grained control.
Signed-off-by: Andres Salomon <dilinger@queued.net>
LKML-Reference: <20100616231928.16b539f0@dev.queued.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Add package level thermal and power limit feature support.
The two MSRs and features are new starting with Intel's Sandy Bridge processor.
Please check Intel 64 and IA-32 Architectures SDMV Vol 3A 14.5.6 Power Limit
Notification and 14.6 Package Level Thermal Management.
This patch also fixes a bug which defines reverse THERM_INT_LOW_ENABLE bit and
THERM_INT_HIGH_ENABLE bit.
[ hpa: fixed up against current tip:x86/cpu ]
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
LKML-Reference: <1280448826-12004-2-git-send-email-fenghua.yu@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Use the stop machine context rather than IPI's to rendezvous all the cpus for
MTRR initialization that happens during cpu bringup or for MTRR modifications
during runtime.
This avoids deadlock scenario (reported by Prarit) like:
cpu A holds a read_lock (tasklist_lock for example) with irqs enabled
cpu B waits for the same lock with irqs disabled using write_lock_irq
cpu C doing set_mtrr() (during AP bringup for example), which will try to
rendezvous all the cpus using IPI's
This will result in C and A come to the rendezvous point and waiting
for B. B is stuck forever waiting for the lock and thus not
reaching the rendezvous point.
Using stop cpu (run in the process context of per cpu based keventd) to do
this rendezvous, avoids this deadlock scenario.
Also make sure all the cpu's are in the rendezvous handler before we proceed
with the local_irq_save() on each cpu. This lock step disabling irqs on all
the cpus will avoid other deadlock scenarios (for example involving
with the blocking smp_call_function's etc).
[ This problem is very old. Marking -stable only for 2.6.35 as the
stop_one_cpu_nowait() API is present only in 2.6.35. Any older
kernel interested in this fix need to do some more work in backporting
this patch. ]
Reported-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1280515602.2682.10.camel@sbsiddha-MOBL3.sc.intel.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Cc: stable@kernel.org [2.6.35]
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
commit 2ca1af9aa3285c6a5f103ed31ad09f7399fc65d7 "PCI: MSI: Remove
unsafe and unnecessary hardware access" changed read_msi_msg_desc() to
return the last MSI message written instead of reading it from the
device, since it may be called while the device is in a reduced
power state.
However, the pSeries platform code really does need to read messages
from the device, since they are initially written by firmware.
Therefore:
- Restore the previous behaviour of read_msi_msg_desc()
- Add new functions get_cached_msi_msg{,_desc}() which return the
last MSI message written
- Use the new functions where appropriate
Acked-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch introduce a CONFIG_XEN_PVHVM compile time option to
enable/disable Xen PV on HVM support.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
HW breakpoints events stopped working correctly with kgdb
as a result of commit: 018cbffe68
(Merge commit 'v2.6.33' into perf/core).
The regression occurred because the behavior changed for setting
NOTIFY_STOP as the return value to the die notifier if the breakpoint
was known to the HW breakpoint API. Because kgdb is using the HW
breakpoint API to register HW breakpoints slots, it must also now
implement the overflow_handler call back else kgdb does not get to see
the events from the die notifier.
The kgdb_ll_trap function will be changed to be general purpose code
which can allow an easy way to implement the hw_breakpoint API
overflow call back.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Dongdong Deng <dongdong.deng@windriver.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Move cmpxchg emulation code from arch/x86/kernel/cpu (which is
otherwise CPU identification) to arch/x86/lib, where other emulation
code lives already.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <AANLkTikAmaDPji-TVDarmG1yD=fwbffcsmEU=YEuP+8r@mail.gmail.com>
Exprot the AMD errata definitions, since they are needed by kvm_amd.ko
if that is built as a module. Doing "make allmodconfig" during
testing would have caught this.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Hans Rosenfeld <hans.rosenfeld@amd.com>
LKML-Reference: <1280336972-865982-1-git-send-email-hans.rosenfeld@amd.com>
Use the AMD errata checking framework instead of open-coding the test.
Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com>
LKML-Reference: <1280336972-865982-3-git-send-email-hans.rosenfeld@amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Remove check_c1e_idle() and use the new AMD errata checking framework
instead.
Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com>
LKML-Reference: <1280336972-865982-2-git-send-email-hans.rosenfeld@amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Errata are defined using the AMD_LEGACY_ERRATUM() or AMD_OSVW_ERRATUM()
macros. The latter is intended for newer errata that have an OSVW id
assigned, which it takes as first argument. Both take a variable number
of family-specific model-stepping ranges created by AMD_MODEL_RANGE().
Iff an erratum has an OSVW id, OSVW is available on the CPU, and the
OSVW id is known to the hardware, it is used to determine whether an
erratum is present. Otherwise, the model-stepping ranges are matched
against the current CPU to find out whether the erratum applies.
For certain special errata, the code using this framework might have to
conduct further checks to make sure an erratum is really (not) present.
Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com>
LKML-Reference: <1280336972-865982-1-git-send-email-hans.rosenfeld@amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This patch simply declares the new sys_fanotify_mark syscall
int fanotify_mark(int fanotify_fd, unsigned int flags, u64_mask,
int dfd const char *pathname)
Signed-off-by: Eric Paris <eparis@redhat.com>
This patch defines a new syscall fanotify_init() of the form:
int sys_fanotify_init(unsigned int flags, unsigned int event_f_flags,
unsigned int priority)
This syscall is used to create and fanotify group. This is very similar to
the inotify_init() syscall.
Signed-off-by: Eric Paris <eparis@redhat.com>
This patch exports the capability of the AMD IOMMU to force
cache coherency of DMA transactions through the IOMMU-API.
This is required to disable some nasty hacks in KVM when
this capability is not available.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This converts the most common of the x86 clocksources over to use
clocksource_register_hz/khz.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-11-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
update_vsyscall() did not provide the wall_to_monotoinc offset,
so arch specific implementations tend to reference wall_to_monotonic
directly. This limits future cleanups in the timekeeping core, so
this patch fixes the update_vsyscall interface to provide
wall_to_monotonic, allowing wall_to_monotonic to be made static
as planned in Documentation/feature-removal-schedule.txt
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tony Luck <tony.luck@intel.com>
LKML-Reference: <1279068988-21864-7-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Due to vtime calling vgettimeofday(), its possible that an application
could call time();create("stuff",O_RDRW); only to see the file's
creation timestamp to be before the value returned by time.
A similar way to reproduce the issue is to compare the vsyscall time()
with the syscall time(), and observe ordering issues.
The modified test case from Oleg Nesterov below can illustrate this:
int main(void)
{
time_t sec1,sec2;
do {
sec1 = time(&sec2);
sec2 = syscall(__NR_time, NULL);
} while (sec1 <= sec2);
printf("vtime: %d.000000\n", sec1);
printf("time: %d.000000\n", sec2);
return 0;
}
The proper fix is to make vtime use the same time value as
current_kernel_time() (which is exported via update_vsyscall) instead of
vgettime().
Thanks to Jiri Olsa for bringing up the issue and catching bugs in
earlier verisons of this fix.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
LKML-Reference: <1279068988-21864-2-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Do not try to disable hpet if it hasn't been initialized before
x86, i8259: Only register sysdev if we have a real 8259 PIC
The Pstate transition latency check was added for broken F10h BIOSen
which wrongly contain a value of 0 for transition and bus master
latency. Fam11h and later, however, (will) have similar transition
latency so extend that behavior for them too.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
The PCC cpufreq driver unmaps the mailbox address range if any CPUs fail to
initialise, but doesn't do anything to remove the registered CPUs from the
cpufreq core resulting in failures further down the line. We're better off
simply returning a failure - the cpufreq core will unregister us cleanly if
we end up with no successfully registered CPUs. Tidy up the failure path
and also add a sanity check to ensure that the firmware gives us a realistic
frequency - the core deals badly with that being set to 0.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
The pcc specification documents an _OSC method that's incompatible with the
one defined as part of the ACPI spec. This shouldn't be a problem as both
are supposed to be guarded with a UUID. Unfortunately approximately nobody
(including HP, who wrote this spec) properly check the UUID on entry to the
_OSC call. Right now this could result in surprising behaviour if the pcc
driver performs an _OSC call on a machine that doesn't implement the pcc
specification. Check whether the PCCH method exists first in order to reduce
this probability.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Commit 2a6b69765a
(ACPI: Store NVS state even when entering suspend to RAM) caused the
ACPI suspend code save the NVS area during suspend and restore it
during resume unconditionally, although it is known that some systems
need to use acpi_sleep=s4_nonvs for hibernation to work. To allow
the affected systems to avoid saving and restoring the NVS area
during suspend to RAM and resume, introduce kernel command line
option acpi_sleep=nonvs and make acpi_sleep=s4_nonvs work as its
alias temporarily (add acpi_sleep=s4_nonvs to the feature removal
file).
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16396 .
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: tomas m <tmezzadra@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
hpet_disable is called unconditionally on machine reboot if hpet support
is compiled in the kernel.
hpet_disable only checks if the machine is hpet capable but doesn't make
sure that hpet has been initialized.
[ tglx: Made it a one liner and removed the redundant hpet_address check ]
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Venkatesh Pallipadi <venki@google.com>
LKML-Reference: <alpine.DEB.2.00.1007211726240.22235@kaball-desktop>
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Set the callback to receive evtchns from Xen, using the
callback vector delivery mechanism.
The traditional way for receiving event channel notifications from Xen
is via the interrupts from the platform PCI device.
The callback vector is a newer alternative that allow us to receive
notifications on any vcpu and doesn't need any PCI support: we allocate
a vector exclusively to receive events, in the vector handler we don't
need to interact with the vlapic, therefore we avoid a VMEXIT.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Initialize basic pv on hvm features adding a new Xen HVM specific
hypervisor_x86 structure.
Don't try to initialize xen-kbdfront and xen-fbfront when running on HVM
because the backends are not available.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
It turns out that there is a bit in the _CST for Intel FFH C3
that tells the OS if we should be checking BM_STS or not.
Linux has been unconditionally checking BM_STS.
If the chip-set is configured to enable BM_STS,
it can retard or completely prevent entry into
deep C-states -- as illustrated by turbostat:
http://userweb.kernel.org/~lenb/acpi/utils/pmtools/turbostat/
ref: Intel Processor Vendor-Specific ACPI Interface Specification
table 4 "_CST FFH GAS Field Encoding"
Bit 1: Set to 1 if OSPM should use Bus Master avoidance for this C-state
https://bugzilla.kernel.org/show_bug.cgi?id=15886
Signed-off-by: Len Brown <len.brown@intel.com>
and fix the broken case if a core's frequency depends on others.
trace_power_frequency was only implemented in a rather ungeneric
way in acpi-cpufreq driver's target() function only.
-> Move the call to trace_power_frequency to
cpufreq.c:cpufreq_notify_transition() where CPUFREQ_POSTCHANGE
notifier is triggered.
This will support power frequency tracing by all cpufreq
drivers.
trace_power_frequency did not trace frequency changes correctly
when the userspace governor was used or when CPU cores'
frequency depend on each other.
-> Moving this into the CPUFREQ_POSTCHANGE notifier and pass the cpu
which gets switched automatically fixes this.
Robert Schoene provided some important fixes on top of my
initial quick shot version which are integrated in this patch:
- Forgot some changes in power_end trace (TP_printk/variable names)
- Variable dummy in power_end must now be cpu_id
- Use static 64 bit variable instead of unsigned int for cpu_id
[akpm@linux-foundation.org: build fix]
Signed-off-by: Thomas Renninger <trenn@suse.de>
Cc: davej@codemonkey.org.uk
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Dave Jones <davej@codemonkey.org.uk>
Acked-by: Arjan van de Ven <arjan@infradead.org>
Cc: Robert Schoene <robert.schoene@tu-dresden.de>
Tested-by: Robert Schoene <robert.schoene@tu-dresden.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Load initial_gs as two 32-bit values instead of splitting a 64-bit value.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1279371808-24804-3-git-send-email-brgerst@gmail.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Use symbolic MSR names instead of hardcoding the MSR index.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1279371808-24804-2-git-send-email-brgerst@gmail.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
In the CONFIG_AUDITSYSCALL fast-path for x86 64-bit system calls,
we can pass a bad return value and/or error indication for the
system call to audit_syscall_exit(). This happens when
TIF_NEED_RESCHED was set as the system call returned, so we went
out to schedule() and came back to the exit-audit fast-path. The
fix is to reload the user return value register from the pt_regs
before using it for audit_syscall_exit().
Both the 32-bit kernel's fast path and the 64-bit kernel's 32-bit
system call fast paths work slightly differently, so that they
always leave the fast path entirely to reschedule and don't return
there, so they don't have the analogous bugs.
Reported-by: Alexander Viro <aviro@redhat.com>
Signed-off-by: Roland McGrath <roland@redhat.com>
xstate_enable_boot_cpu() is, as the name implies, only used on the
boot CPU; furthermore, it invokes alloc_bootmem(), which is __init;
hence it needs to be tagged __init rather than __cpuinit.
Furthermore, it is *not* safe in the long run to rely on CPU 0 only
coming online during the early boot -- at some point we're going to
support offlining (and re-onlining) the boot CPU, and at that point we
must not call xstate_enable_boot_cpu() again.
The code is a fair bit more obscure than one would like, because the
__ref overrides aren't quite powerful enough.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Robert Richter <robert.richter@amd.com>
LKML-Reference: <4C476236.1020302@zytor.com>
This is called only from initialization code.
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279731838-1522-6-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The pointer is only used in xsave.c. Making it static.
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279731838-1522-5-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The patch introduces the XSTATE_CPUID macro and adds a check that
tests if XSTATE_CPUID exists.
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279731838-1522-4-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The patch renames xsave_cntxt_init() and __xsave_init() into
xstate_enable_boot_cpu() and xstate_enable() as this names are more
meaningful.
It also removes the duplicate xcr setup for the boot cpu.
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279731838-1522-3-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
As xsave also supports other than fpu features, it should be
initialized independently of the fpu. This patch moves this out of fpu
initialization.
There is also a lot of cross referencing between fpu and xsave
code. This patch reduces this by making xsave_cntxt_init() and
init_thread_xstate() static functions.
The patch moves the cpu_has_xsave check at the beginning of
xsave_init(). All other checks may removed then.
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279731838-1522-2-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Pointed out by Lucas who found the new one in a comment in
setup_percpu.c. And then I fixed the others that I grepped
for.
Reported-by: Lucas <canolucas@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit e534c7c5f8 ("numa: x86_64: use generic percpu var
numa_node_id() implementation") broke numa systems that don't have ram
on node0 when MEMORY_HOTPLUG is enabled, because cpu_up() will call
cpu_to_node() before per_cpu(numa_node) is setup for APs.
When Node0 doesn't have RAM, on x86, cpus already round it to nearest
node with RAM in x86_cpu_to_node_map. and per_cpu(numa_node) is not set
up until in c_init for APs.
When later cpu_up() calling cpu_to_node() will get 0 again, and make it
online even there is no RAM on node0. so later all APs can not booted up,
and later will have panic.
[ 1.611101] On node 0 totalpages: 0
.........
[ 2.608558] On node 0 totalpages: 0
[ 2.612065] Brought up 1 CPUs
[ 2.615199] Total of 1 processors activated (3990.31 BogoMIPS).
...
93.225341] calling loop_init+0x0/0x1a4 @ 1
[ 93.229314] PERCPU: allocation failed, size=80 align=8, failed to populate
[ 93.246539] Pid: 1, comm: swapper Tainted: G W 2.6.35-rc4-tip-yh-04371-gd64e6c4-dirty #354
[ 93.264621] Call Trace:
[ 93.266533] [<ffffffff81125e43>] pcpu_alloc+0x83a/0x8e7
[ 93.270710] [<ffffffff81125f15>] __alloc_percpu+0x10/0x12
[ 93.285849] [<ffffffff8140786c>] alloc_disk_node+0x94/0x16d
[ 93.291811] [<ffffffff81407956>] alloc_disk+0x11/0x13
[ 93.306157] [<ffffffff81503e51>] loop_alloc+0xa7/0x180
[ 93.310538] [<ffffffff8277ef48>] loop_init+0x9b/0x1a4
[ 93.324909] [<ffffffff8277eead>] ? loop_init+0x0/0x1a4
[ 93.329650] [<ffffffff810001f2>] do_one_initcall+0x57/0x136
[ 93.345197] [<ffffffff827486d0>] kernel_init+0x184/0x20e
[ 93.348146] [<ffffffff81034954>] kernel_thread_helper+0x4/0x10
[ 93.365194] [<ffffffff81c7cc3c>] ? restore_args+0x0/0x30
[ 93.369305] [<ffffffff8274854c>] ? kernel_init+0x0/0x20e
[ 93.386011] [<ffffffff81034950>] ? kernel_thread_helper+0x0/0x10
[ 93.392047] loop: out of memory
...
Try to assign per_cpu(numa_node) early
[akpm@linux-foundation.org: tidy up code comment]
Signed-off-by: Yinghai <yinghai@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch moves boot cpu initialization to xsave_init(). Now all cpus
are initialized in one single function.
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279651857-24639-5-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Boot cpu id is always 0, thus simplifying and unifying boot cpu check.
boot_cpu_id is there for historical reasons and was renamed to
boot_cpu_physical_apicid in patch:
c70dcb7 x86: change boot_cpu_id to boot_cpu_physical_apicid
However, there are some remaining occurrences of boot_cpu_id that are
never touched in the kernel and thus its value is always 0.
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279651857-24639-3-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Just some dead code, no real bugs.
Found by gcc 4.6 -Wall
Signed-off-by: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <201007202219.o6KMJnQ0021072@imap1.linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
My platform makes use of the null_legacy_pic choice and oopses when doing
a shutdown as the shutdown code goes through all the registered sysdevs
and calls their shutdown method which in my case poke on a non-existing
i8259. Imho the i8259 specific sysdev should only be registered if the
i8259 is actually there.
Do not register the sysdev function when the null_legacy_pic is used so
that the i8259 resume, suspend and shutdown functions are not called.
Signed-off-by: Adam Lackorzynski <adam@os.inf.tu-dresden.de>
LKML-Reference: <201007202218.o6KMIJ3m020955@imap1.linux-foundation.org>
Cc: Jacob Pan <jacob.jun.pan@intel.com>
Cc: <stable@kernel.org> 2.6.34
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
addon_cpuid_features.c contains exactly two almost completely
unrelated functions, plus has a long and very generic name. Split it
into two files, scattered.c for the scattered feature flags, and
topology.c for the topology information.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <tip-*@git.kernel.org>
xsaveopt is a more optimized form of xsave specifically designed
for the context switch usage. xsaveopt doesn't save the state that's not
modified from the prior xrstor. And if a specific feature state gets
modified to the init state, then xsaveopt just updates the header bit
in the xsave memory layout without updating the corresponding memory
layout.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100719230205.604014179@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
With xsaveopt, if a processor implementation discern that a processor state
component is in its initialized state it may modify the corresponding bit in
the xsave_hdr.xstate_bv as '0', with out modifying the corresponding memory
layout. Hence wHile presenting the xstate information to the user, we always
ensure that the memory layout of a feature will be in the init state if the
corresponding header bit is zero. This ensures the consistency and avoids the
condition of the user seeing some some stale state in the memory layout during
signal handling, debugging etc.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100719230205.351459480@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Subleaves of the cpuid vector 0xd provides the offset and size of different
feature state that are managed by the xsave/xrstor. Track this for the upcoming
usage during signal handling.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100719230205.262987929@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Enumerate the xsaveopt feature.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100719230205.604014179@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Some cpuid features (like xsaveopt) are enumerated using cpuid
subleaves.
Extend init_scattered_cpuid_features() to take subleaf into account.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100719230205.439900717@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, pci, mrst: Add extra sanity check in walking the PCI extended cap chain
x86: Fix x2apic preenabled system with kexec
x86: Force HPET readback_cmp for all ATI chipsets
pavel@suse.cz no longer works, replace it with working address.
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
In commit f007ea26, the order of the %es and %ds segment registers
got accidentally swapped, so synthesized 'struct pt_regs' frames
have the two values inverted. It's almost sure that these values
never matter, and that they also never differ. But wrong is wrong.
Signed-off-by: Roland McGrath <roland@redhat.com>
Found one x2apic system kexec loop test failed
when CONFIG_NMI_WATCHDOG=y (old) or CONFIG_LOCKUP_DETECTOR=y (current tip)
first kernel can kexec second kernel, but second kernel can not kexec third one.
it can be duplicated on another system with BIOS preenabled x2apic.
First kernel can not kexec second kernel.
It turns out, when kernel boot with pre-enabled x2apic, it will not execute
disable_local_APIC on shutdown path.
when init_apic_mappings() is called in setup_arch, it will skip setting of
apic_phys when x2apic_mode is set. ( x2apic_mode is much early check_x2apic())
Then later, disable_local_APIC() will bail out early because !apic_phys.
So check !x2apic_mode in x2apic_mode in disable_local_APIC with !apic_phys.
another solution could be updating init_apic_mappings() to set apic_phys even
for preenabled x2apic system. Actually even for x2apic system, that lapic
address is mapped already in early stage.
BTW: is there any x2apic preenabled system with apicid of boot cpu > 255?
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4C3EB22B.3000701@kernel.org>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: stable@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Add __NR_prlimit64 syscall numbers to asm-generic. Add them also to
asm-x86, both 32 and 64-bit.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Also needed if pr_<level> becomes a bit more space efficient.
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
LKML-Reference: <1277768808.29157.280.camel@Joe-Laptop.home>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
commit 30a564be (x86, hpet: Restrict read back to affected ATI
chipset) restricted the workaround for the HPET bug to SMX00
chipsets. This was reasonable as those were the only ones against
which we ever got a bug report.
Stephan Wolf reported now that this patch breaks his IXP400 based
machine. Though it's confirmed to work on other IXP400 based systems.
To error out on the safe side, we force the HPET readback workaround
for all ATI SMbus class chipsets.
Reported-by: Stephan Wolf <stephan@letzte-bankreihe.de>
LKML-Reference: <alpine.LFD.2.00.1007142134140.3321@localhost.localdomain>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Stephan Wolf <stephan@letzte-bankreihe.de>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Make the alternatives-patching code BUG on encountering an invalid CPU
feature number. Should have done this a long time ago.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Yinghai Lu <yinhai@kernel.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <tip-df378ccfc4dd04e263426ad805516915874774aa@git.kernel.org>
This is needed so that the staging hyperv can properly access this
symbol.
Signed-off-by: K. Y. Srinivasan <ksrinivasan@novell.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In today's linux-next I got this compile warning:
arch/x86/kernel/apic/es7000_32.c:132: warning: 'base' defined but not used
Current patch solves the issue removing the unused variable.
Signed-off-by: Javier Martinez Canillas <martinez.javier@gmail.com>
Cc: Rakib Mullick <rakib.mullick@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Tejun Heo <tj@kernel.org>
LKML-Reference: <1278546719.9020.4.camel@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Intel has defined CPUID leaf 7 as the next set of feature flags (see
the AVX specification, version 007). Add support for this new feature
flags word.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <tip-*@vger.kernel.org>
It will just return 0 as there is no i8042 controller
Signed-off-by: Feng Tang <feng.tang@intel.com>
LKML-Reference: <1278342202-10973-3-git-send-email-feng.tang@intel.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Some x86 platforms like Intel MID platforms don't have i8042 controllers,
and i8042 driver's probe to some legacy IO ports may hang the MID
processor. With this hook, i8042 driver can runtime check and skip the
probe when the pretection fail which also saves some probe time
[ hpa note: this is currently a compile-time check, which breaks the
i386 allyesconfig build. This patch series thus does fix a regression. ]
Signed-off-by: Feng Tang <feng.tang@intel.com>
LKML-Reference: <1278342202-10973-2-git-send-email-feng.tang@intel.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Export x86_platform to modules in preparation of using it for i8042
discovery control.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <1278342202-10973-1-git-send-email-feng.tang@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
We already have cpufeature indicies above 255, so use a 16-bit number
for the alternatives index. This consumes a padding field and so
doesn't add any size, but it means that abusing the padding field to
create assembly errors on overflow no longer works. We can retain the
test simply by redirecting it to the .discard section, however.
[ v3: updated to include open-coded locations ]
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <tip-f88731e3068f9d1392ba71cc9f50f035d26a0d4f@git.kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rbtree: Undo augmented trees performance damage and regression
x86, Calgary: Limit the max PHB number to 256
fxsave/xsave doesn't touch all the bytes in the memory layout used by
these instructions. Specifically SW reserved (bytes 464..511) fields
in the fxsave frame and the reserved fields in the xsave header.
To present a clean context for the signal handling, just clear these fields
instead of clearing the complete fxsave/xsave memory layout, when we dump these
registers directly to the user signal frame.
Also avoid the call to second xrstor (which inits the state not passed
in the signal frame) in restore_user_xstate() if all the state has already
been restored by the first xrstor.
These changes improve the performance of signal handling(by ~3-5% as measured
by the lat_sig).
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1277249017.2847.85.camel@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
To support cache events we have reserved the low 6 bits in
hw_perf_event::config (which is a part of CCCR register
configuration actually).
These bits represent Replay Event mertic enumerated in
enum P4_PEBS_METRIC. The caller should not care about
which exact bits should be set and how -- the caller
just chooses one P4_PEBS_METRIC entity and puts it into
the config. The kernel will track it and set appropriate
additional MSR registers (metrics) when needed.
The reason for this redesign was the PEBS enable bit, which
should not be set until DS (and PEBS sampling) support will
be implemented properly.
TODO
====
- PEBS sampling (note it's tricky and works with _one_ counter only
so for HT machines it will be not that easy to handle both threads)
- tracking of PEBS registers state, a user might need to turn
PEBS off completely (ie no PEBS enable, no UOP_tag) but some
other event may need it, such events clashes and should not
run simultaneously, at moment we just don't support such events
- eventually export user space bits in separate header which will
allow user apps to configure raw events more conveniently.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1278295769.9540.15.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf, x86: Fix incorrect branches event on AMD CPUs
perf tools: Fix find tids routine by excluding "." and ".."
x86: Send a SIGTRAP for user icebp traps
While doing some performance counter validation tests on some
assembly language programs I noticed that the "branches:u"
count was very wrong on AMD machines.
It looks like the wrong event was selected.
Signed-off-by: Vince Weaver <vweaver1@eecs.utk.edu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@kernel.org>
LKML-Reference: <alpine.DEB.2.00.1007011526010.23160@cl320.eecs.utk.edu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
fs/fs-writeback.c
Merge reason: Resolve the conflict
Note, i picked the version from Linus's tree, which effectively reverts
the fs-writeback.c bits of:
b97181f: fs: remove all rcu head initializations, except on_stack initializations
As the upstream changes to this file changed this code heavily and the
first attempt to resolve the conflict resulted in a non-booting kernel.
It's safer to re-try this portion of the commit cleanly.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The x3950 family can have as many as 256 PCI buses in a single system, so
change the limits to the maximum. Since there can only be 256 PCI buses in one
domain, we no longer need the BUG_ON check.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
LKML-Reference: <20100701004519.GQ15515@tux1.beaverton.ibm.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Before we had a generic breakpoint layer, x86 used to send a
sigtrap for any debug event that happened in userspace,
except if it was caused by lazy dr7 switches.
Currently we only send such signal for single step or breakpoint
events.
However, there are three other kind of debug exceptions:
- debug register access detected: trigger an exception if the
next instruction touches the debug registers. We don't use
it.
- task switch, but we don't use tss.
- icebp/int01 trap. This instruction (0xf1) is undocumented and
generates an int 1 exception. Unlike single step through TF
flag, it doesn't set the single step origin of the exception
in dr6.
icebp then used to be reported in userspace using trap signals
but this have been incidentally broken with the new breakpoint
code. Reenable this. Since this is the only debug event that
doesn't set anything in dr6, this is all we have to check.
This fixes a regression in Wine where World Of Warcraft got broken
as it uses this for software protection checks purposes. And
probably other apps do.
Reported-and-tested-by: Alexandre Julliard <julliard@winehq.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: 2.6.33.x 2.6.34.x <stable@kernel.org>
Fix resume_execution() and is_IF_modifier() to skip x86
instruction prefixes correctly by using x86 instruction
attribute.
Without this fix, resume_execution() can't handle instructions
which have non-REX prefixes (REX prefixes are skipped). This
will cause unexpected kernel panic by hitting bad address when a
kprobe hits on two-byte ret (e.g. "repz ret" generated for
Athlon/K8 optimization), because it just checks "repz" and can't
recognize the "ret" instruction.
These prefixes can be found easily with x86 instruction
attribute. This patch introduces skip_prefixes() and uses it in
resume_execution() and is_IF_modifier() to skip prefixes.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <4C298A6E.8070609@hitachi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Define WQ_MAX_ACTIVE and create keventd with max_active set to half of
it which means that keventd now can process upto WQ_MAX_ACTIVE / 2 - 1
works concurrently. Unless some combination can result in dependency
loop longer than max_active, deadlock won't happen and thus it's
unnecessary to check whether current_is_keventd() before trying to
schedule a work. Kill current_is_keventd().
(Lockdep annotations are broken. We need lock_map_acquire_read_norecurse())
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, Calgary: Increase max PHB number
x86: Fix rebooting on Dell Precision WorkStation T7400
x86: Fix vsyscall on gcc 4.5 with -Os
x86, pat: Proper init of memtype subtree_max_end
um, hweight: Fix UML boot crash due to x86 optimized hweight
x86, setup: Set ax register in boot vga query
percpu, x86: Avoid warnings of unused variables in per cpu
x86, irq: Rename gsi_end gsi_top, and fix off by one errors
x86: use __ASSEMBLY__ rather than __ASSEMBLER__
Newer systems (x3950M2) can have 48 PHBs per chassis and 8
chassis, so bump the limits up and provide an explanation
of the requirements for each class.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Acked-by: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: Corinna Schultz <cschultz@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
LKML-Reference: <20100624212647.GI15515@tux1.beaverton.ibm.com>
[ v2: Fixed build bug, added back PHBS_PER_CALGARY == 4 ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Instruction breakpoints need to have a specific length of 0 to
be working. Bring this support but also take care the user is not
trying to set an unsupported length, like a range breakpoint for
example.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Instruction breakpoints trigger before the instruction executes,
and returning back from the breakpoint handler brings us again
to the instruction that breakpointed. This naturally bring to
a breakpoint recursion.
To solve this, x86 has the Resume Bit trick. When the cpu flags
have the RF flag set, the next instruction won't trigger any
instruction breakpoint, and once this instruction is executed,
RF is cleared back.
This let's us jump back to the instruction that triggered the
breakpoint without recursion.
Use this when an instruction breakpoint triggers.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andres Salomon <dilinger@queued.net>
Cc: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <20100618174653.7755a39a@dev.queued.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
