Commit Graph

53422 Commits

Author SHA1 Message Date
Andi Kleen
f19cccf366 [PATCH] x86-64: Fix allnoconfig error in genapic_flat.c
Fix:

In file included from include2/asm/apic.h:5,
                 from include2/asm/smp.h:15,
                 from linux/arch/x86_64/kernel/genapic_flat.c:18:
linux/include/linux/pm.h: In function ‘call_platform_enable_wakeup’:
linux/include/linux/pm.h:331: error: ‘EIO’ undeclared (first use in this function)
linux/include/linux/pm.h:331: error: (Each undeclared identifier is reported only once
linux/include/linux/pm.h:331: error: for each function it appears in.)

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:21 +02:00
Andi Kleen
2724b6db66 [PATCH] x86-64: Shut up warnings for vfat compat ioctls on other file systems
vfat implements compat handlers for these ioctls, but when they
were executed on other file systems the kernel would still complain
about an unknown compat ioctl.  Just declare them as compatible
and let them be rejected when not needed by the normal path.

This makes wine runs a lot quieter

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:21 +02:00
Andi Kleen
fac15a8e4d [PATCH] x86-64: Share identical video.S between i386 and x86-64
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:21 +02:00
Andi Kleen
2136220d00 [PATCH] x86-64: Remove CONFIG_REORDER
The option never worked well and functionlist wasn't well maintained.
Also it made the build very slow on many binutils version.

So just remove it.

Cc: arjan@linux.intel.com
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:21 +02:00
Andi Kleen
a106009bdf [PATCH] x86-64: Print type and size correctly for unknown compat ioctls
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:21 +02:00
Andi Kleen
c812d6c198 [PATCH] i386: Remove copy_*_user BUG_ONs for (size < 0)
access_ok checks this case anyways, no need to check twice.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:21 +02:00
Andi Kleen
ec1180db2c [PATCH] i386: Little cleanups in smpboot.c
- Remove #if that is always set
- Fix warning

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:21 +02:00
Andi Kleen
3bea9c9793 [PATCH] x86-64: Don't enable NUMA for a single node in K8 NUMA scanning
This was supposed to see the full memory on a ASUS A8SX motherboard
with 4GB RAM where the northbridge reports less memory, but it didn't
help there. But it's a reasonable change so let's include it anyways.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:21 +02:00
Andi Kleen
c5bcb5635a [PATCH] x86: Use RDTSCP for synchronous get_cycles if possible
RDTSCP is already synchronous and doesn't need an explicit CPUID.
This is a little faster and more importantly avoids VMEXITs on Hypervisors.

Original patch from Joerg Roedel, but reworked by AK
Also includes miscompilation fix by Eric Biederman

Cc: "Joerg Roedel" <joerg.roedel@amd.com>

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:21 +02:00
Andi Kleen
9bccb23dc5 [PATCH] i386: Add X86_FEATURE_RDTSCP
Following x86-64
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
3aefbe0746 [PATCH] i386: Implement X86_FEATURE_SYNC_RDTSC on i386
Syncs up with x86-64.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
e859dc553c [PATCH] i386: Implement alternative_io for i386
Ported from x86-64.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
3671df8572 [PATCH] i386: Evaluate constant cpu features at runtime
Redefine cpu_has() to evaluate cpu features already checked in early
boot at compile time.  This way the compiler might eliminate some dead code.
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
c7f81c9453 [PATCH] i386: Verify important CPUID bits in real mode
Check some CPUID bits that are needed for compiler generated early in boot.
When the system is still in real mode before changing the VESA BIOS mode
it is possible to still display an visible error message on the screen.

Similar to x86-64.

Includes cleanups from Eric Biederman

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
484ad39365 [PATCH] i386: Drop -traditional in arch/i386/boot
Needed for followon patch

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
fa0a009109 [PATCH] x86-64: Drop -traditional for arch/x86_64/boot
Follows i386 and useful cleanup.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
72b1b1d013 [PATCH] x86-64: Use symbolic CPU features in early CPUID check
Dead to magic numbers!

Generated code is the same.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
David P. Reed
4637a74cf2 [PATCH] x86-64: Avoid overflows during apic timer calibration
- Use 64bit TSC calculations to avoid handling overflow
- Use 32bit unsigned arithmetic for the APIC timer. This
way overflows are handled correctly.
- Fix exit check of loop to account for apic timer counting down

Signed-off-by: dpreed@reed.com
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
9d016dd43b [PATCH] x86-64: Shut up 32bit emulation for SIOCGIFCOUNT
The kernel doesn't implement it, but some programs like java use it
anyways. Shut the code up.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
421f028100 [PATCH] x86-64: Define IGNORE_IOCTL() macro for compat_ioctls
Define a new IGNORE_IOCTL() to let a compat ioctl not be warned about even when
it is not implemented.

This is the same as COMPATIBLE_IOCTL internally, but better self documentng.

Valid reasons to use this:
- It is implemented with ->compat_ioctl on some device, but programs
  call it on others too.
- The ioctl is not implemented in the native kernel, but programs
  call it commonly anyways.
Most other reasons are not valid.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
05cb007dac [PATCH] x86-64: Use the 32bit wd_ops for 64bit too.
This mainly removes a lot of code, replacing it with calls into the new 32bit
perfctr-watchdog.c

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Andi Kleen
09198e6850 [PATCH] i386: Clean up NMI watchdog code
- Introduce a wd_ops structure
- Convert the various nmi watchdogs over to it
- This allows to split the perfctr reservation from the watchdog
setup cleanly.
- Do perfctr reservation globally as it should have always been
- Remove dead code referenced only by unused EXPORT_SYMBOLs

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Suresh Siddha
e3f1caeef9 [PATCH] x86-64: set node_possible_map at runtime - try 2
Set the node_possible_map at runtime on x86_64.  On a non NUMA system,
num_possible_nodes() will now say '1'.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
2007-05-02 19:27:20 +02:00
Tim Hockin
8a336b0a4b [PATCH] x86-64: Dynamically adjust machine check interval
Background:
 We've found that MCEs (specifically DRAM SBEs) tend to come in bunches,
 especially when we are trying really hard to stress the system out.  The
 current MCE poller uses a static interval which does not care whether it
 has or has not found MCEs recently.

Description:
 This patch makes the MCE poller adjust the polling interval dynamically.
 If we find an MCE, poll 2x faster (down to 10 ms).  When we stop finding
 MCEs, poll 2x slower (up to check_interval seconds).  The check_interval
 tunable becomes the max polling interval.  The "Machine check events
 logged" printk() is rate limited to the check_interval, which should be
 identical behavior to the old functionality.

Result:
 If you start to take a lot of correctable errors (not exceptions), you
 log them faster and more accurately (less chance of overflowing the MCA
 registers).  If you don't take a lot of errors, you will see no change.

Alternatives:
 I considered simply reducing the polling interval to 10 ms immediately
 and keeping it there as long as we continue to find errors.  This felt a
 bit heavy handed, but does perform significantly better for the default
 check_interval of 5 minutes (we're using a few seconds when testing for
 DRAM errors).  I could be convinced to go with this, if anyone felt it
 was not too aggressive.

Testing:
 I used an error-injecting DIMM to create lots of correctable DRAM errors
 and verified that the polling interval accelerates.  The printk() only
 happens once per check_interval seconds.

Patch:
 This patch is against 2.6.21-rc7.

Signed-Off-By: Tim Hockin <thockin@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:19 +02:00
Gerd Hoffmann
f82af20e1a [PATCH] x86-64: ignore vgacon if hardware not present
Avoid trying to set up vgacon if there's no vga hardware present.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Alan <alan@lxorguk.ukuu.org.uk>
Acked-by: Ingo Molnar <mingo@elte.hu>
2007-05-02 19:27:19 +02:00
Andi Kleen
889f21ce27 [PATCH] i386: fix wrong comment for syscall stack layout
`ret_from_sys_call' label no longer exist and `syscall_exit' label was
introduced instead.

Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:19 +02:00
Andrew Morton
425001fea7 [PATCH] x86-64: unexport cpu_llc_id
WARNING: arch/x86_64/kernel/built-in.o - Section mismatch: reference to .init.data:cpu_llc_id from __ksymtab between '__ksymtab_cpu_llc_id' (at offset 0x4a0) and '__ksymtab_smp_num_siblings'

It is strange to export a __cpuinitdata symbols to modules, and no module
appears to use it anyway.

Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:19 +02:00
Eric W. Biederman
f26d6a2bbc [PATCH] i386: convert to the kthread API
This patch just trivial converts from calling kernel_thread and daemonize
to just calling kthread_run.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:19 +02:00
Zachary Amsden
9e5e3162b2 [PATCH] i386: pte simplify ops
Add comment and condense code to make use of native_local_ptep_get_and_clear
function.  Also, it turns out the 2-level and 3-level paging definitions were
identical, so move the common definition into pgtable.h

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:19 +02:00
Zachary Amsden
142dd97591 [PATCH] i386: pte xchg optimization
In situations where page table updates need only be made locally, and there is
no cross-processor A/D bit races involved, we need not use the heavyweight
xchg instruction to atomically fetch and clear page table entries.  Instead,
we can just read and clear them directly.

This introduces a neat optimization for non-SMP kernels; drop the atomic xchg
operations from page table updates.

Thanks to Michel Lespinasse for noting this potential optimization.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:19 +02:00
Zachary Amsden
c2c1accd4b [PATCH] i386: pte clear optimization
When exiting from an address space, no special hypervisor notification of page
table updates needs to occur; direct page table hypervisors, such as Xen,
switch to another address space first (init_mm) and unprotects the page tables
to avoid the cost of trapping to the hypervisor for each pte_clear.  Shadow
mode hypervisors, such as VMI and lhype don't need to do the extra work of
calling through paravirt-ops, and can just directly clear the page table
entries without notifiying the hypervisor, since all the page tables are about
to be freed.

So introduce native_pte_clear functions which bypass any paravirt-ops
notification.  This results in a significant performance win for VMI and
removes some indirect calls from zap_pte_range.

Note the 3-level paging already had a native_pte_clear function, thus
demanding argument conformance and extra args for the 2-level definition.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:19 +02:00
Daniel Walker
df3624aa29 [PATCH] i386: remove xtime_lock'ing around cpufreq notifier
The locking of the xtime_lock around the cpu notifier is unessesary now.
At one time the tsc was used after a frequency change for timekeeping, but
the re-write of timekeeping no longer uses the TSC unless the frequency is
constant.

The variables that are changed in this section of code had also once been
used for timekeeping, but not any longer ..

Signed-off-by: Daniel Walker <dwalker@mvista.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:18 +02:00
Siddha, Suresh B
62918a0361 [PATCH] x86-64: skip cache_free_alien() on non NUMA
Set use_alien_caches to 0 on non NUMA platforms.  And avoid calling the
cache_free_alien() when use_alien_caches is not set.  This will avoid the
cache miss that happens while dereferencing slabp to get nodeid.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:18 +02:00
Andi Kleen
57a4f91ae5 [PATCH] x86-64: Auto compute __NR_syscall_max at compile time
No need to maintain it anymore

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:18 +02:00
Joachim Deguara
2f3c30e6a8 [PATCH] i386: check capability
Currently the i386 architecture checks the family for mce capability and this
removes that and uses the CPUID information.  Tested on a K8 revE and a
family10h processor.

This eliminates checking of a set AMD procesor family if mce is
allowed and relies on the information being in CPUID.

Signed-off-by: Joachim Deguara <joachim.deguara@amd.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:18 +02:00
Keshavamurthy, Anil S
1bdae4583e [PATCH] i386: clean up flush_tlb_others fn
Cleanup flush_tlb_others(), no functional change.

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:18 +02:00
Hisashi Hifumi
62dbc210e2 [PATCH] i386: replace spin_lock_irqsave with spin_lock
IRQ is already disabled through local_irq_disable().  So
spin_lock_irqsave() can be replaced with spin_lock().

Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:18 +02:00
Keshavamurthy, Anil S
e8a72ffa3a [PATCH] i386: avoid checking for cpu gone when CONFIG_HOTPLUG_CPU not defined
Avoid checking for cpu gone in mm hot path when CONFIG_HOTPLUG_CPU is not
defined.

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:18 +02:00
Eric Dumazet
141a892f57 [PATCH] x86-64: move __vgetcpu_mode & __jiffies to the vsyscall_2 zone
We apparently hit the 1024 limit of vsyscall_0 zone when some debugging
options are set, or if __vsyscall_gtod_data is 64 bytes larger.

In order to save 128 bytes from the vsyscall_0 zone, we move __vgetcpu_mode
& __jiffies to vsyscall_2 zone where they really belong, since they are
used only from vgetcpu() (which is in this vsyscall_2 area).

After patch is applied, new layout is :

ffffffffff600000 T vgettimeofday
ffffffffff60004e t vsysc2
ffffffffff600140 t vread_hpet
ffffffffff600150 t vread_tsc
ffffffffff600180 D __vsyscall_gtod_data
ffffffffff600400 T vtime
ffffffffff600413 t vsysc1
ffffffffff600800 T vgetcpu
ffffffffff600870 D __vgetcpu_mode
ffffffffff600880 D __jiffies
ffffffffff600c00 T venosys_1

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:18 +02:00
Jeremy Fitzhardinge
0260c196c9 [PATCH] i386: PARAVIRT: fix startup_ipi_hook config dependency
startup_ipi_hook depends on CONFIG_X86_LOCAL_APIC, so move it to the
right part of the paravirt_ops initialization.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:18 +02:00
Randy Dunlap
25c16b992c [PATCH] i386: fix mtrr sections
Fix section mismatch warnings in mtrr code.
Fix line length on one source line.

WARNING: arch/x86_64/kernel/built-in.o - Section mismatch: reference to .init.data: from .text.get_mtrr_state after 'get_mtrr_state' (at offset 0x103)
WARNING: arch/x86_64/kernel/built-in.o - Section mismatch: reference to .init.text: from .text.get_mtrr_state after 'get_mtrr_state' (at offset 0x180)
WARNING: arch/x86_64/kernel/built-in.o - Section mismatch: reference to .init.text: from .text.get_mtrr_state after 'get_mtrr_state' (at offset 0x199)
WARNING: arch/x86_64/kernel/built-in.o - Section mismatch: reference to .init.text: from .text.get_mtrr_state after 'get_mtrr_state' (at offset 0x1c1)

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:18 +02:00
Fernando Luis [** ISO-8859-1 charset **] VzquezCao
70ae77f497 [PATCH] x86-64: Use safe_apic_wait_icr_idle in __send_IPI_dest_field - x86_64
Use safe_apic_wait_icr_idle to check ICR idle bit if the vector is
NMI_VECTOR to avoid potential hangups in the event of crash when kdump
tries to stop the other CPUs.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:18 +02:00
Fernando Luis [** ISO-8859-1 charset **] VzquezCao
f5efb41e79 [PATCH] i386: Use safe_apic_wait_icr_idle in safe_apic_wait_icr_idle - i386
Use safe_apic_wait_icr_idle to check ICR idle bit if the vector is
NMI_VECTOR to avoid potential hangups in the event of crash when kdump
tries to stop the other CPUs.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:18 +02:00
Fernando Luis [** ISO-8859-1 charset **] VzquezCao
9062d888aa [PATCH] x86-64: __send_IPI_dest_field - x86_64
Implement __send_IPI_dest_field which can be used to send IPIs when the
"destination shorthand" field of the ICR is set to 00 (destination
field). Use it whenever possible.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:18 +02:00
Fernando Luis [** ISO-8859-1 charset **] VzquezCao
45ae5e968e [PATCH] i386: __send_IPI_dest_field - i386
Implement __send_IPI_dest_field which can be used to send IPIs when the
"destination shorthand" field of the ICR is set to 00 (destination
field). Use it whenever possible.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:18 +02:00
Fernando Luis VazquezCao
3144c332fa [PATCH] x86-64: use safe_apic_wait_icr_idle in smpboot.c - x86_64
inquire_remote_apic is used for APIC debugging, so use
safe_apic_wait_icr_idle  instead of apic_wait_icr_idle to avoid possible
lockups when APIC delivery fails.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:17 +02:00
Fernando Luis VazquezCao
4312fa8157 [PATCH] i386: use safe_apic_wait_icr_idle in smpboot.c
__inquire_remote_apic is used for APIC debugging, so use
safe_apic_wait_icr_idle  instead of apic_wait_icr_idle to avoid possible
lockups when APIC delivery fails.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:17 +02:00
Fernando Luis VazquezCao
ea8c733b98 [PATCH] x86-64: use safe_apic_wait_icr_idle in smpboot.c - x86_64
The functionality provided by the new safe_apic_wait_icr_idle is being
open-coded all over "kernel/smpboot.c". Use safe_apic_wait_icr_idle
instead to consolidate code and ease maintenance.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:17 +02:00
Fernando Luis VazquezCao
ae08e43eec [PATCH] i386: use safe_apic_wait_icr_idle - i386
The functionality provided by the new safe_apic_wait_icr_idle is being
open-coded all over "kernel/smpboot.c". Use safe_apic_wait_icr_idle
instead to consolidate code and ease maintenance.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:17 +02:00
Fernando Luis VazquezCao
8339e9fba3 [PATCH] x86-64: safe_apic_wait_icr_idle - x86_64
apic_wait_icr_idle looks like this:

static __inline__ void apic_wait_icr_idle(void)
{
  while (apic_read(APIC_ICR) & APIC_ICR_BUSY)
    cpu_relax();
}

The busy loop in this function would not be problematic if the
corresponding status bit in the ICR were always updated, but that does
not seem to be the case under certain crash scenarios. Kdump uses an IPI
to stop the other CPUs in the event of a crash, but when any of the
other CPUs are locked-up inside the NMI handler the CPU that sends the
IPI will end up looping forever in the ICR check, effectively
hard-locking the whole system.

Quoting from Intel's "MultiProcessor Specification" (Version 1.4), B-3:

"A local APIC unit indicates successful dispatch of an IPI by
resetting the Delivery Status bit in the Interrupt Command
Register (ICR). The operating system polls the delivery status
bit after sending an INIT or STARTUP IPI until the command has
been dispatched.

A period of 20 microseconds should be sufficient for IPI dispatch
to complete under normal operating conditions. If the IPI is not
successfully dispatched, the operating system can abort the
command. Alternatively, the operating system can retry the IPI by
writing the lower 32-bit double word of the ICR. This “time-out”
mechanism can be implemented through an external interrupt, if
interrupts are enabled on the processor, or through execution of
an instruction or time-stamp counter spin loop."

Intel's documentation suggests the implementation of a time-out
mechanism, which, by the way, is already being open-coded in some parts
of the kernel that tinker with ICR.

Create a apic_wait_icr_idle replacement that implements the time-out
mechanism and that can be used to solve the aforementioned problem.

AK: moved both functions out of line
AK: Added improved loop from Keith Owens

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:17 +02:00