Before, the code to do RDTSC looked like:
rdtsc
shl $0x20, %rdx
mov %eax, %eax
or %rdx, %rax
The "mov %eax, %eax" is required to clear the high 32 bits of RAX.
By declaring low and high as 64-bit variables, the code is
simplified to:
rdtsc
shl $0x20,%rdx
or %rdx,%rax
Yes, it's a 2-byte instruction that's not on a critical path,
but there are principles to be upheld.
Every user of EAX_EDX_RET has been checked. I tried to check
users of EAX_EDX_ARGS, but there weren't any, so I deleted it to
be safe.
( There's no benefit to making "high" 64 bits, but it was the
simplest way to proceed. )
Signed-off-by: George Spelvin <linux@horizon.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: jacob.jun.pan@linux.intel.com
Link: http://lkml.kernel.org/r/20150618075906.4615.qmail@ns.horizon.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If it takes longer than 12us to read the PIT counter lsb/msb,
then the error margin will never fall below 500ppm within 50ms,
and Fast TSC calibration will always fail.
This patch detects when that will happen and fails fast. Note
the failure message is not printed in that case because:
1. it will always happen on that class of hardware
2. the absence of the message is more informative than its
presence
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/556EB717.9070607@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull late x86 platform driver updates from Darren Hart:
"The following came in a bit later and I wanted them to bake in next a
few more days before submitting, thus the second pull.
A new intel_pmc_ipc driver, a symmetrical allocation and free fix in
dell-laptop, a couple minor fixes, and some updated documentation in
the dell-laptop comments.
intel_pmc_ipc:
- Add Intel Apollo Lake PMC IPC driver
tc1100-wmi:
- Delete an unnecessary check before the function call "kfree"
dell-laptop:
- Fix allocating & freeing SMI buffer page
- Show info about WiGig and UWB in debugfs
- Update information about wireless control"
* tag 'platform-drivers-x86-v4.2-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
intel_pmc_ipc: Add Intel Apollo Lake PMC IPC driver
tc1100-wmi: Delete an unnecessary check before the function call "kfree"
dell-laptop: Fix allocating & freeing SMI buffer page
dell-laptop: Show info about WiGig and UWB in debugfs
dell-laptop: Update information about wireless control
Pull kvm fixes from Paolo Bonzini:
"Except for the preempt notifiers fix, these are all small bugfixes
that could have been waited for -rc2. Sending them now since I was
taking care of Peter's patch anyway"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
kvm: add hyper-v crash msrs values
KVM: x86: remove data variable from kvm_get_msr_common
KVM: s390: virtio-ccw: don't overwrite config space values
KVM: x86: keep track of LVT0 changes under APICv
KVM: x86: properly restore LVT0
KVM: x86: make vapics_in_nmi_mode atomic
sched, preempt_notifier: separate notifier registration from static_key inc/dec
Pull x86 fixes from Ingo Molnar:
"Two FPU rewrite related fixes. This addresses all known x86
regressions at this stage. Also some other misc fixes"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fpu: Fix boot crash in the early FPU code
x86/asm/entry/64: Update path names
x86/fpu: Fix FPU related boot regression when CPUID masking BIOS feature is enabled
x86/boot/setup: Clean up the e820_reserve_setup_data() code
x86/kaslr: Fix typo in the KASLR_FLAG documentation
Pull perf updates from Ingo Molnar:
"This tree includes an x86 PMU scheduling fix, but most changes are
late breaking tooling fixes and updates:
User visible fixes:
- Create config.detected into OUTPUT directory, fixing parallel
builds sharing the same source directory (Aaro Kiskinen)
- Allow to specify custom linker command, fixing some MIPS64 builds.
(Aaro Kiskinen)
- Fix to show proper convergence stats in 'perf bench numa' (Srikar
Dronamraju)
User visible changes:
- Validate syscall list passed via -e argument to 'perf trace'.
(Arnaldo Carvalho de Melo)
- Introduce 'perf stat --per-thread' (Jiri Olsa)
- Check access permission for --kallsyms and --vmlinux (Li Zhang)
- Move toggling event logic from 'perf top' and into hists browser,
allowing freeze/unfreeze with event lists with more than one entry
(Namhyung Kim)
- Add missing newlines when dumping PERF_RECORD_FINISHED_ROUND and
showing the Aggregated stats in 'perf report -D' (Adrian Hunter)
Infrastructure fixes:
- Add missing break for PERF_RECORD_ITRACE_START, which caused those
events samples to be parsed as well as PERF_RECORD_LOST_SAMPLES.
ITRACE_START only appears when Intel PT or BTS are present, so..
(Jiri Olsa)
- Call the perf_session destructor when bailing out in the inject,
kmem, report, kvm and mem tools (Taeung Song)
Infrastructure changes:
- Move stuff out of 'perf stat' and into the lib for further use
(Jiri Olsa)
- Reference count the cpu_map and thread_map classes (Jiri Olsa)
- Set evsel->{cpus,threads} from the evlist, if not set, allowing the
generalization of some 'perf stat' functions that previously were
accessing private static evlist variable (Jiri Olsa)
- Delete an unnecessary check before the calling free_event_desc()
(Markus Elfring)
- Allow auxtrace data alignment (Adrian Hunter)
- Allow events with dot (Andi Kleen)
- Fix failure to 'perf probe' events on arm (He Kuang)
- Add testing for Makefile.perf (Jiri Olsa)
- Add test for make install with prefix (Jiri Olsa)
- Fix single target build dependency check (Jiri Olsa)
- Access thread_map entries via accessors, prep patch to hold more
info per entry, for ongoing 'perf stat --per-thread' work (Jiri
Olsa)
- Use __weak definition from compiler.h (Sukadev Bhattiprolu)
- Split perf_pmu__new_alias() (Sukadev Bhattiprolu)"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
perf tools: Allow to specify custom linker command
perf tools: Create config.detected into OUTPUT directory
perf mem: Fill in the missing session freeing after an error occurs
perf kvm: Fill in the missing session freeing after an error occurs
perf report: Fill in the missing session freeing after an error occurs
perf kmem: Fill in the missing session freeing after an error occurs
perf inject: Fill in the missing session freeing after an error occurs
perf tools: Add missing break for PERF_RECORD_ITRACE_START
perf/x86: Fix 'active_events' imbalance
perf symbols: Check access permission when reading symbol files
perf stat: Introduce --per-thread option
perf stat: Introduce print_counters function
perf stat: Using init_stats instead of memset
perf stat: Rename print_interval to process_interval
perf stat: Remove perf_evsel__read_cb function
perf stat: Move perf_stat initialization counter process code
perf stat: Move zero_per_pkg into counter process code
perf stat: Separate counters reading and processing
perf stat: Introduce read_counters function
perf stat: Introduce perf_evsel__read function
...
Jan Kara and Thomas Gleixner reported boot crashes in the FPU
code:
general protection fault: 0000 [#1] SMP
RIP: 0010:[<ffffffff81048a6c>] [<ffffffff81048a6c>] mxcsr_feature_mask_init+0x1c/0x40
2b:* 0f ae 85 00 fe ff ff fxsave -0x200(%rbp)
and bisected it down to the following FPU commit:
91a8c2a5b4 ("x86/fpu: Clean up and fix MXCSR handling")
The reason is that the on-stack FPU registers state variable,
used by the FXSAVE instruction, did not have the required
minimum alignment of 16 bytes, causing the general protection
fault.
This is most likely a GCC bug in older GCC versions, but the
offending commit also added a bogus extra 32-byte alignment
(which GCC ignored too).
So fix this bug by making the variable static again, but also
mark it __initdata this time, because fpu__init_system_mxcsr()
is now an __init function.
Reported-and-bisected-by: Jan Kara <jack@suse.cz>
Reported-bisected-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150704075819.GA9201@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 609e36d372 ("KVM: x86: pass host_initiated to functions that
read MSRs") modified kvm_get_msr_common function to use msr_info->data
instead of data but missed one occurrence. Replace it and remove the
unused local variable.
Fixes: 609e36d372 ("KVM: x86: pass host_initiated to functions that
read MSRs")
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Memory-mapped LVT0 register already contains the new value when APICv
traps so we can't directly detect a change.
Memorize a bit we are interested in to enable legacy NMI watchdog.
Suggested-by: Yoshida Nobuo <yoshida.nb@ncos.nec.co.jp>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Writes were a bit racy, but hard to turn into a bug at the same time.
(Particularly because modern Linux doesn't use this feature anymore.)
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
[Actually the next patch makes it much, much easier to trigger the race
so I'm including this one for stable@ as well. - Paolo]
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull init.h/module.h fragility fixes from Paul Gortmaker:
"Fixup various init.h misuses that are fragile wrt code moving to
module.h
What started as a removal of no longer required include <linux/init.h>
due to the earlier __cpuinit and __devinit removal led to the
observation that some module specfic support was living in init.h
itself, thus preventing the full removal from introducing compile
regressions.
This series includes a few final fixups needed prior to the relocation
of the modular init code from <init.h> to <module.h>. These are
things that weren't easily categorized into any of the other previous
series categories already requested for pull.
That said, each fixup branch (including this one) is independent and
there are no ordering constraints. Only the final code relocation
(which is NOT in this pull) requires that all my cleanup branches be
merged first"
* tag 'module-misc-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
tile: add init.h to usb.c to avoid compile failure
arm: fix implicit #include <linux/init.h> in entry asm.
x86: replace __init_or_module with __init in non-modular vsmp_64.c
Pull module_init replacement part two from Paul Gortmaker:
"Replace module_init with appropriate alternate initcall in non
modules.
This series converts non-modular code that is using the module_init()
call to hook itself into the system to instead use one of our
alternate priority initcalls.
Unlike the previous series that used device_initcall and hence was a
runtime no-op, these commits change to one of the alternate initcalls,
because (a) we have them and (b) it seems like the right thing to do.
For example, it would seem logical to use arch_initcall for arch
specific setup code and fs_initcall for filesystem setup code.
This does mean however, that changes in the init ordering will be
taking place, and so there is a small risk that some kind of implicit
init ordering issue may lie uncovered. But I think it is still better
to give these ones sensible priorities than to just assign them all to
device_initcall in order to exactly preserve the old ordering.
Thad said, we have already made similar changes in core kernel code in
commit c96d6660dc ("kernel: audit/fix non-modular users of
module_init in core code") without any regressions reported, so this
type of change isn't without precedent. It has also got the same
local testing and linux-next coverage as all the other pull requests
that I'm sending for this merge window have got.
Once again, there is an unused module_exit function removal that shows
up as an outlier upon casual inspection of the diffstat"
* tag 'module_init-alternate_initcall-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
x86: perf_event_intel_pt.c: use arch_initcall to hook in enabling
x86: perf_event_intel_bts.c: use arch_initcall to hook in enabling
mm/page_owner.c: use late_initcall to hook in enabling
lib/list_sort: use late_initcall to hook in self tests
arm: use subsys_initcall in non-modular pl320 IPC code
powerpc: don't use module_init for non-modular core hugetlb code
powerpc: use subsys_initcall for Freescale Local Bus
x86: don't use module_init for non-modular core bootflag code
netfilter: don't use module_init/exit in core IPV4 code
fs/notify: don't use module_init for non-modular inotify_user code
mm: replace module_init usages with subsys_initcall in nommu.c
Pull module_init replacement part one from Paul Gortmaker:
"Replace module_init with equivalent device_initcall in non modules.
This series of commits converts non-modular code that is using the
module_init() call to hook itself into the system to instead use
device_initcall().
The conversion is a runtime no-op, since module_init actually becomes
__initcall in the non-modular case, and that in turn gets mapped onto
device_initcall. A couple files show a larger negative diffstat,
representing ones that had a module_exit function that we remove here
vs previously relying on the linker to dispose of it.
We make this conversion now, so that we can relocate module_init from
init.h into module.h in the future.
The files changed here are just limited to those that would otherwise
have to add module.h to obviously non-modular code, in order to avoid
a compile fail, as testing has shown"
* tag 'module_init-device_initcall-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
MIPS: don't use module_init in non-modular cobalt/mtd.c file
drivers/leds: don't use module_init in non-modular leds-cobalt-raq.c
cris: don't use module_init for non-modular core eeprom.c code
tty/metag_da: Avoid module_init/module_exit in non-modular code
drivers/clk: don't use module_init in clk-nomadik.c which is non-modular
xtensa: don't use module_init for non-modular core network.c code
sh: don't use module_init in non-modular psw.c code
mn10300: don't use module_init in non-modular flash.c code
parisc64: don't use module_init for non-modular core perf code
parisc: don't use module_init for non-modular core pdc_cons code
cris: don't use module_init for non-modular core intmem.c code
ia64: don't use module_init in non-modular sim/simscsi.c code
ia64: don't use module_init for non-modular core kernel/mca.c code
arm: don't use module_init in non-modular mach-vexpress/spc.c code
powerpc: don't use module_init in non-modular 83xx suspend code
powerpc: use device_initcall for registering rtc devices
x86: don't use module_init in non-modular devicetree.c code
x86: don't use module_init in non-modular intel_mid_vrtc.c
Merge third patchbomb from Andrew Morton:
- the rest of MM
- scripts/gdb updates
- ipc/ updates
- lib/ updates
- MAINTAINERS updates
- various other misc things
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (67 commits)
genalloc: rename of_get_named_gen_pool() to of_gen_pool_get()
genalloc: rename dev_get_gen_pool() to gen_pool_get()
x86: opt into HAVE_COPY_THREAD_TLS, for both 32-bit and 64-bit
MAINTAINERS: add zpool
MAINTAINERS: BCACHE: Kent Overstreet has changed email address
MAINTAINERS: move Jens Osterkamp to CREDITS
MAINTAINERS: remove unused nbd.h pattern
MAINTAINERS: update brcm gpio filename pattern
MAINTAINERS: update brcm dts pattern
MAINTAINERS: update sound soc intel patterns
MAINTAINERS: remove website for paride
MAINTAINERS: update Emulex ocrdma email addresses
bcache: use kvfree() in various places
libcxgbi: use kvfree() in cxgbi_free_big_mem()
target: use kvfree() in session alloc and free
IB/ehca: use kvfree() in ipz_queue_{cd}tor()
drm/nouveau/gem: use kvfree() in u_free()
drm: use kvfree() in drm_free_large()
cxgb4: use kvfree() in t4_free_mem()
cxgb3: use kvfree() in cxgb_free_mem()
...
Pull crypto fixes from Herbert Xu:
"This fixes the aesni setkey error and removes a couple of unnecessary
NULL checks in the Intel qat driver"
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
crypto: aesni - fix failing setkey for rfc4106-gcm-aesni
crypto: qat - Deletion of unnecessary checks before two function calls
Pull xen updates from David Vrabel:
"Xen features and cleanups for 4.2-rc0:
- add "make xenconfig" to assist in generating configs for Xen guests
- preparatory cleanups necessary for supporting 64 KiB pages in ARM
guests
- automatically use hvc0 as the default console in ARM guests"
* tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
block/xen-blkback: s/nr_pages/nr_segs/
block/xen-blkfront: Remove invalid comment
block/xen-blkfront: Remove unused macro MAXIMUM_OUTSTANDING_BLOCK_REQS
arm/xen: Drop duplicate define mfn_to_virt
xen/grant-table: Remove unused macro SPP
xen/xenbus: client: Fix call of virt_to_mfn in xenbus_grant_ring
xen: Include xen/page.h rather than asm/xen/page.h
kconfig: add xenconfig defconfig helper
kconfig: clarify kvmconfig is for kvm
xen/pcifront: Remove usage of struct timeval
xen/tmem: use BUILD_BUG_ON() in favor of BUG_ON()
hvc_xen: avoid uninitialized variable warning
xenbus: avoid uninitialized variable warning
xen/arm: allow console=hvc0 to be omitted for guests
arm,arm64/xen: move Xen initialization earlier
arm/xen: Correctly check if the event channel interrupt is present
