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Similar to how relative extables are implemented, it is possible to emit
the kallsyms table in such a way that it contains offsets relative to
some anchor point in the kernel image rather than absolute addresses.
On 64-bit architectures, it cuts the size of the kallsyms address table
in half, since offsets between kernel symbols can typically be expressed
in 32 bits. This saves several hundreds of kilobytes of permanent
.rodata on average. In addition, the kallsyms address table is no
longer subject to dynamic relocation when CONFIG_RELOCATABLE is in
effect, so the relocation work done after decompression now doesn't have
to do relocation updates for all these values. This saves up to 24
bytes (i.e., the size of a ELF64 RELA relocation table entry) per value,
which easily adds up to a couple of megabytes of uncompressed __init
data on ppc64 or arm64. Even if these relocation entries typically
compress well, the combined size reduction of 2.8 MB uncompressed for a
ppc64_defconfig build (of which 2.4 MB is __init data) results in a ~500
KB space saving in the compressed image.
Since it is useful for some architectures (like x86) to retain the
ability to emit absolute values as well, this patch also adds support
for capturing both absolute and relative values when
KALLSYMS_ABSOLUTE_PERCPU is in effect, by emitting absolute per-cpu
addresses as positive 32-bit values, and addresses relative to the
lowest encountered relative symbol as negative values, which are
subtracted from the runtime address of this base symbol to produce the
actual address.
Support for the above is enabled by default for all architectures except
IA-64 and Tile-GX, whose symbols are too far apart to capture in this
manner.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By default, page poisoning uses a poison value (0xaa) on free. If this
is changed to 0, the page is not only sanitized but zeroing on alloc
with __GFP_ZERO can be skipped as well. The tradeoff is that detecting
corruption from the poisoning is harder to detect. This feature also
cannot be used with hibernation since pages are not guaranteed to be
zeroed after hibernation.
Credit to Grsecurity/PaX team for inspiring this work
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jianyu Zhan <nasa4836@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 4b94ffdc4163 ("x86, mm: introduce vmem_altmap to augment
vmemmap_populate()"), introduced the to_vmem_altmap() function.
The comments in this function contain two typos (one misspelling of the
Kconfig option CONFIG_SPARSEMEM_VMEMMAP, and one missing letter 'n'),
let's fix them up.
Signed-off-by: Andreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
$ make tags
GEN tags
ctags: Warning: drivers/acpi/processor_idle.c:64: null expansion of name pattern "\1"
ctags: Warning: drivers/xen/events/events_2l.c:41: null expansion of name pattern "\1"
ctags: Warning: kernel/locking/lockdep.c:151: null expansion of name pattern "\1"
ctags: Warning: kernel/rcu/rcutorture.c:133: null expansion of name pattern "\1"
ctags: Warning: kernel/rcu/rcutorture.c:135: null expansion of name pattern "\1"
ctags: Warning: kernel/workqueue.c:323: null expansion of name pattern "\1"
ctags: Warning: net/ipv4/syncookies.c:53: null expansion of name pattern "\1"
ctags: Warning: net/ipv6/syncookies.c:44: null expansion of name pattern "\1"
ctags: Warning: net/rds/page.c:45: null expansion of name pattern "\1"
Which are all the result of the DEFINE_PER_CPU pattern:
scripts/tags.sh:200: '/\<DEFINE_PER_CPU([^,]*, *\([[:alnum:]_]*\)/\1/v/'
scripts/tags.sh:201: '/\<DEFINE_PER_CPU_SHARED_ALIGNED([^,]*, *\([[:alnum:]_]*\)/\1/v/'
The below cures them. All except the workqueue one are within reasonable
distance of the 80 char limit. TJ do you have any preference on how to
fix the wq one, or shall we just not care its too long?
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull cpu hotplug updates from Thomas Gleixner:
"This is the first part of the ongoing cpu hotplug rework:
- Initial implementation of the state machine
- Runs all online and prepare down callbacks on the plugged cpu and
not on some random processor
- Replaces busy loop waiting with completions
- Adds tracepoints so the states can be followed"
More detailed commentary on this work from an earlier email:
"What's wrong with the current cpu hotplug infrastructure?
- Asymmetry
The hotplug notifier mechanism is asymmetric versus the bringup and
teardown. This is mostly caused by the notifier mechanism.
- Largely undocumented dependencies
While some notifiers use explicitely defined notifier priorities,
we have quite some notifiers which use numerical priorities to
express dependencies without any documentation why.
- Control processor driven
Most of the bringup/teardown of a cpu is driven by a control
processor. While it is understandable, that preperatory steps,
like idle thread creation, memory allocation for and initialization
of essential facilities needs to be done before a cpu can boot,
there is no reason why everything else must run on a control
processor. Before this patch series, bringup looks like this:
Control CPU Booting CPU
do preparatory steps
kick cpu into life
do low level init
sync with booting cpu sync with control cpu
bring the rest up
- All or nothing approach
There is no way to do partial bringups. That's something which is
really desired because we waste e.g. at boot substantial amount of
time just busy waiting that the cpu comes to life. That's stupid
as we could very well do preparatory steps and the initial IPI for
other cpus and then go back and do the necessary low level
synchronization with the freshly booted cpu.
- Minimal debuggability
Due to the notifier based design, it's impossible to switch between
two stages of the bringup/teardown back and forth in order to test
the correctness. So in many hotplug notifiers the cancel
mechanisms are either not existant or completely untested.
- Notifier [un]registering is tedious
To [un]register notifiers we need to protect against hotplug at
every callsite. There is no mechanism that bringup/teardown
callbacks are issued on the online cpus, so every caller needs to
do it itself. That also includes error rollback.
What's the new design?
The base of the new design is a symmetric state machine, where both
the control processor and the booting/dying cpu execute a well
defined set of states. Each state is symmetric in the end, except
for some well defined exceptions, and the bringup/teardown can be
stopped and reversed at almost all states.
So the bringup of a cpu will look like this in the future:
Control CPU Booting CPU
do preparatory steps
kick cpu into life
do low level init
sync with booting cpu sync with control cpu
bring itself up
The synchronization step does not require the control cpu to wait.
That mechanism can be done asynchronously via a worker or some
other mechanism.
The teardown can be made very similar, so that the dying cpu cleans
up and brings itself down. Cleanups which need to be done after
the cpu is gone, can be scheduled asynchronously as well.
There is a long way to this, as we need to refactor the notion when a
cpu is available. Today we set the cpu online right after it comes
out of the low level bringup, which is not really correct.
The proper mechanism is to set it to available, i.e. cpu local
threads, like softirqd, hotplug thread etc. can be scheduled on that
cpu, and once it finished all booting steps, it's set to online, so
general workloads can be scheduled on it. The reverse happens on
teardown. First thing to do is to forbid scheduling of general
workloads, then teardown all the per cpu resources and finally shut it
off completely.
This patch series implements the basic infrastructure for this at the
core level. This includes the following:
- Basic state machine implementation with well defined states, so
ordering and prioritization can be expressed.
- Interfaces to [un]register state callbacks
This invokes the bringup/teardown callback on all online cpus with
the proper protection in place and [un]installs the callbacks in
the state machine array.
For callbacks which have no particular ordering requirement we have
a dynamic state space, so that drivers don't have to register an
explicit hotplug state.
If a callback fails, the code automatically does a rollback to the
previous state.
- Sysfs interface to drive the state machine to a particular step.
This is only partially functional today. Full functionality and
therefor testability will be achieved once we converted all
existing hotplug notifiers over to the new scheme.
- Run all CPU_ONLINE/DOWN_PREPARE notifiers on the booting/dying
processor:
Control CPU Booting CPU
do preparatory steps
kick cpu into life
do low level init
sync with booting cpu sync with control cpu
wait for boot
bring itself up
Signal completion to control cpu
In a previous step of this work we've done a full tree mechanical
conversion of all hotplug notifiers to the new scheme. The balance
is a net removal of about 4000 lines of code.
This is not included in this series, as we decided to take a
different approach. Instead of mechanically converting everything
over, we will do a proper overhaul of the usage sites one by one so
they nicely fit into the symmetric callback scheme.
I decided to do that after I looked at the ugliness of some of the
converted sites and figured out that their hotplug mechanism is
completely buggered anyway. So there is no point to do a
mechanical conversion first as we need to go through the usage
sites one by one again in order to achieve a full symmetric and
testable behaviour"
* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
cpu/hotplug: Document states better
cpu/hotplug: Fix smpboot thread ordering
cpu/hotplug: Remove redundant state check
cpu/hotplug: Plug death reporting race
rcu: Make CPU_DYING_IDLE an explicit call
cpu/hotplug: Make wait for dead cpu completion based
cpu/hotplug: Let upcoming cpu bring itself fully up
arch/hotplug: Call into idle with a proper state
cpu/hotplug: Move online calls to hotplugged cpu
cpu/hotplug: Create hotplug threads
cpu/hotplug: Split out the state walk into functions
cpu/hotplug: Unpark smpboot threads from the state machine
cpu/hotplug: Move scheduler cpu_online notifier to hotplug core
cpu/hotplug: Implement setup/removal interface
cpu/hotplug: Make target state writeable
cpu/hotplug: Add sysfs state interface
cpu/hotplug: Hand in target state to _cpu_up/down
cpu/hotplug: Convert the hotplugged cpu work to a state machine
cpu/hotplug: Convert to a state machine for the control processor
cpu/hotplug: Add tracepoints
...
Pull irq updates from Thomas Gleixner:
"The 4.6 pile of irq updates contains:
- Support for IPI irqdomains to support proper integration of IPIs to
and from coprocessors. The first user of this new facility is
MIPS. The relevant MIPS patches come with the core to avoid merge
ordering issues and have been acked by Ralf.
- A new command line option to set the default interrupt affinity
mask at boot time.
- Support for some more new ARM and MIPS interrupt controllers:
tango, alpine-msix and bcm6345-l1
- Two small cleanups for x86/apic which we merged into irq/core to
avoid yet another branch in x86 with two tiny commits.
- The usual set of updates, cleanups in drivers/irqchip. Mostly in
the area of ARM-GIC, arada-37-xp and atmel chips. Nothing
outstanding here"
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (56 commits)
irqchip/irq-alpine-msi: Release the correct domain on error
irqchip/mxs: Fix error check of of_io_request_and_map()
irqchip/sunxi-nmi: Fix error check of of_io_request_and_map()
genirq: Export IRQ functions for module use
irqchip/gic/realview: Support more RealView DCC variants
Documentation/bindings: Document the Alpine MSIX driver
irqchip: Add the Alpine MSIX interrupt controller
irqchip/gic-v3: Always return IRQ_SET_MASK_OK_DONE in gic_set_affinity
irqchip/gic-v3-its: Mark its_init() and its children as __init
irqchip/gic-v3: Remove gic_root_node variable from the ITS code
irqchip/gic-v3: ACPI: Add redistributor support via GICC structures
irqchip/gic-v3: Add ACPI support for GICv3/4 initialization
irqchip/gic-v3: Refactor gic_of_init() for GICv3 driver
x86/apic: Deinline _flat_send_IPI_mask, save ~150 bytes
x86/apic: Deinline __default_send_IPI_*, save ~200 bytes
dt-bindings: interrupt-controller: Add SoC-specific compatible string to Marvell ODMI
irqchip/mips-gic: Add new DT property to reserve IPIs
MIPS: Delete smp-gic.c
MIPS: Make smp CMP, CPS and MT use the new generic IPI functions
MIPS: Add generic SMP IPI support
...
Pull timer updates from Thomas Gleixner:
"The timer department delivers this time:
- Support for cross clock domain timestamps in the core code plus a
first user. That allows more precise timestamping for PTP and
later for audio and other peripherals.
The ptp/e1000e patches have been acked by the relevant maintainers
and are carried in the timer tree to avoid merge ordering issues.
- Support for unregistering the current clocksource watchdog. That
lifts a limitation for switching clocksources which has been there
from day 1
- The usual pile of fixes and updates to the core and the drivers.
Nothing outstanding and exciting"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
time/timekeeping: Work around false positive GCC warning
e1000e: Adds hardware supported cross timestamp on e1000e nic
ptp: Add PTP_SYS_OFFSET_PRECISE for driver crosstimestamping
x86/tsc: Always Running Timer (ART) correlated clocksource
hrtimer: Revert CLOCK_MONOTONIC_RAW support
time: Add history to cross timestamp interface supporting slower devices
time: Add driver cross timestamp interface for higher precision time synchronization
time: Remove duplicated code in ktime_get_raw_and_real()
time: Add timekeeping snapshot code capturing system time and counter
time: Add cycles to nanoseconds translation
jiffies: Use CLOCKSOURCE_MASK instead of constant
clocksource: Introduce clocksource_freq2mult()
clockevents/drivers/exynos_mct: Implement ->set_state_oneshot_stopped()
clockevents/drivers/arm_global_timer: Implement ->set_state_oneshot_stopped()
clockevents/drivers/arm_arch_timer: Implement ->set_state_oneshot_stopped()
clocksource/drivers/arm_global_timer: Register delay timer
clocksource/drivers/lpc32xx: Support timer-based ARM delay
clocksource/drivers/lpc32xx: Support periodic mode
clocksource/drivers/lpc32xx: Don't use the prescaler counter for clockevents
clocksource/drivers/rockchip: Add err handle for rk_timer_init
...
Pull x86 asm updates from Ingo Molnar:
"This is another big update. Main changes are:
- lots of x86 system call (and other traps/exceptions) entry code
enhancements. In particular the complex parts of the 64-bit entry
code have been migrated to C code as well, and a number of dusty
corners have been refreshed. (Andy Lutomirski)
- vDSO special mapping robustification and general cleanups (Andy
Lutomirski)
- cpufeature refactoring, cleanups and speedups (Borislav Petkov)
- lots of other changes ..."
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
x86/cpufeature: Enable new AVX-512 features
x86/entry/traps: Show unhandled signal for i386 in do_trap()
x86/entry: Call enter_from_user_mode() with IRQs off
x86/entry/32: Change INT80 to be an interrupt gate
x86/entry: Improve system call entry comments
x86/entry: Remove TIF_SINGLESTEP entry work
x86/entry/32: Add and check a stack canary for the SYSENTER stack
x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup
x86/entry: Only allocate space for tss_struct::SYSENTER_stack if needed
x86/entry: Vastly simplify SYSENTER TF (single-step) handling
x86/entry/traps: Clear DR6 early in do_debug() and improve the comment
x86/entry/traps: Clear TIF_BLOCKSTEP on all debug exceptions
x86/entry/32: Restore FLAGS on SYSEXIT
x86/entry/32: Filter NT and speed up AC filtering in SYSENTER
x86/entry/compat: In SYSENTER, sink AC clearing below the existing FLAGS test
selftests/x86: In syscall_nt, test NT|TF as well
x86/asm-offsets: Remove PARAVIRT_enabled
x86/entry/32: Introduce and use X86_BUG_ESPFIX instead of paravirt_enabled
uprobes: __create_xol_area() must nullify xol_mapping.fault
x86/cpufeature: Create a new synthetic cpu capability for machine check recovery
...
Pull NOHZ updates from Ingo Molnar:
"NOHZ enhancements, by Frederic Weisbecker, which reorganizes/refactors
the NOHZ 'can the tick be stopped?' infrastructure and related code to
be data driven, and harmonizes the naming and handling of all the
various properties"
[ This makes the ugly "fetch_or()" macro that the scheduler used
internally a new generic helper, and does a bad job at it.
I'm pulling it, but I've asked Ingo and Frederic to get this
fixed up ]
* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched-clock: Migrate to use new tick dependency mask model
posix-cpu-timers: Migrate to use new tick dependency mask model
sched: Migrate sched to use new tick dependency mask model
sched: Account rr tasks
perf: Migrate perf to use new tick dependency mask model
nohz: Use enum code for tick stop failure tracing message
nohz: New tick dependency mask
nohz: Implement wide kick on top of irq work
atomic: Export fetch_or()
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle are:
- Make schedstats a runtime tunable (disabled by default) and
optimize it via static keys.
As most distributions enable CONFIG_SCHEDSTATS=y due to its
instrumentation value, this is a nice performance enhancement.
(Mel Gorman)
- Implement 'simple waitqueues' (swait): these are just pure
waitqueues without any of the more complex features of full-blown
waitqueues (callbacks, wake flags, wake keys, etc.). Simple
waitqueues have less memory overhead and are faster.
Use simple waitqueues in the RCU code (in 4 different places) and
for handling KVM vCPU wakeups.
(Peter Zijlstra, Daniel Wagner, Thomas Gleixner, Paul Gortmaker,
Marcelo Tosatti)
- sched/numa enhancements (Rik van Riel)
- NOHZ performance enhancements (Rik van Riel)
- Various sched/deadline enhancements (Steven Rostedt)
- Various fixes (Peter Zijlstra)
- ... and a number of other fixes, cleanups and smaller enhancements"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits)
sched/cputime: Fix steal_account_process_tick() to always return jiffies
sched/deadline: Remove dl_new from struct sched_dl_entity
Revert "kbuild: Add option to turn incompatible pointer check into error"
sched/deadline: Remove superfluous call to switched_to_dl()
sched/debug: Fix preempt_disable_ip recording for preempt_disable()
sched, time: Switch VIRT_CPU_ACCOUNTING_GEN to jiffy granularity
time, acct: Drop irq save & restore from __acct_update_integrals()
acct, time: Change indentation in __acct_update_integrals()
sched, time: Remove non-power-of-two divides from __acct_update_integrals()
sched/rt: Kick RT bandwidth timer immediately on start up
sched/debug: Add deadline scheduler bandwidth ratio to /proc/sched_debug
sched/debug: Move sched_domain_sysctl to debug.c
sched/debug: Move the /sys/kernel/debug/sched_features file setup into debug.c
sched/rt: Fix PI handling vs. sched_setscheduler()
sched/core: Remove duplicated sched_group_set_shares() prototype
sched/fair: Consolidate nohz CPU load update code
sched/fair: Avoid using decay_load_missed() with a negative value
sched/deadline: Always calculate end of period on sched_yield()
sched/cgroup: Fix cgroup entity load tracking tear-down
rcu: Use simple wait queues where possible in rcutree
...
Pull perf updates from Ingo Molnar:
"Main kernel side changes:
- Big reorganization of the x86 perf support code. The old code grew
organically deep inside arch/x86/kernel/cpu/perf* and its naming
became somewhat messy.
The new location is under arch/x86/events/, using the following
cleaner hierarchy of source code files:
perf/x86: Move perf_event.c .................. => x86/events/core.c
perf/x86: Move perf_event_amd.c .............. => x86/events/amd/core.c
perf/x86: Move perf_event_amd_ibs.c .......... => x86/events/amd/ibs.c
perf/x86: Move perf_event_amd_iommu.[ch] ..... => x86/events/amd/iommu.[ch]
perf/x86: Move perf_event_amd_uncore.c ....... => x86/events/amd/uncore.c
perf/x86: Move perf_event_intel_bts.c ........ => x86/events/intel/bts.c
perf/x86: Move perf_event_intel.c ............ => x86/events/intel/core.c
perf/x86: Move perf_event_intel_cqm.c ........ => x86/events/intel/cqm.c
perf/x86: Move perf_event_intel_cstate.c ..... => x86/events/intel/cstate.c
perf/x86: Move perf_event_intel_ds.c ......... => x86/events/intel/ds.c
perf/x86: Move perf_event_intel_lbr.c ........ => x86/events/intel/lbr.c
perf/x86: Move perf_event_intel_pt.[ch] ...... => x86/events/intel/pt.[ch]
perf/x86: Move perf_event_intel_rapl.c ....... => x86/events/intel/rapl.c
perf/x86: Move perf_event_intel_uncore.[ch] .. => x86/events/intel/uncore.[ch]
perf/x86: Move perf_event_intel_uncore_nhmex.c => x86/events/intel/uncore_nmhex.c
perf/x86: Move perf_event_intel_uncore_snb.c => x86/events/intel/uncore_snb.c
perf/x86: Move perf_event_intel_uncore_snbep.c => x86/events/intel/uncore_snbep.c
perf/x86: Move perf_event_knc.c .............. => x86/events/intel/knc.c
perf/x86: Move perf_event_p4.c ............... => x86/events/intel/p4.c
perf/x86: Move perf_event_p6.c ............... => x86/events/intel/p6.c
perf/x86: Move perf_event_msr.c .............. => x86/events/msr.c
(Borislav Petkov)
- Update various x86 PMU constraint and hw support details (Stephane
Eranian)
- Optimize kprobes for BPF execution (Martin KaFai Lau)
- Rewrite, refactor and fix the Intel uncore PMU driver code (Thomas
Gleixner)
- Rewrite, refactor and fix the Intel RAPL PMU code (Thomas Gleixner)
- Various fixes and smaller cleanups.
There are lots of perf tooling updates as well. A few highlights:
perf report/top:
- Hierarchy histogram mode for 'perf top' and 'perf report',
showing multiple levels, one per --sort entry: (Namhyung Kim)
On a mostly idle system:
# perf top --hierarchy -s comm,dso
Then expand some levels and use 'P' to take a snapshot:
# cat perf.hist.0
- 92.32% perf
58.20% perf
22.29% libc-2.22.so
5.97% [kernel]
4.18% libelf-0.165.so
1.69% [unknown]
- 4.71% qemu-system-x86
3.10% [kernel]
1.60% qemu-system-x86_64 (deleted)
+ 2.97% swapper
#
- Add 'L' hotkey to dynamicly set the percent threshold for
histogram entries and callchains, i.e. dynamicly do what the
--percent-limit command line option to 'top' and 'report' does.
(Namhyung Kim)
perf mem:
- Allow specifying events via -e in 'perf mem record', also listing
what events can be specified via 'perf mem record -e list' (Jiri
Olsa)
perf record:
- Add 'perf record' --all-user/--all-kernel options, so that one
can tell that all the events in the command line should be
restricted to the user or kernel levels (Jiri Olsa), i.e.:
perf record -e cycles:u,instructions:u
is equivalent to:
perf record --all-user -e cycles,instructions
- Make 'perf record' collect CPU cache info in the perf.data file header:
$ perf record usleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.017 MB perf.data (7 samples) ]
$ perf report --header-only -I | tail -10 | head -8
# CPU cache info:
# L1 Data 32K [0-1]
# L1 Instruction 32K [0-1]
# L1 Data 32K [2-3]
# L1 Instruction 32K [2-3]
# L2 Unified 256K [0-1]
# L2 Unified 256K [2-3]
# L3 Unified 4096K [0-3]
Will be used in 'perf c2c' and eventually in 'perf diff' to
allow, for instance running the same workload in multiple
machines and then when using 'diff' show the hardware difference.
(Jiri Olsa)
- Improved support for Java, using the JVMTI agent library to do
jitdumps that then will be inserted in synthesized
PERF_RECORD_MMAP2 events via 'perf inject' pointed to synthesized
ELF files stored in ~/.debug and keyed with build-ids, to allow
symbol resolution and even annotation with source line info, see
the changeset comments to see how to use it (Stephane Eranian)
perf script/trace:
- Decode data_src values (e.g. perf.data files generated by 'perf
mem record') in 'perf script': (Jiri Olsa)
# perf script
perf 693 [1] 4.088652: 1 cpu/mem-loads,ldlat=30/P: ffff88007d0b0f40 68100142 L1 hit|SNP None|TLB L1 or L2 hit|LCK No <SNIP>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- Improve support to 'data_src', 'weight' and 'addr' fields in
'perf script' (Jiri Olsa)
- Handle empty print fmts in 'perf script -s' i.e. when running
python or perl scripts (Taeung Song)
perf stat:
- 'perf stat' now shows shadow metrics (insn per cycle, etc) in
interval mode too. E.g:
# perf stat -I 1000 -e instructions,cycles sleep 1
# time counts unit events
1.000215928 519,620 instructions # 0.69 insn per cycle
1.000215928 752,003 cycles
<SNIP>
- Port 'perf kvm stat' to PowerPC (Hemant Kumar)
- Implement CSV metrics output in 'perf stat' (Andi Kleen)
perf BPF support:
- Support converting data from bpf events in 'perf data' (Wang Nan)
- Print bpf-output events in 'perf script': (Wang Nan).
# perf record -e bpf-output/no-inherit,name=evt/ -e ./test_bpf_output_3.c/map:channel.event=evt/ usleep 1000
# perf script
usleep 4882 21384.532523: evt: ffffffff810e97d1 sys_nanosleep ([kernel.kallsyms])
BPF output: 0000: 52 61 69 73 65 20 61 20 Raise a
0008: 42 50 46 20 65 76 65 6e BPF even
0010: 74 21 00 00 t!..
BPF string: "Raise a BPF event!"
#
- Add API to set values of map entries in a BPF object, be it
individual map slots or ranges (Wang Nan)
- Introduce support for the 'bpf-output' event (Wang Nan)
- Add glue to read perf events in a BPF program (Wang Nan)
- Improve support for bpf-output events in 'perf trace' (Wang Nan)
... and tons of other changes as well - see the shortlog and git log
for details!"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (342 commits)
perf stat: Add --metric-only support for -A
perf stat: Implement --metric-only mode
perf stat: Document CSV format in manpage
perf hists browser: Check sort keys before hot key actions
perf hists browser: Allow thread filtering for comm sort key
perf tools: Add sort__has_comm variable
perf tools: Recalc total periods using top-level entries in hierarchy
perf tools: Remove nr_sort_keys field
perf hists browser: Cleanup hist_browser__fprintf_hierarchy_entry()
perf tools: Remove hist_entry->fmt field
perf tools: Fix command line filters in hierarchy mode
perf tools: Add more sort entry check functions
perf tools: Fix hist_entry__filter() for hierarchy
perf jitdump: Build only on supported archs
tools lib traceevent: Add '~' operation within arg_num_eval()
perf tools: Omit unnecessary cast in perf_pmu__parse_scale
perf tools: Pass perf_hpp_list all the way through setup_sort_list
perf tools: Fix perf script python database export crash
perf jitdump: DWARF is also needed
perf bench mem: Prepare the x86-64 build for upstream memcpy_mcsafe() changes
...
Pull read-only kernel memory updates from Ingo Molnar:
"This tree adds two (security related) enhancements to the kernel's
handling of read-only kernel memory:
- extend read-only kernel memory to a new class of formerly writable
kernel data: 'post-init read-only memory' via the __ro_after_init
attribute, and mark the ARM and x86 vDSO as such read-only memory.
This kind of attribute can be used for data that requires a once
per bootup initialization sequence, but is otherwise never modified
after that point.
This feature was based on the work by PaX Team and Brad Spengler.
(by Kees Cook, the ARM vDSO bits by David Brown.)
- make CONFIG_DEBUG_RODATA always enabled on x86 and remove the
Kconfig option. This simplifies the kernel and also signals that
read-only memory is the default model and a first-class citizen.
(Kees Cook)"
* 'mm-readonly-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ARM/vdso: Mark the vDSO code read-only after init
x86/vdso: Mark the vDSO code read-only after init
lkdtm: Verify that '__ro_after_init' works correctly
arch: Introduce post-init read-only memory
x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option
mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings
asm-generic: Consolidate mark_rodata_ro()
Pull locking changes from Ingo Molnar:
"Various updates:
- Futex scalability improvements: remove page lock use for shared
futex get_futex_key(), which speeds up 'perf bench futex hash'
benchmarks by over 40% on a 60-core Westmere. This makes anon-mem
shared futexes perform close to private futexes. (Mel Gorman)
- lockdep hash collision detection and fix (Alfredo Alvarez
Fernandez)
- lockdep testing enhancements (Alfredo Alvarez Fernandez)
- robustify lockdep init by using hlists (Andrew Morton, Andrey
Ryabinin)
- mutex and csd_lock micro-optimizations (Davidlohr Bueso)
- small x86 barriers tweaks (Michael S Tsirkin)
- qspinlock updates (Waiman Long)"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
locking/csd_lock: Use smp_cond_acquire() in csd_lock_wait()
locking/csd_lock: Explicitly inline csd_lock*() helpers
futex: Replace barrier() in unqueue_me() with READ_ONCE()
locking/lockdep: Detect chain_key collisions
locking/lockdep: Prevent chain_key collisions
tools/lib/lockdep: Fix link creation warning
tools/lib/lockdep: Add tests for AA and ABBA locking
tools/lib/lockdep: Add userspace version of READ_ONCE()
tools/lib/lockdep: Fix the build on recent kernels
locking/qspinlock: Move __ARCH_SPIN_LOCK_UNLOCKED to qspinlock_types.h
locking/mutex: Allow next waiter lockless wakeup
locking/pvqspinlock: Enable slowpath locking count tracking
locking/qspinlock: Use smp_cond_acquire() in pending code
locking/pvqspinlock: Move lock stealing count tracking code into pv_queued_spin_steal_lock()
locking/mcs: Fix mcs_spin_lock() ordering
futex: Remove requirement for lock_page() in get_futex_key()
futex: Rename barrier references in ordering guarantees
locking/atomics: Update comment about READ_ONCE() and structures
locking/lockdep: Eliminate lockdep_init()
locking/lockdep: Convert hash tables to hlists
...
Pull ram resource handling changes from Ingo Molnar:
"Core kernel resource handling changes to support NVDIMM error
injection.
This tree introduces a new I/O resource type, IORESOURCE_SYSTEM_RAM,
for System RAM while keeping the current IORESOURCE_MEM type bit set
for all memory-mapped ranges (including System RAM) for backward
compatibility.
With this resource flag it no longer takes a strcmp() loop through the
resource tree to find "System RAM" resources.
The new resource type is then used to extend ACPI/APEI error injection
facility to also support NVDIMM"
* 'core-resources-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ACPI/EINJ: Allow memory error injection to NVDIMM
resource: Kill walk_iomem_res()
x86/kexec: Remove walk_iomem_res() call with GART type
x86, kexec, nvdimm: Use walk_iomem_res_desc() for iomem search
resource: Add walk_iomem_res_desc()
memremap: Change region_intersects() to take @flags and @desc
arm/samsung: Change s3c_pm_run_res() to use System RAM type
resource: Change walk_system_ram() to use System RAM type
drivers: Initialize resource entry to zero
xen, mm: Set IORESOURCE_SYSTEM_RAM to System RAM
kexec: Set IORESOURCE_SYSTEM_RAM for System RAM
arch: Set IORESOURCE_SYSTEM_RAM flag for System RAM
ia64: Set System RAM type and descriptor
x86/e820: Set System RAM type and descriptor
resource: Add I/O resource descriptor
resource: Handle resource flags properly
resource: Add System RAM resource type
* pm-cpufreq: (94 commits)
intel_pstate: Do not skip samples partially
intel_pstate: Remove freq calculation from intel_pstate_calc_busy()
intel_pstate: Move intel_pstate_calc_busy() into get_target_pstate_use_performance()
intel_pstate: Optimize calculation for max/min_perf_adj
intel_pstate: Remove extra conversions in pid calculation
cpufreq: Move scheduler-related code to the sched directory
Revert "cpufreq: postfix policy directory with the first CPU in related_cpus"
cpufreq: Reduce cpufreq_update_util() overhead a bit
cpufreq: Select IRQ_WORK if CPU_FREQ_GOV_COMMON is set
cpufreq: Remove 'policy->governor_enabled'
cpufreq: Rename __cpufreq_governor() to cpufreq_governor()
cpufreq: Relocate handle_update() to kill its declaration
cpufreq: governor: Drop unnecessary checks from show() and store()
cpufreq: governor: Fix race in dbs_update_util_handler()
cpufreq: governor: Make gov_set_update_util() static
cpufreq: governor: Narrow down the dbs_data_mutex coverage
cpufreq: governor: Make dbs_data_mutex static
cpufreq: governor: Relocate definitions of tuners structures
cpufreq: governor: Move per-CPU data to the common code
cpufreq: governor: Make governor private data per-policy
...
* acpi-pci:
x86/ACPI/PCI: Recognize that Interrupt Line 255 means "not connected"
* acpi-soc:
i2c: designware: Add device HID for future AMD I2C controller
* pnp:
PNP / ACPI: add ACPI_RESOURCE_TYPE_SERIAL_BUS as a valid type
Function is processed in thread context, not in user context.
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Commit 931ef163309e moved the smpboot thread park/unpark invocation to the
state machine. The move of the unpark invocation was premature as it depends
on work in progress patches.
As a result cpu down can fail, because rcu synchronization in takedown_cpu()
eventually requires a functional softirq thread. I never encountered the
problem in testing, but 0day testing managed to provide a reliable reproducer.
Remove the smpboot_threads_park() call from the state machine for now and put
it back into the original place after the rcu synchronization.
I'm embarrassed as I knew about the dependency and still managed to get it
wrong. Hotplug induced brain melt seems to be the only sensible explanation
for that.
Fixes: 931ef163309e "cpu/hotplug: Unpark smpboot threads from the state machine"
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Create cpufreq.c under kernel/sched/ and move the cpufreq code
related to the scheduler to that file and to sched.h.
Redefine cpufreq_update_util() as a static inline function to avoid
function calls at its call sites in the scheduler code (as suggested
by Peter Zijlstra).
Also move the definition of struct update_util_data and declaration
of cpufreq_set_update_util_data() from include/linux/cpufreq.h to
include/linux/sched.h.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Export irq_chip_*_parent(), irq_domain_create_hierarchy(),
irq_domain_set_hwirq_and_chip(), irq_domain_reset_irq_data(),
irq_domain_alloc/free_irqs_parent()
So gpio drivers can be built as modules. First user: gpio-xgene-sb
Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Phong Vo <pvo@apm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: patches@apm.com
Cc: Loc Ho <lho@apm.com>
Cc: Keyur Chudgar <kchudgar@apm.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Link: https://lists.01.org/pipermail/kbuild-all/2016-February/017914.html
Link: http://lkml.kernel.org/r/1457017012-10628-1-git-send-email-qnguyen@apm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We can micro-optimize this call and mildly relax the
barrier requirements by relying on ctrl + rmb, keeping
the acquire semantics. In addition, this is pretty much
the now standard for busy-waiting under such restraints.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1457574936-19065-3-git-send-email-dbueso@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While the compiler tends to already to it for us (except for
csd_unlock), make it explicit. These helpers mainly deal with
the ->flags, are short-lived and can be called, for example,
from smp_call_function_many().
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1457574936-19065-2-git-send-email-dbueso@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Lots of places in the kernel use memcpy(buf, comm, TASK_COMM_LEN); but
the result is typically passed to print("%s", buf) and extra bytes
after zero don't cause any harm.
In bpf the result of bpf_get_current_comm() is used as the part of
map key and was causing spurious hash map mismatches.
Use strlcpy() to guarantee zero-terminated string.
bpf verifier checks that output buffer is zero-initialized,
so even for short task names the output buffer don't have junk bytes.
Note it's not a security concern, since kprobe+bpf is root only.
Fixes: ffeedafbf023 ("bpf: introduce current->pid, tgid, uid, gid, comm accessors")
Reported-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
0-day bot reported build error:
kernel/built-in.o: In function `map_lookup_elem':
>> kernel/bpf/.tmp_syscall.o:(.text+0x329b3c): undefined reference to `bpf_stackmap_copy'
when CONFIG_BPF_SYSCALL is set and CONFIG_PERF_EVENTS is not.
Add weak definition to resolve it.
This code path in map_lookup_elem() is never taken
when CONFIG_PERF_EVENTS is not set.
Fixes: 557c0c6e7df8 ("bpf: convert stackmap to pre-allocation")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
In memremap's helper function try_ram_remap(), we dereference a struct
page pointer that was derived from a PFN that is known to be covered by
a 'System RAM' iomem region, and is thus assumed to be a 'valid' PFN,
i.e., a PFN that has a struct page associated with it and is covered by
the kernel direct mapping.
However, the assumption that there is a 1:1 relation between the System
RAM iomem region and the kernel direct mapping is not universally valid
on all architectures, and on ARM and arm64, 'System RAM' may include
regions for which pfn_valid() returns false.
Generally speaking, both __va() and pfn_to_page() should only ever be
called on PFNs/physical addresses for which pfn_valid() returns true, so
add that check to try_ram_remap().
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Functions which the compiler has instrumented for KASAN place poison on
the stack shadow upon entry and remove this poision prior to returning.
In the case of CPU hotplug, CPUs exit the kernel a number of levels deep
in C code. Any instrumented functions on this critical path will leave
portions of the stack shadow poisoned.
When a CPU is subsequently brought back into the kernel via a different
path, depending on stackframe, layout calls to instrumented functions
may hit this stale poison, resulting in (spurious) KASAN splats to the
console.
To avoid this, clear any stale poison from the idle thread for a CPU
prior to bringing a CPU online.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The check for whether we overlap "System RAM" needs to be done at
section granularity. For example a system with the following mapping:
100000000-37bffffff : System RAM
37c000000-837ffffff : Persistent Memory
...is unable to use devm_memremap_pages() as it would result in two
zones colliding within a given section.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Given we have uninitialized list_heads being passed to list_add() it
will always be the case that those uninitialized values randomly trigger
the poison value. Especially since a list_add() operation will seed the
stack with the poison value for later stack allocations to trip over.
For example, see these two false positive reports:
list_add attempted on force-poisoned entry
WARNING: at lib/list_debug.c:34
[..]
NIP [c00000000043c390] __list_add+0xb0/0x150
LR [c00000000043c38c] __list_add+0xac/0x150
Call Trace:
__list_add+0xac/0x150 (unreliable)
__down+0x4c/0xf8
down+0x68/0x70
xfs_buf_lock+0x4c/0x150 [xfs]
list_add attempted on force-poisoned entry(0000000000000500),
new->next == d0000000059ecdb0, new->prev == 0000000000000500
WARNING: at lib/list_debug.c:33
[..]
NIP [c00000000042db78] __list_add+0xa8/0x140
LR [c00000000042db74] __list_add+0xa4/0x140
Call Trace:
__list_add+0xa4/0x140 (unreliable)
rwsem_down_read_failed+0x6c/0x1a0
down_read+0x58/0x60
xfs_log_commit_cil+0x7c/0x600 [xfs]
Fixes: commit 5c2c2587b132 ("mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Eryu Guan <eguan@redhat.com>
Tested-by: Eryu Guan <eguan@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
klp_find_callback() stops the search when sympos is not defined and
a second symbol of the same name is found. It means that the current
error message about the unresolvable ambiguity always prints "(2 matches)".
Let's remove this information. The total number of occurrences is
not much helpful. The author of the patch still must put a non-trivial
effort into searching the right position in the object file.
[jkosina@suse.cz: fixed grammar as suggested by Josh]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Chris J Arges <chris.j.arges@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
insert_resource() and remove_resouce() are called by producers
of resources, such as FW modules and bus drivers. These modules
may be implemented as loadable modules.
Export insert_resource() and remove_resouce() so that they can
be called from such modules.
link: https://lkml.org/lkml/2016/3/8/872
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
insert_resource() and insert_resource_conflict() are called
by resource producers to insert a new resource. When there
is any conflict, they move conflicting resources down to the
children of the new resource. There is no destructor of these
interfaces, however.
Add remove_resource(), which removes a resource previously
inserted by insert_resource() or insert_resource_conflict(),
and moves the children up to where they were before.
__release_resource() is changed to have @release_child, so
that this function can be used for remove_resource() as well.
Also add comments to clarify that these functions are intended
for producers of resources to avoid any confusion with
request/release_resource() for consumers.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
__request_region() sets 'flags' of a new resource from @parent
as it inherits the parent's attribute. When a target resource
has a conflict, this function inserts the new resource entry
under the conflicted entry by updating @parent. In this case,
the new resource entry needs to inherit attribute from the updated
parent. This conflict is a typical case since __request_region()
is used to allocate a new resource from a specific resource range.
For instance, request_mem_region() calls __request_region() with
@parent set to &iomem_resource, which is the root entry of the
whole iomem range. When this request results in inserting a new
entry "DEV-A" under "BUS-1", "DEV-A" needs to inherit from the
immediate parent "BUS-1" as it holds specific attribute for the
range.
root (&iomem_resource)
:
+ "BUS-1"
+ "DEV-A"
Change __request_region() to set 'flags' and 'desc' of a new entry
from the immediate parent.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Introduce a mechanism by which parts of the cpufreq subsystem
("setpolicy" drivers or the core) can register callbacks to be
executed from cpufreq_update_util() which is invoked by the
scheduler's update_load_avg() on CPU utilization changes.
This allows the "setpolicy" drivers to dispense with their timers
and do all of the computations they need and frequency/voltage
adjustments in the update_load_avg() code path, among other things.
The update_load_avg() changes were suggested by Peter Zijlstra.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Per the x86-specific footnote to PCI spec r3.0, sec 6.2.4, the value 255 in
the Interrupt Line register means "unknown" or "no connection."
Previously, when we couldn't derive an IRQ from the _PRT, we fell back to
using the value from Interrupt Line as an IRQ. It's questionable whether
we should do that at all, but the spec clearly suggests we shouldn't do it
for the value 255 on x86.
Calling request_irq() with IRQ 255 may succeed, but the driver won't
receive any interrupts. Or, if IRQ 255 is shared with another device, it
may succeed, and the driver's ISR will be called at random times when the
*other* device interrupts. Or it may fail if another device is using IRQ
255 with incompatible flags. What we *want* is for request_irq() to fail
predictably so the driver can fall back to polling.
On x86, assume 255 in the Interrupt Line means the INTx line is not
connected. In that case, set dev->irq to IRQ_NOTCONNECTED so request_irq()
will fail gracefully with -ENOTCONN.
We found this problem on a system where Secure Boot firmware assigned
Interrupt Line 255 to an i801_smbus device and another device was already
using MSI-X IRQ 255. This was in v3.10, where i801_probe() fails if
request_irq() fails:
i801_smbus 0000:00:1f.3: enabling device (0140 -> 0143)
i801_smbus 0000:00:1f.3: can't derive routing for PCI INT C
i801_smbus 0000:00:1f.3: PCI INT C: no GSI
genirq: Flags mismatch irq 255. 00000080 (i801_smbus) vs. 00000000 (megasa)
CPU: 0 PID: 2487 Comm: kworker/0:1 Not tainted 3.10.0-229.el7.x86_64 #1
Hardware name: FUJITSU PRIMEQUEST 2800E2/D3736, BIOS PRIMEQUEST 2000 Serie5
Call Trace:
dump_stack+0x19/0x1b
__setup_irq+0x54a/0x570
request_threaded_irq+0xcc/0x170
i801_probe+0x32f/0x508 [i2c_i801]
local_pci_probe+0x45/0xa0
i801_smbus 0000:00:1f.3: Failed to allocate irq 255: -16
i801_smbus: probe of 0000:00:1f.3 failed with error -16
After aeb8a3d16ae0 ("i2c: i801: Check if interrupts are disabled"),
i801_probe() will fall back to polling if request_irq() fails. But we
still need this patch because request_irq() may succeed or fail depending
on other devices in the system. If request_irq() fails, i801_smbus will
work by falling back to polling, but if it succeeds, i801_smbus won't work
because it expects interrupts that it may not receive.
Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
It was observed that calling bpf_get_stackid() from a kprobe inside
slub or from spin_unlock causes similar deadlock as with hashmap,
therefore convert stackmap to use pre-allocated memory.
The call_rcu is no longer feasible mechanism, since delayed freeing
causes bpf_get_stackid() to fail unpredictably when number of actual
stacks is significantly less than user requested max_entries.
Since elements are no longer freed into slub, we can push elements into
freelist immediately and let them be recycled.
However the very unlikley race between user space map_lookup() and
program-side recycling is possible:
cpu0 cpu1
---- ----
user does lookup(stackidX)
starts copying ips into buffer
delete(stackidX)
calls bpf_get_stackid()
which recyles the element and
overwrites with new stack trace
To avoid user space seeing a partial stack trace consisting of two
merged stack traces, do bucket = xchg(, NULL); copy; xchg(,bucket);
to preserve consistent stack trace delivery to user space.
Now we can move memset(,0) of left-over element value from critical
path of bpf_get_stackid() into slow-path of user space lookup.
Also disallow lookup() from bpf program, since it's useless and
program shouldn't be messing with collected stack trace.
Note that similar race between user space lookup and kernel side updates
is also present in hashmap, but it's not a new race. bpf programs were
always allowed to modify hash and array map elements while user space
is copying them.
Fixes: d5a3b1f69186 ("bpf: introduce BPF_MAP_TYPE_STACK_TRACE")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
If kprobe is placed on spin_unlock then calling kmalloc/kfree from
bpf programs is not safe, since the following dead lock is possible:
kfree->spin_lock(kmem_cache_node->lock)...spin_unlock->kprobe->
bpf_prog->map_update->kmalloc->spin_lock(of the same kmem_cache_node->lock)
and deadlocks.
The following solutions were considered and some implemented, but
eventually discarded
- kmem_cache_create for every map
- add recursion check to slow-path of slub
- use reserved memory in bpf_map_update for in_irq or in preempt_disabled
- kmalloc via irq_work
At the end pre-allocation of all map elements turned out to be the simplest
solution and since the user is charged upfront for all the memory, such
pre-allocation doesn't affect the user space visible behavior.
Since it's impossible to tell whether kprobe is triggered in a safe
location from kmalloc point of view, use pre-allocation by default
and introduce new BPF_F_NO_PREALLOC flag.
While testing of per-cpu hash maps it was discovered
that alloc_percpu(GFP_ATOMIC) has odd corner cases and often
fails to allocate memory even when 90% of it is free.
The pre-allocation of per-cpu hash elements solves this problem as well.
Turned out that bpf_map_update() quickly followed by
bpf_map_lookup()+bpf_map_delete() is very common pattern used
in many of iovisor/bcc/tools, so there is additional benefit of
pre-allocation, since such use cases are must faster.
Since all hash map elements are now pre-allocated we can remove
atomic increment of htab->count and save few more cycles.
Also add bpf_map_precharge_memlock() to check rlimit_memlock early to avoid
large malloc/free done by users who don't have sufficient limits.
Pre-allocation is done with vmalloc and alloc/free is done
via percpu_freelist. Here are performance numbers for different
pre-allocation algorithms that were implemented, but discarded
in favor of percpu_freelist:
1 cpu:
pcpu_ida 2.1M
pcpu_ida nolock 2.3M
bt 2.4M
kmalloc 1.8M
hlist+spinlock 2.3M
pcpu_freelist 2.6M
4 cpu:
pcpu_ida 1.5M
pcpu_ida nolock 1.8M
bt w/smp_align 1.7M
bt no/smp_align 1.1M
kmalloc 0.7M
hlist+spinlock 0.2M
pcpu_freelist 2.0M
8 cpu:
pcpu_ida 0.7M
bt w/smp_align 0.8M
kmalloc 0.4M
pcpu_freelist 1.5M
32 cpu:
kmalloc 0.13M
pcpu_freelist 0.49M
pcpu_ida nolock is a modified percpu_ida algorithm without
percpu_ida_cpu locks and without cross-cpu tag stealing.
It's faster than existing percpu_ida, but not as fast as pcpu_freelist.
bt is a variant of block/blk-mq-tag.c simlified and customized
for bpf use case. bt w/smp_align is using cache line for every 'long'
(similar to blk-mq-tag). bt no/smp_align allocates 'long'
bitmasks continuously to save memory. It's comparable to percpu_ida
and in some cases faster, but slower than percpu_freelist
hlist+spinlock is the simplest free list with single spinlock.
As expeceted it has very bad scaling in SMP.
kmalloc is existing implementation which is still available via
BPF_F_NO_PREALLOC flag. It's significantly slower in single cpu and
in 8 cpu setup it's 3 times slower than pre-allocation with pcpu_freelist,
but saves memory, so in cases where map->max_entries can be large
and number of map update/delete per second is low, it may make
sense to use it.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce simple percpu_freelist to keep single list of elements
spread across per-cpu singly linked lists.
/* push element into the list */
void pcpu_freelist_push(struct pcpu_freelist *, struct pcpu_freelist_node *);
/* pop element from the list */
struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *);
The object is pushed to the current cpu list.
Pop first trying to get the object from the current cpu list,
if it's empty goes to the neigbour cpu list.
For bpf program usage pattern the collision rate is very low,
since programs push and pop the objects typically on the same cpu.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
if kprobe is placed within update or delete hash map helpers
that hold bucket spin lock and triggered bpf program is trying to
grab the spinlock for the same bucket on the same cpu, it will
deadlock.
Fix it by extending existing recursion prevention mechanism.
Note, map_lookup and other tracing helpers don't have this problem,
since they don't hold any locks and don't modify global data.
bpf_trace_printk has its own recursive check and ok as well.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Several cases of overlapping changes, as well as one instance
(vxlan) of a bug fix in 'net' overlapping with code movement
in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
Some controllers, perf_event for now and possibly freezer in the
future, don't really make sense to control explicitly through
"cgroup.subtree_control". For example, the primary role of perf_event
is identifying the cgroups of tasks; however, because the controller
also keeps a small amount of state per cgroup, it can't be replaced
with simple cgroup membership tests.
This patch implements cgroup_subsys->implicit_on_dfl flag. When set,
the controller is implicitly enabled on all cgroups on the v2
hierarchy so that utility type controllers such as perf_event can be
enabled and function transparently.
An implicit controller doesn't show up in "cgroup.controllers" or
"cgroup.subtree_control", is exempt from no internal process rule and
can be stolen from the default hierarchy even if there are non-root
csses.
v2: Reimplemented on top of the recent updates to css handling and
subsystem rebinding. Rebinding implicit subsystems is now a
simple matter of exempting it from the busy subsystem check.
Signed-off-by: Tejun Heo <tj@kernel.org>
Migration can be multi-target on the default hierarchy when a
controller is enabled - processes belonging to each child cgroup have
to be moved to the child cgroup itself to refresh css association.
This isn't a problem for cgroup_migrate_add_src() as each source
css_set still maps to single source and target cgroups; however,
cgroup_migrate_prepare_dst() is called once after all source css_sets
are added and thus might not have a single destination cgroup. This
is currently worked around by specifying NULL for @dst_cgrp and using
the source's default cgroup as destination as the only multi-target
migration in use is self-targetting. While this works, it's subtle
and clunky.
As all taget cgroups are already specified while preparing the source
css_sets, this clunkiness can easily be removed by recording the
target cgroup in each source css_set. This patch adds
css_set->mg_dst_cgrp which is recorded on cgroup_migrate_src() and
used by cgroup_migrate_prepare_dst(). This also makes migration code
ready for arbitrary multi-target migration.
Signed-off-by: Tejun Heo <tj@kernel.org>
On the default hierarchy, a migration can be multi-source and/or
multi-destination. cgroup_taskest_migrate() used to incorrectly
assume single destination cgroup but the bug has been fixed by
1f7dd3e5a6e4 ("cgroup: fix handling of multi-destination migration
from subtree_control enabling").
Since the commit, @dst_cgrp to cgroup[_taskset]_migrate() is only used
to determine which subsystems are affected or which cgroup_root the
migration is taking place in. As such, @dst_cgrp is misleading. This
patch replaces @dst_cgrp with @root.
Signed-off-by: Tejun Heo <tj@kernel.org>
