Merge updates from Andrew Morton:
"A few little subsystems and a start of a lot of MM patches.
Subsystems affected by this patch series: squashfs, ocfs2, parisc,
vfs. With mm subsystems: slab-generic, slub, debug, pagecache, gup,
swap, memcg, pagemap, memory-failure, vmalloc, kasan"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (128 commits)
kasan: move kasan_report() into report.c
mm/mm_init.c: report kasan-tag information stored in page->flags
ubsan: entirely disable alignment checks under UBSAN_TRAP
kasan: fix clang compilation warning due to stack protector
x86/mm: remove vmalloc faulting
mm: remove vmalloc_sync_(un)mappings()
x86/mm/32: implement arch_sync_kernel_mappings()
x86/mm/64: implement arch_sync_kernel_mappings()
mm/ioremap: track which page-table levels were modified
mm/vmalloc: track which page-table levels were modified
mm: add functions to track page directory modifications
s390: use __vmalloc_node in stack_alloc
powerpc: use __vmalloc_node in alloc_vm_stack
arm64: use __vmalloc_node in arch_alloc_vmap_stack
mm: remove vmalloc_user_node_flags
mm: switch the test_vmalloc module to use __vmalloc_node
mm: remove __vmalloc_node_flags_caller
mm: remove both instances of __vmalloc_node_flags
mm: remove the prot argument to __vmalloc_node
mm: remove the pgprot argument to __vmalloc
...
Pull vfs updates from Al Viro:
"Assorted patches from Miklos.
An interesting part here is /proc/mounts stuff..."
The "/proc/mounts stuff" is using a cursor for keeeping the location
data while traversing the mount listing.
Also probably worth noting is the addition of faccessat2(), which takes
an additional set of flags to specify how the lookup is done
(AT_EACCESS, AT_SYMLINK_NOFOLLOW, AT_EMPTY_PATH).
* 'from-miklos' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: add faccessat2 syscall
vfs: don't parse "silent" option
vfs: don't parse "posixacl" option
vfs: don't parse forbidden flags
statx: add mount_root
statx: add mount ID
statx: don't clear STATX_ATIME on SB_RDONLY
uapi: deprecate STATX_ALL
utimensat: AT_EMPTY_PATH support
vfs: split out access_override_creds()
proc/mounts: add cursor
aio: fix async fsync creds
vfs: allow unprivileged whiteout creation
Pull RCU updates from Ingo Molnar:
"The RCU updates for this cycle were:
- RCU-tasks update, including addition of RCU Tasks Trace for BPF use
and TASKS_RUDE_RCU
- kfree_rcu() updates.
- Remove scheduler locking restriction
- RCU CPU stall warning updates.
- Torture-test updates.
- Miscellaneous fixes and other updates"
* tag 'core-rcu-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (103 commits)
rcu: Allow for smp_call_function() running callbacks from idle
rcu: Provide rcu_irq_exit_check_preempt()
rcu: Abstract out rcu_irq_enter_check_tick() from rcu_nmi_enter()
rcu: Provide __rcu_is_watching()
rcu: Provide rcu_irq_exit_preempt()
rcu: Make RCU IRQ enter/exit functions rely on in_nmi()
rcu/tree: Mark the idle relevant functions noinstr
x86: Replace ist_enter() with nmi_enter()
x86/mce: Send #MC singal from task work
x86/entry: Get rid of ist_begin/end_non_atomic()
sched,rcu,tracing: Avoid tracing before in_nmi() is correct
sh/ftrace: Move arch_ftrace_nmi_{enter,exit} into nmi exception
lockdep: Always inline lockdep_{off,on}()
hardirq/nmi: Allow nested nmi_enter()
arm64: Prepare arch_nmi_enter() for recursion
printk: Disallow instrumenting print_nmi_enter()
printk: Prepare for nested printk_nmi_enter()
rcutorture: Convert ULONG_CMP_LT() to time_before()
torture: Add a --kasan argument
torture: Save a few lines by using config_override_param initially
...
Pull kprobes updates from Ingo Molnar:
"Various kprobes updates, mostly centered around cleaning up the
no-instrumentation logic.
Instead of the current per debug facility blacklist, use the more
generic .noinstr.text approach, combined with a 'noinstr' marker for
functions.
Also add instrumentation_begin()/end() to better manage the exact
place in entry code where instrumentation may be used.
And add a kprobes blacklist for modules"
* tag 'core-kprobes-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
kprobes: Prevent probes in .noinstr.text section
vmlinux.lds.h: Create section for protection against instrumentation
samples/kprobes: Add __kprobes and NOKPROBE_SYMBOL() for handlers.
kprobes: Support NOKPROBE_SYMBOL() in modules
kprobes: Support __kprobes blacklist in modules
kprobes: Lock kprobe_mutex while showing kprobe_blacklist
Pull pstore updates from Kees Cook:
"Fixes and new features for pstore.
This is a pretty big set of changes (relative to past pstore pulls),
but it has been in -next for a while. The biggest change here is the
ability to support a block device as a pstore backend, which has been
desired for a while. A lot of additional fixes and refactorings are
also included, mostly in support of the new features.
- refactor pstore locking for safer module unloading (Kees Cook)
- remove orphaned records from pstorefs when backend unloaded (Kees
Cook)
- refactor dump_oops parameter into max_reason (Pavel Tatashin)
- introduce pstore/zone for common code for contiguous storage
(WeiXiong Liao)
- introduce pstore/blk for block device backend (WeiXiong Liao)
- introduce mtd backend (WeiXiong Liao)"
* tag 'pstore-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (35 commits)
mtd: Support kmsg dumper based on pstore/blk
pstore/blk: Introduce "best_effort" mode
pstore/blk: Support non-block storage devices
pstore/blk: Provide way to query pstore configuration
pstore/zone: Provide way to skip "broken" zone for MTD devices
Documentation: Add details for pstore/blk
pstore/zone,blk: Add ftrace frontend support
pstore/zone,blk: Add console frontend support
pstore/zone,blk: Add support for pmsg frontend
pstore/blk: Introduce backend for block devices
pstore/zone: Introduce common layer to manage storage zones
ramoops: Add "max-reason" optional field to ramoops DT node
pstore/ram: Introduce max_reason and convert dump_oops
pstore/platform: Pass max_reason to kmesg dump
printk: Introduce kmsg_dump_reason_str()
printk: honor the max_reason field in kmsg_dumper
printk: Collapse shutdown types into a single dump reason
pstore/ftrace: Provide ftrace log merging routine
pstore/ram: Refactor ftrace buffer merging
pstore/ram: Refactor DT size parsing
...
Commit 702f098052 ("powerpc/64s/exception: Remove lite interrupt
return") changed the interrupt return path to not restore non-volatile
registers by default, and explicitly restore them in paths where it is
required.
But it missed that the facility unavailable exception can sometimes
modify user registers, ie. when it does emulation of move from DSCR.
This is seen as a failure of the dscr_sysfs_thread_test:
test: dscr_sysfs_thread_test
[cpu 0] User DSCR should be 1 but is 0
failure: dscr_sysfs_thread_test
So restore non-volatile GPRs after facility unavailable exceptions.
Currently the hypervisor facility unavailable exception is also wired
up to call facility_unavailable_exception().
In practice we should never take a hypervisor facility unavailable
exception for the DSCR. On older bare metal systems we set HFSCR_DSCR
unconditionally in __init_HFSCR, or on newer systems it should be
enabled via the "data-stream-control-register" device tree CPU
feature.
Even if it's not, since commit f3c99f97a3 ("KVM: PPC: Book3S HV:
Don't access HFSCR, LPIDR or LPCR when running nested"), the KVM code
has unconditionally set HFSCR_DSCR when running guests.
So we should only get a hypervisor facility unavailable for the DSCR
if skiboot has disabled the "data-stream-control-register" feature,
and we are somehow in guest context but not via KVM.
Given all that, it should be unnecessary to add a restore of
non-volatile GPRs after the hypervisor facility exception, because we
never expect to hit that path. But equally we may as well add the
restore, because we never expect to hit that path, and if we ever did,
at least we would correctly restore the registers to their post
emulation state.
In future we can split the non-HV and HV facility unavailable handling
so that there is no emulation in the HV handler, and then remove the
restore for the HV case.
Fixes: 702f098052 ("powerpc/64s/exception: Remove lite interrupt return")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200526061808.2472279-1-mpe@ellerman.id.au
Some code pathes, especially the low level entry code, must be protected
against instrumentation for various reasons:
- Low level entry code can be a fragile beast, especially on x86.
- With NO_HZ_FULL RCU state needs to be established before using it.
Having a dedicated section for such code allows to validate with tooling
that no unsafe functions are invoked.
Add the .noinstr.text section and the noinstr attribute to mark
functions. noinstr implies notrace. Kprobes will gain a section check
later.
Provide also a set of markers: instrumentation_begin()/end()
These are used to mark code inside a noinstr function which calls
into regular instrumentable text section as safe.
The instrumentation markers are only active when CONFIG_DEBUG_ENTRY is
enabled as the end marker emits a NOP to prevent the compiler from merging
the annotation points. This means the objtool verification requires a
kernel compiled with this option.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134100.075416272@linutronix.de
POSIX defines faccessat() as having a fourth "flags" argument, while the
linux syscall doesn't have it. Glibc tries to emulate AT_EACCESS and
AT_SYMLINK_NOFOLLOW, but AT_EACCESS emulation is broken.
Add a new faccessat(2) syscall with the added flags argument and implement
both flags.
The value of AT_EACCESS is defined in glibc headers to be the same as
AT_REMOVEDIR. Use this value for the kernel interface as well, together
with the explanatory comment.
Also add AT_EMPTY_PATH support, which is not documented by POSIX, but can
be useful and is trivial to implement.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
To prevent verifying the kernel module appended signature
twice (finit_module), once by the module_sig_check() and again by IMA,
powerpc secure boot rules define an IMA architecture specific policy
rule only if CONFIG_MODULE_SIG_FORCE is not enabled. This,
unfortunately, does not take into account the ability of enabling
"sig_enforce" on the boot command line (module.sig_enforce=1).
Including the IMA module appraise rule results in failing the
finit_module syscall, unless the module signing public key is loaded
onto the IMA keyring.
This patch fixes secure boot policy rules to be based on
CONFIG_MODULE_SIG instead.
Fixes: 4238fad366 ("powerpc/ima: Add support to initialize ima policy rules")
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/1588342612-14532-1-git-send-email-nayna@linux.ibm.com
Interrupts that use fast_interrupt_return actually do lock AMR, but
they have been ones which tend to come from userspace (or kernel bugs)
in radix mode. With kuap on hash, segment interrupts are taken in
kernel often, which quickly breaks due to the missing restore.
Fixes: 890274c2dc ("powerpc/64s: Implement KUAP for Radix MMU")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200429065654.1677541-6-npiggin@gmail.com
Hugh reported that his trusty G5 crashed after a few hours under load
with an "Unrecoverable exception 380".
The crash is in interrupt_return() where we check lazy_irq_pending(),
which calls get_paca() and with CONFIG_DEBUG_PREEMPT=y that goes to
check_preemption_disabled() via debug_smp_processor_id().
As Nick explained on the list:
Problem is MSR[RI] is cleared here, ready to do the last few things
for interrupt return where we're not allowed to take any other
interrupts.
SLB interrupts can happen just about anywhere aside from kernel
text, global variables, and stack. When that hits, it appears to be
unrecoverable due to RI=0.
The problematic access is in preempt_count() which is:
return READ_ONCE(current_thread_info()->preempt_count);
Because of THREAD_INFO_IN_TASK, current_thread_info() just points to
current, so the access is to somewhere in kernel memory, but not on
the stack or in .data, which means it can cause an SLB miss. If we
take an SLB miss with RI=0 it is fatal.
The easiest solution is to add a version of lazy_irq_pending() that
doesn't do the preemption check and call it from the interrupt return
path.
Fixes: 68b34588e2 ("powerpc/64/sycall: Implement syscall entry/exit logic in C")
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200502143316.929341-1-mpe@ellerman.id.au
If {i,d}-cache-block-size is set and {i,d}-cache-line-size is not, use
the block-size value for both. Per the devicetree spec cache-line-size
is only needed if it differs from the block size.
Originally the code would fallback from block size to line size. An
error message was printed if both properties were missing.
Later the code was refactored to use clearer names and logic but it
inadvertently made line size a required property, meaning on systems
without a line size property we fall back to the default from the
cputable.
On powernv (OPAL) platforms, since the introduction of device tree CPU
features (5a61ef74f2 ("powerpc/64s: Support new device tree binding
for discovering CPU features")), that has led to the wrong value being
used, as the fallback value is incorrect for Power8/Power9 CPUs.
The incorrect values flow through to the VDSO and also to the sysconf
values, SC_LEVEL1_ICACHE_LINESIZE etc.
Fixes: bd067f83b0 ("powerpc/64: Fix naming of cache block vs. cache line")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reported-by: Qian Cai <cai@lca.pw>
[mpe: Add even more detail to change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200416221908.7886-1-chris.packham@alliedtelesis.co.nz
Pull more powerpc updates from Michael Ellerman:
"The bulk of this is the series to make CONFIG_COMPAT user-selectable,
it's been around for a long time but was blocked behind the
syscall-in-C series.
Plus there's also a few fixes and other minor things.
Summary:
- A fix for a crash in machine check handling on pseries (ie. guests)
- A small series to make it possible to disable CONFIG_COMPAT, and
turn it off by default for ppc64le where it's not used.
- A few other miscellaneous fixes and small improvements.
Thanks to: Alexey Kardashevskiy, Anju T Sudhakar, Arnd Bergmann,
Christophe Leroy, Dan Carpenter, Ganesh Goudar, Geert Uytterhoeven,
Geoff Levand, Mahesh Salgaonkar, Markus Elfring, Michal Suchanek,
Nicholas Piggin, Stephen Boyd, Wen Xiong"
* tag 'powerpc-5.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
selftests/powerpc: Always build the tm-poison test 64-bit
powerpc: Improve ppc_save_regs()
Revert "powerpc/64: irq_work avoid interrupt when called with hardware irqs enabled"
powerpc/time: Replace <linux/clk-provider.h> by <linux/of_clk.h>
powerpc/pseries/ddw: Extend upper limit for huge DMA window for persistent memory
powerpc/perf: split callchain.c by bitness
powerpc/64: Make COMPAT user-selectable disabled on littleendian by default.
powerpc/64: make buildable without CONFIG_COMPAT
powerpc/perf: consolidate valid_user_sp -> invalid_user_sp
powerpc/perf: consolidate read_user_stack_32
powerpc: move common register copy functions from signal_32.c to signal.c
powerpc: Add back __ARCH_WANT_SYS_LLSEEK macro
powerpc/ps3: Set CONFIG_UEVENT_HELPER=y in ps3_defconfig
powerpc/ps3: Remove an unneeded NULL check
powerpc/ps3: Remove duplicate error message
powerpc/powernv: Re-enable imc trace-mode in kernel
powerpc/perf: Implement a global lock to avoid races between trace, core and thread imc events.
powerpc/pseries: Fix MCE handling on pseries
selftests/eeh: Skip ahci adapters
powerpc/64s: Fix doorbell wakeup msgclr optimisation
Pull powerpc updates from Michael Ellerman:
"Slightly late as I had to rebase mid-week to insert a bug fix:
- A large series from Nick for 64-bit to further rework our exception
vectors, and rewrite portions of the syscall entry/exit and
interrupt return in C. The result is much easier to follow code
that is also faster in general.
- Cleanup of our ptrace code to split various parts out that had
become badly intertwined with #ifdefs over the years.
- Changes to our NUMA setup under the PowerVM hypervisor which should
hopefully avoid non-sensical topologies which can lead to warnings
from the workqueue code and other problems.
- MAINTAINERS updates to remove some of our old orphan entries and
update the status of others.
- Quite a few other small changes and fixes all over the map.
Thanks to: Abdul Haleem, afzal mohammed, Alexey Kardashevskiy, Andrew
Donnellan, Aneesh Kumar K.V, Balamuruhan S, Cédric Le Goater, Chen
Zhou, Christophe JAILLET, Christophe Leroy, Christoph Hellwig, Clement
Courbet, Daniel Axtens, David Gibson, Douglas Miller, Fabiano Rosas,
Fangrui Song, Ganesh Goudar, Gautham R. Shenoy, Greg Kroah-Hartman,
Greg Kurz, Gustavo Luiz Duarte, Hari Bathini, Ilie Halip, Jan Kara,
Joe Lawrence, Joe Perches, Kajol Jain, Larry Finger, Laurentiu Tudor,
Leonardo Bras, Libor Pechacek, Madhavan Srinivasan, Mahesh Salgaonkar,
Masahiro Yamada, Masami Hiramatsu, Mauricio Faria de Oliveira, Michael
Neuling, Michal Suchanek, Mike Rapoport, Nageswara R Sastry, Nathan
Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nick
Desaulniers, Oliver O'Halloran, Po-Hsu Lin, Pratik Rajesh Sampat,
Rasmus Villemoes, Ravi Bangoria, Roman Bolshakov, Sam Bobroff,
Sandipan Das, Santosh S, Sedat Dilek, Segher Boessenkool, Shilpasri G
Bhat, Sourabh Jain, Srikar Dronamraju, Stephen Rothwell, Tyrel
Datwyler, Vaibhav Jain, YueHaibing"
* tag 'powerpc-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (158 commits)
powerpc: Make setjmp/longjmp signature standard
powerpc/cputable: Remove unnecessary copy of cpu_spec->oprofile_type
powerpc: Suppress .eh_frame generation
powerpc: Drop -fno-dwarf2-cfi-asm
powerpc/32: drop unused ISA_DMA_THRESHOLD
powerpc/powernv: Add documentation for the opal sensor_groups sysfs interfaces
selftests/powerpc: Fix try-run when source tree is not writable
powerpc/vmlinux.lds: Explicitly retain .gnu.hash
powerpc/ptrace: move ptrace_triggered() into hw_breakpoint.c
powerpc/ptrace: create ppc_gethwdinfo()
powerpc/ptrace: create ptrace_get_debugreg()
powerpc/ptrace: split out ADV_DEBUG_REGS related functions.
powerpc/ptrace: move register viewing functions out of ptrace.c
powerpc/ptrace: split out TRANSACTIONAL_MEM related functions.
powerpc/ptrace: split out SPE related functions.
powerpc/ptrace: split out ALTIVEC related functions.
powerpc/ptrace: split out VSX related functions.
powerpc/ptrace: drop PARAMETER_SAVE_AREA_OFFSET
powerpc/ptrace: drop unnecessary #ifdefs CONFIG_PPC64
powerpc/ptrace: remove unused header includes
...
Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your
current tree, that should be trivial to handle (one file modified by
two things, one file deleted.)
All three of these have been in linux-next for a while, with no
reported issues other than the merge conflict"
* tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
ASoC: MT6660: make spdxcheck.py happy
.gitignore: add SPDX License Identifier
.gitignore: remove too obvious comments
This reverts commit ebb37cf3ff.
That commit does not play well with soft-masked irq state
manipulations in idle, interrupt replay, and possibly others due to
tracing code sometimes using irq_work_queue (e.g., in
trace_hardirqs_on()). That can cause PACA_IRQ_DEC to become set when
it is not expected, and be ignored or cleared or cause warnings.
The net result seems to be missing an irq_work until the next timer
interrupt in the worst case which is usually not going to be noticed,
however it could be a long time if the tick is disabled, which is
against the spirit of irq_work and might cause real problems.
The idea is still solid, but it would need more work. It's not really
clear if it would be worth added complexity, so revert this for
now (not a straight revert, but replace with a comment explaining why
we might see interrupts happening, and gives git blame something to
find).
Fixes: ebb37cf3ff ("powerpc/64: irq_work avoid interrupt when called with hardware irqs enabled")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200402120401.1115883-1-npiggin@gmail.com
Pull devicetree updates from Rob Herring:
- Unit test for overlays with GPIO hogs
- Improve dma-ranges parsing to handle dma-ranges with multiple entries
- Update dtc to upstream version v1.6.0-2-g87a656ae5ff9
- Improve overlay error reporting
- Device link support for power-domains and hwlocks bindings
- Add vendor prefixes for Beacon, Topwise, ENE, Dell, SG Micro, Elida,
PocketBook, Xiaomi, Linutronix, OzzMaker, Waveshare Electronics, and
ITE Tech
- Add deprecated Marvell vendor prefix 'mrvl'
- A bunch of binding conversions to DT schema continues. Of note, the
common serial and USB connector bindings are converted.
- Add more Arm CPU compatibles
- Drop Mark Rutland as DT maintainer :(
* tag 'devicetree-for-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (106 commits)
MAINTAINERS: drop an old reference to stm32 pwm timers doc
MAINTAINERS: dt: update etnaviv file reference
dt-bindings: usb: dwc2: fix bindings for amlogic, meson-gxbb-usb
dt-bindings: uniphier-system-bus: fix warning in the example
dt-bindings: display: meson-vpu: fix indentation of reg-names' "items"
dt-bindings: iio: Fix adi, ltc2983 uint64-matrix schema constraints
dt-bindings: power: Fix example for power-domain
dt-bindings: arm: Add some constraints for PSCI nodes
of: some unittest overlays not untracked
of: gpio unittest kfree() wrong object
dt-bindings: phy: convert phy-rockchip-inno-usb2 bindings to yaml
dt-bindings: serial: sh-sci: Convert to json-schema
dt-bindings: serial: Document serialN aliases
dt-bindings: thermal: tsens: Set 'additionalProperties: false'
dt-bindings: thermal: tsens: Fix nvmem-cell-names schema
dt-bindings: vendor-prefixes: Add Beacon vendor prefix
dt-bindings: vendor-prefixes: Add Topwise
of: of_private.h: Replace zero-length array with flexible-array member
docs: dt: fix a broken reference to input.yaml
docs: dt: fix references to ap806-system-controller.txt
...
Commit 3282a3da25 ("powerpc/64: Implement soft interrupt replay in C")
broke the doorbell wakeup optimisation introduced by commit a9af97aa0a
("powerpc/64s: msgclr when handling doorbell exceptions from system
reset").
This patch restores the msgclr, in C code. It's now done in the system
reset wakeup path rather than doorbell interrupt replay where it used
to be, because it is always the right thing to do in the wakeup case,
but it may be rarely of use in other interrupt replay situations in
which case it's wasted work - we would have to run measurements to see
if that was a worthwhile optimisation, and I suspect it would not be.
The results are similar to those in the original commit, test on POWER8
of context_switch selftests benchmark with polling idle disabled (e.g.,
always nap, giving cross-CPU IPIs) gives the following results:
broken patched
Different threads, same core: 317k/s 375k/s +18.7%
Different cores: 280k/s 282k/s +1.0%
Fixes: 3282a3da25 ("powerpc/64: Implement soft interrupt replay in C")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200402121212.1118218-1-npiggin@gmail.com
Relocatable kernel builds produce a warning about .gnu.hash being an
orphan section:
ld: warning: orphan section `.gnu.hash' from `linker stubs' being placed in section `.gnu.hash'
If we try to discard it the build fails:
ld -EL -m elf64lppc -pie --orphan-handling=warn --build-id -o
.tmp_vmlinux1 -T ./arch/powerpc/kernel/vmlinux.lds --whole-archive
arch/powerpc/kernel/head_64.o arch/powerpc/kernel/entry_64.o
...
sound/built-in.a net/built-in.a virt/built-in.a --no-whole-archive
--start-group lib/lib.a --end-group
ld: could not find section .gnu.hash
So add an entry to explicitly retain it, as we do for .hash.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200227045933.22967-1-mpe@ellerman.id.au
