irq_work's use of the DEC SPR is racy with guest<->host switch and guest
entry which flips the DEC interrupt to guest, which could lose a host
work interrupt.
This patch closes one race, and attempts to comment another class of
races.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-11-npiggin@gmail.com
When CONFIG_IRQ_TIME_ACCOUNTING and CONFIG_VIRT_CPU_ACCOUNTING_GEN, powerpc
does not enable "sched_clock_irqtime" and can not utilize irq time
accounting.
Like x86, powerpc does not use the sched_clock_register() interface. So it
needs an dedicated call to enable_sched_clock_irqtime() to enable irq time
accounting.
Fixes: 518470fe96 ("powerpc: Add HAVE_IRQ_TIME_ACCOUNTING")
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
[mpe: Add fixes tag]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1603349479-26185-1-git-send-email-kernelfans@gmail.com
- Switch to the generic C VDSO, as well as some cleanups of our VDSO
setup/handling code.
- Support for KUAP (Kernel User Access Prevention) on systems using the hashed
page table MMU, using memory protection keys.
- Better handling of PowerVM SMT8 systems where all threads of a core do not
share an L2, allowing the scheduler to make better scheduling decisions.
- Further improvements to our machine check handling.
- Show registers when unwinding interrupt frames during stack traces.
- Improvements to our pseries (PowerVM) partition migration code.
- Several series from Christophe refactoring and cleaning up various parts of
the 32-bit code.
- Other smaller features, fixes & cleanups.
Thanks to:
Alan Modra, Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Ard
Biesheuvel, Athira Rajeev, Balamuruhan S, Bill Wendling, Cédric Le Goater,
Christophe Leroy, Christophe Lombard, Colin Ian King, Daniel Axtens, David
Hildenbrand, Frederic Barrat, Ganesh Goudar, Gautham R. Shenoy, Geert
Uytterhoeven, Giuseppe Sacco, Greg Kurz, Harish, Jan Kratochvil, Jordan
Niethe, Kaixu Xia, Laurent Dufour, Leonardo Bras, Madhavan Srinivasan, Mahesh
Salgaonkar, Mathieu Desnoyers, Nathan Lynch, Nicholas Piggin, Oleg Nesterov,
Oliver O'Halloran, Oscar Salvador, Po-Hsu Lin, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sandipan Das, Sebastian Andrzej Siewior ,
Segher Boessenkool, Srikar Dronamraju, Tyrel Datwyler, Uwe Kleine-König,
Vincent Stehlé, Youling Tang, Zhang Xiaoxu.
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Merge tag 'powerpc-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Switch to the generic C VDSO, as well as some cleanups of our VDSO
setup/handling code.
- Support for KUAP (Kernel User Access Prevention) on systems using the
hashed page table MMU, using memory protection keys.
- Better handling of PowerVM SMT8 systems where all threads of a core
do not share an L2, allowing the scheduler to make better scheduling
decisions.
- Further improvements to our machine check handling.
- Show registers when unwinding interrupt frames during stack traces.
- Improvements to our pseries (PowerVM) partition migration code.
- Several series from Christophe refactoring and cleaning up various
parts of the 32-bit code.
- Other smaller features, fixes & cleanups.
Thanks to: Alan Modra, Alexey Kardashevskiy, Andrew Donnellan, Aneesh
Kumar K.V, Ard Biesheuvel, Athira Rajeev, Balamuruhan S, Bill Wendling,
Cédric Le Goater, Christophe Leroy, Christophe Lombard, Colin Ian King,
Daniel Axtens, David Hildenbrand, Frederic Barrat, Ganesh Goudar,
Gautham R. Shenoy, Geert Uytterhoeven, Giuseppe Sacco, Greg Kurz,
Harish, Jan Kratochvil, Jordan Niethe, Kaixu Xia, Laurent Dufour,
Leonardo Bras, Madhavan Srinivasan, Mahesh Salgaonkar, Mathieu
Desnoyers, Nathan Lynch, Nicholas Piggin, Oleg Nesterov, Oliver
O'Halloran, Oscar Salvador, Po-Hsu Lin, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sandipan Das, Sebastian Andrzej
Siewior , Segher Boessenkool, Srikar Dronamraju, Tyrel Datwyler, Uwe
Kleine-König, Vincent Stehlé, Youling Tang, and Zhang Xiaoxu.
* tag 'powerpc-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (304 commits)
powerpc/32s: Fix cleanup_cpu_mmu_context() compile bug
powerpc: Add config fragment for disabling -Werror
powerpc/configs: Add ppc64le_allnoconfig target
powerpc/powernv: Rate limit opal-elog read failure message
powerpc/pseries/memhotplug: Quieten some DLPAR operations
powerpc/ps3: use dma_mapping_error()
powerpc: force inlining of csum_partial() to avoid multiple csum_partial() with GCC10
powerpc/perf: Fix Threshold Event Counter Multiplier width for P10
powerpc/mm: Fix hugetlb_free_pmd_range() and hugetlb_free_pud_range()
KVM: PPC: Book3S HV: Fix mask size for emulated msgsndp
KVM: PPC: fix comparison to bool warning
KVM: PPC: Book3S: Assign boolean values to a bool variable
powerpc: Inline setup_kup()
powerpc/64s: Mark the kuap/kuep functions non __init
KVM: PPC: Book3S HV: XIVE: Add a comment regarding VP numbering
powerpc/xive: Improve error reporting of OPAL calls
powerpc/xive: Simplify xive_do_source_eoi()
powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_EOI_FW
powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_MASK_FW
powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_SHIFT_BUG
...
This is way to catch some cases of decrementer overflow, when the
decrementer has underflowed an odd number of times, while MSR[EE] was
disabled.
With a typical small decrementer, a timer that fires when MSR[EE] is
disabled will be "lost" if MSR[EE] remains disabled for between 4.3 and
8.6 seconds after the timer expires. In any case, the decrementer
interrupt would be taken at 8.6 seconds and the timer would be found at
that point.
So this check is for catching extreme latency events, and it prevents
those latencies from being a further few seconds long. It's not obvious
this is a good tradeoff. This is already a watchdog magnitude event and
that situation is not improved a significantly with this check. For
large decrementers, it's useless.
Therefore remove this check, which avoids a mftb when enabling hard
disabled interrupts (e.g., when enabling after coming from hardware
interrupt handlers). Perhaps more importantly, it also removes the
clunky MSR[EE] vs PACA_IRQ_HARD_DIS incoherency in soft-interrupt replay
which simplifies the code.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201107014336.2337337-1-npiggin@gmail.com
The 3 architectures implementing CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
all have their own version of irq time accounting that dispatch the
cputime to the appropriate index: hardirq, softirq, system, idle,
guest... from an all-in-one function.
Instead of having these ad-hoc versions, move the cputime destination
dispatch decision to the core code and leave only the actual per-index
cputime accounting to the architecture.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201202115732.27827-4-frederic@kernel.org
get_tbl() is confusing as it returns the content of TBL register
on PPC32 but the concatenation of TBL and TBU on PPC64.
Use mftb() instead.
Do the same with get_tbu() for consistency allthough it's name
is less confusing.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/41573406a4eab98838decaa91649086fef1e6119.1601556145.git.christophe.leroy@csgroup.eu
In order to use <asm/percpu.h> in lockdep.h, we need to make sure
asm/percpu.h does not itself depend on lockdep.
The below seems to make that so and builds powerpc64-defconfig +
PROVE_LOCKING.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
https://lkml.kernel.org/r/20200623083721.336906073@infradead.org
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
The PowerPC time code is not a clock provider, and just needs to call
of_clk_init().
Hence it can include <linux/of_clk.h> instead of <linux/clk-provider.h>.
Remove the #ifdef protecting the of_clk_init() call, as a stub is
available for the !CONFIG_COMMON_CLK case.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200213083804.24315-1-geert+renesas@glider.be
The hdec interrupt handler is reported to sometimes fire in Linux if
KVM leaves it pending after a guest exists. This is harmless, so there
is a no-op handler for it.
The interrupt handler currently uses the regular kernel stack. Change
this to avoid touching the stack entirely.
This should be the last place where the regular Linux stack can be
accessed with asynchronous interrupts (including PMI) soft-masked.
It might be possible to take advantage of this invariant, e.g., to
context switch the kernel stack SLB entry without clearing MSR[EE].
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200225173541.1549955-17-npiggin@gmail.com
clock_getres in the vDSO library has to preserve the same behaviour
of posix_get_hrtimer_res().
In particular, posix_get_hrtimer_res() does:
sec = 0;
ns = hrtimer_resolution;
and hrtimer_resolution depends on the enablement of the high
resolution timers that can happen either at compile or at run time.
Fix the powerpc vdso implementation of clock_getres keeping a copy of
hrtimer_resolution in vdso data and using that directly.
Fixes: a7f290dad3 ("[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel")
Cc: stable@vger.kernel.org
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
[chleroy: changed CLOCK_REALTIME_RES to CLOCK_HRTIMER_RES]
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a55eca3a5e85233838c2349783bcb5164dae1d09.1575273217.git.christophe.leroy@c-s.fr
This is a series of cleanups for the y2038 work, mostly intended
for namespace cleaning: the kernel defines the traditional
time_t, timeval and timespec types that often lead to y2038-unsafe
code. Even though the unsafe usage is mostly gone from the kernel,
having the types and associated functions around means that we
can still grow new users, and that we may be missing conversions
to safe types that actually matter.
There are still a number of driver specific patches needed to
get the last users of these types removed, those have been
submitted to the respective maintainers.
Link: https://lore.kernel.org/lkml/20191108210236.1296047-1-arnd@arndb.de/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'y2038-cleanups-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground
Pull y2038 cleanups from Arnd Bergmann:
"y2038 syscall implementation cleanups
This is a series of cleanups for the y2038 work, mostly intended for
namespace cleaning: the kernel defines the traditional time_t, timeval
and timespec types that often lead to y2038-unsafe code. Even though
the unsafe usage is mostly gone from the kernel, having the types and
associated functions around means that we can still grow new users,
and that we may be missing conversions to safe types that actually
matter.
There are still a number of driver specific patches needed to get the
last users of these types removed, those have been submitted to the
respective maintainers"
Link: https://lore.kernel.org/lkml/20191108210236.1296047-1-arnd@arndb.de/
* tag 'y2038-cleanups-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (26 commits)
y2038: alarm: fix half-second cut-off
y2038: ipc: fix x32 ABI breakage
y2038: fix typo in powerpc vdso "LOPART"
y2038: allow disabling time32 system calls
y2038: itimer: change implementation to timespec64
y2038: move itimer reset into itimer.c
y2038: use compat_{get,set}_itimer on alpha
y2038: itimer: compat handling to itimer.c
y2038: time: avoid timespec usage in settimeofday()
y2038: timerfd: Use timespec64 internally
y2038: elfcore: Use __kernel_old_timeval for process times
y2038: make ns_to_compat_timeval use __kernel_old_timeval
y2038: socket: use __kernel_old_timespec instead of timespec
y2038: socket: remove timespec reference in timestamping
y2038: syscalls: change remaining timeval to __kernel_old_timeval
y2038: rusage: use __kernel_old_timeval
y2038: uapi: change __kernel_time_t to __kernel_old_time_t
y2038: stat: avoid 'time_t' in 'struct stat'
y2038: ipc: remove __kernel_time_t reference from headers
y2038: vdso: powerpc: avoid timespec references
...
Highlights:
- Infrastructure for secure boot on some bare metal Power9 machines. The
firmware support is still in development, so the code here won't actually
activate secure boot on any existing systems.
- A change to xmon (our crash handler / pseudo-debugger) to restrict it to
read-only mode when the kernel is lockdown'ed, otherwise it's trivial to drop
into xmon and modify kernel data, such as the lockdown state.
- Support for KASLR on 32-bit BookE machines (Freescale / NXP).
- Fixes for our flush_icache_range() and __kernel_sync_dicache() (VDSO) to work
with memory ranges >4GB.
- Some reworks of the pseries CMM (Cooperative Memory Management) driver to
make it behave more like other balloon drivers and enable some cleanups of
generic mm code.
- A series of fixes to our hardware breakpoint support to properly handle
unaligned watchpoint addresses.
Plus a bunch of other smaller improvements, fixes and cleanups.
Thanks to:
Alastair D'Silva, Andrew Donnellan, Aneesh Kumar K.V, Anthony Steinhauser,
Cédric Le Goater, Chris Packham, Chris Smart, Christophe Leroy, Christopher M.
Riedl, Christoph Hellwig, Claudio Carvalho, Daniel Axtens, David Hildenbrand,
Deb McLemore, Diana Craciun, Eric Richter, Geert Uytterhoeven, Greg
Kroah-Hartman, Greg Kurz, Gustavo L. F. Walbon, Hari Bathini, Harish, Jason
Yan, Krzysztof Kozlowski, Leonardo Bras, Mathieu Malaterre, Mauro S. M.
Rodrigues, Michal Suchanek, Mimi Zohar, Nathan Chancellor, Nathan Lynch, Nayna
Jain, Nick Desaulniers, Oliver O'Halloran, Qian Cai, Rasmus Villemoes, Ravi
Bangoria, Sam Bobroff, Santosh Sivaraj, Scott Wood, Thomas Huth, Tyrel
Datwyler, Vaibhav Jain, Valentin Longchamp, YueHaibing.
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Merge tag 'powerpc-5.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Highlights:
- Infrastructure for secure boot on some bare metal Power9 machines.
The firmware support is still in development, so the code here
won't actually activate secure boot on any existing systems.
- A change to xmon (our crash handler / pseudo-debugger) to restrict
it to read-only mode when the kernel is lockdown'ed, otherwise it's
trivial to drop into xmon and modify kernel data, such as the
lockdown state.
- Support for KASLR on 32-bit BookE machines (Freescale / NXP).
- Fixes for our flush_icache_range() and __kernel_sync_dicache()
(VDSO) to work with memory ranges >4GB.
- Some reworks of the pseries CMM (Cooperative Memory Management)
driver to make it behave more like other balloon drivers and enable
some cleanups of generic mm code.
- A series of fixes to our hardware breakpoint support to properly
handle unaligned watchpoint addresses.
Plus a bunch of other smaller improvements, fixes and cleanups.
Thanks to: Alastair D'Silva, Andrew Donnellan, Aneesh Kumar K.V,
Anthony Steinhauser, Cédric Le Goater, Chris Packham, Chris Smart,
Christophe Leroy, Christopher M. Riedl, Christoph Hellwig, Claudio
Carvalho, Daniel Axtens, David Hildenbrand, Deb McLemore, Diana
Craciun, Eric Richter, Geert Uytterhoeven, Greg Kroah-Hartman, Greg
Kurz, Gustavo L. F. Walbon, Hari Bathini, Harish, Jason Yan, Krzysztof
Kozlowski, Leonardo Bras, Mathieu Malaterre, Mauro S. M. Rodrigues,
Michal Suchanek, Mimi Zohar, Nathan Chancellor, Nathan Lynch, Nayna
Jain, Nick Desaulniers, Oliver O'Halloran, Qian Cai, Rasmus Villemoes,
Ravi Bangoria, Sam Bobroff, Santosh Sivaraj, Scott Wood, Thomas Huth,
Tyrel Datwyler, Vaibhav Jain, Valentin Longchamp, YueHaibing"
* tag 'powerpc-5.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (144 commits)
powerpc/fixmap: fix crash with HIGHMEM
x86/efi: remove unused variables
powerpc: Define arch_is_kernel_initmem_freed() for lockdep
powerpc/prom_init: Use -ffreestanding to avoid a reference to bcmp
powerpc: Avoid clang warnings around setjmp and longjmp
powerpc: Don't add -mabi= flags when building with Clang
powerpc: Fix Kconfig indentation
powerpc/fixmap: don't clear fixmap area in paging_init()
selftests/powerpc: spectre_v2 test must be built 64-bit
powerpc/powernv: Disable native PCIe port management
powerpc/kexec: Move kexec files into a dedicated subdir.
powerpc/32: Split kexec low level code out of misc_32.S
powerpc/sysdev: drop simple gpio
powerpc/83xx: map IMMR with a BAT.
powerpc/32s: automatically allocate BAT in setbat()
powerpc/ioremap: warn on early use of ioremap()
powerpc: Add support for GENERIC_EARLY_IOREMAP
powerpc/fixmap: Use __fix_to_virt() instead of fix_to_virt()
powerpc/8xx: use the fixmapped IMMR in cpm_reset()
powerpc/8xx: add __init to cpm1 init functions
...
As a preparation to stop using 'struct timespec' in the kernel,
change the powerpc vdso implementation:
- split up the vdso data definition to have equivalent members
for seconds and nanoseconds instead of an xtime structure
- use timespec64 as an intermediate for the xtime update
- change the asm-offsets definition to be based the appropriate
fixed-length types
This is only a temporary fix for changing the types, in order
to actually support a 64-bit safe vdso32 version of clock_gettime(),
the entire powerpc vdso should be replaced with the generic
lib/vdso/ implementation. If that happens first, this patch
becomes obsolete.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
accumulate_stolen_time() is called prior to interrupt state being
reconciled, which can trip the warning in arch_local_irq_restore():
WARNING: CPU: 5 PID: 1017 at arch/powerpc/kernel/irq.c:258 .arch_local_irq_restore+0x9c/0x130
...
NIP .arch_local_irq_restore+0x9c/0x130
LR .rb_start_commit+0x38/0x80
Call Trace:
.ring_buffer_lock_reserve+0xe4/0x620
.trace_function+0x44/0x210
.function_trace_call+0x148/0x170
.ftrace_ops_no_ops+0x180/0x1d0
ftrace_call+0x4/0x8
.accumulate_stolen_time+0x1c/0xb0
decrementer_common+0x124/0x160
For now just mark it as notrace. We may change the ordering to call it
after interrupt state has been reconciled, but that is a larger
change.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191024055932.27940-1-mpe@ellerman.id.au
vtime_account_system() decides if we need to account the time to the
system (__vtime_account_system()) or to the guest (vtime_account_guest()).
So this function is a misnomer as we are on a higher level than
"system". All we know when we call that function is that we are
accounting kernel cputime. Whether it belongs to guest or system time
is a lower level detail.
Rename this function to vtime_account_kernel(). This will clarify things
and avoid too many underscored vtime_account_system() versions.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Link: https://lkml.kernel.org/r/20191003161745.28464-2-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On TOD/TB errors timebase register stops/freezes until HMI error recovery
gets TOD/TB back into running state. On successful recovery, TB starts
running again and udelay() that relies on TB value continues to function
properly. But in case when HMI fails to recover from TOD/TB errors, the
TB register stay freezed. With TB not running the __delay() function
keeps looping and never return. If __delay() is called while in panic
path then system hangs and never reboots after panic.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Remove linux/rtc.h which is included more than once
Signed-off-by: Brajeswar Ghosh <brajeswar.linux@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
If CONFIG_PPC_SPLPAR is not selected, steal_time will always
be NUL, so accounting it is pointless
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
scaled cputime is only meaningfull when the processor has
SPURR and/or PURR, which means only on PPC64.
Removing it on PPC32 significantly reduces the size of
vtime_account_system() and vtime_account_idle() on an 8xx:
Before:
00000000 l F .text 000000a8 vtime_delta
00000280 g F .text 0000010c vtime_account_system
0000038c g F .text 00000048 vtime_account_idle
After:
(vtime_delta gets inlined inside the two functions)
000001d8 g F .text 000000a0 vtime_account_system
00000278 g F .text 00000038 vtime_account_idle
In terms of performance, we also get approximatly 7% improvement on
task switch. The following small benchmark app is run with perf stat:
void *thread(void *arg)
{
int i;
for (i = 0; i < atoi((char*)arg); i++)
pthread_yield();
}
int main(int argc, char **argv)
{
pthread_t th1, th2;
pthread_create(&th1, NULL, thread, argv[1]);
pthread_create(&th2, NULL, thread, argv[1]);
pthread_join(th1, NULL);
pthread_join(th2, NULL);
return 0;
}
Before the patch:
Performance counter stats for 'chrt -f 98 ./sched 100000' (50 runs):
8228.476465 task-clock (msec) # 0.954 CPUs utilized ( +- 0.23% )
200004 context-switches # 0.024 M/sec ( +- 0.00% )
After the patch:
Performance counter stats for 'chrt -f 98 ./sched 100000' (50 runs):
7649.070444 task-clock (msec) # 0.955 CPUs utilized ( +- 0.27% )
200004 context-switches # 0.026 M/sec ( +- 0.00% )
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
scaled cputime is only meaningfull when the processor has
SPURR and/or PURR, which means only on PPC64.
In preparation of the following patch that will remove
CONFIG_ARCH_HAS_SCALED_CPUTIME on PPC32, this patch moves
all scaled cputing accounting logic into dedicated functions.
This patch doesn't change any functionality. It's only code
reorganisation.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In the recent commit 8b78fdb045 ("powerpc/time: Use
clockevents_register_device(), fixing an issue with large
decrementer") we changed the way we initialise the decrementer
clockevent(s).
We no longer initialise the mult & shift values of
decrementer_clockevent itself.
This has the effect of breaking PR KVM, because it uses those values
in kvmppc_emulate_dec(). The symptom is guest kernels spin forever
mid-way through boot.
For now fix it by assigning back to decrementer_clockevent the mult
and shift values.
Fixes: 8b78fdb045 ("powerpc/time: Use clockevents_register_device(), fixing an issue with large decrementer")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
If CONFIG_PPC_WATCHDOG is enabled we always cap the decrementer to
0x7fffffff:
if (IS_ENABLED(CONFIG_PPC_WATCHDOG))
set_dec(0x7fffffff);
else
set_dec(decrementer_max);
If there are no future events, we don't reprogram the decrementer
after this and we end up with 0x7fffffff even on a large decrementer
capable system.
As suggested by Nick, add a set_state_oneshot_stopped callback
so we program the decrementer with decrementer_max if there are
no future events.
Signed-off-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We currently cap the decrementer clockevent at 4 seconds, even on systems
with large decrementer support. Fix this by converting the code to use
clockevents_register_device() which calculates the upper bound based on
the max_delta passed in.
Signed-off-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
arch_vtime_task_switch() is a small function which is called
only from vtime_common_task_switch(), so it is worth inlining
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
to_tm() is now completely unused, the only reference being in the
_dump_time() helper that is also unused. This removes both, leaving
the rest of the powerpc RTC code y2038 safe to as far as the hardware
supports.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
update_persistent_clock() is deprecated because it suffers from overflow
in 2038 on 32-bit architectures. This changes powerpc to use the
update_persistent_clock64() replacement, and to pass down 64-bit
timestamps consistently.
This is now simpler, as we no longer have to worry about the offset
numbers in tm_year and tm_mon that are different between the Linux
conventions and RTAS.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Looking through the remaining users of the deprecated mktime()
function, I found the powerpc rtc handlers, which use it in
place of rtc_tm_to_time64().
To clean this up, I'm changing over the read_persistent_clock()
function to the read_persistent_clock64() variant, and change
all the platform specific handlers along with it.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
These are not local timer interrupts but IPIs. It's good to be able
to see how timer offloading is behaving, so split these out into
their own category.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Large decrementers (e.g., POWER9) can take a very long time to wrap,
so when the timer iterrupt handler sets the decrementer to max so as
to avoid taking another decrementer interrupt when hard enabling
interrupts before running timers, it effectively disables the soft
NMI coverage for timer interrupts.
Fix this by using the traditional 31-bit value instead, which wraps
after a few seconds. masked interrupt code does the same thing, and
in normal operation neither of these paths would ever wrap even the
31 bit value.
Note: the SMP watchdog should catch timer interrupt lockups, but it
is preferable for the local soft-NMI to catch them, mainly to avoid
the IPI.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The broadcast tick recipient can call tick_receive_broadcast rather
than re-running the full timer interrupt.
It does not have to check for the next event time, because the sender
already determined the timer has expired. It does not have to test
irq_work_pending, because that's a direct decrementer interrupt and
does not go through the clock events subsystem. And it does not have
to read PURR because that was removed with the previous patch.
This results in no code size change, but both the decrementer and
broadcast path lengths are reduced.
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
For SPLPAR, lparcfg provides a sum of PURR registers for all CPUs.
Currently this is done by reading PURR in context switch and timer
interrupt, and storing that into a per-CPU variable. These are summed
to provide the value.
This does not work with all timer schemes (e.g., NO_HZ_FULL), and it
is sub-optimal for performance because it reads the PURR register on
every context switch, although that's been difficult to distinguish
from noise in the contxt_switch microbenchmark.
This patch implements the sum by calling a function on each CPU, to
read and add PURR values of each CPU.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
irq_work_raise should not cause a decrementer exception unless it is
called from NMI context. Doing so often just results in an immediate
masked decrementer interrupt:
<...>-550 90d... 4us : update_curr_rt <-dequeue_task_rt
<...>-550 90d... 5us : dbs_update_util_handler <-update_curr_rt
<...>-550 90d... 6us : arch_irq_work_raise <-irq_work_queue
<...>-550 90d... 7us : soft_nmi_interrupt <-soft_nmi_common
<...>-550 90d... 7us : printk_nmi_enter <-soft_nmi_interrupt
<...>-550 90d.Z. 8us : rcu_nmi_enter <-soft_nmi_interrupt
<...>-550 90d.Z. 9us : rcu_nmi_exit <-soft_nmi_interrupt
<...>-550 90d... 9us : printk_nmi_exit <-soft_nmi_interrupt
<...>-550 90d... 10us : cpuacct_charge <-update_curr_rt
The soft_nmi_interrupt here is the call into the watchdog, due to the
decrementer interrupt firing with irqs soft-disabled. This is
harmless, but sub-optimal.
When it's not called from NMI context or with interrupts enabled, mark
the decrementer pending in the irq_happened mask directly, rather than
having the masked decrementer interupt handler do it. This will be
replayed at the next local_irq_enable. See the comment for details.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit 8e0b634b13 ("powerpc/64s: Do not allocate lppaca if we are
not virtualized") removed allocation of lppaca on bare metal
platforms. But with CONFIG_PPC_SPLPAR enabled, we still access the
lppaca on bare metal in some code paths.
Fix this but adding runtime checks for SPLPAR (shared processor LPAR).
Fixes: 8e0b634b13 ("powerpc/64s: Do not allocate lppaca if we are not virtualized")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The RTC core is always calling rtc_valid_tm after the read_time callback.
It is not necessary to call it just before returning from the callback.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Rename the paca->soft_enabled to paca->irq_soft_mask as it is no
longer used as a flag for interrupt state, but a mask.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add a new wrapper function, soft_enabled_return(), added to return
paca->soft_enabled value.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Move set_soft_enabled() from powerpc/kernel/irq.c to asm/hw_irq.c, to
encourage updates to paca->soft_enabled done via these access
function. Add "memory" clobber to hint compiler since
paca->soft_enabled memory is the target here.
Renaming it as soft_enabled_set() will make namespaces works better as
prefix than a postfix when new soft_enabled manipulation functions are
introduced.
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Two #defines IRQS_ENABLED and IRQS_DISABLED are added to be used when
updating paca->soft_enabled. Replace the hardcoded values used when
updating paca->soft_enabled with IRQ_(EN|DIS)ABLED #define. No logic
change.
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Use the different spin loop primitives in some simple powerpc
spin loops, including those which will spin as a common case.
This will help to test the spin loop primitives before more
conversions are done.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add some includes of <linux/processor.h>]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This converts the powerpc VDSO time update function to use the new
interface introduced in commit 576094b7f0 ("time: Introduce new
GENERIC_TIME_VSYSCALL", 2012-09-11). Where the old interface gave
us the time as of the last update in seconds and whole nanoseconds,
with the new interface we get the nanoseconds part effectively in
a binary fixed-point format with tk->tkr_mono.shift bits to the
right of the binary point.
With the old interface, the fractional nanoseconds got truncated,
meaning that the value returned by the VDSO clock_gettime function
would have about 1ns of jitter in it compared to the value computed
by the generic timekeeping code in the kernel.
The powerpc VDSO time functions (clock_gettime and gettimeofday)
already work in units of 2^-32 seconds, or 0.23283 ns, because that
makes it simple to split the result into seconds and fractional
seconds, and represent the fractional seconds in either microseconds
or nanoseconds. This is good enough accuracy for now, so this patch
avoids changing how the VDSO works or the interface in the VDSO data
page.
This patch converts the powerpc update_vsyscall_old to be called
update_vsyscall and use the new interface. We convert the fractional
second to units of 2^-32 seconds without truncating to whole nanoseconds.
(There is still a conversion to whole nanoseconds for any legacy users
of the vdso_data/systemcfg stamp_xtime field.)
In addition, this improves the accuracy of the computation of tb_to_xs
for those systems with high-frequency timebase clocks (>= 268.5 MHz)
by doing the right shift in two parts, one before the multiplication and
one after, rather than doing the right shift before the multiplication.
(We can't do all of the right shift after the multiplication unless we
use 128-bit arithmetic.)
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Since trace_clock is in a different file and already marked with notrace,
enable tracing in time.c by removing it from the disabled list in Makefile.
Also annotate clocksource read functions and sched_clock with notrace.
Testing: Timer and ftrace selftests run with different trace clocks.
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin