Steal time initialization requires mapping a memory region which
invokes a memory allocation. Doing this at CPU starting time results
in the following trace when CONFIG_DEBUG_ATOMIC_SLEEP is enabled:
BUG: sleeping function called from invalid context at mm/slab.h:498
in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 0, name: swapper/1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.9.0-rc5+ #1
Call trace:
dump_backtrace+0x0/0x208
show_stack+0x1c/0x28
dump_stack+0xc4/0x11c
___might_sleep+0xf8/0x130
__might_sleep+0x58/0x90
slab_pre_alloc_hook.constprop.101+0xd0/0x118
kmem_cache_alloc_node_trace+0x84/0x270
__get_vm_area_node+0x88/0x210
get_vm_area_caller+0x38/0x40
__ioremap_caller+0x70/0xf8
ioremap_cache+0x78/0xb0
memremap+0x9c/0x1a8
init_stolen_time_cpu+0x54/0xf0
cpuhp_invoke_callback+0xa8/0x720
notify_cpu_starting+0xc8/0xd8
secondary_start_kernel+0x114/0x180
CPU1: Booted secondary processor 0x0000000001 [0x431f0a11]
However we don't need to initialize steal time at CPU starting time.
We can simply wait until CPU online time, just sacrificing a bit of
accuracy by returning zero for steal time until we know better.
While at it, add __init to the functions that are only called by
pv_time_init() which is __init.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Fixes: e0685fa228 ("arm64: Retrieve stolen time as paravirtualized guest")
Cc: stable@vger.kernel.org
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20200916154530.40809-1-drjones@redhat.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Instead of maintaining 2 sets of enums/macros for tracking SMCCC version,
let us drop smccc_version enum and use ARM_SMCCC_VERSION_1_x directly
instead.
This is in preparation to drop smccc_version here and move it separately
under drivers/firmware/smccc.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Etienne Carriere <etienne.carriere@st.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Etienne Carriere <etienne.carriere@st.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200518091222.27467-5-sudeep.holla@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Enable paravirtualization features when running under a hypervisor
supporting the PV_TIME_ST hypercall.
For each (v)CPU, we ask the hypervisor for the location of a shared
page which the hypervisor will use to report stolen time to us. We set
pv_time_ops to the stolen time function which simply reads the stolen
value from the shared page for a VCPU. We guarantee single-copy
atomicity using READ_ONCE which means we can also read the stolen
time for another VCPU than the currently running one while it is
potentially being updated by the hypervisor.
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <maz@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 version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 655 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce CONFIG_PARAVIRT and PARAVIRT_TIME_ACCOUNTING on ARM64.
Necessary duplication of paravirt.h and paravirt.c with ARM.
The only paravirt interface supported is pv_time_ops.steal_clock, so no
runtime pvops patching needed.
This allows us to make use of steal_account_process_tick for stolen
ticks accounting.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Andrew Jones