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linux_dsm_epyc7002/arch/powerpc/kernel
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Valentin Schneider 3c51d82d0b sched/core: Initialize the idle task with preemption disabled 
[ Upstream commit f1a0a376ca0c4ef1fc3d24e3e502acbb5b795674 ]

As pointed out by commit

  de9b8f5dcb ("sched: Fix crash trying to dequeue/enqueue the idle thread")

init_idle() can and will be invoked more than once on the same idle
task. At boot time, it is invoked for the boot CPU thread by
sched_init(). Then smp_init() creates the threads for all the secondary
CPUs and invokes init_idle() on them.

As the hotplug machinery brings the secondaries to life, it will issue
calls to idle_thread_get(), which itself invokes init_idle() yet again.
In this case it's invoked twice more per secondary: at _cpu_up(), and at
bringup_cpu().

Given smp_init() already initializes the idle tasks for all *possible*
CPUs, no further initialization should be required. Now, removing
init_idle() from idle_thread_get() exposes some interesting expectations
with regards to the idle task's preempt_count: the secondary startup always
issues a preempt_disable(), requiring some reset of the preempt count to 0
between hot-unplug and hotplug, which is currently served by
idle_thread_get() -> idle_init().

Given the idle task is supposed to have preemption disabled once and never
see it re-enabled, it seems that what we actually want is to initialize its
preempt_count to PREEMPT_DISABLED and leave it there. Do that, and remove
init_idle() from idle_thread_get().

Secondary startups were patched via coccinelle:

  @begone@
  @@

  -preempt_disable();
  ...
  cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210512094636.2958515-1-valentin.schneider@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:55:50 +02:00
..
ptrace powerpc/watchpoint/ptrace: Introduce PPC_DEBUG_FEATURE_DATA_BP_ARCH_31 2020-09-15 22:13:20 +10:00
syscalls mm/madvise: introduce process_madvise() syscall: an external memory hinting API 2020-10-18 09:27:10 -07:00
trace powerpc: Add a ppc_inst_as_str() helper 2020-07-23 17:41:36 +10:00
vdso32 Kbuild updates for v5.10 2020-10-22 13:13:57 -07:00
vdso64 powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64() semantics 2021-02-13 13:55:02 +01:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
align.c powerpc: Use fallthrough pseudo-keyword 2020-07-29 21:09:37 +10:00
asm-offsets.c powerpc/64: Fix stack trace not displaying final frame 2021-03-17 17:06:24 +01:00
audit.c
btext.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
cacheinfo.c powerpc/cacheinfo: Warn if cache object chain becomes unordered 2020-07-30 22:53:48 +10:00
cacheinfo.h powerpc/cacheinfo: add cacheinfo_teardown, cacheinfo_rebuild 2019-06-15 16:52:06 +10:00
compat_audit.c
cpu_setup_6xx.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
cpu_setup_44x.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cpu_setup_fsl_booke.S powerpc/booke: Spelling s/date/data/ 2019-11-17 01:56:31 -06:00
cpu_setup_pa6t.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
cpu_setup_power.S powerpc/perf: Initialize power10 PMU registers in cpu setup routine 2020-07-26 23:34:23 +10:00
cpu_setup_ppc970.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cputable.c powerpc/64s: Remove TM from Power10 features 2020-10-20 23:33:51 +11:00
crash_dump.c powerpc: Add prefixed instructions to instruction data type 2020-05-19 00:10:39 +10:00
dawr.c powerpc/watchpoint: Guest support for 2nd DAWR hcall 2020-07-26 23:34:19 +10:00
dbell.c powerpc: Inline doorbell sending functions 2020-07-29 21:02:09 +10:00
dma-iommu.c dma-mapping: add a new dma_alloc_pages API 2020-09-25 06:20:47 +02:00
dma-mask.c dma-mapping, powerpc: simplify the arch dma_set_mask override 2019-02-18 22:41:03 +11:00
dma-swiotlb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
dt_cpu_ftrs.c powerpc: untangle cputable mce include 2020-10-06 23:22:22 +11:00
early_32.c powerpc/fsl_booke/32: implement KASLR infrastructure 2019-11-13 19:27:40 +11:00
eeh_cache.c powerpc/eeh_cache: Fix a possible debugfs deadlock 2020-11-02 12:54:20 +11:00
eeh_driver.c pci-v5.9-changes 2020-08-07 18:48:15 -07:00
eeh_event.c powerpc/eeh: Fix build with STACKTRACE=n 2019-09-14 00:01:14 +10:00
eeh_pe.c powerpc/eeh: Delete eeh_pe->config_addr 2020-10-07 22:34:47 +11:00
eeh_sysfs.c powerpc/eeh: Pass eeh_dev to eeh_ops->resume_notify() 2020-07-26 23:34:20 +10:00
eeh.c powerpc/eeh: Fix EEH handling for hugepages in ioremap space. 2021-05-11 14:47:35 +02:00
entry_32.S powerpc/32s: Add missing call to kuep_lock on syscall entry 2021-03-04 11:38:40 +01:00
entry_64.S powerpc/64s: fix scv entry fallback flush vs interrupt 2021-01-27 11:55:12 +01:00
epapr_hcalls.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
epapr_paravirt.c powerpc: Use a datatype for instructions 2020-05-19 00:10:37 +10:00
exceptions-64e.S powerpc/64e: remove 64s specific interrupt soft-mask code 2020-10-06 23:22:23 +11:00
exceptions-64s.S powerpc/64s/exception: Clean up a missed SRR specifier 2021-03-17 17:06:34 +01:00
fadump.c powerpc/fadump: Mark fadump_calculate_reserve_size as __init 2021-05-14 09:50:30 +02:00
firmware.c powerpc/pseries: Add KVM guest doorbell restrictions 2020-07-29 21:02:10 +10:00
fpu.S powerpc: Drop SYNC_601() ISYNC_601() and SYNC() 2020-10-08 21:17:13 +11:00
fsl_booke_entry_mapping.S powerpc/fsl_booke/32: implement KASLR infrastructure 2019-11-13 19:27:40 +11:00
head_8xx.S powerpc/8xx: Fix software emulation interrupt 2021-03-04 11:38:05 +01:00
head_32.h powerpc/32: Statically initialise first emergency context 2021-05-19 10:12:54 +02:00
head_40x.S powerpc/40x: Always fault when _PAGE_ACCESSED is not set 2020-11-05 23:34:16 +11:00
head_44x.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
head_64.S powerpc/64: Fix an EMIT_BUG_ENTRY in head_64.S 2020-12-30 11:53:32 +01:00
head_book3s_32.S powerpc/603: Fix protection of user pages mapped with PROT_NONE 2021-03-17 17:06:13 +01:00
head_booke.h powerpc: Remove SYNC on non 6xx 2020-10-08 21:17:12 +11:00
head_fsl_booke.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
hw_breakpoint_constraints.c powerpc/watchpoint: Move DAWR detection logic outside of hw_breakpoint.c 2020-09-15 22:13:19 +10:00
hw_breakpoint.c powerpc/watchpoint: Move DAWR detection logic outside of hw_breakpoint.c 2020-09-15 22:13:19 +10:00
idle_6xx.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
idle_book3e.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
idle_book3s.S powerpc/64s: Reimplement power4_idle code in C 2020-01-16 14:59:37 +10:00
idle_e500.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
idle.c sched/idle: Fix arch_cpu_idle() vs tracing 2020-11-24 16:47:35 +01:00
ima_arch.c powerpc/ima: Fix secure boot rules in ima arch policy 2020-05-07 17:25:54 +10:00
io-workarounds.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
io.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
iomap.c iomap: constify ioreadX() iomem argument (as in generic implementation) 2020-08-14 19:56:57 -07:00
iommu.c powerpc/iommu: Annotate nested lock for lockdep 2021-05-19 10:12:58 +02:00
irq.c powerpc/kuap: Restore AMR after replaying soft interrupts 2021-03-04 11:38:06 +01:00
isa-bridge.c powerpc: remove __ioremap_at and __iounmap_at 2020-06-02 10:59:10 -07:00
jump_label.c powerpc: Use a datatype for instructions 2020-05-19 00:10:37 +10:00
kgdb.c maccess: make get_kernel_nofault() check for minimal type compatibility 2020-06-18 12:10:37 -07:00
kprobes-ftrace.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
kprobes.c powerpc/kprobes: Fix validation of prefixed instructions across page boundary 2021-06-10 13:39:27 +02:00
kvm_emul.S powerpc/kvm: Add ifdefs around template code 2019-09-14 00:04:40 +10:00
kvm.c powerpc/kvm: Explicitly mark kvm guest code as __init 2019-09-14 00:04:40 +10:00
l2cr_6xx.S powerpc: Drop SYNC_601() ISYNC_601() and SYNC() 2020-10-08 21:17:13 +11:00
legacy_serial.c tty/serial: Migrate 8250_fsl to use has_sysrq 2019-12-18 15:04:42 +01:00
Makefile powerpc: Avoid broken GCC __attribute__((optimize)) 2020-12-30 11:53:15 +01:00
mce_power.c powerpc/powernv: Machine check handler for POWER10 2020-07-23 17:43:30 +10:00
mce.c powerpc/mce: Avoid nmi_enter/exit in real mode on pseries hash 2020-10-16 20:13:55 +11:00
misc_32.S powerpc: Rewrite FSL_BOOKE flush_cache_instruction() in C 2020-09-02 11:00:21 +10:00
misc_64.S powerpc: Remove SYNC on non 6xx 2020-10-08 21:17:12 +11:00
misc.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
module_32.c powerpc: module_[32|64].c: replace swap function with built-in one 2020-05-11 23:15:14 +10:00
module_64.c maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
module.c powerpc: Use MODULES_VADDR if defined 2020-07-27 00:01:30 +10:00
msi.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
note.S powerpc: Add PowerPC Capabilities ELF note 2019-08-30 09:40:15 +10:00
nvram_64.c powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
of_platform.c powerpc/eeh: Remove eeh_dev_phb_init_dynamic() 2020-07-26 23:34:19 +10:00
optprobes_head.S powerpc: Add prefixed instructions to instruction data type 2020-05-19 00:10:39 +10:00
optprobes.c powerpc: Add ppc_inst_as_u64() 2020-05-26 23:36:57 +10:00
paca.c powerpc: Avoid broken GCC __attribute__((optimize)) 2020-12-30 11:53:15 +01:00
pci_32.c powerpc/64: Adjust order in pcibios_init() 2019-08-22 23:11:48 +10:00
pci_64.c powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
pci_dn.c powerpc/eeh: Rename eeh_{add_to|remove_from}_parent_pe() 2020-07-26 23:34:21 +10:00
pci_of_scan.c powerpc/pci: Remove pcibios_setup_bus_devices() 2020-01-06 16:25:29 +11:00
pci-common.c powerpc/pci: Add ppc_md.discover_phbs() 2021-03-17 17:06:23 +01:00
pci-hotplug.c powerpc/eeh: Release EEH device state synchronously 2020-05-18 21:58:44 +10:00
pmc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ppc32.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ppc_save_regs.S powerpc: Improve ppc_save_regs() 2020-04-04 21:40:57 +11:00
proc_powerpc.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
process.c powerpc/64: Fix stack trace not displaying final frame 2021-03-17 17:06:24 +01:00
prom_init_check.sh powerpc/prom_init: Undo relocation before entering secure mode 2019-10-29 15:12:17 +11:00
prom_init.c powerpc/prom: Fix "ibm,arch-vec-5-platform-support" scan 2021-03-04 11:38:35 +01:00
prom_parse.c
prom.c powerpc/prom: Mark identical_pvr_fixup as __init 2021-05-14 09:50:30 +02:00
reloc_32.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
reloc_64.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
rtas_flash.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
rtas_pci.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
rtas-proc.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
rtas-rtc.c
rtas.c powerpc/rtas: Fix typo of ibm,open-errinjct in RTAS filter 2020-12-30 11:54:15 +01:00
rtasd.c powerpc/rtasd: simplify handle_rtas_event(), emit message on events 2020-07-16 13:12:38 +10:00
secure_boot.c powerpc/pseries: Detect secure and trusted boot state of the system. 2020-07-16 14:49:53 +10:00
security.c powerpc/security: Fix link stack flush instruction 2020-10-08 12:50:52 +11:00
secvar-ops.c powerpc/powernv: Add OPAL API interface to access secure variable 2019-11-13 00:33:22 +11:00
secvar-sysfs.c powerpc: expose secure variables to userspace via sysfs 2019-11-13 00:33:22 +11:00
setup_32.c powerpc/32: Statically initialise first emergency context 2021-05-19 10:12:54 +02:00
setup_64.c powerpc: Fix early setup to make early_ioremap() work 2021-05-26 12:06:50 +02:00
setup-common.c powerpc/64: Set up a kernel stack for secondaries before cpu_restore() 2020-12-30 11:53:01 +01:00
setup.h powerpc: Avoid broken GCC __attribute__((optimize)) 2020-12-30 11:53:15 +01:00
signal_32.c powerpc/signal_32: Simplify loop in PPC64 save_general_regs() 2020-07-15 12:04:40 +10:00
signal_64.c powerpc/signal64: Don't opencode page prefaulting 2020-07-15 12:04:40 +10:00
signal.c arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
signal.h powerpc/64/sycall: Implement syscall entry/exit logic in C 2020-04-01 13:42:13 +11:00
smp-tbsync.c
smp.c sched/core: Initialize the idle task with preemption disabled 2021-07-14 16:55:50 +02:00
stacktrace.c powerpc/stacktrace: Fix spurious "stale" traces in raise_backtrace_ipi() 2021-07-14 16:55:46 +02:00
suspend.c PM: hibernate: powerpc: Expose pfn_is_nosave() prototype 2019-06-14 10:48:56 +02:00
swsusp_32.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
swsusp_64.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
swsusp_asm64.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
swsusp_booke.S
swsusp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sys_ppc32.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
syscall_64.c powerpc: Only include kup-radix.h for 64-bit Book3S 2020-11-19 23:47:20 +11:00
syscalls.c y2038: syscalls: change remaining timeval to __kernel_old_timeval 2019-11-15 14:38:29 +01:00
sysfs.c powerpc/sysfs: Remove unused 'err' variable in sysfs_create_dscr_default() 2020-09-18 20:05:24 +10:00
systbl_chk.sh treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
systbl.S powerpc/64/sycall: Implement syscall entry/exit logic in C 2020-04-01 13:42:13 +11:00
tau_6xx.c powerpc/tau: Disable TAU between measurements 2020-09-15 22:13:30 +10:00
time.c powerpc/time: Enable sched clock for irqtime 2021-03-04 11:38:01 +01:00
tm.S powerpc/tm: Save and restore AMR on treclaim and trechkpt 2020-10-06 23:22:25 +11:00
traps.c powerpc: improve handling of unrecoverable system reset 2021-03-17 17:06:23 +01:00
ucall.S powerpc/kernel: Add ucall_norets() ultravisor call handler 2019-08-30 09:40:15 +10:00
udbg_16550.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
udbg.c powerpc/udbg: Make it safe to call udbg_printf() always 2019-10-11 19:33:25 +11:00
uprobes.c powerpc: Add ppc_inst_next() 2020-05-26 23:36:51 +10:00
vdso.c powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64() semantics 2021-02-13 13:55:02 +01:00
vecemu.c powerpc: Define and use get_user_instr() et. al. 2020-05-19 00:10:37 +10:00
vector.S powerpc: re-initialise lazy FPU/VEC counters on every fault 2020-07-16 13:00:24 +10:00
vmlinux.lds.S powerpc/64s: fix scv entry fallback flush vs interrupt 2021-01-27 11:55:12 +01:00
watchdog.c powerpc/watchdog: Use hrtimers for per-CPU heartbeat 2019-04-30 11:31:02 +10:00