linux/arch/arc/kernel
Vineet Gupta c6317bc7c5 ARCv2: perf: Ensure perf intr gets enabled on all cores
This was the second perf intr issue

perf sampling on multicore requires intr to be enabled on all cores.
ARC perf probe code used helper arc_request_percpu_irq() which calls
 - request_percpu_irq() on core0
 - enable_percpu_irq() on all all cores (including core0)

genirq requires that request be made ahead of enable call.
However if perf probe happened on non core0 (observed on a 3.18 kernel),
enable would get called ahead of request, failing obviously and
rendering perf intr disabled on all such cores

[   11.120000] 1 ARC perf       : 8 counters (48 bits), 113 conditions, [overflow IRQ support]
[   11.130000] 1 -----> enable_percpu_irq() IRQ 20 failed
[   11.140000] 3 -----> enable_percpu_irq() IRQ 20 failed
[   11.140000] 2 -----> enable_percpu_irq() IRQ 20 failed
[   11.140000] 0 =====> request_percpu_irq() IRQ 20
[   11.140000] 0 -----> enable_percpu_irq() IRQ 20

Fix this fragility, by calling request_percpu_irq() on whatever core
calls probe (there is no requirement on which core calls this anyways)
and then calling enable on each cores.

Interestingly this started as invesigation of STAR 9000838902:
"sporadically IRQs enabled on perf prob"

which was about occassional boot spew as request_percpu_irq got called
non-locally (from an IPI), and re-enabled interrupts in following path
proc_mkdir ->  spin_unlock_irq()

which the irq work code didn't like.

| ARC perf     : 8 counters (48 bits), 113 conditions, [overflow IRQ support]
|
| BUG: failure at ../kernel/irq_work.c:135/irq_work_run_list()!
| CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.18.10-01127-g285efb8e66d1 #2
|
| Stack Trace:
|  arc_unwind_core.constprop.1+0x94/0x104
|  dump_stack+0x62/0x98
|  irq_work_run_list+0xb0/0xb4
|  irq_work_run+0x22/0x3c
|  do_IPI+0x74/0x9c
|  handle_irq_event_percpu+0x34/0x164
|  handle_percpu_irq+0x58/0x78
|  generic_handle_irq+0x1e/0x2c
|  arch_do_IRQ+0x3c/0x60
|  ret_from_exception+0x0/0x8

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: <stable@vger.kernel.org> #4.2+
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-12-12 16:03:59 +05:30
..
.gitignore ARC: Add some .gitignore entries 2013-08-26 09:40:24 +05:30
arc_hostlink.c ARC: Hostlink Pseudo-Driver for Metaware Debugger 2013-02-15 23:16:10 +05:30
arcksyms.c ARC: Build system: Makefiles, Kconfig, Linker script 2013-02-11 20:00:25 +05:30
asm-offsets.c ARCv2: [vdk] dts files and defconfig for HS38 VDK 2015-06-25 06:00:21 +05:30
clk.c ARC: fix typo with clock speed 2013-05-07 13:43:54 +05:30
ctx_sw_asm.S ARC: remove SYNC from __switch_to() 2015-11-17 22:05:30 +05:30
ctx_sw.c ARC: remove SYNC from __switch_to() 2015-11-17 22:05:30 +05:30
devtree.c ARCv2: [axs103] Support ARC SDP FPGA platform for HS38x cores 2015-06-25 06:00:20 +05:30
disasm.c ARC: rename kconfig option for unaligned emulation 2014-10-13 14:46:15 +05:30
entry-arcv2.S ARC: [arcompact] Handle bus error from userspace as Interrupt not exception 2015-11-14 13:12:20 +05:30
entry-compact.S ARC: [arcompact] Handle bus error from userspace as Interrupt not exception 2015-11-14 13:12:20 +05:30
entry.S ARC: [arcompact] Handle bus error from userspace as Interrupt not exception 2015-11-14 13:12:20 +05:30
fpu.c ARC: Process-creation/scheduling/idle-loop 2013-02-11 20:00:38 +05:30
head.S ARC: boot: Non Master cpus only need to call EARLY_CPU_SETUP once 2015-10-28 16:13:42 +05:30
intc-arcv2.c ARCv2: intc: Fix random perf irq disabling in SMP setup 2015-12-12 16:03:41 +05:30
intc-compact.c ARC: smp: irqchip: handle IPI as percpu irq like timer 2015-10-28 16:13:39 +05:30
irq.c ARC: intc: No need to clear IRQ_NOAUTOEN 2015-12-12 16:03:59 +05:30
kgdb.c ARC: kgdb: generic kgdb_arch_pc() suffices 2014-10-22 16:14:04 -06:00
kprobes.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-11-15 16:47:22 -08:00
Makefile ARCv2: SMP: Support ARConnect (MCIP) for Inter-Core-Interrupts et al 2015-06-22 14:06:56 +05:30
mcip.c ARCv2: smp: [plat-*]: No need to explicitly call mcip_init_smp() 2015-10-28 16:13:41 +05:30
module.c ARC: Fix coding style issues 2013-04-09 12:21:14 +05:30
perf_event.c ARCv2: perf: Ensure perf intr gets enabled on all cores 2015-12-12 16:03:59 +05:30
process.c ARC: Abstract out ISA specific SLEEP args 2015-11-16 14:17:02 +05:30
ptrace.c ARCv2: Support for ARCv2 ISA and HS38x cores 2015-06-22 14:06:55 +05:30
reset.c arc: export symbol for pm_power_off in reset.c 2013-11-06 10:41:44 +05:30
setup.c ARC: smp: Introduce smp hook @init_early_smp for Master core 2015-10-28 16:13:40 +05:30
signal.c ARCv2: Support for ARCv2 ISA and HS38x cores 2015-06-22 14:06:55 +05:30
smp.c ARC: smp: Introduce smp hook @init_irq_cpu called for all cores 2015-10-28 16:13:41 +05:30
stacktrace.c ARC: stack unwinder to bail if PC is not kernel mode 2015-06-19 18:09:29 +05:30
sys.c ARC: ABIv3: fork/vfork wrappers not needed in "no-legacy-syscall" ABI 2013-03-11 19:01:10 +05:30
time.c ARC: remove @init_time, @init_irq platform callbacks 2015-10-28 16:13:39 +05:30
traps.c ARC: rename unhandled exception handler 2015-04-13 15:14:57 +05:30
troubleshoot.c ARC: fix unused var wanring 2015-07-06 11:09:01 +05:30
unaligned.c ARC: change some branchs to jumps to resolve linkage errors 2015-08-20 18:53:15 +05:30
unwind.c ARC: dw2 unwind: Remove falllback linear search thru FDE entries 2015-11-23 21:36:49 +05:30
vmlinux.lds.S ARC: boot: Support Halt-on-reset and Run-on-reset SMP booting modes 2015-10-28 16:08:17 +05:30