linux/arch/arc/kernel
Vineet Gupta dec2b2849c ARCv2: intc: Allow interruption by lowest priority interrupt
ARC HS Cores support configurable multiple interrupt priorities of upto
16 levels.

There is processor "interrupt preemption threshhold" in STATUS32.E[4:1]
And several places need to set this up:
1. seed value as kernel is booting
2. seed value for user space programs
3. Arg to SLEEP instruction in idle task (what interrupt prio can wake)
4. Per-IRQ line prioirty (i.e. what is the priority of interrupt
   raised by a peripheral or timer or perf counter...

Currently above sites use the highest priority 0. This can be potential
problem when multiple priorities are supported. e.g. user space could
only be interrupted by P0 interrupt, not others...
So turn this over and instead make default interruption level to be
the lowest priority possible 15. This should be fine even if there are
fewer priority levels configured (say two: P0 HIGH, P1 LOW)

This feature also effectively disables FIRQ feature if present in
hardware config. With old code, a P0 interrupt would be FIRQ, needing
special handling (ISR or Register Banks) which is NOT supported yet.
Now it not be P0 (P15 or whatever is lowest prio) so FIRQ is not
triggered.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2016-02-10 06:38:50 +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
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.c ARC: remove SYNC from __switch_to() 2015-11-17 22:05:30 +05:30
ctx_sw_asm.S 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 ARCv2: STAR 9000950267: Handle return from intr to Delay Slot #2 2016-01-22 17:25:03 +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: Allow interruption by lowest priority interrupt 2016-02-10 06:38:50 +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: smp: Rename platform hook @init_cpu_smp -> @init_per_cpu 2015-12-17 12:56:56 +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: clocksource: Rename GRTC -> GFRC ... 2016-01-29 16:51:02 +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 ARCv2: Check for LL-SC livelock only if LLSC is enabled 2016-01-29 16:51:04 +05:30
signal.c ARCv2: Support for ARCv2 ISA and HS38x cores 2015-06-22 14:06:55 +05:30
smp.c ARC: smp: Rename platform hook @init_cpu_smp -> @init_per_cpu 2015-12-17 12:56:56 +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 ARCv2: clocksource: Rename GRTC -> GFRC ... 2016-01-29 16:51:02 +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: Catch Dwarf SNAFUs early 2015-12-21 14:01:49 +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