* print aliasing or not, VIPT/PIPT etc
* compress param storage using bitfields
* more use of IS_ENABLED to de-uglify code
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
pt_regs->event was set with artificial values to identify the low level
system event (syscall trap / breakpoint trap / exceptions / interrupts)
With r8 saving out of the way, the full word can be used to save real
ECR (Exception Cause Register) which helps idenify the event naturally,
including additional info such as cause code, param.
Only for Interrupts, where ECR is not applicable, do we resort to
synthetic non ECR values.
SAVE_ALL_TRAP/EXCEPTIONS can now be merged as they both use ECR with
different runtime values.
The ptrace helpers now use the sub-fields of ECR to distinguish the
events (e.g. vector 0x25 is trap, param 0 is syscall...)
The following benefits will follow:
(1) This centralizes the location of where ECR is saved and will allow
the cleanup of task->thread.cause_code ECR placeholder which is set
in non-uniform way. Then ARC VM code can safely rely on it being
there for purpose of finer grained VM_EXEC dcache flush (based on
exec fault: I-TLB Miss)
(2) Further, ECR being passed around from low level handlers as arg can
be eliminated as it is part of standard reg-file in pt_regs
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* Number of (i|d)cache ways can be retrieved from BCRs and hence no need
to cross check with with built-in constants
* Use of IS_ENABLED() to check for a Kconfig option
* is_not_cache_aligned() not used anymore
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* Move the various sub-system defines/types into relevant files/functions
(reduces compilation time)
* move CPU specific stuff out of asm/tlb.h into asm/mmu.h
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC700 MMU provides for tagging TLB entries with a 8-bit ASID to avoid
having to flush the TLB every task switch.
It also allows for a quick way to invalidate all the TLB entries for
task useful for:
* COW sementics during fork()
* task exit()ing
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC700 has VIPT L1 Caches
* Caches don't snoop and are not coherent
* Given the PAGE_SIZE and Cache associativity, we don't support aliasing
D$ configurations (yet), but do allow aliasing I$ configs
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC700 includes 2 in-core 32bit timers TIMER0 and TIMER1.
Both have exactly same capabilies.
* programmable to count from TIMER<n>_CNT to TIMER<n>_LIMIT
* for count 0 and LIMIT ~1, provides a free-running counter by
auto-wrapping when limit is reached.
* optionally interrupt when LIMIT is reached (oneshot event semantics)
* rearming the interrupt provides periodic semantics
* run at CPU clk
ARC Linux uses TIMER0 for clockevent (periodic/oneshot) and TIMER1 for
clocksource (free-running clock).
Newer cores provide RTSC insn which gives a 64bit cpu clk snapshot hence
is more apt for clocksource when available.
SMP poses a bit of challenge for global timekeeping clocksource /
sched_clock() backend:
-TIMER1 based local clocks are out-of-sync hence can't be used
(thus we default to jiffies based cs as well as sched_clock() one/both
of which platform can override with it's specific hardware assist)
-RTSC is only allowed in SMP if it's cross-core-sync (Kconfig glue
ensures that) and thus usable for both requirements.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
ARC700 has an in-core intc which provides 2 priorities (a.k.a.) "levels"
of interrupts (per IRQ) hencforth referred to as L1/L2 interrupts.
CPU flags register STATUS32 has Interrupt Enable bits per level (E1/E2)
to globally enable (or disable) all IRQs at a level. Hence the
implementation of arch_local_irq_{save,restore,enable,disable}( )
The STATUS32 reg can be r/w only using the AUX Interface of ARC, hence
the use of LR/SR instructions. Further, E1/E2 bits in there can only be
updated using the FLAG insn.
The intc supports 32 interrupts - and per IRQ enabling is controlled by
a bit in the AUX_IENABLE register, hence the implmentation of
arch_{,un}mask_irq( ) routines.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Vineet Gupta