TLB invalidate didn't contain a barrier operation in csky cpu and
we need to prevent previous PTW response after TLB invalidation
instruction. Of cause, the ASID changing also needs to take care
of the issue.
CPU0 CPU1
=============== ===============
set_pte
sync_is() -> See the previous set_pte for all harts
tlbi.vas -> Invalidate all harts TLB entry & flush pipeline
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
There are two generations of tlb operation instruction for C-SKY.
First generation is use mcr register and it need software do more
things, second generation is use specific instructions, eg:
tlbi.va, tlbi.vas, tlbi.alls
We implemented the following functions:
- flush_tlb_range (a range of entries)
- flush_tlb_page (one entry)
Above functions use asid from vma->mm to invalid tlb entries and
we could use tlbi.vas instruction for newest generation csky cpu.
- flush_tlb_kernel_range
- flush_tlb_one
Above functions don't care asid and it invalid the tlb entries only
with vpn and we could use tlbi.vaas instruction for newest generat-
ion csky cpu.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Current C-SKY ASID mechanism is from mips and it doesn't work well
with multi-cores. ASID per core mechanism is not suitable for C-SKY
SMP tlb maintain operations, eg: tlbi.vas need share the same asid
in all processors and it'll invalid the tlb entry in all cores with
the same asid.
This patch is prepare for new ASID mechanism.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>