freebsd-skq/sys/riscv
br e5126bd290 Support RISC-V implementations that do not manage the A and D bits
(e.g. RocketChip, lowRISC and derivatives).

RISC-V page table entries support A (accessed) and D (dirty) bits. The
spec makes hardware support for these bits optional. Implementations that
do not manage these bits in hardware raise page faults for accesses to a
valid page without A set and writes to a writable page without D set.
Check for these types of faults when handling a page fault and fixup the
PTE without calling vm_fault if they occur.

Reviewed by:	jhb, markj
Approved by:	re (gjb)
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D17424
2018-10-18 15:25:07 +00:00
..
conf Add support for the UART device found in lowRISC system-on-a-chip. 2018-10-12 15:19:41 +00:00
include Support RISC-V implementations that do not manage the A and D bits 2018-10-18 15:25:07 +00:00
riscv Support RISC-V implementations that do not manage the A and D bits 2018-10-18 15:25:07 +00:00