Alan Cox fd2dae0a30 Implement an alternative solution to the amd64 and i386 pmap problem that we ... previously addressed in r348246. This pmap problem also exists on arm64 and riscv. However, the original solution developed for amd64 and i386 cannot be used on arm64 and riscv. In particular, arm64 and riscv do not define a PG_PROMOTED flag in their level 2 PTEs. (A PG_PROMOTED flag makes no sense on arm64, where unlike x86 or riscv we are required to break the old 4KB mappings before making the 2MB mapping; and on riscv there are no unused bits in the PTE to define a PG_PROMOTED flag.) This commit implements an alternative solution that can be used on all four architectures. Moreover, this solution has two other advantages. First, on older AMD processors that required the Erratum 383 workaround, it is less costly. Specifically, it avoids unnecessary calls to pmap_fill_ptp() on a superpage demotion. Second, it enables the elimination of some calls to pagezero() in pmap_kernel_remove_{l2,pde}(). In addition, remove a related stale comment from pmap_enter_{l2,pde}(). Reviewed by: kib, markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D20538		2019-06-09 03:36:10 +00:00
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conf
include	Add support for HiFive Unleashed -- the board with a multi-core RISC-V SoC	2019-05-12 16:17:05 +00:00
riscv	Implement an alternative solution to the amd64 and i386 pmap problem that we	2019-06-09 03:36:10 +00:00