Pull RISC-V fixes from Palmer Dabbelt:
"Two fixes:
- 16KiB kernel stacks on rv64, which fixes a lot of crashes.
- Rolling an mmiowb() into the scheduler, which when combined with
Will's fix to the mmiowb()-on-spinlock should fix the PREEMPT
issues we've been seeing"
* tag 'riscv-for-linus-5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
RISC-V: Upgrade smp_mb__after_spinlock() to iorw,iorw
riscv: use 16KB kernel stack on 64-bit