riscv/mmu: fix some code typos in hrev57298 that lead to boot failure

Change-Id: If0b2fded13ac079e505038fb51d05f7cfcb3d161
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6953
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

riscv64/mmu: use struct bitfield for flags and std::atomic

Fixes some PTE concurrent access bugs.

Change-Id: I09ec56861fae389a8a3e228b17a3921b85202c8b
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6949
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>

mmu/riscv64: implement global page mapping support

ASID allocation is not supported yet, so always use ASID 0 for user pages for now.

Change-Id: I021e77dae692c22984bc625dd0588362bece45b7
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6698
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>

riscv: use atomic CSR bit set/clear operations, refactor

Fix race conditions that cause broken timer interrupts.

Change-Id: I78e13a18d394b1566977e894a1def16a66c9ca5f
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5883
Reviewed-by: X512 <danger_mail@list.ru>
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>

haiku_loader.riscv: update

* Moved machine mode code from kernel.
* Added MMU page table generation.
* Added QEMU ramfb video driver.

Change-Id: Icd67cd2e8dbf2b568d81ab8dd0d6127ca3cd97a8
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4302
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>

haiku_loader: initial support for RISC-V TinyEMU

Change-Id: Ie102f466725f45072db25a9629fa8e28526484eb
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3882
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>