switching. The indirect costs being unnecessary TLB misses that are
incurred when ASIDs are not used. In fact, currently, when we perform a
context switch on one processor, we issue a broadcast TLB invalidation that
flushes the TLB contents on every processor.
Mark all user-space ("ttbr0") page table entries with the non-global flag so
that they are cached in the TLB under their ASID.
Correct an error in pmap_pinit0(). The pointer to the root of the page
table was being initialized to the root of the kernel-space page table
rather than a user-space page table. However, the root of the page table
that was being cached in process 0's md_l0addr field correctly pointed to a
user-space page table. As long as ASIDs weren't being used, this was
harmless, except that it led to some unnecessary page table switches in
pmap_switch(). Specifically, other kernel processes besides process 0 would
have their md_l0addr field set to the root of the kernel-space page table,
and so pmap_switch() would actually change page tables when switching
between process 0 and other kernel processes.
Implement a workaround for Cavium erratum 27456 affecting ThunderX machines.
(I would like to thank andrew@ for providing the code to detect the affected
machines.)
Address integer overflow in the definition of TCR_ASID_16.
Setup TCR according to the PARange and ASIDBits fields from
ID_AA64MMFR0_EL1. Previously, TCR_ASID_16 was unconditionally set.
Modify build_l1_block_pagetable so that lower attributes, such as ATTR_nG,
can be specified as a parameter.
Eliminate some unused code.
Earlier versions were tested to varying degrees by: andrew, emaste, markj
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D21922
Its absence meant that GEOM direct dispatch was disabled (the service
routines check the current thread's stack usage to determine whether
to hand off the request to a dedicated thread), and this change is
sufficient to enable direct dispatch by default.
Reviewed by: allanjude
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D15527
Right now I'm using two Raspberry Pi's (2 and 3) to test CloudABI
support for armv6, armv7 and aarch64. It would be nice if I could
restrict this to just a single instance when testing smaller changes.
This is why I'd like to get COMPAT_CLOUDABI32 to work on arm64.
As COMPAT_CLOUDABI32 depends on COMPAT_FREEBSD32, at least for the ELF
loading, this change adds all of the bits necessary to at least build a
kernel with COMPAT_FREEBSD32. All of the machine dependent system calls
are still stubbed out, for the reason that implementations for these are
only useful if actual support for running FreeBSD binaries is added.
This is outside the scope of this work.
Reviewed by: andrew
Differential Revision: https://reviews.freebsd.org/D13144
from machine/proc.h, consistently on all architectures.
Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
X-Differential revision: https://reviews.freebsd.org/D11080
