- Use isync/lwsync unconditionally for acquire/release. Use of isync
guarantees a complete memory barrier, which is important for serialization
of bus space accesses with mutexes on multi-processor systems.
- Go back to using sync as the I/O memory barrier, which solves the same
problem as above with respect to mutex release using lwsync, while not
penalizing non-I/O operations like a return to sync on the atomic release
operations would.
- Place an acquisition barrier around thread lock acquisition in
cpu_switchin().
not provide general barriers, but only barriers in the context of the
atomic sequences here. As such, make them private and keep the global
*mb() routines using a variant of sync.
isync to implement read and write barriers, following Appendix B.2 of
Book II of the architecture manual. This provides a 25% speed increase
to fork() on the PowerPC G4.
of sync (lwsync is an alternate encoding of sync on systems that do not
support it, providing graceful fallback). This provides more than an order
of magnitude reduction in the time required to acquire or release a mutex.
MFC after: 2 months
sync performs a strict superset of the functions of eieio, so using both
is redundant. While here, expand bus barriers to all bus_space operations,
since many drivers do not correctly use bus_space_barrier().
In principle, we can also replace sync just with eieio, for a significant
performance increase, but it remains to be seen whether any poorly-written
drivers currently depend on the side effects of sync to properly function.
MFC after: 1 week
(slightly) different semantics and renaming it prevents a (harmless)
WITNESS warning during bootup for 32-bit kernels on 64-bit CPUs.
MFC after: 5 days
be less ambiguous and more clearly identify what it means. This
attribute is what Intel refers to as UC-, and it's only difference
relative to normal UC memory is that a WC MTRR will override a UC-
PAT entry causing the memory to be treated as WC, whereas a UC PAT
entry will always override the MTRR.
- Remove the VM_MEMATTR_UNCACHED alias from powerpc.
New kernel events can be added at various location for sampling or counting.
This will for example allow easy system profiling whatever the processor is
with known tools like pmcstat(8).
Simultaneous usage of software PMC and hardware PMC is possible, for example
looking at the lock acquire failure, page fault while sampling on
instructions.
Sponsored by: NETASQ
MFC after: 1 month
didn't already have them. This is because the ternary expression will
return int, due to the Usual Arithmetic Conversions. Such casts are not
needed for the 32 and 64 bit variants.
While here, add additional parentheses around the x86 variant, to
protect against unintended consequences.
MFC after: 2 weeks
Without this patch we were not able to see the assembly function.
Only the function descriptor was visible.
- Distinguish between user-land and kernel when creating the ENTRY() point of
assembly source.
- Make the ENTRY() macro more readable, replace the .align directive with the
gas platform independant .p2align directive.
- Create an END()macro for later use to provide traceback tables on powerpc64.
profiling and kernel profiling. To enable kernel profiling one has to build
kgmon(8). I will enable the build once I managed to build and test powerpc
(32-bit) kernels with profiling support.
- add a powerpc64 PROF_PROLOGUE for _mcount.
- add macros to avoid adding the PROF_PROLOGUE in certain assembly entries.
- apply these macros where needed.
- add size information to the MCOUNT function.
MFC after: 3 weeks, together with r230291
that the compiler promotes floats to double precision in computations, but
inspection of the output of a cross-compiler indicates that this isn't the
case on powerpc.
possible, and double faults within an SLB trap handler are not. The result
is that it possible to take an SLB fault at any time, on any address, for
any reason, at any point in the kernel.
This lets us do two important things. First, it removes the (soft) 16 GB RAM
ceiling on PPC64 as well as any architectural limitations on KVA space.
Second, it lets the kernel tolerate poorly designed hypervisors that
have a tendency to fail to restore the SLB properly after a hypervisor
context switch.
MFC after: 6 weeks
AIM systems to 4 GB on 32-bit systems and 2^64 bytes on 64-bit systems.
VM_MAXUSER_ADDRESS remains at 2 GB on pending Book-E, pending review of
an increase to 3 GB by those more familiar with Book-E.
pmap_remove() for large sparse requests. This can prevent pmap_remove()
operations on 64-bit process destruction or swapout that would take
several hundred times the lifetime of the universe to complete. This
behavior is largely indistinguishable from a hang.
implement a deprecated FPU control interface in addition to the
standard one. To make this clearer, further deprecate ieeefp.h
by not declaring the function prototypes except on architectures
that implement them already.
Currently i386 and amd64 implement the ieeefp.h interface for
compatibility, and for fp[gs]etprec(), which doesn't exist on
most other hardware. Powerpc, sparc64, and ia64 partially implement
it and probably shouldn't, and other architectures don't implement it
at all.
to VPO_UNMANAGED (and also making the flag protected by the vm object
lock, instead of vm page queue lock).
- Mark the fake pages with both PG_FICTITIOUS (as it is now) and
VPO_UNMANAGED. As a consequence, pmap code now can use use just
VPO_UNMANAGED to decide whether the page is unmanaged.
Reviewed by: alc
Tested by: pho (x86, previous version), marius (sparc64),
marcel (arm, ia64, powerpc), ray (mips)
Sponsored by: The FreeBSD Foundation
Approved by: re (bz)
This patch is going to help in cases like mips flavours where you
want a more granular support on MAXCPU.
No MFC is previewed for this patch.
Tested by: pluknet
Approved by: re (kib)
instead of a PCPU field for curthread. This averts a race on SMP systems
with a high interrupt rate where the thread looking up the value of
curthread could be preempted and migrated between obtaining the PCPU
pointer and reading the value of pc_curthread, resulting in curthread being
observed to be the current thread on the thread's original CPU. This played
merry havoc with the system, in particular with mutexes. Many thanks to
jhb for helping me work this one out.
Note that Book-E is in principle susceptible to the same problem, but has
not been modified yet due to lack of Book-E hardware.
MFC after: 2 weeks
Renovate and improve the AIM Open Firmware support:
- Add RTAS (Run-Time Abstraction Services) support, found on all IBM systems
and some Apple ones
- Improve support for 32-bit real mode Open Firmware systems
- Pull some more OF bits over from the AIM directory
- Fix memory detection on IBM LPARs and systems with more than one /memory
node (by andreast@)
o In bare_probe(), change the logic that determines the maximum
number of processors/cores into a switch statement and take
advantage of the fact that bit 3 of the SVR value indicates
whether we're running on a security enabled version. Since we
don't care about that here, mask the bit. All -E versions
are taken care of automatically.
Rewrite atomic operations for powerpc in order to achieve the following:
- Produce a type-clean implementation (in terms of functions arguments
and returned values) for the primitives.
- Fix errors with _long() atomics where they ended up with the wrong
arguments to be accepted.
- Follow the sys/type.h specifics that define the numbered types starting
from standard C types.
- Let _ptr() version to not auto-magically cast arguments, but leave
the burden on callers, as _ptr() atomic is intended to be used
relatively rarely.
Fix cfi in order to support the latest point.
In collabouration with: bde
Tested by: andreast, nwhitehorn, jceel
MFC after: 2 weeks
architectures (i386, for example) the virtual memory space may be
constrained enough that 2MB is a large chunk. Use 64K for arches
other than amd64 and ia64, with special handling for sparc64 due to
differing hardware.
Also commit the comment changes to kmem_init_zero_region() that I
missed due to not saving the file. (Darn the unfamiliar development
environment).
Arch maintainers, please feel free to adjust ZERO_REGION_SIZE as you
see fit.
Requested by: alc
MFC after: 1 week
MFC with: r221853
