SBI version 0.2 introduces functions for obtaining the details of the
SBI implementation, such as version and implemntation ID. Print this
info at startup when it is available.
Reviewed by: jhb, kp
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D22327
The Supervisor Binary Interface (SBI) specification v0.2 is a backwards
incompatible update to the SBI call interface for kernels running in
supervisor mode. The goal of this update was to make it easier for new
and optional functionality to be added to the SBI.
SBI functions are now called by passing an "extension ID" and a
"function ID" which are passed in a7 and a6 respectively. SBI calls
will also return an error and value in the following struct:
struct sbi_ret {
long error;
long value;
}
This version introduces several new functions under the "base"
extension. It is expected that all SBI implementations >= 0.2 will
support this base set of functions, as they implement some essential
services such as obtaining the SBI version, CPU implementation info, and
extension probing.
Existing SBI functions have been designated as "legacy". For the time
being they will remain implemented, but it is expected that in the
future their functionality will be duplicated or replaced by new SBI
extensions. Each legacy function has been assigned its own extension ID,
and for now we simply probe and assert for their existence.
Compatibility with legacy SBI implementations (such as BBL) is
maintained by checking the output of sbi_get_spec_version(). This
function is guaranteed to succeed by the new spec, but will return an
error in legacy implementations. We use this as an indicator of whether
or not we can rely on the new SBI base extensions.
For further info on the Supervisor Binary Interface, see:
https://github.com/riscv/riscv-sbi-doc/blob/master/riscv-sbi.adoc
Reviewed by: kp, jhb
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D22326
Allow for an additional argument to sbi_call which will be passed in a6.
This is required for SBI spec 0.2 support, as a6 will indicate the SBI
function ID.
While here, introduce some macros to clean up the calls.
Reviewed by: kp, jhb
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D22325
Our PLIC implementation only enables interrupts on the boot cpu.
Implement plic_bind_intr() so that they can be redistributed near the
end of boot during intr_irq_shuffle().
This also slightly modifies how enable bits are handled in an attempt to
better fit the PIC interface. plic_enable_intr()/plic_disable_intr() are
converted to manage an interrupt source's threshold value, since this
value can be used as to globally enable/disable an irq. All handing of the
per-context enable bits is moved to the new methods plic_setup_intr()
and plic_bind_intr().
Reviewed by: br
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D21928
The RISC-V PLIC (platform level interrupt controller) registers are divided up
by "context", which is purposefully left ambiguous in the PLIC spec. Currently
we assume each CPU number corresponds 1-to-1 with a context number, but that is
not correct. Most existing PLIC implementations (such as SiFive's) have
multiple contexts per-cpu. For example, a single CPU might have a context for
machine mode interrupts and a context for supervisor mode interrupts. To
complicate things further, FreeBSD renumbers the CPUs during boot, but the PLIC
driver still assumes that CPU ID equals the RISC-V hart number, meaning
interrupt enables/claims might be performed for the wrong context registers.
To fix this, we must calculate each CPU's context number during
attachment. This is done by reading the interrupt properties from the
device tree, from which a mapping from context to RISC-V hart to CPU
number can be created.
Reviewed by: br
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D21927
This option is causing boot to fail for the Hifive Unleashed and older
versions of QEMU (3.1.1). Remove it from the GENERIC config for now.
Reported by: br
MFC after: 1 week
The fill_elf_hwcap() function expects to find only cpu nodes under the
/cpus entry of the device tree. Newer versions of QEMU insert a cpu-map
node which describes the CPU topology, breaking this function. To fix
this, simply skip any non-cpu entries.
Reviewed by: markj, kp, jhb
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D22151
The lr.w instruction used to read the value from memory sign-extends
the value read from memory. GCC sign-extends the 32-bit comparison
value passed in whereas clang currently does not. As a result, if the
value being compared has the MSB set, the comparison fails for
matching 32-bit values when compiled with clang.
Use a cast to explicitly sign-extend the unsigned comparison value.
This works with both GCC and clang.
There is commentary in the RISC-V spec that suggests that GCC's
approach is more correct, but it is not clear if the commentary in the
RISC-V spec is binding.
Reviewed by: mhorne
Obtained from: Axiado
MFC after: 2 weeks
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D22084
- td_kstack_pages was not being initialized.
- td_kstack is supposed to be the base address of the stack region,
not the top.
The arm ports seem to have similar problems and will be fixed next.
Reported by: Jenkins via lwhsu
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
After r352110 the page lock no longer protects a page's identity, so
there is no purpose in locking the page in pmap_mincore(). Instead,
if vm.mincore_mapped is set to the non-default value of 0, re-lookup
the page after acquiring its object lock, which holds the page's
identity stable.
The change removes the last callers of vm_page_pa_tryrelock(), so
remove it.
Reviewed by: kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21823
callers hold it.
This simplifies pmap code and removes a dependency on the object lock.
Reviewed by: kib, markj
Tested by: pho
Sponsored by: Netflix, Intel
Differential Revision: https://reviews.freebsd.org/D21596
busy acquires while held.
This allows code that would need to acquire and release a very large number
of page busy locks to use the old mechanism where busy is only checked and
not held. This comes at the cost of false positives but never false
negatives which the single consumer, vm_fault_soft_fast(), handles.
Reviewed by: kib
Tested by: pho
Sponsored by: Netflix, Intel
Differential Revision: https://reviews.freebsd.org/D21592
be called on bootverbose. Do so on RISV-V too.
Submitted by: Nicholas O'Brien <nickisobrien_gmail.com>
Reviewed by: imp, kp
Sponsored by: Axiado
Differential Revision: https://reviews.freebsd.org/D21998
the static device mappings.
While RISC-V support was added to subr_devmap.c in r298631, it was never
actually initialised in the machine dependent code.
Submitted by: Nicholas O'Brien <nickisobrien_gmail.com>
Reviewed by: br, kp
Sponsored by: Axiado
Differential Revision: https://reviews.freebsd.org/D21975
During a CoW fault, we must check for both 4KB and 2MB mappings before
clearing PGA_WRITEABLE on the old mapping's page. Previously we were
only checking for 4KB mappings. This was missed in r344106.
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
pmap_remove_l3() may remove the last mapping of a page, in which case
it must clear PGA_WRITEABLE.
Reported by: Jenkins, via lwhsu
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
We must also check for large mappings. pmap_page_is_mapped() is
mostly used in assertions, so the problem was not very noticeable.
Reviewed by: alc
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D21824
Centralize calculation of signal and ucode delivered on unhandled page
fault in new function vm_fault_trap(). MD trap_pfault() now almost
always uses the signal numbers and error codes calculated in
consistent MI way.
This introduces the protection fault compatibility sysctls to all
non-x86 architectures which did not have that bug, but apparently they
were already much more wrong in selecting delivered signals on
protection violations.
Change the delivered signal for accesses to mapped area after the
backing object was truncated. According to POSIX description for
mmap(2):
The system shall always zero-fill any partial page at the end of an
object. Further, the system shall never write out any modified
portions of the last page of an object which are beyond its
end. References within the address range starting at pa and
continuing for len bytes to whole pages following the end of an
object shall result in delivery of a SIGBUS signal.
An implementation may generate SIGBUS signals when a reference
would cause an error in the mapped object, such as out-of-space
condition.
Adjust according to the description, keeping the existing
compatibility code for SIGSEGV/SIGBUS on protection failures.
For situations where kernel cannot handle page fault due to resource
limit enforcement, SIGBUS with a new error code BUS_OBJERR is
delivered. Also, provide a new error code SEGV_PKUERR for SIGSEGV on
amd64 due to protection key access violation.
vm_fault_hold() is renamed to vm_fault(). Fixed some nits in
trap_pfault()s like mis-interpreting Mach errors as errnos. Removed
unneeded truncations of the fault addresses reported by hardware.
PR: 211924
Reviewed by: alc
Discussed with: jilles, markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D21566
In a few cases, the symbol lookup is missing before attempting to
perform the relocation. While the relocation types affected are
currently unused, this results in an uninitialized variable warning,
that is escalated to an error when building with clang.
Reviewed by: markj
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D21773
Fix some style(9) violations.
This also changes the name of the machine-dependent sysctl kern.debug_kld to
debug.kld_reloc, and changes its type from int to bool. This is acceptable
since we are not currently concerned with preserving the RISC-V ABI.
Reviewed by: markj, kp
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D21772
Convert all remaining references to that field to "ref_count" and update
comments accordingly. No functional change intended.
Reviewed by: alc, kib
Sponsored by: Intel, Netflix
Differential Revision: https://reviews.freebsd.org/D21768
The EARLY_AP_STARTUP option initializes non-boot processors
much sooner during startup. This adds support for this option
on RISC-V and enables it by default for GENERIC.
Reviewed by: jhb, markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D21661
- Remove a dead variable from the amd64 pmap_extract_and_hold().
- Fix grammar in the vm_page_wire man page.
Reported by: alc
Reviewed by: alc, kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21639
This is re-appearance of the nop code removed from other arches in r287625.
Reviewed by: alc (as part of the larger patch), markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
DIfferential revision: https://reviews.freebsd.org/D21645
fdt_is_compatible_strict() inspects the first compatible property.
We need to inspect the following properties for 'riscv'.
ofw_bus_node_is_compatible() does a recursive search.
This patch fixes "Can't find CPU" error message when bootverbose = true.
Submitted by: Nicholas O'Brien (nickisobrien_gmail.com)
Reviewed by: philip, kp
Sponsored by: Axiado
Differential Revision: https://reviews.freebsd.org/D21576
There are several mechanisms by which a vm_page reference is held,
preventing the page from being freed back to the page allocator. In
particular, holding the page's object lock is sufficient to prevent the
page from being freed; holding the busy lock or a wiring is sufficent as
well. These references are protected by the page lock, which must
therefore be acquired for many per-page operations. This results in
false sharing since the page locks are external to the vm_page
structures themselves and each lock protects multiple structures.
Transition to using an atomically updated per-page reference counter.
The object's reference is counted using a flag bit in the counter. A
second flag bit is used to atomically block new references via
pmap_extract_and_hold() while removing managed mappings of a page.
Thus, the reference count of a page is guaranteed not to increase if the
page is unbusied, unmapped, and the object's write lock is held. As
a consequence of this, the page lock no longer protects a page's
identity; operations which move pages between objects are now
synchronized solely by the objects' locks.
The vm_page_wire() and vm_page_unwire() KPIs are changed. The former
requires that either the object lock or the busy lock is held. The
latter no longer has a return value and may free the page if it releases
the last reference to that page. vm_page_unwire_noq() behaves the same
as before; the caller is responsible for checking its return value and
freeing or enqueuing the page as appropriate. vm_page_wire_mapped() is
introduced for use in pmap_extract_and_hold(). It fails if the page is
concurrently being unmapped, typically triggering a fallback to the
fault handler. vm_page_wire() no longer requires the page lock and
vm_page_unwire() now internally acquires the page lock when releasing
the last wiring of a page (since the page lock still protects a page's
queue state). In particular, synchronization details are no longer
leaked into the caller.
The change excises the page lock from several frequently executed code
paths. In particular, vm_object_terminate() no longer bounces between
page locks as it releases an object's pages, and direct I/O and
sendfile(SF_NOCACHE) completions no longer require the page lock. In
these latter cases we now get linear scalability in the common scenario
where different threads are operating on different files.
__FreeBSD_version is bumped. The DRM ports have been updated to
accomodate the KPI changes.
Reviewed by: jeff (earlier version)
Tested by: gallatin (earlier version), pho
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20486
The branch from _start to mpentry has to cross a large section of data;
an offset larger than can be specified with a 12-bit branch immediate.
Fix this by converting the branch to an unconditional jump. The gcc
assembler does this conversion silently but it is not done automatically
by clang.
Reported by: Jeremy Bennett <jeremy.bennett@embecosm.com>
Reviewed by: markj
Approved by: markj (mentor)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D21437
Many extern struct pcpu <something>__pcpu declarations were
copied/pasted in sources. The issue is that the definition is MD, but
it cannot be provided by machine/pcpu.h due to actual struct pcpu
defined in sys/pcpu.h later than the inclusion of machine/pcpu.h.
This forced the copying when other code needed direct access to
__pcpu. There is no way around it, due to machine/pcpu.h supplying
part of struct pcpu fields.
To work around the problem, add a new machine/pcpu_aux.h header, which
should fill any needed MD definitions after struct pcpu definition is
completed. This allows to remove copies of __pcpu spread around the
source. Also on x86 it makes it possible to remove work arounds like
OFFSETOF_CURTHREAD or clang specific warnings supressions.
Reported and tested by: lwhsu, bcran
Reviewed by: imp, markj (previous version)
Discussed with: jhb
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21418
doing so adds more flexibility with less redundant code.
Reviewed by: jhb, markj, kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21250
r343275 introduced a performance optimisation to the copyin/copyout
routines by attempting to copy word-per-word rather than byte-per-byte
where possible.
This optimisation failed to account for cases where the buffer is longer
than XLEN_BYTES, but due to misalignment does not not allow for any
word-sized copies. E.g. a 9 byte buffer (with XLEN_BYTES == 8) which is
misaligned by 2 bytes. The code nevertheless did a single full-word
copy, which meant we copied too much data. This potentially clobbered
other data.
This is most easily demonstrated by a simple `sysctl -a`.
Fix it by not assuming that we'll always have at least one full-word
copy to do, but instead checking the remaining length first.
Reviewed by: markj@, mhorne@, br@ (previous version)
MFC after: 1 week
Sponsored by: Axiado
Differential Revision: https://reviews.freebsd.org/D21100
if a demotion succeeds, then all of the 4KB page mappings within the
superpage-sized region must be valid, so there is no point in testing the
validity of the 4KB page mapping that is going to be write protected.
Deindent the nearby code.
Reviewed by: kib, markj
Tested by: pho (amd64, i386)
X-MFC after: r350004 (this change depends on arm64 dirty bit emulation)
Differential Revision: https://reviews.freebsd.org/D21027
We can't use a u_int to compute the physical address in
pmap_early_vtophys(). Our int is 32-bit, but the physical address is
64-bit. This works fine if everything lives in below 0x100000000, but as
soon as it doesn't this breaks.
MFC after: 1 week
Sponsored by: Axiado
syscallret() doesn't use error anymore. Fix a few other places to permit
removing the return value from syscallenter() entirely.
- Remove a duplicated assertion from arm's syscall().
- Use td_errno for amd64_syscall_ret_flush_l1d.
Reviewed by: kib
MFC after: 1 month
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D2090
pmap_ts_referenced() does not necessarily clear the access bit from
all accessed mappings of a given page. Thus, if a scan of the mappings
needs to be restarted, we should be careful to avoid double-counting
accessed mappings whose access bits were not cleared in a previous
attempt.
Reported by: alc
Reviewed by: alc
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20926
Casueword(9) on ll/sc architectures must be prepared for userspace
constantly modifying the same cache line as containing the CAS word,
and not loop infinitely. Otherwise, rogue userspace livelocks the
kernel.
To fix the issue, change casueword(9) interface to return new value 1
indicating that either comparision or store failed, instead of relying
on the oldval == *oldvalp comparison. The primitive no longer retries
the operation if it failed spuriously. Modify callers of
casueword(9), all in kern_umtx.c, to handle retries, and react to
stops and requests to terminate between retries.
On x86, despite cmpxchg should not return spurious failures, we can
take advantage of the new interface and just return PSL.ZF.
Reviewed by: andrew (arm64, previous version), markj
Tested by: pho
Reported by: https://xenbits.xen.org/xsa/advisory-295.txt
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D20772
The hold_count and wire_count fields of struct vm_page are separate
reference counters with similar semantics. The remaining essential
differences are that holds are not counted as a reference with respect
to LRU, and holds have an implicit free-on-last unhold semantic whereas
vm_page_unwire() callers must explicitly determine whether to free the
page once the last reference to the page is released.
This change removes the KPIs which directly manipulate hold_count.
Functions such as vm_fault_quick_hold_pages() now return wired pages
instead. Since r328977 the overhead of maintaining LRU for wired pages
is lower, and in many cases vm_fault_quick_hold_pages() callers would
swap holds for wirings on the returned pages anyway, so with this change
we remove a number of page lock acquisitions.
No functional change is intended. __FreeBSD_version is bumped.
Reviewed by: alc, kib
Discussed with: jeff
Discussed with: jhb, np (cxgbe)
Tested by: pho (previous version)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D19247
vm_page_dirty() when, in fact, we are write protecting the page and the L3
entry has PTE_D set. However, pmap_protect() was always calling
vm_page_dirty() when an L2 entry has PTE_D set. Handle L2 entries the
same as L3 entries so that we won't perform unnecessary calls to
vm_page_dirty().
Simplify the loop calling vm_page_dirty() on L2 entries.
