for a bit before retrying to resend an IPI in order to avoid
deadlocks if the other CPU is also trying to send one.
OpenSolaris uses a delay of 1 microsecond here but waiting 2
microseconds with interrupts enabled like Linux does shouldn't
hurt but is a bit safer.
MFC after: 1 day
Originally, I had adopted sparc64's name, pmap_clear_write(), for the
function that is now pmap_remove_write(). However, this function is more
like pmap_remove_all() than like pmap_clear_modify() or
pmap_clear_reference(), hence, the name change.
The higher-level rationale behind this change is described in
src/sys/amd64/amd64/pmap.c revision 1.567. The short version is that I'm
trying to clean up and fix our support for execute access.
Reviewed by: marcel@ (ia64)
and pc98 MD files. Remove nodevice and nooption lines specific
to sio(4) from ia64, powerpc and sparc64 NOTES. There were no
such lines for arm yet.
sio(4) is usable on less than half the platforms, not counting
a future mips platform. Its presence in MI files is therefore
increasingly becoming a burden.
mark system calls as being MPSAFE:
- Stop conditionally acquiring Giant around system call invocations.
- Remove all of the 'M' prefixes from the master system call files.
- Remove support for the 'M' prefix from the script that generates the
syscall-related files from the master system call files.
- Don't explicitly set SYF_MPSAFE when registering nfssvc.
implementations and adjust some of the checks while I'm here:
- Add a new check to make sure we don't return from a syscall in a critical
section.
- Add a new explicit check before userret() to make sure we don't return
with any locks held. The advantage here is that we can include the
syscall number and name in syscall() whereas that info is not available
in userret().
- Drop the mtx_assert()'s of sched_lock and Giant. They are replaced by
the more general checks just added.
MFC after: 2 weeks
system's machine-dependent and machine-independent layers. Once
pmap_clear_write() is implemented on all of our supported
architectures, I intend to replace all calls to pmap_page_protect() by
calls to pmap_clear_write(). Why? Both the use and implementation of
pmap_page_protect() in our virtual memory system has subtle errors,
specifically, the management of execute permission is broken on some
architectures. The "prot" argument to pmap_page_protect() should
behave differently from the "prot" argument to other pmap functions.
Instead of meaning, "give the specified access rights to all of the
physical page's mappings," it means "don't take away the specified
access rights from all of the physical page's mappings, but do take
away the ones that aren't specified." However, owing to our i386
legacy, i.e., no support for no-execute rights, all but one invocation
of pmap_page_protect() specifies VM_PROT_READ only, when the intent
is, in fact, to remove only write permission. Consequently, a
faithful implementation of pmap_page_protect(), e.g., ia64, would
remove execute permission as well as write permission. On the other
hand, some architectures that support execute permission have
basically ignored whether or not VM_PROT_EXECUTE is passed to
pmap_page_protect(), e.g., amd64 and sparc64. This change represents
the first step in replacing pmap_page_protect() by the less subtle
pmap_clear_write() that is already implemented on amd64, i386, and
sparc64.
Discussed with: grehan@ and marcel@
install custom pager functions didn't actually happen in practice (they
all just used the simple pager and passed in a local quit pointer). So,
just hardcode the simple pager as the only pager and make it set a global
db_pager_quit flag that db commands can check when the user hits 'q' (or a
suitable variant) at the pager prompt. Also, now that it's easy to do so,
enable paging by default for all ddb commands. Any command that wishes to
honor the quit flag can do so by checking db_pager_quit. Note that the
pager can also be effectively disabled by setting $lines to 0.
Other fixes:
- 'show idt' on i386 and pc98 now actually checks the quit flag and
terminates early.
- 'show intr' now actually checks the quit flag and terminates early.
in 1999, and there are changes to the sysctl names compared to PR,
according to that discussion. The description is in sys/conf/NOTES.
Lines in the GENERIC files are added in commented-out form.
I'll attach the test script I've used to PR.
PR: kern/14584
Submitted by: babkin
an explicit comment that it's needed for the linuxolator. This is not the
case anymore. For all other architectures there was only a "KEEP THIS".
I'm (and other people too) running a COMPAT_43-less kernel since it's not
necessary anymore for the linuxolator. Roman is running such a kernel for a
for longer time. No problems so far. And I doubt other (newer than ia32
or alpha) architectures really depend on it.
This may result in a small performance increase for some workloads.
If the removal of COMPAT_43 results in a not working program, please
recompile it and all dependencies and try again before reporting a
problem.
The only place where COMPAT_43 is needed (as in: does not compile without
it) is in the (outdated/not usable since too old) svr4 code.
Note: this does not remove the COMPAT_43TTY option.
Nagging by: rdivacky
There is a race with the current locking scheme and removing
it should have no measurable performance impact.
This fixes page faults leading to panics in pmap_enter_quick_locked()
on amd64/i386.
Reviewed by: alc,jhb,peter,ps
moving the typedef of bus_space_tag_t from sys/sparc64/include/bus.h
to sys/sparc64/include/_bus.h. This brings sparc64 in sync with the
other platforms and fixes the compilation of drivers which include
<sys/rman.h> before <machine/bus.h> after sys/sys/rman.h rev. 1.34.
- Remove the definition of bus_type_t from sys/sparc64/include/_bus.h
as it's unused since sys/sparc64/include/bus.h rev. 1.6 and
sys/sparc64/sparc64/bus_machdep.c rev. 1.3.
- Remove some pointless comments.
the arm to compile without all the extras that don't appear, at least
not in the flavors of ARM I deal with. This helps us save about 100k.
If I've botched the available devices on a platform, please let me
know and I'll correct ASAP.
Map the device memory belonging to resources of type SYS_RES_MEMORY into
KVA upon activation so that rman_get_virtual() works as expected.
- In sbus_alloc_resource() checking whether toffs is 0 as an indication
that no applicable child range was found isn't appropriate as it's
perfectly valid for the requested SYS_RES_MEMORY resource to start at
the beginning of a child range. So check for the RMAN still being NULL
instead.
- As a minor runtime speed optimization break out of the loop where we
search for the applicable child range in sbus_alloc_resource() as soon
as it's found.
- Let sbus_setup_intr() return ENOMEM rather than 0 if it can't allocate
memory for the interrupt clearing info.
- Actually do what the comment in sbus_setup_intr() says and disable the
respective interrupt while fiddling with it.
- Remove some superfluous INTVEC() around inr, which already only contains
the interrupt vector, in sbus_setup_intr().
- While here, fix a style(9) bug in sbus_setup_intr() (don't use function
calls in initializers).
The first two changes are required for a CG6 driver.
MFC after: 2 weeks
Retire pmap_track_modified(). We no longer need it because we do not
create managed mappings within the clean submap. To prevent regressions,
add assertions blocking the creation of managed mappings within the clean
submap.
above what's used for fast interrupts, only interrupts with the level of
the interrupt which led to calling intr_fast() (which is used with both
fast and ithread interrupts) are blocked while in that function. Thus
intr_fast() can be preempted by a fast interrupt (which are of a higher
level than ithread interrupts) while servicing an ithread interrupt. This
can lead to a stale pointer to the head of the active interrupt requests
list when back in the ithread interrupt invocation of intr_fast(), in turn
resulting in corruption of the interrupt request lists and consequently
in a panic. Solve this be turning off interrupts in intr_fast() before
reading the pointer to the head of the active list rather than after. [1]
- Add a KASSERT in intr_fast() which asserts that ir_func is non-zero before
calling it. [1]
- Increment interrupt stats after calling the handlers rather than before.
This reduces the delay until direct and fast handlers are serviced, in my
testings by 30% on average for the direct tick interrupt handler, in turn
resulting in less clock drift.
PR: 94778 [1]
Submitted by: Andrew Belashov [1]
MFC after: 2 weeks
PCI devices apparently was changed from a special deferred trap with TPC
pointing to the membar #Sync following the failing load/store instruction
to a precise trap with TPC pointing to the failing load/store instruction.
Thus remove the check the check whether TPC points to a membar #Sync in
case of a data access trap as it's off-by-one for USIII CPUs and it should
be sufficient to check whether the trap happend while in fasword*() to
properly detect traps caused by peeking/poking. This also corresponds to
what other OSs do. Note that also only the USIIi manual suggests to check
the TPC for such traps while the USII one doesn't (in the public USIII
manual device peeking/poking isn't mentioned at all).
PCB in which the context of stopped CPUs is stored. To access this
PCB from KDB, we introduce a new define, called KDB_STOPPEDPCB. The
definition, when present, lives in <machine/kdb.h> and abstracts
where MD code saves the context. Define KDB_STOPPEDPCB on i386,
amd64, alpha and sparc64 in accordance to previous code.
- Use FBSDID in trap.c
- Make the global trap_sig[] static as it's not used outside of trap.c.
- In sendsig() remove an unused variable.
- In trap() sync with the other archs; for fast data access MMU miss and
data access protection traps set ksi_addr to the SFAR reg which contains
the faulting address and otherwise to the TPC reg. Generally the TCP reg
contains the address of the instruction that caused the exception, except
for fast instruction access traps (and some others; more refinement may
be needed here) it also contains the faulting address.
Previously sendsig() always set si_addr to the SFAR reg which is wrong
for most traps.
- In sendsig() add support for FreeBSD old-style signals.
These changes are inspired by kmacy's sun4v changes and allow libsigsegv
to build on FreeBSD/sparc64, but it doesn't pass all checks and tests it
actually should, yet.
MFC after: 5 days
foreign per-CPU pages in cpu_ipi_send() in order to get the module IDs
of the other CPUs can cause a page fault. If this happens when doing a
TLB shootdown while dealing with another page fault this causes a panic
due to the recursive page fault. As I don't spot other code that assumes
or requires that accessing foreign per-CPU pages must not page fault
solve this by adding a statically allocated (and therefore locked in the
kernel pages) array which establishes a FreeBSD CPU ID -> module ID
relation and use that in cpu_ipi_selected() (instead of statically
allocating the per-CPU pages which would just waste memory on say a dual
CPU machine as sun4u theoretically supports up to 128 CPUs or wasting
dTLB slots for the foreign per-CPU pages). [1]
- Fix a potential race in cpu_ipi_send(); as we don't serialize the access
to cpu_ipi_selected() between MI and MD use (only MI-MI and MD-MD) we
might catch the NACK bit caused by sending another IPI. Solve this by
checking the NACK bit in the contents of the interrupt dispatch status
reg read while interrupts were still turned off instead of reading that
reg anew after interrupts were turned on again. This is also what the
CPU docs suggest to do.
- Add a workaround for the SpitFire erratum #54 bug (affecting interrupt
dispatch). While public info regarding what this CPU bug actually causes
is not available testing shows that with the workaround in place it's
less likely to get a "couldn't send ipi" panic, it doesn't solve these
panics entirely though. [2]
Reported by: kris [1]
Some clue from: kmacy [1]
Info from: Linux, OpenSolaris [2]
Additional testing by: kris
MFC after: 3 days
as we have to call tick_init() before cninit() in order to provide the
low-level console drivers with a working DELAY() which in turn means we
cannot use panic() in tick_init().
- s,to high, too high, in the panic string
Inspired by: kmacy's sun4v changes
MFC after: 3 days
when option DEBUG_LOCKS is used. Trap frames are determined by checking
whether the caller was one of the tl0_*() or tl1_*() asm functions via
a newly added pair of dummy symbols in exception.S which mark the begin
and end of these functions. The tl_trap_* pair marks those in the special
.trap section and the tl_text_* in the regular .text section. Because
of their performance penalty db_search_symbol()/db_symbol_values() and
linker_ddb_search_symbol()/linker_ddb_symbol_values() aren't used here
for determining the caller, with db_search_symbol()/db_symbol_values()
additionally not being reentrant.
- For consistency, change db_backtrace() to also use the new markers for
determining the tl0_*() and tl1_*() asm functions instead of bcmp()'ing
the symbol name.
- Use FBSDID in db_trace.c.
PR: 93226
Based on a patch by: Antoine Brodin <antoine.brodin@laposte.net>
Ok'ed by: jhb
pages, not a count of bytes. The sysctl handler for hw.realmem already
uses ctob() to convert realmem from pages to bytes. Thus, on archs that
were storing a byte count in the realmem variable, hw.realmem was inflated.
Reported by: Valerio daelli valerio dot daelli at gmail dot com (alpha)
MFC after: 3 days
Keep accounting time (in per-cpu) cputicks and the statistics counts
in the thread and summarize into struct proc when at context switch.
Don't reach across CPUs in calcru().
Add code to calibrate the top speed of cpu_tickrate() for variable
cpu_tick hardware (like TSC on power managed machines).
Don't enforce monotonicity (at least for now) in calcru. While the
calibrated cpu_tickrate ramps up it may not be true.
Use 27MHz counter on i386/Geode.
Use TSC on amd64 & i386 if present.
Use tick counter on sparc64
Rename struct thread's td_sticks to td_pticks, we will need the
other name for more appropriately named use shortly. Reduce it
from uint64_t to u_int.
Clear td_pticks whenever we enter the kernel instead of recording
its value as reference for userret(). Use the absolute value of
td->pticks in userret() and eliminate third argument.
Keep track of time spent by the cpu in various contexts in units of
"cputicks" and scale to real-world microsec^H^H^H^H^H^H^H^Hclock_t
only when somebody wants to inspect the numbers.
For now "cputicks" are still derived from the current timecounter
and therefore things should by definition remain sensible also on
SMP machines. (The main reason for this first milestone commit is
to verify that hypothesis.)
On slower machines, the avoided multiplications to normalize timestams
at every context switch, comes out as a 5-7% better score on the
unixbench/context1 microbenchmark. On more modern hardware no change
in performance is seen.
