mutex releases to not require flags for the cases when preemption is
not allowed:
The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent
switching to a higher priority thread on mutex releease and swi schedule,
respectively when that switch is not safe. Now that the critical section
API maintains a per-thread nesting count, the kernel can easily check
whether or not it should switch without relying on flags from the
programmer. This fixes a few bugs in that all current callers of
swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from
fast interrupt handlers and the swi_sched of softclock needed this flag.
Note that to ensure that swi_sched()'s in clock and fast interrupt
handlers do not switch, these handlers have to be explicitly wrapped
in critical_enter/exit pairs. Presently, just wrapping the handlers is
sufficient, but in the future with the fully preemptive kernel, the
interrupt must be EOI'd before critical_exit() is called. (critical_exit()
can switch due to a deferred preemption in a fully preemptive kernel.)
I've tested the changes to the interrupt code on i386 and alpha. I have
not tested ia64, but the interrupt code is almost identical to the alpha
code, so I expect it will work fine. PowerPC and ARM do not yet have
interrupt code in the tree so they shouldn't be broken. Sparc64 is
broken, but that's been ok'd by jake and tmm who will be fixing the
interrupt code for sparc64 shortly.
Reviewed by: peter
Tested on: i386, alpha
and it's associated state variables: icu_lock with the name "icu". This
renames the imen_mtx for x86 SMP, but also uses the lock to protect
access to the 8259 PIC on x86 UP. This also adds an appropriate lock to
the various Alpha chipsets which fixes problems with Alpha SMP machines
dropping interrupts with an SMP kernel.
for this file, but here goes nothing. This was my first attempt at
tidying up this file. Unfortunately, it just exposes many more horrors
in the code itself that had been masked by the eyesore that was there
before. I think this just needs to be put out of its misery.
- The MD functions critical_enter/exit are renamed to start with a cpu_
prefix.
- MI wrapper functions critical_enter/exit maintain a per-thread nesting
count and a per-thread critical section saved state set when entering
a critical section while at nesting level 0 and restored when exiting
to nesting level 0. This moves the saved state out of spin mutexes so
that interlocking spin mutexes works properly.
- Most low-level MD code that used critical_enter/exit now use
cpu_critical_enter/exit. MI code such as device drivers and spin
mutexes use the MI wrappers. Note that since the MI wrappers store
the state in the current thread, they do not have any return values or
arguments.
- mtx_intr_enable() is replaced with a constant CRITICAL_FORK which is
assigned to curthread->td_savecrit during fork_exit().
Tested on: i386, alpha
- The MI portions of struct globaldata have been consolidated into a MI
struct pcpu. The MD per-CPU data are specified via a macro defined in
machine/pcpu.h. A macro was chosen over a struct mdpcpu so that the
interface would be cleaner (PCPU_GET(my_md_field) vs.
PCPU_GET(md.md_my_md_field)).
- All references to globaldata are changed to pcpu instead. In a UP kernel,
this data was stored as global variables which is where the original name
came from. In an SMP world this data is per-CPU and ideally private to each
CPU outside of the context of debuggers. This also included combining
machine/globaldata.h and machine/globals.h into machine/pcpu.h.
- The pointer to the thread using the FPU on i386 was renamed from
npxthread to fpcurthread to be identical with other architectures.
- Make the show pcpu ddb command MI with a MD callout to display MD
fields.
- The globaldata_register() function was renamed to pcpu_init() and now
init's MI fields of a struct pcpu in addition to registering it with
the internal array and list.
- A pcpu_destroy() function was added to remove a struct pcpu from the
internal array and list.
Tested on: alpha, i386
Reviewed by: peter, jake
- Now that apm loadable module can inform its existence to other kernel
components (e.g. i386/isa/clock.c:startrtclock()'s TCS hack).
- Exchange priority of SI_SUB_CPU and SI_SUB_KLD for above purpose.
- Add simple arbitration mechanism for APM vs. ACPI. This prevents
the kernel enables both of them.
- Remove obsolete `#ifdef DEV_APM' related code.
- Add abstracted interface for Powermanagement operations. Public apm(4)
functions, such as apm_suspend(), should be replaced new interfaces.
Currently only power_pm_suspend (successor of apm_suspend) is implemented.
Reviewed by: peter, arch@ and audit@
- sys/pc98/pc98/npx.c 1.87 (2001/09/15; author: imp)
I don't think pc98 has acpi at all, so ifdef the acpi attachments for
now.
This completes merging sys/pc98/pc98/npx.c into sys/i386/isa/npx.c so
that the former can be removed.
and the irq are different for pc98, and are not very well handled (we
use a historical mess of hard-coded values, values from header files
and values from hints).
- 1.58 (2000/09/01; author: kato)
Fixed FPU_ERROR_BROKEN code. It had old-isa code.
- 1.33 (1998/03/09; author: kato)
Make FPU_ERROR_BROKEN a new-style option.
- 1.7 (1996/10/09; author: asami)
Make sure FPU is recognized for non-Intel CPUs.
The log for rev.1.7 should have said something like:
Added FPU_ERROR_BROKEN option. This forces a successful probe for
exception 16, so that hardware with a broken FPU error signal can sort
of work.
Use the normal interrupt handler (npx_intr()) instead of a special
probe-time interrupt handler, although this causes problems due to
the bus_teardown_intr() not actually even tearing down the interrupt
(these problems were avoided by doing interrupt attachment for the
special interrupt handler directly). Fixed minor bitrot in comments.
The reason for the npxprobe()/npxprobe1() split mostly went away at
about the same time it was made (in 1992 or 1993 just before the
beginning of history). 386BSD ran all probes with interrupts completely
masked, and I didn't want to disturb this when I added an irq probe
to npxprobe(). An irq (not necessarily npx) must be acked for at least
external npx's to take the cpu out of the wait state that it enters
when an npx error occurs, so the probe must be done with a suitable
irq unmasked. npxprobe() went to great lengths to unmask precisely
the npx irq.
Running probes with all interrupts masked was never really needed in
FreeBSD, since FreeBSD always masked interrupts well enough using
splhigh(), but it wasn't until rev.1.48 (1995/12/12) of autoconf.c
that all probes were run with CPU interrupts enabled. This permits
npxprobe() to probe its irq using normal interrupt resources. Note
that most drivers still can't depend on this. It depends on the
interrupt handler being fast and the irq not being shared.
lost when the buggy code goes away completely:
- don't assume that the npx irq number is >= 8. Rev.1.73 only reversed
part of the hard-coding of it to 13 in rev.1.66.
- backed out the part of rev.1.84 that added a highly confused comment
about an enable_intr() being "highly bogus". The whole reason for
existence of npxprobe() (separate from the main probe, npxprobe1())
is to handle the complications to make this enable_intr() safe.
- backed out the part of rev.1.94 that modified npxprobe(). It mainly
broke the enable_intr() to restore_intr(). Restoring the interrupt
state in a nested way is precisely what is not wanted here. It was
harmless in practice because npxprobe() is called with interrupts
enabled, so restoring the interrupt state enables interrupts. Most
of npxprobe() is a no-op for the same reason...
code in ipl.s and icu_ipl.s that used them was removed when the
interrupt thread system was committed. Debuggers also knew about
Xresume* because these labels hide the real names of the interrupt
handlers (Xintr*), and debuggers need to special-case interrupt
handlers to get the interrupt frame.
Both gdb and ddb will now use the Xintr* and Xfastintr* symbols to
detect interrupt frames. Fast interrupt frames were never identified
correctly before, so this fixes the problem of the running stack
frame getting lost in a ddb or gdb trace generated from a fast
interrupt - e.g. when debugging a simple infinite loop in the kernel
using a serial console, the frame containing the loop would never
appear in a gdb or ddb trace.
Reviewed by: jhb, bde
already does the initialization (though it didn't set pca_initialized, so
we always initialized twice) and since attach calls make_dev(), there's no
way that pcaopen() can be called before pcaattach().
The type of bus_space_tag_t is now a pointer to bus_space_tag structure,
and the bus_space_tag structure saves pointers to functions for direct
access and relocate access.
Added bsh_bam member to the bus_space_handle structure, it saves access
method either direct access or relocate access which is called by
bus_space_* functions.
Added the mecia device support. If the bs_da and bs_ra in bus tag are set
NEPC_io_space_tag and NEPC_mem_space_tag respectively, new bus_space stuff
changes the register of mecia automatically for 16bit access.
Obtained from: NetBSD/pc98
the current interrupt thread routines will guarantee the condition this is
checking for at a higher level but inthand_add() and inthand_remove() as
they currently exist don't satisfy this condition. (Which does need to be
fixed but which will take a bit more work.) This fixes shared interrupts.
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
with system statistics monitoring tools (such as systat, vmstat...)
because of stopping RTC interrupts generation.
Restore all the timers (RTC and i8254) atomically.
Reviewed by: bde
MFC after: 1 week
flags with interrupts disabled to see if we should call ast() during
doreti. This was mostly submitted by Bruce, but his original patch did
the looping in ast() in assembly rather than in the ast() function itself.
Once we've actually called into the ast() function, it's cheaper to just
loop inside the function rather than returning from the function,
performing the check, and then calling the function again. However, we
can optimize the first check to avoid calling the function at all.
Other architectures may choose to implement this optimization if they
wish but it is not required for correct operation.
Submitted by: bde
the process of exiting the kernel. The ast() function now loops as long
as the PS_ASTPENDING or PS_NEEDRESCHED flags are set. It returns with
preemption disabled so that any further AST's that arrive via an
interrupt will be delayed until the low-level MD code returns to user
mode.
- Use u_int's to store the tick counts for profiling purposes so that we
do not need sched_lock just to read p_sticks. This also closes a
problem where the call to addupc_task() could screw up the arithmetic
due to non-atomic reads of p_sticks.
- Axe need_proftick(), aston(), astoff(), astpending(), need_resched(),
clear_resched(), and resched_wanted() in favor of direct bit operations
on p_sflag.
- Fix up locking with sched_lock some. In addupc_intr(), use sched_lock
to ensure pr_addr and pr_ticks are updated atomically with setting
PS_OWEUPC. In ast() we clear pr_ticks atomically with clearing
PS_OWEUPC. We also do not grab the lock just to test a flag.
- Simplify the handling of Giant in ast() slightly.
Reviewed by: bde (mostly)
