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freebsd-dev/sys/i386/isa/icu.s
David Greenman d230622648 New interrupt code from Bruce Evans. In additional to Bruce's attached 
list of changes, I've made the following additional changes:

1) i386/include/ipl.h renamed to spl.h as the name conflicts with the
   file of the same name in i386/isa/ipl.h.
2) changed all use of *mask (i.e. netmask, biomask, ttymask, etc) to
   *_imask (net_imask, etc).
3) changed vestige of splnet use in if_is to splimp.
4) got rid of "impmask" completely (Bruce had gotten rid of netmask),
   and are now using net_imask instead.
5) dozens of minor cruft to glue in Bruce's changes.

   These require changes I made to config(8) as well, and thus it must
be rebuilt.

-DG

from Bruce Evans:

sio:
	o No diff is supplied.  Remove the define of setsofttty().  I hope
	  that is enough.

*.s:
	o i386/isa/debug.h no longer exists.  The event counters became too
	  much trouble to maintain.  All function call entry and exception
	  entry counters can be recovered by using profiling kernel (the new
	  profiling supports all entry points; however, it is too slow to
	  leave enabled all the time; it also).  Only BDBTRAP() from debug.h
	  is now used.  That is moved to exception.s.  It might be worth
	  preserving SHOW_BITS() and calling it from _mcount() (if enabled).
	o T_ASTFLT is now only set just before calling trap().
	o All exception handlers set SWI_AST_MASK in cpl as soon as possible
	  after entry and arrange for _doreti to restore it atomically with
	  exiting.  It is not possible to set it atomically with entering
	  the kernel, so it must be checked against the user mode bits in
	  the trap frame before committing to using it.  There is no place
	  to store the old value of cpl for syscalls or traps, so there are
	  some complications restoring it.

Profiling stuff (mostly in *.s):
	o Changes to kern/subr_mcount.c, gcc and gprof are not supplied yet.
	o All interesting labels `foo' are renamed `_foo' and all
	  uninteresting labels `_bar' are renamed `bar'.  A small change
	  to gprof allows ignoring labels not starting with underscores.
	o MCOUNT_LABEL() is to provide names for counters for times spent
	  in exception handlers.
	o FAKE_MCOUNT() is a version of MCOUNT() suitable for exception
	  handlers.  Its arg is the pc where the exception occurred.  The
	  new mcount() pretends that this was a call from that pc to a
	  suitable MCOUNT_LABEL().
	o MEXITCOUNT is to turn off any timer started by MCOUNT().

/usr/src/sys/i386/i386/exception.s:
	o The non-BDB BPTTRAP() macros were doing a sti even when interrupts
	  were disabled when the trap occurred.  The sti (fixed) sti is
	  actually a no-op unless you have my changes to machdep.c that make
	  the debugger trap gates interrupt gates, but fixing that would
	  make the ifdefs messier.  ddb seems to be unharmed by both
	  interrupts always disabled and always enabled (I had the branch in
	  the fix back to front for some time :-().
	o There is no known pushal bug.
	o tf_err can be left as garbage for syscalls.

/usr/src/sys/i386/i386/locore.s:
	o Fix and update BDE_DEBUGGER support.
	o ENTRY(btext) before initialization was dangerous.
	o Warm boot shot was longer than intended.

/usr/src/sys/i386/i386/machdep.c:
	o DON'T APPLY ALL OF THIS DIFF.  It's what I'm using, but may require
	  other changes.
	  Use the following:
		o Remove aston() and setsoftclock().
	  Maybe use the following:
		o No netisr.h.
		o Spelling fix.
		o Delay to read the Rebooting message.
		o Fix for vm system unmapping a reduced area of memory
		  after bounds_check_with_label() reduces the size of
		  a physical i/o for a partition boundary.  A similar
		  fix is required in kern_physio.c.
		o Correct use of __CONCAT.  It never worked here for non-
		  ANSI cpp's.  Is it time to drop support for non-ANSI?
		o gdt_segs init.  0xffffffffUL is bogus because ssd_limit
		  is not 32 bits.  The replacement may have the same
		  value :-), but is more natural.
		o physmem was one page too low.  Confusing variable names.
	  Don't use the following:
		o Better numbers of buffers.  Each 8K page requires up to
		  16 buffer headers.  On my system, this results in 5576
		  buffers containing [up to] 2854912 bytes of memory.
		  The usual allocation of about 384 buffers only holds
		  192K of disk if you use it on an fs with a block size
		  of 512.
		o gdt changes for bdb.
		o *TGT -> *IDT changes for bdb.
		o #ifdefed changes for bdb.

/usr/src/sys/i386/i386/microtime.s:
	o Use the correct asm macros.  I think asm.h was copied from Mach
	  just for microtime and isn't used now.  It certainly doesn't
	  belong in <sys>.  Various macros are also duplicated in
	  sys/i386/boot.h and libc/i386/*.h.
	o Don't switch to and from the IRR; it is guaranteed to be selected
	  (default after ICU init and explicitly selected in isa.c too, and
	  never changed until the old microtime clobbered it).

/usr/src/sys/i386/i386/support.s:
	o Non-essential changes (none related to spls or profiling).
	o Removed slow loads of %gs again.  The LDT support may require
	  not relying on %gs, but loading it is not the way to fix it!
	  Some places (copyin ...) forgot to load it.  Loading it clobbers
	  the user %gs.  trap() still loads it after certain types of
	  faults so that fuword() etc can rely on it without loading it
	  explicitly.  Exception handlers don't restore it.  If we want
	  to preserve the user %gs, then the fastest method is to not
	  touch it except for context switches.  Comparing with
	  VM_MAXUSER_ADDRESS and branching takes only 2 or 4 cycles on
	  a 486, while loading %gs takes 9 cycles and using it takes
	  another.
	o Fixed a signed branch to unsigned.

/usr/src/sys/i386/i386/swtch.s:
	o Move spl0() outside of idle loop.
	o Remove cli/sti from idle loop.  sw1 does a cli, and in the
	  unlikely event of an interrupt occurring and whichqs becoming
	  zero, sw1 will just jump back to _idle.
	o There's no spl0() function in asm any more, so use splz().
	o swtch() doesn't need to be superaligned, at least with the
	  new mcounting.
	o Fixed a signed branch to unsigned.
	o Removed astoff().

/usr/src/sys/i386/i386/trap.c:
	o The decentralized extern decls were inconsistent, of course.
	o Fixed typo MATH_EMULTATE in comments. */
	o Removed unused variables.
	o Old netmask is now impmask; print it instead.  Perhaps we
	  should print some of the new masks.
	o BTW, trap() should not print anything for normal debugger
	  traps.

/usr/src/sys/i386/include/asmacros.h:
	o DON'T APPLY ALL OF THIS DIFF.  Just use some of the null macros
	  as necessary.

/usr/src/sys/i386/include/cpu.h:
	o CLKF_BASEPRI() changes since cpl == SWI_AST_MASK is now normal
	  while the kernel is running.
	o Don't use var++ to set boolean variables.  It fails after a mere
	  4G times :-) and is slower than storing a constant on [3-4]86s.

/usr/src/sys/i386/include/cpufunc.h:
	o DON'T APPLY ALL OF THIS DIFF.  You need mainly the include of
	  <machine/ipl.h>.  Unfortunately, <machine/ipl.h> is needed by
	  almost everything for the inlines.

/usr/src/sys/i386/include/ipl.h:
	o New file.  Defines spl inlines and SWI macros and declares most
	  variables related to hard and soft interrupt masks.

/usr/src/sys/i386/isa/icu.h:
	o Moved definitions to <machine/ipl.h>

/usr/src/sys/i386/isa/icu.s:
	o Software interrupts (SWIs) and delayed hardware interrupts (HWIs)
	  are now handled uniformally, and dispatching them from splx() is
	  more like dispatching them from _doreti.  The dispatcher is
	  essentially *(handler[ffs(ipending & ~cpl)]().
	o More care (not quite enough) is taken to avoid unbounded nesting
	  of interrupts.
	o The interface to softclock() is changed so that a trap frame is
	  not required.
	o Fast interrupt handlers are now handled more uniformally.
	  Configuration is still too early (new handlers would require
	  bits in <machine/ipl.h> and functions to vector.s).
	o splnnn() and splx() are no longer here; they are inline functions
	  (could be macros for other compilers).  splz() is the nontrivial
	  part of the old splx().

/usr/src/sys/i386/isa/ipl.h
	o New file.  Supposed to have only bus-dependent stuff.  Perhaps
	  the h/w masks should be declared here.

/usr/src/sys/i386/isa/isa.c:
	o DON'T APPLY ALL OF THIS DIFF.  You need only things involving
	  *mask and *MASK and comments about them.  netmask is now a pure
	  software mask.  It works like the softclock mask.

/usr/src/sys/i386/isa/vector.s:
	o Reorganize AUTO_EOI* macros.
	o Option FAST_INTR_HANDLER_USERS_ES for people who don't trust
	  fastintr handlers.
	o fastintr handlers need to metamorphose into ordinary interrupt
	  handlers if their SWI bit has become set.  Previously, sio had
	  unintended latency for handling output completions and input
	  of SLIP framing characters because this was not done.

/usr/src/sys/net/netisr.h:
	o The machine-dependent stuff is now imported from <machine/ipl.h>.

/usr/src/sys/sys/systm.h
	o DON'T APPLY ALL OF THIS DIFF.  You need mainly the different
	  splx() prototype.  The spl*() prototypes are duplicated as
	  inlines in <machine/ipl.h> but they need to be duplicated here
	  in case there are no inlines.  I sent systm.h and cpufunc.h
	  to Garrett.  We agree that spl0 should be replaced by splnone
	  and not the other way around like I've done.

/usr/src/sys/kern/kern_clock.c
	o splsoftclock() now lowers cpl so the direct call to softclock()
	  works as intended.
	o softclock() interface changed to avoid passing the whole frame
	  (some machines may need another change for profile_tick()).
	o profiling renamed _profiling to avoid ANSI namespace pollution.
	  (I had to improve the mcount() interface and may as well fix it.)
	  The GUPROF variant doesn't actually reference profiling here,
	  but the 'U' in GUPROF should mean to select the microtimer
	  mcount() and not change the interface.
1994-04-02 07:00:53 +00:00

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/*-
* Copyright (c) 1989, 1990 William F. Jolitz.
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)icu.s 7.2 (Berkeley) 5/21/91
*
* $Id: icu.s,v 1.7 1993/12/20 14:58:21 wollman Exp $
*/
/*
* AT/386
* Vector interrupt control section
*/
/*
* XXX this file should be named ipl.s. All spls are now soft and the
* only thing related to the hardware icu is that the h/w interrupt
* numbers are used without translation in the masks.
*/
#include "../net/netisr.h"
.data
.globl _cpl
_cpl: .long HWI_MASK | SWI_MASK /* current priority (all off) */
.globl _imen
_imen: .long HWI_MASK /* interrupt mask enable (all h/w off) */
_high_imask: .long HWI_MASK | SWI_MASK
.globl _tty_imask
_tty_imask: .long 0
.globl _bio_imask
_bio_imask: .long 0
.globl _net_imask
_net_imask: .long 0
.globl _ipending
_ipending: .long 0
.globl _astpending
_astpending: .long 0 /* tells us an AST needs to be taken */
.globl _netisr
_netisr: .long 0 /* set with bits for which queue to service */
vec:
.long vec0, vec1, vec2, vec3, vec4, vec5, vec6, vec7
.long vec8, vec9, vec10, vec11, vec12, vec13, vec14, vec15
.text
/*
* Handle return from interrupts, traps and syscalls.
*/
SUPERALIGN_TEXT
_doreti:
FAKE_MCOUNT(_bintr) /* init "from" _bintr -> _doreti */
addl $4,%esp /* discard unit number */
popl %eax /* cpl to restore */
doreti_next:
/*
* Check for pending HWIs and SWIs atomically with restoring cpl
* and exiting. The check has to be atomic with exiting to stop
* (ipending & ~cpl) changing from zero to nonzero while we're
* looking at it (this wouldn't be fatal but it would increase
* interrupt latency). Restoring cpl has to be atomic with exiting
* so that the stack cannot pile up (the nesting level of interrupt
* handlers is limited by the number of bits in cpl).
*/
movl %eax,%ecx
notl %ecx
cli
andl _ipending,%ecx
jne doreti_unpend
doreti_exit:
movl %eax,_cpl
MEXITCOUNT
popl %es
popl %ds
popal
addl $8,%esp
iret
ALIGN_TEXT
doreti_unpend:
/*
* Enabling interrupts is safe because we haven't restored cpl yet.
* The locking from the "btrl" test is probably no longer necessary.
* We won't miss any new pending interrupts because we will check
* for them again.
*/
sti
bsfl %ecx,%ecx /* slow, but not worth optimizing */
btrl %ecx,_ipending
jnc doreti_next /* some intr cleared memory copy */
movl ihandlers(,%ecx,4),%edx
testl %edx,%edx
je doreti_next /* "can't happen" */
cmpl $NHWI,%ecx
jae doreti_swi
cli
movl %eax,_cpl
MEXITCOUNT
jmp %edx
ALIGN_TEXT
doreti_swi:
pushl %eax
/*
* The SWI_AST handler has to run at cpl = SWI_AST_MASK and the
* SWI_CLOCK handler at cpl = SWI_CLOCK_MASK, so we have to restore
* all the h/w bits in cpl now and have to worry about stack growth.
* The worst case is currently (30 Jan 1994) 2 SWI handlers nested
* in dying interrupt frames and about 12 HWIs nested in active
* interrupt frames. There are only 4 different SWIs and the HWI
* and SWI masks limit the nesting further.
*/
orl imasks(,%ecx,4),%eax
movl %eax,_cpl
call %edx
popl %eax
jmp doreti_next
ALIGN_TEXT
swi_ast:
addl $8,%esp /* discard raddr & cpl to get trap frame */
testb $SEL_RPL_MASK,TRAPF_CS_OFF(%esp)
je swi_ast_phantom
movl $T_ASTFLT,(2+8+0)*4(%esp)
call _trap
subl %eax,%eax /* recover cpl */
jmp doreti_next
ALIGN_TEXT
swi_ast_phantom:
/*
* These happen when there is an interrupt in a trap handler before
* ASTs can be masked or in an lcall handler before they can be
* masked or after they are unmasked. They could be avoided for
* trap entries by using interrupt gates, and for lcall exits by
* using by using cli, but they are unavoidable for lcall entries.
*/
cli
orl $SWI_AST_PENDING,_ipending
jmp doreti_exit /* SWI_AST is highest so we must be done */
/*
* Interrupt priority mechanism
* -- soft splXX masks with group mechanism (cpl)
* -- h/w masks for currently active or unused interrupts (imen)
* -- ipending = active interrupts currently masked by cpl
*/
ENTRY(splz)
/*
* The caller has restored cpl and checked that (ipending & ~cpl)
* is nonzero. We have to repeat the check since if there is an
* interrupt while we're looking, _doreti processing for the
* interrupt will handle all the unmasked pending interrupts
* because we restored early. We're repeating the calculation
* of (ipending & ~cpl) anyway so that the caller doesn't have
* to pass it, so this only costs one "jne". "bsfl %ecx,%ecx"
* is undefined when %ecx is 0 so we can't rely on the secondary
* btrl tests.
*/
movl _cpl,%eax
splz_next:
/*
* We don't need any locking here. (ipending & ~cpl) cannot grow
* while we're looking at it - any interrupt will shrink it to 0.
*/
movl %eax,%ecx
notl %ecx
andl _ipending,%ecx
jne splz_unpend
ret
ALIGN_TEXT
splz_unpend:
bsfl %ecx,%ecx
btrl %ecx,_ipending
jnc splz_next
movl ihandlers(,%ecx,4),%edx
testl %edx,%edx
je splz_next /* "can't happen" */
cmpl $NHWI,%ecx
jae splz_swi
/*
* We would prefer to call the intr handler directly here but that
* doesn't work for badly behaved handlers that want the interrupt
* frame. Also, there's a problem determining the unit number.
* We should change the interface so that the unit number is not
* determined at config time.
*/
jmp *vec(,%ecx,4)
ALIGN_TEXT
splz_swi:
cmpl $SWI_AST,%ecx
je splz_next /* "can't happen" */
pushl %eax
orl imasks(,%ecx,4),%eax
movl %eax,_cpl
call %edx
popl %eax
movl %eax,_cpl
jmp splz_next
/*
* Fake clock IRQ so that it appears to come from our caller and not from
* vec0, so that kernel profiling works.
* XXX do this more generally (for all vectors; look up the C entry point).
* XXX frame bogusness stops us from just jumping to the C entry point.
*/
ALIGN_TEXT
vec0:
popl %eax /* return address */
pushfl
#define KCSEL 8
pushl $KCSEL
pushl %eax
cli
MEXITCOUNT
jmp _Vclk
#define BUILD_VEC(irq_num) \
ALIGN_TEXT ; \
vec/**/irq_num: ; \
int $ICU_OFFSET + (irq_num) ; \
ret
BUILD_VEC(1)
BUILD_VEC(2)
BUILD_VEC(3)
BUILD_VEC(4)
BUILD_VEC(5)
BUILD_VEC(6)
BUILD_VEC(7)
BUILD_VEC(8)
BUILD_VEC(9)
BUILD_VEC(10)
BUILD_VEC(11)
BUILD_VEC(12)
BUILD_VEC(13)
BUILD_VEC(14)
BUILD_VEC(15)
ALIGN_TEXT
swi_clock:
MCOUNT
subl %eax,%eax
cmpl $_splz,(%esp) /* XXX call from splz()? */
jae 1f /* yes, usermode = 0 */
movl 4+4+TRAPF_CS_OFF(%esp),%eax /* no, check trap frame */
andl $SEL_RPL_MASK,%eax
1:
pushl %eax
call _softclock
addl $4,%esp
ret
#define DONET(s, c, event) ; \
.globl c ; \
btrl $s,_netisr ; \
jnc 9f ; \
call c ; \
9:
ALIGN_TEXT
swi_net:
MCOUNT
#if 0
DONET(NETISR_RAW, _rawintr,netisr_raw)
#endif
#ifdef INET
DONET(NETISR_IP, _ipintr,netisr_ip)
#endif
#ifdef IMP
DONET(NETISR_IMP, _impintr,netisr_imp)
#endif
#ifdef NS
DONET(NETISR_NS, _nsintr,netisr_ns)
#endif
#ifdef ISO
DONET(NETISR_ISO, _clnlintr,netisr_iso)
#endif
#ifdef CCITT
DONET(NETISR_X25, _pkintr, 29)
DONET(NETISR_HDLC, _hdintr, 30)
#endif
ret
ALIGN_TEXT
swi_tty:
MCOUNT
#include "sio.h"
#if NSIO > 0
jmp _siopoll
#else
ret
#endif
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