freebsd-nq/sys/i386/isa/ipl_funcs.c
Steve Passe 8ee0110a44 A clean fix for the spl "deadlock before smp_active" problem.
Added a new variable, 'bsp_apic_ready', which is set as soon as the bootstrap
CPU has initialized its local APIC.  Conditionalize the GENSPLR functions
to call ss_lock ONLY after bsp_apic_ready is TRUE;  This should prevent
any problems with races between the time the 1st AP becomes ready and the
time smp_active is set.
1997-08-24 20:33:32 +00:00

260 lines
6.1 KiB
C

/*-
* Copyright (c) 1997 Bruce Evans.
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* $Id: ipl_funcs.c,v 1.7 1997/08/24 20:18:28 smp Exp smp $
*/
#include <sys/types.h>
#include <sys/systm.h>
#include <machine/ipl.h>
#ifndef SMP
/*
* The volatile bitmap variables must be set atomically. This normally
* involves using a machine-dependent bit-set or `or' instruction.
*/
#define DO_SETBITS(name, var, bits) \
void name(void) \
{ \
setbits(var, bits); \
}
DO_SETBITS(setdelayed, &ipending, loadandclear((unsigned *)&idelayed))
DO_SETBITS(setsoftast, &ipending, SWI_AST_PENDING)
DO_SETBITS(setsoftclock, &ipending, SWI_CLOCK_PENDING)
DO_SETBITS(setsoftnet, &ipending, SWI_NET_PENDING)
DO_SETBITS(setsofttty, &ipending, SWI_TTY_PENDING)
DO_SETBITS(schedsoftnet, &idelayed, SWI_NET_PENDING)
DO_SETBITS(schedsofttty, &idelayed, SWI_TTY_PENDING)
unsigned
softclockpending(void)
{
return (ipending & SWI_CLOCK_PENDING);
}
#define GENSPL(name, set_cpl) \
unsigned name(void) \
{ \
unsigned x; \
\
x = cpl; \
set_cpl; \
return (x); \
}
GENSPL(splbio, cpl |= bio_imask)
GENSPL(splclock, cpl = HWI_MASK | SWI_MASK)
GENSPL(splhigh, cpl = HWI_MASK | SWI_MASK)
GENSPL(splimp, cpl |= net_imask)
GENSPL(splnet, cpl |= SWI_NET_MASK)
GENSPL(splsoftclock, cpl = SWI_CLOCK_MASK)
GENSPL(splsofttty, cpl |= SWI_TTY_MASK)
GENSPL(splstatclock, cpl |= stat_imask)
GENSPL(spltty, cpl |= tty_imask)
GENSPL(splvm, cpl |= net_imask | bio_imask)
void
spl0(void)
{
cpl = SWI_AST_MASK;
if (ipending & ~SWI_AST_MASK)
splz();
}
void
splx(unsigned ipl)
{
cpl = ipl;
if (ipending & ~ipl)
splz();
}
#else /* !SMP */
#include <machine/param.h>
#include <machine/smp.h>
extern int bspEarly; /* XXX */
#if defined(REAL_IFCPL)
#define IFCPL_LOCK() SCPL_LOCK()
#define IFCPL_UNLOCK() SCPL_UNLOCK()
#else /* REAL_IFCPL */
#define IFCPL_LOCK()
#define IFCPL_UNLOCK()
#endif /* REAL_IFCPL */
/*
* The volatile bitmap variables must be set atomically. This normally
* involves using a machine-dependent bit-set or `or' instruction.
*/
#define DO_SETBITS(name, var, bits) \
void name(void) \
{ \
IFCPL_LOCK(); \
setbits(var, bits); \
IFCPL_UNLOCK(); \
}
DO_SETBITS(setdelayed, &ipending, loadandclear((unsigned *)&idelayed))
DO_SETBITS(setsoftast, &ipending, SWI_AST_PENDING)
DO_SETBITS(setsoftclock, &ipending, SWI_CLOCK_PENDING)
DO_SETBITS(setsoftnet, &ipending, SWI_NET_PENDING)
DO_SETBITS(setsofttty, &ipending, SWI_TTY_PENDING)
DO_SETBITS(schedsoftnet, &idelayed, SWI_NET_PENDING)
DO_SETBITS(schedsofttty, &idelayed, SWI_TTY_PENDING)
unsigned
softclockpending(void)
{
unsigned x;
IFCPL_LOCK();
x = ipending & SWI_CLOCK_PENDING;
IFCPL_UNLOCK();
return x;
}
#ifdef notneeded
#define GENSPL(name, set_cpl) \
unsigned name(void) \
{ \
unsigned x; \
\
IFCPL_LOCK(); \
x = cpl; \
/* XXX test cil */ \
set_cpl; \
IFCPL_UNLOCK(); \
\
return (x); \
}
#endif /* notneeded */
/*
* This version has to check for bsp_apic_ready,
* as calling simple_lock() (ie ss_lock) before then deadlocks the system.
* A sample count of GENSPLR calls before bsp_apic_ready was set: 2193
*/
#define GENSPLR(name, set_cpl) \
unsigned name(void) \
{ \
unsigned x; \
\
if (bsp_apic_ready) \
IFCPL_LOCK(); \
x = cpl; \
/* XXX test cil */ \
set_cpl; \
if (bsp_apic_ready) \
IFCPL_UNLOCK(); \
\
return (x); \
}
GENSPLR(splbio, cpl |= bio_imask)
GENSPLR(splclock, cpl = HWI_MASK | SWI_MASK)
GENSPLR(splhigh, cpl = HWI_MASK | SWI_MASK)
GENSPLR(splimp, cpl |= net_imask)
GENSPLR(splnet, cpl |= SWI_NET_MASK)
GENSPLR(splsoftclock, cpl = SWI_CLOCK_MASK)
GENSPLR(splsofttty, cpl |= SWI_TTY_MASK)
GENSPLR(splstatclock, cpl |= stat_imask)
GENSPLR(spltty, cpl |= tty_imask)
GENSPLR(splvm, cpl |= net_imask | bio_imask)
void
spl0(void)
{
IFCPL_LOCK();
/* XXX test cil */
cpl = SWI_AST_MASK;
if (ipending & ~SWI_AST_MASK) {
IFCPL_UNLOCK();
splz();
}
else
IFCPL_UNLOCK();
}
void
splx(unsigned ipl)
{
if (bsp_apic_ready)
IFCPL_LOCK();
/* XXX test cil */
cpl = ipl;
if (ipending & ~ipl) {
if (bsp_apic_ready)
IFCPL_UNLOCK();
splz();
}
else
if (bsp_apic_ready)
IFCPL_UNLOCK();
}
/*
* Replaces UP specific inline found in (?) pci/pci_support.c.
*
* Stefan said:
* You know, that splq() is used in the shared interrupt multiplexer, and that
* the SMP version should not have too much overhead. If it is significantly
* slower, then moving the splq() out of the loop in intr_mux() and passing in
* the logical OR of all mask values might be a better solution than the
* current code. (This logical OR could of course be pre-calculated whenever
* another shared interrupt is registered ...)
*/
intrmask_t
splq(intrmask_t mask)
{
intrmask_t tmp;
IFCPL_LOCK();
tmp = cpl;
cpl |= mask;
IFCPL_UNLOCK();
return (tmp);
}
#endif /* !SMP */