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When sending an IPI to a specific target, disable interrupts inside the

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critical region in order to avoid sending the IPI to the wrong target.
This commit is contained in:
Tor Egge 1998-03-03 19:54:49 +00:00
parent 221e0c595b
commit ff27571284
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=34018
1 changed files with 70 additions and 8 deletions
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78
sys/i386/i386/mpapic.c
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@ -22,7 +22,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: mpapic.c,v 1.26 1997/08/21 05:08:25 fsmp Exp $
* $Id: mpapic.c,v 1.27 1997/12/08 18:36:02 fsmp Exp $
*/
#include "opt_smp.h"
@ -488,6 +488,73 @@ apic_ipi(int dest_type, int vector, int delivery_mode)
return 0;
}
static int
apic_ipi_singledest(int cpu, int vector, int delivery_mode)
{
u_long icr_lo;
u_long icr_hi;
u_long eflags;
#if defined(DETECT_DEADLOCK)
#define MAX_SPIN1 10000000
#define MAX_SPIN2 1000
int x;
/* "lazy delivery", ie we only barf if they stack up on us... */
for (x = MAX_SPIN1; x; --x) {
if ((lapic.icr_lo & APIC_DELSTAT_MASK) == 0)
break;
}
if (x == 0)
panic("apic_ipi was stuck");
#endif /* DETECT_DEADLOCK */
eflags = read_eflags();
__asm __volatile("cli" : : : "memory");
icr_hi = lapic.icr_hi & ~APIC_ID_MASK;
icr_hi |= (CPU_TO_ID(cpu) << 24);
lapic.icr_hi = icr_hi;
/* build IRC_LOW */
icr_lo = (lapic.icr_lo & APIC_RESV2_MASK)
| APIC_DEST_DESTFLD | delivery_mode | vector;
/* write APIC ICR */
lapic.icr_lo = icr_lo;
write_eflags(eflags);
/* wait for pending status end */
#if defined(DETECT_DEADLOCK)
for (x = MAX_SPIN2; x; --x) {
if ((lapic.icr_lo & APIC_DELSTAT_MASK) == 0)
break;
}
#ifdef needsattention
/*
* XXX FIXME:
* The above loop waits for the message to actually be delivered.
* It breaks out after an arbitrary timout on the theory that it eventually
* will be delivered and we will catch a real failure on the next entry to
* this function, which would panic().
* We could skip this wait entirely, EXCEPT it probably protects us from
* other "less robust" routines that assume the message was delivered and
* acted upon when this function returns. TLB shootdowns are one such
* "less robust" function.
*/
if (x == 0)
printf("apic_ipi might be stuck\n");
#endif
#undef MAX_SPIN2
#undef MAX_SPIN1
#else
while (lapic.icr_lo & APIC_DELSTAT_MASK)
/* spin */ ;
#endif /* DETECT_DEADLOCK */
/** XXX FIXME: return result */
return 0;
}
/*
* Send APIC IPI 'vector' to 'target's via 'delivery_mode'.
@ -501,21 +568,16 @@ selected_apic_ipi(u_int target, int vector, int delivery_mode)
{
int x;
int status;
u_long icr_hi;
if (target & ~0x7fff)
return -1; /* only 15 targets allowed */
for (status = 0, x = 0; x <= 14; ++x)
if (target & (1 << x)) {
/* write the destination field for the target AP */
icr_hi = lapic.icr_hi & ~APIC_ID_MASK;
icr_hi |= (CPU_TO_ID(x) << 24);
lapic.icr_hi = icr_hi;
/* send the IPI */
if (apic_ipi(APIC_DEST_DESTFLD, vector,
delivery_mode) == -1)
if (apic_ipi_singledest(x, vector,
delivery_mode) == -1)
status |= (1 << x);
}
return status;