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If an I/O APIC returns 0xffffffff for its version register after we map it,

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assume it is bogus and return NULL instead of trying to parse it as an
APIC.

Inspired by:	linux bug reports via njl
This commit is contained in:
jhb 2005-04-14 05:55:34 +00:00
parent aa156413c0
commit 76c3b17df6
1 changed files with 11 additions and 2 deletions
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13
sys/i386/i386/io_apic.c
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@ -502,11 +502,20 @@ ioapic_create(uintptr_t addr, int32_t apic_id, int intbase)
u_int numintr, i;
uint32_t value;
/* Map the register window so we can access the device. */
apic = (ioapic_t *)pmap_mapdev(addr, IOAPIC_MEM_REGION);
mtx_lock_spin(&icu_lock);
numintr = ((ioapic_read(apic, IOAPIC_VER) & IOART_VER_MAXREDIR) >>
MAXREDIRSHIFT) + 1;
value = ioapic_read(apic, IOAPIC_VER);
mtx_unlock_spin(&icu_lock);
/* If it's version register doesn't seem to work, punt. */
if (value == 0xffffff) {
pmap_unmapdev(apic, IOAPIC_MEM_REGION);
return (NULL);
}
/* Determine the number of vectors and set the APIC ID. */
numintr = ((value & IOART_VER_MAXREDIR) >> MAXREDIRSHIFT) + 1;
io = malloc(sizeof(struct ioapic) +
numintr * sizeof(struct ioapic_intsrc), M_IOAPIC, M_WAITOK);
io->io_pic = ioapic_template;