diff options
| -rw-r--r-- | sys/i386/i386/io_apic.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/sys/i386/i386/io_apic.c b/sys/i386/i386/io_apic.c index a403eebc68a9..b6c9446a7439 100644 --- a/sys/i386/i386/io_apic.c +++ b/sys/i386/i386/io_apic.c @@ -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; |