diff options
| -rw-r--r-- | arch/ia64/kernel/setup.c | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c index 1f5c26dbe70..e256b114bf4 100644 --- a/arch/ia64/kernel/setup.c +++ b/arch/ia64/kernel/setup.c @@ -244,28 +244,31 @@ find_initrd (void) static void __init io_port_init (void) { - extern unsigned long ia64_iobase; unsigned long phys_iobase; /* - * Set `iobase' to the appropriate address in region 6 (uncached access range). + * Set `iobase' based on the EFI memory map or, failing that, the + * value firmware left in ar.k0. * - * The EFI memory map is the "preferred" location to get the I/O port space base, - * rather the relying on AR.KR0. This should become more clear in future SAL - * specs. We'll fall back to getting it out of AR.KR0 if no appropriate entry is - * found in the memory map. + * Note that in ia32 mode, IN/OUT instructions use ar.k0 to compute + * the port's virtual address, so ia32_load_state() loads it with a + * user virtual address. But in ia64 mode, glibc uses the + * *physical* address in ar.k0 to mmap the appropriate area from + * /dev/mem, and the inX()/outX() interfaces use MMIO. In both + * cases, user-mode can only use the legacy 0-64K I/O port space. + * + * ar.k0 is not involved in kernel I/O port accesses, which can use + * any of the I/O port spaces and are done via MMIO using the + * virtual mmio_base from the appropriate io_space[]. */ phys_iobase = efi_get_iobase(); - if (phys_iobase) - /* set AR.KR0 since this is all we use it for anyway */ - ia64_set_kr(IA64_KR_IO_BASE, phys_iobase); - else { + if (!phys_iobase) { phys_iobase = ia64_get_kr(IA64_KR_IO_BASE); - printk(KERN_INFO "No I/O port range found in EFI memory map, falling back " - "to AR.KR0\n"); - printk(KERN_INFO "I/O port base = 0x%lx\n", phys_iobase); + printk(KERN_INFO "No I/O port range found in EFI memory map, " + "falling back to AR.KR0 (0x%lx)\n", phys_iobase); } ia64_iobase = (unsigned long) ioremap(phys_iobase, 0); + ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase)); /* setup legacy IO port space */ io_space[0].mmio_base = ia64_iobase; |