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Commit fa5b8a30 authored by Pavel Machek's avatar Pavel Machek Committed by Thomas Gleixner
Browse files

aperture_64.c: duplicated code, buggy? 



Hi!

void __init early_gart_iommu_check(void)

contains

	for (num = 24; num < 32; num++) {
		if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
			continue;

loop, with very similar loop duplicated in

void __init gart_iommu_hole_init(void)

. First copy of a loop seems to be buggy, too. It uses 0 as a "nothing
set" value, which may actually bite us in last_aper_enabled case
(because it may be often zero).

(Beware, it is hard to test this patch, because this code has about
2^8 different code paths, depending on hardware and cmdline settings).

Plus, the second loop does not check for consistency of
aper_enabled. Should it?

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent dd564d0c

arch/x86/kernel/aperture_64.c

+12 −9
Original line number Diff line number Diff line
@@ -271,16 +271,16 @@ void __init early_gart_iommu_check(void) 
	 * or BIOS forget to put that in reserved.

	 * try to update e820 to make that region as reserved.

	 */

	int fix, slot;

	int i, fix, slot;

	u32 ctl;

	u32 aper_size = 0, aper_order = 0, last_aper_order = 0;

	u64 aper_base = 0, last_aper_base = 0;

	int aper_enabled = 0, last_aper_enabled = 0;

	int i;

	int aper_enabled = 0, last_aper_enabled = 0, last_valid = 0;



	if (!early_pci_allowed())

		return;



	/* This is mostly duplicate of iommu_hole_init */

	fix = 0;

	for (i = 0; i < ARRAY_SIZE(bus_dev_ranges); i++) {

		int bus;
@@ -301,19 +301,22 @@ void __init early_gart_iommu_check(void) 
			aper_base = read_pci_config(bus, slot, 3, AMD64_GARTAPERTUREBASE) & 0x7fff;

			aper_base <<= 25;



			if ((last_aper_order && aper_order != last_aper_order) ||

			    (last_aper_base && aper_base != last_aper_base) ||

			    (last_aper_enabled && aper_enabled != last_aper_enabled)) {

			if (last_valid) {

				if ((aper_order != last_aper_order) ||

				    (aper_base != last_aper_base) ||

				    (aper_enabled != last_aper_enabled)) {

					fix = 1;

				goto out;

					break;

				}

			}



			last_aper_order = aper_order;

			last_aper_base = aper_base;

			last_aper_enabled = aper_enabled;

			last_valid = 1;

		}

	}



out:

	if (!fix && !aper_enabled)

		return;