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aperture_64.c: duplicated code, buggy?

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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: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Pavel Machek 2008-05-26 20:40:47 +02:00 committed by Thomas Gleixner
parent dd564d0cf0
commit fa5b8a30cf
1 changed files with 12 additions and 9 deletions
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27
arch/x86/kernel/aperture_64.c
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@ -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;
}
last_aper_order = aper_order;
last_aper_base = aper_base;
last_aper_enabled = aper_enabled;
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;