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: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index 6eea42e..e5b17f9 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -271,16 +271,16 @@
* 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 @@
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)) {
- fix = 1;
- goto out;
+ if (last_valid) {
+ if ((aper_order != last_aper_order) ||
+ (aper_base != last_aper_base) ||
+ (aper_enabled != last_aper_enabled)) {
+ fix = 1;
+ 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;