[BUG 2.6.31-rc1] HIGHMEM64G causes hang in PCI init on 32-bit x86

From: Mikael Pettersson
Date: Fri Jun 26 2009 - 11:59:33 EST

The combination of HIGHMEM64G and PCI doesn't work in 2.6.31-rc1,
causing a hang in PCI initialisation during boot:

Linux version 2.6.31-rc1 (mikpe@brewer) (gcc version 4.3.4 20090621 (prerelease) (GCC) ) #1 Fri Jun 26 16:01:50 CEST 2009
KERNEL supported cpus:
Intel GenuineIntel
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000009ec00 (usable)
BIOS-e820: 000000000009ec00 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000e4000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 000000007ff90000 (usable)
BIOS-e820: 000000007ff90000 - 000000007ff9e000 (ACPI data)
BIOS-e820: 000000007ff9e000 - 000000007ffe0000 (ACPI NVS)
BIOS-e820: 000000007ffe0000 - 0000000080000000 (reserved)
BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
BIOS-e820: 00000000ffb00000 - 0000000100000000 (reserved)
BIOS-e820: 0000000100000000 - 0000000200000000 (usable)
DMI 2.4 present.
last_pfn = 0x200000 max_arch_pfn = 0x1000000
init_memory_mapping: 0000000000000000-00000000379fe000
NX (Execute Disable) protection: active
RAMDISK: 37ebb000 - 37fef7c6
Allocated new RAMDISK: 00221000 - 003557c6
Move RAMDISK from 0000000037ebb000 - 0000000037fef7c5 to 00221000 - 003557c5
7302MB HIGHMEM available.
889MB LOWMEM available.
mapped low ram: 0 - 379fe000
low ram: 0 - 379fe000
node 0 low ram: 00000000 - 379fe000
node 0 bootmap 00009000 - 0000ff40
(7 early reservations) ==> bootmem [0000000000 - 00379fe000]
#0 [0000000000 - 0000001000] BIOS data page ==> [0000000000 - 0000001000]
#1 [0000100000 - 000021cf18] TEXT DATA BSS ==> [0000100000 - 000021cf18]
#2 [000009ec00 - 0000100000] BIOS reserved ==> [000009ec00 - 0000100000]
#3 [000021d000 - 000022022c] BRK ==> [000021d000 - 000022022c]
#4 [0000007000 - 0000009000] PGTABLE ==> [0000007000 - 0000009000]
#5 [0000221000 - 00003557c6] NEW RAMDISK ==> [0000221000 - 00003557c6]
#6 [0000009000 - 0000010000] BOOTMAP ==> [0000009000 - 0000010000]
Zone PFN ranges:
DMA 0x00000000 -> 0x00001000
Normal 0x00001000 -> 0x000379fe
HighMem 0x000379fe -> 0x00200000
Movable zone start PFN for each node
early_node_map[3] active PFN ranges
0: 0x00000000 -> 0x0000009e
0: 0x00000100 -> 0x0007ff90
0: 0x00100000 -> 0x00200000
Allocating PCI resources starting at 80000000 (gap: 80000000:7ee00000)
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 1556269
Kernel command line: ro root=LABEL=32/ console=ttyS0,115200
PID hash table entries: 4096 (order: 12, 16384 bytes)
Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
Initializing CPU#0
Initializing HighMem for node 0 (000379fe:00200000)
Memory: 6220996k/8388608k available (691k kernel code, 68768k reserved, 203k data, 144k init, 5379656k highmem)
virtual kernel memory layout:
fixmap : 0xfffe6000 - 0xfffff000 ( 100 kB)
pkmap : 0xffa00000 - 0xffc00000 (2048 kB)
vmalloc : 0xf81fe000 - 0xff9fe000 ( 120 MB)
lowmem : 0xc0000000 - 0xf79fe000 ( 889 MB)
.init : 0xc01e2000 - 0xc0206000 ( 144 kB)
.data : 0xc01acd86 - 0xc01dfbdc ( 203 kB)
.text : 0xc0100000 - 0xc01acd86 ( 691 kB)
Checking if this processor honours the WP bit even in supervisor mode...Ok.
NR_IRQS:16
Fast TSC calibration using PIT
Detected 2400.277 MHz processor.
Console: colour VGA+ 80x25
console [ttyS0] enabled
Calibrating delay loop (skipped), value calculated using timer frequency.. 4800.55 BogoMIPS (lpj=24002770)
Mount-cache hash table entries: 512
CPU: L1 I cache: 32K, L1 D cache: 32K
CPU: L2 cache: 4096K
using mwait in idle threads.
CPU: Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz stepping 06
Checking 'hlt' instruction... OK.
PCI: PCI BIOS revision 3.00 entry at 0xf0031, last bus=2
PCI: Using configuration type 1 for base access
PCI: Probing PCI hardware
pci 0000:00:01.0: PME# supported from D0 D3hot D3cold
pci 0000:00:01.0: PME# disabled
pci 0000:00:1a.7: PME# supported from D0 D3hot D3cold
pci 0000:00:1a.7: PME# disabled
pci 0000:00:1b.0: PME# supported from D0 D3hot D3cold
pci 0000:00:1b.0: PME# disabled
pci 0000:00:1d.7: PME# supported from D0 D3hot D3cold
pci 0000:00:1d.7: PME# disabled
pci 0000:00:1f.0: quirk: region 0800-087f claimed by ICH6 ACPI/GPIO/TCO
pci 0000:00:1f.0: quirk: region 0480-04bf claimed by ICH6 GPIO
pci 0000:00:1f.0: ICH7 LPC Generic IO decode 1 PIO at 0294 (mask 0003)
pci 0000:00:1f.2: PME# supported from D3hot
pci 0000:00:1f.2: PME# disabled
pci 0000:02:02.0: PME# supported from D1 D2 D3hot D3cold
pci 0000:02:02.0: PME# disabled
pci 0000:00:1e.0: transparent bridge
pci 0000:00:1f.0: PIIX/ICH IRQ router [8086:2810]

At this point the kernel hangs hard until rebooted.

Rebooting with mem=2048M (to avoid issues with mappings >= 4GB)
allows PCI init to proceed and print:

pci 0000:00:01.0: PCI bridge, secondary bus 0000:01
pci 0000:00:01.0: IO window: 0x9000-0xbfff
pci 0000:00:01.0: MEM window: 0xff800000-0xff8fffff
pci 0000:00:01.0: PREFETCH window: 0x000000bff00000-0x000000dfefffff
pci 0000:00:1e.0: PCI bridge, secondary bus 0000:02
pci 0000:00:1e.0: IO window: 0xc000-0xcfff
pci 0000:00:1e.0: MEM window: 0xff900000-0xff9fffff
pci 0000:00:1e.0: PREFETCH window: disabled
pci 0000:00:01.0: found PCI INT A -> IRQ 11
pci 0000:00:01.0: sharing IRQ 11 with 0000:00:1a.0
pci 0000:00:01.0: sharing IRQ 11 with 0000:01:00.0
Unpacking initramfs...
Freeing initrd memory: 1233k freed
platform rtc_cmos: registered platform RTC device (no PNP device found)
Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
Platform driver 'serial8250' needs updating - please use dev_pm_ops
Freeing unused kernel memory: 144k freed
Red Hat nash version 5.1.19.0.3 starting
...

Booting with pci=off also allows the kernel to boot.
Reconfiguring with NOHIGHMEM or HIGHMEM4G also allows the kernel to boot.

This is a regression from 2.6.30 and earlier kernels.

/Mikael
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