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

Mikael Pettersson
2009-06-30T09:11:25Z

Yinghai Lu writes:
> Linus Torvalds wrote:
> >
> > On Mon, 29 Jun 2009, Yinghai Lu wrote:
> >> + end = round_up(start, ram_alignment(start)) - 1;
> >> + if (start > (resource_size_t)end)
> >> continue;
> >> - reserve_region_with_split(&iomem_resource, start,
> >> - end - 1, "RAM buffer");
> >> + reserve_region_with_split(&iomem_resource, (resource_size_t)start,
> >> + (resource_size_t)end, "RAM buffer");
> >
> > Hmm. You shouldn't need the casts with reserve_region_with_split(), and
> > they just make things uglier.
> >
> > Also, I wonder if we should do something like this instead
> >
> > #define MAX_RESOURCE_SIZE ((resource_size_t)-1)
> >
> > ...
> > end = round_up(start, ram_alignment(start)) - 1;
> > if (end > MAX_RESOURCE_SIZE)
> > end = MAX_RESOURCE_SIZE;
> > if (start > end)
> > continue;
> >
> > Because otherwise we'll just be ignoring resources that cross the resource
> > size boundary, which sounds wrong.
> >
> > We _could_ have a RAM resource that crosses the 4GB boundary, after all.
> >
> > Yeah, it doesn't happen much in practice, because usually the 3G-4G range
> > is left for PCI mappings etc, so we might never hit this in practice, but
> > still, this sounds like a more correct thing to do.
> >
> > It also avoids the cast. We simply cap the end to the max that
> > 'resource_size_t' can hold.
>
> Mikael, please try this on your system, and send out /proc/iomem
>
> Thanks
>
> Yinghai
>
> [PATCH] x86: add boundary check for 32bit res before expand e820 resource to alignment
>
> fix hang with HIGHMEM_64G and 32bit resource.
>
> according to hpa and Linus, use (resource_size_t)-1 to fend off big ranges.
>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>

Thanks, 2.6.31-rc1 vanilla (which didn't boot) plus this one does boot.
/proc/iomem now looks as follows:

00000000-0009ebff : System RAM
0009ec00-0009ffff : reserved
000a0000-000bffff : Video RAM area
000c0000-000ccfff : Video ROM
000e4000-000fffff : reserved
000f0000-000fffff : System ROM
00100000-7ff8ffff : System RAM
00100000-002e022e : Kernel code
002e022f-0038aaf7 : Kernel data
003d8000-003fc9f3 : Kernel bss
7ff90000-7ff9dfff : ACPI Tables
7ff9e000-7ffdffff : ACPI Non-volatile Storage
7ffe0000-7fffffff : reserved
80000000-800000ff : 0000:00:1f.3
bff00000-dfefffff : PCI Bus 0000:01
c0000000-cfffffff : 0000:01:00.0
e0000000-efffffff : PCI MMCONFIG 0 [00-ff]
e0000000-efffffff : pnp 00:0e
febfe000-febfec00 : pnp 00:09
fec00000-fec00fff : IOAPIC 0
fec00000-fec00fff : pnp 00:0b
fed00000-fed003ff : HPET 0
fed14000-fed19fff : pnp 00:01
fed1c000-fed1ffff : pnp 00:09
fed20000-fed8ffff : pnp 00:09
fee00000-fee00fff : Local APIC
fee00000-fee00fff : reserved
fee00000-fee00fff : pnp 00:0b
ff800000-ff8fffff : PCI Bus 0000:01
ff8c0000-ff8dffff : 0000:01:00.0
ff8e0000-ff8effff : 0000:01:00.1
ff8f0000-ff8fffff : 0000:01:00.0
ff900000-ff9fffff : PCI Bus 0000:02
ff9ffc00-ff9ffcff : 0000:02:02.0
ff9ffc00-ff9ffcff : 8139too
ffaf8000-ffafbfff : 0000:00:1b.0
ffaf8000-ffafbfff : ICH HD audio
ffaff000-ffaff3ff : 0000:00:1d.7
ffaff000-ffaff3ff : ehci_hcd
ffaff400-ffaff7ff : 0000:00:1a.7
ffaff400-ffaff7ff : ehci_hcd
ffaff800-ffafffff : 0000:00:1f.2
ffaff800-ffafffff : ahci
ffb00000-ffffffff : reserved
ffb00000-ffbfffff : pnp 00:09
fff00000-fffffffe : pnp 00:09
100000000-1ffffffff : System RAM