[coreboot] MPTable can not be high-memory on Linux
yinghai at kernel.org
Sun Feb 22 22:33:35 CET 2009
Rafael J. Wysocki wrote:
> On Sunday 22 February 2009, Kevin O'Connor wrote:
>> Hi Stefan,
>> I'm CC'ing lkml and coreboot mailing lists.
> (added more CCs)
>> On Thu, Feb 19, 2009 at 10:26:17PM +0100, Stefan Reinauer wrote:
>>> OK, I played some more, and I finally found out it's earlyprintk and not
>>> early_printk. Plus there is bootmem_debug:
>>> Initializing cgroup subsys cpuset
>>> Initializing cgroup subsys cpu
>>> Linux version 126.96.36.199-9-default (geeko at buildhost) (gcc version 4.3.2
>>> [gcc-4_3-branch re0
>>> PAT WC disabled due to known CPU erratum.
>>> BIOS-provided physical RAM map:
>>> BIOS-e820: 0000000000000000 - 0000000000001000 (reserved)
>>> BIOS-e820: 0000000000001000 - 0000000000090000 (usable)
>>> BIOS-e820: 0000000000090000 - 0000000000100000 (reserved)
>>> BIOS-e820: 0000000000100000 - 000000003f7f0000 (usable)
>>> BIOS-e820: 000000003f7f0000 - 0000000040000000 (reserved)
>>> BIOS-e820: 00000000f0000000 - 00000000f4000000 (reserved)
>>> ACPI: no DMI BIOS year, acpi=force is required to enable ACPI
>>> ACPI: Disabling ACPI support
>>> found SMP MP-table at [c00f9fc0] 000f9fc0
>>> bootmem::mark_bootmem_node nid=0 start=f9 end=fb reserve=1 flags=0
>>> bootmem::__reserve nid=0 start=f9 end=fb flags=0
>>> bootmem::__reserve silent double reserve of PFN f9
>>> bootmem::__reserve silent double reserve of PFN fa
>>> BUG: Int 6: CR2 00000000
>>> EDI c00f9fd0 ESI 3f7f5410 EBP 0003f7f5 ESP c0535f20
>>> EBX c056c00c EDX 00000006 ECX 00000001 EAX c056c03c
>>> err 00000000 EIP c054f8f0 CS 00000060 flg 00010046
>>> Stack: 00000000 00000000 00000001 00038000 0003f7f5 f880abf0 3f7f5410
>>> 00000001 c054f91d 00000000 c054571a c0413e7e c00f9fc0 000f9fc0
>>> 3f7bf64d 00000000 3e2c5000 c054578a 00000000 c053f3b6 3f7bf64d
>>> So it dies because of the way it tries to reserve the MP-table.
>>> Here's the stack trace.
>>> [<c054f8f0>] mark_bootmem+0x9b/0xab
>>> [<c054f91d>] reserve_bootmem+0x1d/0x1f
>>> [<c054571a>] smp_scan_config+0xd9/0xfa
>>> [<c054578a>] __find_smp_config+0x4f/0x6e
>>> [<c053f3b6>] setup_arch+0x576/0x639
>>> [<c054ebc4>] cgroup_init_subsys+0x29/0xc9
>>> [<c053a6ac>] start_kernel+0x6b/0x31f
>> It looks like the problem is that the MPTable is located in the last
>> 64K of memory (instead of the first few megabytes). There is a
>> comment about this in arch/x86/kernel/mpparse.c:
>> * We cannot access to MPC table to compute
>> * table size yet, as only few megabytes from
>> * the bottom is mapped now.
>> * PC-9800's MPC table places on the very last
>> * of physical memory; so that simply reserving
>> * PAGE_SIZE from mpg->mpf_physptr yields BUG()
>> * in reserve_bootmem.
>> However, that comment is in an #ifdef specific to 32bit kernels.
>> (Though, it's not clear to me how that code would help as it sets size
>> to be a negative number.)
that should work for a long time.
0xf9fc0 < 1M is quite < max_low_pfn, so wonder why bootmem could panic.
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