[OpenBIOS] [PATCH 5/5] Change OFMEM to allocate memory from the top of RAM downwards.

[Mark Cave-Ayland]

Andreas Färber wrote:

> While I'm not against reversing the direction, your above statement 
> worries me. Our claim code should only claim free memory. So either the 
> respective boot loader doesn't actually claim the memory it's using (the 
> recent ppc bug that broke Haiku), or there's a bug in ofmem that you're 
> hiding by this change. Both directions should in theory work, I believe.

Okay - having played with this a bit further, it seems that it's the 
physical memory allocations that need to be reversed in order to prevent 
my Solaris 8 kernel from crashing mid-boot. Below is the log from my 
OFMEM-enabled SPARC32 OpenBIOS booting Solaris 8 with physical memory 
allocated from the bottom upwards:


OFMEM: ofmem_map_page_range ffe27000 -> d00000000 00001000 mode 0000003c
Configuration device id QEMU version 1 machine id 32
OFMEM: ofmem_map_page_range ffe26000 -> 010000000 00001000 mode 0000003c
OFMEM: ofmem_map_page_range ffe25000 -> 071100000 00001000 mode 0000003c
OFMEM: ofmem_map_page_range ffe24000 -> 071000000 00001000 mode 0000003c
OFMEM: ofmem_map_page_range ffe22000 -> 071200000 00002000 mode 0000003c
OFMEM: ofmem_map_page_range ffe21000 -> 071400000 00001000 mode 0000003c
OFMEM: ofmem_map_page_range ffe20000 -> 071910000 00001000 mode 0000003c
OFMEM: ofmem_map_page_range ffe1f000 -> 071f00000 00001000 mode 0000003c
OFMEM: ofmem_map_page_range ffe0e000 -> 071d00000 00011000 mode 0000003c
OFMEM: ofmem_map_page_range ffdfd000 -> 071e00000 00011000 mode 0000003c
OFMEM: ofmem_map_page_range ffdfc000 -> 007fff000 00001000 mode 0000003c
OFMEM: ofmem_map_page_range ffdfb000 -> 010001000 00001000 mode 0000003c
OFMEM: ofmem_map_page_range ffdfa000 -> 078400000 00001000 mode 0000003c
OFMEM: ofmem_map_page_range ffdf9000 -> 078800000 00001000 mode 0000003c
CPUs: 1 x FMI,MB86904
UUID: 00000000-0000-0000-0000-000000000000
Welcome to OpenBIOS v1.0 built on Dec 22 2010 01:15
   Type 'help' for detailed information
Trying cdrom:d...
Not a bootable ELF image
Loading a.out image...
Loaded 7680 bytes
entry point is 0x4000
bootpath: /iommu/sbus/espdma/esp/sd at 2,0:d

Jumping to entry point 00004000 for type 00000005...
switching to new context:
OFMEM: ofmem_claim phys=ffffffffffffffff size=00040000 align=00000008
OFMEM: ofmem_claim phys returned 000000000
OFMEM: ofmem_claim_virt virt=f0040000 size=00040000 align=00000000
OFMEM: ofmem_map_page_range f0040000 -> 000000000 00040000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00019000 align=00000008
OFMEM: ofmem_claim phys returned 000040000
OFMEM: ofmem_claim_virt virt=f0240000 size=00019000 align=00000000
OFMEM: ofmem_map_page_range f0240000 -> 000040000 00019000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00007000 align=00000008
OFMEM: ofmem_claim phys returned 000059000
OFMEM: ofmem_claim_virt virt=f0080000 size=00007000 align=00000000
OFMEM: ofmem_map_page_range f0080000 -> 000059000 00007000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00001000 align=00000008
OFMEM: ofmem_claim phys returned 000060000
OFMEM: ofmem_claim_virt virt=f0087000 size=00001000 align=00000000
OFMEM: ofmem_map_page_range f0087000 -> 000060000 00001000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00001000 align=00000008
OFMEM: ofmem_claim phys returned 000061000
OFMEM: ofmem_claim_virt virt=f0088000 size=00001000 align=00000000
OFMEM: ofmem_map_page_range f0088000 -> 000061000 00001000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00003000 align=00000008
OFMEM: ofmem_claim phys returned 000062000
OFMEM: ofmem_claim_virt virt=f0089000 size=00003000 align=00000000
OFMEM: ofmem_map_page_range f0089000 -> 000062000 00003000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00003000 align=00000008
OFMEM: ofmem_claim phys returned 000065000
OFMEM: ofmem_claim_virt virt=f008c000 size=00003000 align=00000000
OFMEM: ofmem_map_page_range f008c000 -> 000065000 00003000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00001000 align=00000008
OFMEM: ofmem_claim phys returned 000068000
OFMEM: ofmem_claim_virt virt=f0259000 size=00001000 align=00000000
OFMEM: ofmem_map_page_range f0259000 -> 000068000 00001000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00001000 align=00000008
OFMEM: ofmem_claim phys returned 000069000
OFMEM: ofmem_claim_virt virt=f025a000 size=00001000 align=00000000
OFMEM: ofmem_map_page_range f025a000 -> 000069000 00001000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00001000 align=00000008
OFMEM: ofmem_claim phys returned 00006a000
OFMEM: ofmem_claim_virt virt=f025b000 size=00001000 align=00000000
OFMEM: ofmem_map_page_range f025b000 -> 00006a000 00001000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00001000 align=00000008
OFMEM: ofmem_claim phys returned 00006b000
OFMEM: ofmem_claim_virt virt=f025c000 size=00001000 align=00000000
OFMEM: ofmem_map_page_range f025c000 -> 00006b000 00001000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=000c9000 align=00000008
OFMEM: ofmem_claim phys returned 00006c000
OFMEM: ofmem_claim_virt virt=f008f000 size=000c9000 align=00000000
OFMEM: ofmem_map_page_range f008f000 -> 00006c000 000c9000 mode 000000bc
OFMEM: ofmem_claim phys=ffffffffffffffff size=00018000 align=00000008
OFMEM: ofmem_claim phys returned 000135000
OFMEM: ofmem_claim_virt virt=f025d000 size=00018000 align=00000000
OFMEM: ofmem_map_page_range f025d000 -> 000135000 00018000 mode 000000bc

(hangs at this point)


The Solaris boot loader appears to be claiming specific virtual 
addresses, but claiming the physical addresses from the pool. The last 
physical address allocated from the pool before the crash is 0x135000 
which I think may be overwriting the kernel itself as I have something 
in the back of my mind that says the kernel is loaded at 0x100000 - Blue 
any ideas?


ATB,

Mark.

-- 
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
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