I see the following when I boot up below, and when I go looking for the coreboot tables I find it at 0x500... with the first entry at 0x518 being a FORWARD record pointing to 0x1f7d1400.
However, when I try to access that pointer, the system panics.
How do I get at the RAM in this region here?
BIOS-e820: 000000001f7cf000 - 000000001f7e0000 (reserved)
and where is Linux remapping it to? I tried to call phys_to_virt() on that address, but it panics the system when I do a read access.
How do I access that window of memory?
==== console output
root (hd0,0) Filesystem type is ext2fs, partition type 0x83 kernel /boot/vmlinuz block2mtd.block2mtd=/dev/sda2,65536,rootfs root=/dev/mtdb lock0 rootfstype=squashfs rootwait console=ttyS0,115200n8 noinitrd reboot=bios [Linux-bzImage, setup=0x3000, size=0x174e00] boot Linux version 2.6.39.3 (philipp@builder) (gcc version 4.5.4 20110526 (prerelease) (Linaro GCC 4.5-2011.06-0) ) #1 Thu Aug 11 16:29:25 MDT 2011 KERNEL supported cpus: AMD AuthenticAMD BIOS-provided physical RAM map: BIOS-e820: 0000000000000000 - 000000000009fc00 (usable) BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved) BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved) BIOS-e820: 0000000000100000 - 000000001f7cf000 (usable) BIOS-e820: 000000001f7cf000 - 000000001f7e0000 (reserved) Notice: NX (Execute Disable) protection missing in CPU! DMI 2.4 present. last_pfn = 0x1f7cf max_arch_pfn = 0x100000 init_memory_mapping: 0000000000000000-000000001f7cf000 503MB LOWMEM available. mapped low ram: 0 - 1f7cf000 low ram: 0 - 1f7cf000 Zone PFN ranges: DMA 0x00000010 -> 0x00001000 Normal 0x00001000 -> 0x0001f7cf Movable zone start PFN for each node early_node_map[2] active PFN ranges 0: 0x00000010 -> 0x0000009f 0: 0x00000100 -> 0x0001f7cf Using APIC driver default No local APIC present or hardware disabled APIC: disable apic facility APIC: switched to apic NOOP Allocating PCI resources starting at 1f7e0000 (gap: 1f7e0000:e0820000) Built 1 zonelists in Zone order, mobility grouping on. Total pages: 127854 Kernel command line: block2mtd.block2mtd=/dev/sda2,65536,rootfs root=/dev/mtdblock0 rootfstype=squashfs rootwait console=ttyS0,115200n8 noinitrd reboot=bios PID hash table entries: 2048 (order: 1, 8192 bytes) Dentry cache hash table entries: 65536 (order: 6, 262144 bytes) Inode-cache hash table entries: 32768 (order: 5, 131072 bytes) Initializing CPU#0 Memory: 508036k/515900k available (1839k kernel code, 7412k reserved, 742k data, 204k init, 0k highmem) virtual kernel memory layout: fixmap : 0xfffa4000 - 0xfffff000 ( 364 kB) vmalloc : 0xdffcf000 - 0xfffa2000 ( 511 MB) lowmem : 0xc0000000 - 0xdf7cf000 ( 503 MB) .init : 0xc1286000 - 0xc12b9000 ( 204 kB) .data : 0xc11cbef7 - 0xc1285800 ( 742 kB) .text : 0xc1000000 - 0xc11cbef7 (1839 kB) Checking if this processor honours the WP bit even in supervisor mode...Ok. SLUB: Genslabs=15, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1 NR_IRQS:288 console [ttyS0] enabled Fast TSC calibration using PIT Detected 498.058 MHz processor. Calibrating delay loop (skipped), value calculated using timer frequency.. 996.11 BogoMIPS (lpj=4980580) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 512 CPU: Geode(TM) Integrated Processor by AMD PCS stepping 02 Performance Events: no PMU driver, software events only. NET: Registered protocol family 16 PCI: PCI BIOS revision 2.10 entry at 0xfc8b7, last bus=0 PCI: Using configuration type 1 for base access bio: create slab <bio-0> at 0 SCSI subsystem initialized PCI: Probing PCI hardware Switching to clocksource pit NET: Registered protocol family 2 IP route cache hash table entries: 4096 (order: 2, 16384 bytes) TCP established hash table entries: 16384 (order: 5, 131072 bytes) TCP bind hash table entries: 16384 (order: 4, 65536 bytes) TCP: Hash tables configured (established 16384 bind 16384) TCP reno registered UDP hash table entries: 256 (order: 0, 4096 bytes) UDP-Lite hash table entries: 256 (order: 0, 4096 bytes) NET: Registered protocol family 1 platform rtc_cmos: registered platform RTC device (no PNP device found) ...