Hello Manu,
Could you try the attached patch to arch/ppc/mm/4xx_mmu.c and see if it
solves your problem?
Best regards,
Magnus
manu wrote:
Hello,
I work on a custom board based on a virtex 2 pro FPGA and 8Mbytes of SDRAM.
Untill now I used a 2.4.31 linux ppc kernel with John Williams patches
and uclinux distribution and everything worked perfectly.
I've decided to move to the latest 2.6 version from kernel.org
(2.6.23.1) with an initramfs containing a busybox.
My complete zImage including the initramfs has a size of 900Kbytes.
I made some tests with a ML300 board and I managed to get a shell easily.
When I migrated to the custom board, I had the "Now booting the kernel"
message and then nothing.
When I trace the code running on the ppc with the debugger, execution
seems to be stuck in some early initialization code.
I managed to reproduce the problem on the ML300 using "mem=8m" parameter
on the bootline.
With "mem=16m" the kernel boots correctly.
I'm really surprised by the amount of RAM required to boot the kernel.
Is there a way to make it boot with only 8Mbytes of RAM ?
Thanks for your help.
Manu
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--
Magnus Hjorth, M.Sc.
Omnisys Instruments AB
Gruvgatan 8
SE-421 30 Västra Frölunda, SWEDEN
Phone: +46 31 734 34 09
Fax: +46 31 734 34 29
http://www.omnisys.se
--- 4xx_mmu_old.c 2007-10-25 08:54:46.000000000 +0200
+++ 4xx_mmu.c 2007-10-25 08:55:57.000000000 +0200
@@ -105,7 +105,7 @@
return s;
}
- while (s <= (total_lowmem - LARGE_PAGE_SIZE_16M)) {
+ while (s + LARGE_PAGE_SIZE_16M <= total_lowmem) {
pmd_t *pmdp;
unsigned long val = p | _PMD_SIZE_16M | _PAGE_HWEXEC |
_PAGE_HWWRITE;
@@ -120,7 +120,7 @@
s += LARGE_PAGE_SIZE_16M;
}
- while (s <= (total_lowmem - LARGE_PAGE_SIZE_4M)) {
+ while (s + LARGE_PAGE_SIZE_4M <= total_lowmem) {
pmd_t *pmdp;
unsigned long val = p | _PMD_SIZE_4M | _PAGE_HWEXEC |
_PAGE_HWWRITE;
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