On Mon, Nov 26, 2007 at 11:41:38AM +0530, vijay baskar wrote:

Hi friends,

Kernel virtual space is divided into 3 different zones namely ZONE_DMA, 
ZONE_NORMAL, ZONE_HIGHMEM.Remember that the kernel follows the 3GB/1GB 
split ie 3 GB for user space and 1  GB for kernel space. Since your ram 
is 1 GB, 896 MB will be mapped one to one with the kernel virtual space. 
This one to one mapping will be done in the ZONE_NORMAL and ZONE_DMA of 
kernel virtual space.Remaining 128 MB of kernel virtual address space 
will be used for setting up kernel  data structures and for ioremaps and 
vmallocs that  the kernel will need to perform during boot up.  If  u 
configure high memory this 128 MB will be used for accessing unmapped 
memory regions in the ram and there wont be sufficient  virtual 
addresses for ioremaps and vmallocs. Thats why your kernel did not boot 
when high mem is configured.

1. The split is 768/256 on powerpc, not 896/128.
2. Why do you think this is insufficient?

                   Since u want to have 1 GB of ram an alternative to 
this is that u can try 2 GB/ 2 GB split which is configurable ie 2 GB 
for user space and 2 GB for kernel space in your kernel.

1. He said he wanted 2GB of RAM, not 1.
2. I don't think this mode of operation has been tested very well on
powerpc.

quoted

=> bootm fed00000 fe900000                                                      
## Booting image at fed00000 ...                                                
  Image Name:   Linux-2.6.11                                                   
  Image Type:   PowerPC Linux Kernel Image (gzip compressed)                   
  Data Size:    1054435 Bytes =  1 MB                                          
  Load Address: 00000000                                                       
  Entry Point:  00000000                                                       
  Verifying Checksum ... OK                                                    
  Uncompressing Kernel Image ... OK                                            
## Loading RAMDisk Image at fe900000 ...                                        
  Image Name:   uboot ext2 ramdisk rootfs                                      
  Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)                  
  Data Size:    3195657 Bytes =  3 MB                                          
  Load Address: 00000000                                                       
  Entry Point:  00000000                                                       
  Verifying Checksum ... OK                                                    
  Loading Ramdisk to 0fc9a000, end 0ffa6309 ... OK

Could you try with a more recent, arch/powerpc kernel?

-Scott