Hi,
Chandan12 K wrote:
> I checked.. through and fond out that one of the following check condition
> is failing
>
> 516 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
> 517 (ehdr.e_type != ET_CORE) ||
> 518 !vmcore_elf_check_arch(&ehdr) ||
> 519 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
> 520 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
> 521 ehdr.e_version != EV_CURRENT ||
> 522 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
> 523 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
> 524 ehdr.e_phnum == 0) {
> 525 printk(KERN_WARNING "Warning: Core image elf
> header is not"
> 526 "sane:%ld\n",elfcorehdr_addr);
> 527 return -EINVAL
> 528 }
>
> If I comment this return at line 527, then the code flows through and the
> vmcore is getting generated.
>
> However, I am facing a new issue, my user space is 32 bit and the kernel
> is 64 bit. And I want to access the high memory (high_memory -
> BACK_UP_SIZE) area of the previous/primary kernel. Where some log data I
> had saved. The toral RAM is 8GB.
>
> As the 32 bit pointers could not reach there... means simple file
> operations lseek() , read etc are not working.. to access some region
> around 8GB.
>
> Can you please suggest me some way to reach that memory and read my raw
> data from the user space.
>
> I am able to read the data from kernel space( a simple kernel module via
> /proc interface to transfer the data from kernel to user space using
> physical address of the primary kernel).
If compiling your user space program with tree options
(-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE),
it can access the high memory.
Thanks
Ken'ichi Ohmichi
