On Fri, May 13, 2011 at 7:12 AM, Dave Hylands <dhylands@xxxxxxxxx> wrote: > > Hi Vikram, > > ...snip... > > So when compiling the kernel, what is the purpose of the other > > files(mentioned below) > > linux-2.6/vmlinux - ELF executable, not stripped > > linux-2.6/arch/x86/boot/vmlinux.bin - Raw binary (Guess this is the > > one which is inside the bzImage) > > linux-2.6/arch/x86/boot/compressed/vmlinux.bin - ELF executable, stripped > > linux-2.6/arch/x86/boot/compressed/vmlinux - ELF executable, not stripped > > Take luca's email and start at the bottom working towards the top. > > linux-2.6/vmlinux is the output of the linker. As such, it is an ELF file. > A binary is then extracted from this to create > arch/x86/boot/compressed/vmlinux.bin > This binary is then compressed to produce > arch/x86/boot/compressed/vmlinux.bin.gz > This gzipped binary is then converted into an object file (which just > contains the gzipped data) but now we're back to having an ELF file > called arch/x86/boot/compressed/piggy.o > The linker then compiles a decompressor (misc.o) and piggy.o together > to produce arch/x86/boot/compressed/vmlinux (an ELF file). > objcopy is used again to convert this ELF into a binary: > arch/x86/boot/compressed/vmlinux arch/x86/boot/vmlinux.bin > Finally, the binary is compressed to produce bzImage. > > So what you get is a compressed binary which contains a decompressor > and another compressed binary, this inner compressed binary being the > kernel. > > GRUB loads bzImage into memory and decompresses it and then executes > the resulting binary. > This binary starts with a decompressor which then decompresses the > kernel, and executes the resulting binary. > This binary may relocate itself (probably depends on the architecture) > to a different spot in memory, and then runs. > The kernel is now running. Thanks for the detailed explanation. Clarified. :) - Thanks Vikram _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
