Fundu wrote: > Hi, > First off i have a ppc based board. > and i'm trying to load a kernel image with ramdisk rootfs. > > i have build the kernel. it spit uImage,zImage and vmlinux.gz > my question are. > 1) what are all the different image types ? > i know the uImage is just the kernel, what are the rest (zImage & vmlinux.gz)? vmlinux is the uncompressed result of compiling and linking the kernel. I presume that vmlinux.gz is a gzipped version of vmlinux. zImage is some other compressed kernel image format. uImage is another kernel image format, with information specifically for loading with U-Boot. You can see what commands are being used to create these different images by using "V=1" with your kernel make. (e.g. make V=1 uImage) On my machine, I see the following: /bin/sh /a/home/tbird/work/tiny/branch_ss/scripts/mkuboot.sh -A arm -O linux -T kernel -C none -a 0x10008000 -e 0x10008000 -n 'Linux-2.6.23.17-alp_nl-gfcc28266' -d arch/arm/boot/zImage arch/arm/boot/uImage If I recall correctly, mkuboot.sh prepends the size and start location for the kernel onto the zImage, in order to create the uImage. However, don't take my word for it -- see the U-Boot documentation, or even better read the mkuboot.sh source, or the source for U-Boot itself. That's the beauty of open source. You can see all the software and examine/modify any part you want. If the source is impenetrable, there's always the U-Boot mailing list. > 2) i'm using u-boot as the bootldr. so i download the uImage (cause > zImage and vmlinux.gz aren't bootlable) from tftp server and then do > bootm <address> the kernel only load partially. How does the kernel > know where/how to load the rootfs ? Usually, you tell it with a command line option (root=...). The command line can come from the boot loader, or it may be compiled into the kernel binary. See Documentation/kernel-parameters.txt for information about kernel command line options. This mentions root=, but I didn't see any examples in my quick glance just now. Here are some examples I use: Use the first partition on the first IDE hard drive: root=/dev/hda1 or (later kernels): root=/dev/sda1 Use NFS root filesystem (kernel config must support this) root=/dev/nfs (Usually you need to add some other arguments to make sure the kernel IP address gets configured, or to specify the host NFS path.) Use flash device partition 2: root/dev/mtd/2 I hope this helps. -- Tim ============================= Tim Bird Architecture Group Chair, CE Linux Forum Senior Staff Engineer, Sony Corporation of America ============================= -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
