On Mon, Nov 19, 2012 at 08:56:22AM -0800, Eric W. Biederman wrote: > > Remove kexec/arch/i386/compat_x6_64.S > purgatory/arch/i386/linux-entry16.S and purgatory/arch/i386/entry16.S > Those were early attempts at entry32-16.S that should have been > deleted long ago. > > Strip the purgatory code of debug symbols. There is no need to carry > debug symbols we will never use around in /sbin/kexec. > > On x86_64 use -mcmodel=large so that the code is built without > any 32bit assumptions. -mcmodel=medium and -mcmodel=small > result int code that has 32bit relocations against variables > that can live anywhere in the address space > > Modify the assembly in entry64.S and setup-x86_64.S to use %rip > relative addressing of variables so no relocates are emitted. > > Modify entry64-32.S so that it does not have any relocations that can > not be processed when purgatory is loaded above 4G. entry64-32.S > jumps to a 32bit entry point and can not itself be used above 4G so > these changes merely prevent it from being a problem in the other case. > > eip is modifed to be a 64bit value of which only the low 32bits are > exported outside of entry64-32.S > > The long mode exit code is modified to run with a %cs value whose > base address is the address of the symbol entry32. From there > all of the 32bit code in entry64-32.S can read variables by reading > them through %cs. Until the final jump to the the target address > which is made a far jump reloading %cs and the intstruction pointer. > > Modify entry32-16.S and entry32-16-debug.S to be position independent > 32bit code. At their start make a short call to push the current value > of %eip on the stack and pop it off. Allowing the calculation of the > address of entry16 which the code has always kept in %ebx. > > Update the pointer to the gdt in the gdt so that lgdt will work. > > Modify the instructions in entry32-16.S and entry32-16-debug.S so > that the 32bit code uses offsets from %ebx which points at entry16. > > Tested-by: Yinghai Lu <yinghai at kernel.org> > Signed-off-by: "Eric W. Biederman" <ebiederm at xmission.com> Thanks, applied.
