On Mon, Sep 11, 2006 at 02:12:13PM +0800, Zou Nan hai wrote: > On Mon, 2006-09-11 at 14:56, Keith Owens wrote: > > entering ia64_init_handler, r1 must be set to what the kernel expects > > to be in r1. The standard kernel's r1 is a region 7 address, not a > > region 5 address. The kernel (including __gp) is compiled as region 5 > > but relocated to region 7 during kernel load. > > > > Is the kexec kernel running in region 5? That may be where the > > confusion is coming from. > > > Hi Keith, > For 2.6 kernel, I think GP is a region 5 address when inside kernel. > The entire kernel image is resided in region 5 without relocate to > region 7. Nanhai is right here. The kernel is linked at region 5 addresses and mapped into physical memory by ITR[0]/DTR[0] Code in head.S that initializes r1 before we call any C code is a simple "movl gp=__gp". Disassembling vmlinux, I see that became: "movl r1=0xa000000100b6ea80". Peeking with a debugger at the running kernel I see a region 5 address in r1. Perhaps you are remembering the tricks that we play with the address of "init_task" ... that has truly schizophrenic existance between region5 and region7 (and our preferred access address has changed from region7 to region5 as the years have gone by to make list_structs inside init_task work correctly). -Tony - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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