From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yu Luming <luming.yu@intel.com>
Date: Thu, 07 Sep 2006 08:48:19 +0000
Subject: Re: [Fastboot] [PATCH]IA64 kexec/kdump patch for INIT
Message-Id: <200609071648.20275.luming.yu@intel.com>
List-Id: <linux-ia64.vger.kernel.org>
References: <82C6D21B8B7A9Cindou.takao@jp.fujitsu.com>
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To: linux-ia64@vger.kernel.org

> I agree. I'm also happy if kdb and kdump share the code.
> I'll check kdb code.
>
> >>+		/* change region of gp to region5 */
> >>+		asm volatile ("movl gp=__gp"::: "memory");
> >
> >Why?  gp is already pointing at the kernel code before we enter
> >ia64_init_handler().
>
> The purpose of this code is just changing region of gp from region7 to
> region5. For example, if gp is e000000004ace170, I want to change gp to
> a000000104ace170, but I couldn't find good method. Is there good method
> to change region?
>
Did  saved Os gp in SAL OS state  somehow get overridden before 
ia64_set_kernel_registers prior to invocation of ia64_init_handler?

I assume the following code (in ia64_set_kernel_registers ) should restore 
correct GP value.

ia64_set_kernel_registers:
	...
        ;;
        ld8 r1=[temp4]          // OS GP from SAL OS state

-- 
Thanks,
Luming