> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Takao Indoh
> Sent: 2006年9月7日 9:19
> To: Zou, Nanhai
> Cc: Takao Indoh; Keith Owens; [email protected];
> [email protected]
> Subject: Re: [Fastboot] [PATCH]IA64 kexec/kdump patch for INIT
> 
> On Thu, 7 Sep 2006 08:57:13 +0800, "Zou, Nanhai" wrote:
> 
> >> On Wed, 06 Sep 2006 18:06:53 +0900, Takao Indoh wrote:
> >>
> >> >>>+               /* 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
> >>                                 ~~~~~~~~~~~~~~~~e000000000ace170
> >> Sorry, I mistook address...
> >>
> >>
> >> Regards,
> >> Takao Indoh
> >>
> >  You don't need to set gp here. Control page does not use GP, and
> >purgatory code will set GP to a physical address which was pre-calculated
> >at the time of crash kernel loading.
> 
> If gp points region7, panic occurs at kdump_disable_iosapic.
> 
> kdump_disable_iosapic(void)
> {
>       u32 low32;
>       struct iosapic_intr_info *info;
>       struct iosapic_rte_info *rte;
>       for (info = iosapic_intr_info; info <
>                       iosapic_intr_info + IA64_NUM_VECTORS; ++info) {
>               low32 = info->low32 |= IOSAPIC_MASK;
>               list_for_each_entry(rte, &info->rtes,
>                               rte_list) {
> (snip)
> 
> The panic occurs at list_for_each_entry. When I found this problem,
> &info->rtes and rte->rte_list pointed same data but they had different
> address.
> 
> &info->rtes   => 0xe0000000049231e0
> rte->rte_list => 0xa0000001009231e0
> 
> info->rtes points region7 because its address is calculated from gp.
> This difference of address caused panic.
> 
> Regards,
> Takao Indoh
>

  Ok, ia64_setreg should be better.
We should avoid put inline asm code in C file.

  Thanks
  Zou Nan hai
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