linux-kernel - Re: [crash, bisected] Re: [PATCH 3/4] x86

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Message-ID: <488A3236.5070404@sgi.com>
Date:	Fri, 25 Jul 2008 13:06:14 -0700
From:	Mike Travis <travis@....com>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
CC:	"Eric W. Biederman" <ebiederm@...ssion.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jack Steiner <steiner@....com>
Subject: Re: [crash, bisected] Re: [PATCH 3/4] x86_64: Fold pda into per cpu
 area

Jeremy Fitzhardinge wrote:
...
> Last time it was doing this, it was a result of a triple-fault caused by
> loading %ds with an all-zero gdt.  I modified Xen to dump the CPU state
> on triple-faults, so it was easy to pinpoint.  I can do that again if it
> helps.
> 
>    J

Hi Jeremy,

There are two question marks for my patchset.  The first is in

arch/x86/xen/smp.c:xen_cpu_up()

287 #ifdef CONFIG_X86_64
288         /* Allocate node local memory for AP pdas */
289         WARN_ON(cpu == 0);
290         if (cpu > 0) {
291                 rc = get_local_pda(cpu);
292                 if (rc)
293                         return rc;
294         }
295 #endif

and the second is at:

arch/x86/xen/enlighten.c:xen_start_kernel()

1748 #ifdef CONFIG_X86_64
1749         /* Disable until direct per-cpu data access. */
1750         have_vcpu_info_placement = 0;
1751         x86_64_init_pda();
1752 #endif

I believe with the pda folded into the percpu area, get_local_pda()
and x86_64_init_pda() have been removed, so these are no longer
required, yes?

Also, arch/x86/kernel/acpi/sleep.c:acpi_save_state_mem() sets up
the startup code address with:

102         initial_code = (unsigned long)wakeup_long64;
103         saved_magic = 0x123456789abcdef0;

Should the pda and gdt_page address also be setup as is done in
smpboot.c:do_boot_cpu():

(CONFIG_X86_64)
 801         initial_pda = (unsigned long)get_cpu_pda(cpu);
 802 #endif
 803         early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
 804         initial_code = (unsigned long)start_secondary;


Thanks!
Mike
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