linux-kernel - Re: [PATCH, DEBUG] x86/32: Add small delay after resume

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Message-ID: <55809616.80204@zytor.com>
Date:	Tue, 16 Jun 2015 14:33:10 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Ingo Molnar <mingo@...nel.org>
CC:	mingo@...hat.com, tglx@...utronix.de, pavel@....cz,
	rjw@...ysocki.net, x86@...nel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Denys Vlasenko <dvlasenk@...hat.com>,
	Andy Lutomirski <luto@...capital.net>,
	Borislav Petkov <bp@...en8.de>,
	Brian Gerst <brgerst@...il.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	"Kleen, Andi" <andi.kleen@...el.com>
Subject: Re: [PATCH, DEBUG] x86/32: Add small delay after resume

On 06/15/2015 09:10 AM, Srinivas Pandruvada wrote:
>>
>> So is it true that we always execute wakeup_pmode_return first after we return 
>> from the BIOS?
>>
>> If so then the BIOS touching DS cannot be an issue, as we re-initialize all 
>> segment selectors, which reloads the descriptors:
>>
>> ENTRY(wakeup_pmode_return)
>> wakeup_pmode_return:
>>         movw    $__KERNEL_DS, %ax
>>         movw    %ax, %ss
>>         movw    %ax, %ds
>>         movw    %ax, %es
>>         movw    %ax, %fs
>>         movw    %ax, %gs
>>
>>         # reload the gdt, as we need the full 32 bit address
>>         lidt    saved_idt
>>         lldt    saved_ldt
>>         ljmp    $(__KERNEL_CS), $1f
>>

Where does the GDT get initialized?

	-hpa


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