linux-kernel - Re: [PATCH] i386: do a global tlb flush in S4 resume

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Message-Id: <201003042049.46240.rjw@sisk.pl>
Date:	Thu, 4 Mar 2010 20:49:46 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Shaohua Li <shaohua.li@...el.com>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"mingo@...e.hu" <mingo@...e.hu>,
	"colin.king@...onical.com" <colin.king@...onical.com>
Subject: Re: [PATCH] i386: do a global tlb flush in S4 resume

On Thursday 04 March 2010, Shaohua Li wrote:
> On Thu, Mar 04, 2010 at 10:30:02AM +0800, H. Peter Anvin wrote:
> > On 03/03/2010 05:23 PM, Shaohua Li wrote:
> > > Colin reported a strange oops in S4 resume code path (see below). The test
> > > system has i5/i7 CPU. The kernel doesn't open PAE, so 4M page table is used.
> > > The oops always happen a virtual address 0xc03ff000, which is mapped to the
> > > last 4k of first 4M memory. Doing a global tlb flush fixes the issue.
> > > 
> > > EIP: 0060:[<c0493a01>] EFLAGS: 00010086 CPU: 0
> > > EIP is at copy_loop+0xe/0x15
> > > EAX: 36aeb000 EBX: 00000000 ECX: 00000400 EDX: f55ad46c
> > > ESI: 0f800000 EDI: c03ff000 EBP: f67fbec4 ESP: f67fbea8
> > >  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
> > > ...
> > > ...
> > > CR2: 00000000c03ff000
> > > 
> > > Tested-by: Colin Ian King <colin.king@...onical.com>
> > > Signed-off-by: Shaohua Li <shaohua.li@...el.com>
> > > ---
> > >  arch/x86/power/hibernate_asm_32.S |   11 +++++++++++
> > >  1 files changed, 11 insertions(+), 0 deletions(-)
> > > 
> > > diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S
> > > index b641388..9e4ef64 100644
> > > --- a/arch/x86/power/hibernate_asm_32.S
> > > +++ b/arch/x86/power/hibernate_asm_32.S
> > > @@ -27,10 +27,21 @@ ENTRY(swsusp_arch_suspend)
> > >  	ret
> > >  
> > >  ENTRY(restore_image)
> > > +	movl	mmu_cr4_features, %ecx
> > >  	movl	resume_pg_dir, %eax
> > >  	subl	$__PAGE_OFFSET, %eax
> > >  	movl	%eax, %cr3
> > >  
> > > +	jecxz	1f	# cr4 Pentium and higher, skip if zero
> > > +	movl	%ecx, %edx
> > > +	andl	$~(X86_CR4_PGE), %edx
> > > +	movl	%edx, %cr4;  # turn off PGE
> > > +1:
> > > +	movl	%cr3, %eax;  # flush TLB
> > > +	movl	%eax, %cr3
> > > +	jecxz	1f	# cr4 Pentium and higher, skip if zero
> > > +	movl	%ecx, %cr4;  # turn PGE back on
> > > +1:
> > >  	movl	restore_pblist, %edx
> > >  	.p2align 4,,7
> > >  
> > 
> > Since we're about to do another global page flush a bit further down in
> > the same code, why not just leave PGE off until then?
> sure, updated patch.
> 
> 
> i386: do a global tlb flush in S4 resume
> 
>     Colin reported a strange oops in S4 resume code path (see below). The test
>     system has i5/i7 CPU. The kernel doesn't open PAE, so 4M page table is used.
>     The oops always happen a virtual address 0xc03ff000, which is mapped to the
>     last 4k of first 4M memory. Doing a global tlb flush fixes the issue.
> 
>     EIP: 0060:[<c0493a01>] EFLAGS: 00010086 CPU: 0
>     EIP is at copy_loop+0xe/0x15
>     EAX: 36aeb000 EBX: 00000000 ECX: 00000400 EDX: f55ad46c
>     ESI: 0f800000 EDI: c03ff000 EBP: f67fbec4 ESP: f67fbea8
>      DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
>     ...
>     ...
>     CR2: 00000000c03ff000
> 
>     Tested-by: Colin Ian King <colin.king@...onical.com>
>     Signed-off-by: Shaohua Li <shaohua.li@...el.com>
> 
> diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S
> index b641388..cd5e878 100644
> --- a/arch/x86/power/hibernate_asm_32.S
> +++ b/arch/x86/power/hibernate_asm_32.S
> @@ -27,10 +27,17 @@ ENTRY(swsusp_arch_suspend)
>  	ret
>  
>  ENTRY(restore_image)
> +	movl	mmu_cr4_features, %ecx
>  	movl	resume_pg_dir, %eax
>  	subl	$__PAGE_OFFSET, %eax
>  	movl	%eax, %cr3
>  
> +	jecxz	1f	# cr4 Pentium and higher, skip if zero
> +	andl	$~(X86_CR4_PGE), %ecx
> +	movl	%ecx, %cr4;  # turn off PGE
> +	movl	%cr3, %eax;  # flush TLB
> +	movl	%eax, %cr3
> +1:
>  	movl	restore_pblist, %edx
>  	.p2align 4,,7

In that case please also remove the turning GPE off down the road.

Rafael
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