[PATCH] x86: do not enable efi boot for sgi uv machine

[PATCH] x86: do not enable efi boot for sgi uv machine

[Dave Young]

kexec/kdump uefi support depends on the 1:1 mapping scheme
in 3.14 kernel but SGI reported that 1:1 mapping does not work on
their UV system. thus there's below commit to switch back to
old ioremap way for sgi uv machines.

So for kexec-tools before we got the 1:1 mapping support on those
machines we should also use old way that means boot 2nd kernel
without uefi.

Tested on a uv1 machine.

Here is the kernel commit to quirk out SGI UV:
commit a5d90c923bcfb9632d998ed06e9569216ad695f3
Author: Borislav Petkov <bp@suse.de>
Date:   Tue Mar 4 17:02:17 2014 +0100

    x86/efi: Quirk out SGI UV
    
    Alex reported hitting the following BUG after the EFI 1:1 virtual
    mapping work was merged,
    
     kernel BUG at arch/x86/mm/init_64.c:351!
     invalid opcode: 0000 [#1] SMP
     Call Trace:
      [<ffffffff818aa71d>] init_extra_mapping_uc+0x13/0x15
      [<ffffffff818a5e20>] uv_system_init+0x22b/0x124b
      [<ffffffff8108b886>] ? clockevents_register_device+0x138/0x13d
      [<ffffffff81028dbb>] ? setup_APIC_timer+0xc5/0xc7
      [<ffffffff8108b620>] ? clockevent_delta2ns+0xb/0xd
      [<ffffffff818a3a92>] ? setup_boot_APIC_clock+0x4a8/0x4b7
      [<ffffffff8153d955>] ? printk+0x72/0x74
      [<ffffffff818a1757>] native_smp_prepare_cpus+0x389/0x3d6
      [<ffffffff818957bc>] kernel_init_freeable+0xb7/0x1fb
      [<ffffffff81535530>] ? rest_init+0x74/0x74
      [<ffffffff81535539>] kernel_init+0x9/0xff
      [<ffffffff81541dfc>] ret_from_fork+0x7c/0xb0
      [<ffffffff81535530>] ? rest_init+0x74/0x74
    
    Getting this thing to work with the new mapping scheme would need more
    work, so automatically switch to the old memmap layout for SGI UV.


Signed-off-by: Dave Young <dyoung@redhat.com>
---
 kexec/arch/i386/x86-linux-setup.c |   15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

--- kexec-tools.orig/kexec/arch/i386/x86-linux-setup.c
+++ kexec-tools/kexec/arch/i386/x86-linux-setup.c
@@ -817,12 +817,25 @@ out:
 	return;
 }
 
+static int is_sgi_uv_machine(void)
+{
+	DIR *sgi_dir;
+
+	sgi_dir = opendir("/sys/firmware/sgi_uv");
+	if (sgi_dir) {
+		closedir(sgi_dir);
+		return 1;
+	}
+
+	return 0;
+}
+
 void setup_linux_system_parameters(struct kexec_info *info,
 				   struct x86_linux_param_header *real_mode)
 {
 	/* get subarch from running kernel */
 	setup_subarch(real_mode);
-	if (bzImage_support_efi_boot)
+	if (bzImage_support_efi_boot && !is_sgi_uv_machine())
 		setup_efi_info(info, real_mode);
 	
 	/* Default screen size */

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Vivek Goyal]

On Fri, May 23, 2014 at 06:14:55PM +0800, Dave Young wrote:
> 
> kexec/kdump uefi support depends on the 1:1 mapping scheme
> in 3.14 kernel but SGI reported that 1:1 mapping does not work on
> their UV system. thus there's below commit to switch back to
> old ioremap way for sgi uv machines.
> 
> So for kexec-tools before we got the 1:1 mapping support on those
> machines we should also use old way that means boot 2nd kernel
> without uefi.
> 
> Tested on a uv1 machine.
> 
> Here is the kernel commit to quirk out SGI UV:
> commit a5d90c923bcfb9632d998ed06e9569216ad695f3
> Author: Borislav Petkov <bp@suse.de>
> Date:   Tue Mar 4 17:02:17 2014 +0100
> 
>     x86/efi: Quirk out SGI UV
>     
>     Alex reported hitting the following BUG after the EFI 1:1 virtual
>     mapping work was merged,
>     
>      kernel BUG at arch/x86/mm/init_64.c:351!
>      invalid opcode: 0000 [#1] SMP
>      Call Trace:
>       [<ffffffff818aa71d>] init_extra_mapping_uc+0x13/0x15
>       [<ffffffff818a5e20>] uv_system_init+0x22b/0x124b
>       [<ffffffff8108b886>] ? clockevents_register_device+0x138/0x13d
>       [<ffffffff81028dbb>] ? setup_APIC_timer+0xc5/0xc7
>       [<ffffffff8108b620>] ? clockevent_delta2ns+0xb/0xd
>       [<ffffffff818a3a92>] ? setup_boot_APIC_clock+0x4a8/0x4b7
>       [<ffffffff8153d955>] ? printk+0x72/0x74
>       [<ffffffff818a1757>] native_smp_prepare_cpus+0x389/0x3d6
>       [<ffffffff818957bc>] kernel_init_freeable+0xb7/0x1fb
>       [<ffffffff81535530>] ? rest_init+0x74/0x74
>       [<ffffffff81535539>] kernel_init+0x9/0xff
>       [<ffffffff81541dfc>] ret_from_fork+0x7c/0xb0
>       [<ffffffff81535530>] ? rest_init+0x74/0x74
>     
>     Getting this thing to work with the new mapping scheme would need more
>     work, so automatically switch to the old memmap layout for SGI UV.
> 
> 
> Signed-off-by: Dave Young <dyoung@redhat.com>
> ---
>  kexec/arch/i386/x86-linux-setup.c |   15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> --- kexec-tools.orig/kexec/arch/i386/x86-linux-setup.c
> +++ kexec-tools/kexec/arch/i386/x86-linux-setup.c
> @@ -817,12 +817,25 @@ out:
>  	return;
>  }
>  
> +static int is_sgi_uv_machine(void)
> +{
> +	DIR *sgi_dir;
> +
> +	sgi_dir = opendir("/sys/firmware/sgi_uv");
> +	if (sgi_dir) {
> +		closedir(sgi_dir);
> +		return 1;
> +	}
> +
> +	return 0;
> +}
> +
>  void setup_linux_system_parameters(struct kexec_info *info,
>  				   struct x86_linux_param_header *real_mode)
>  {
>  	/* get subarch from running kernel */
>  	setup_subarch(real_mode);
> -	if (bzImage_support_efi_boot)
> +	if (bzImage_support_efi_boot && !is_sgi_uv_machine())
>  		setup_efi_info(info, real_mode);

Hi Dave,

I think instead of always falling back to old "noefi" method for SGI UV
machines, we should probably provide a config option to override default
behavior. Something like "--nouefi". And let user/distributions decide
in what cases to use that parameter.

Reason being, that at some point of time this limitation will be fixed.
And at that point of time if we modify kexec-tools, then it will stop
working with older kernels. And then same issue will arise that
kexec-tools is not working with older kernels.

If we just provide a way to override default, then distributions in their
scripts should know what kernels work what way and automatically use or
not use option accordingly.

Thanks
Vivek

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Dave Young]

Hi,

Vivek, replying with webmail, sorry for the formatting issue.

Another way is export the mapping scheme in sysfs. So if kernel boot
with efi=old_map we can detect it as well. OTOH in future there's probably
other quirk system.

So kexec-tools can switch to use old way if kernel use ioremap.

Adding Matt and Boris to cc, to see if they have idea.

Thanks
Dave

----- Original Message -----
From: "Vivek Goyal" <vgoyal@redhat.com>
To: "Dave Young" <dyoung@redhat.com>
Cc: horms@verge.net.au, kexec@lists.infradead.org
Sent: Friday, May 23, 2014 9:28:34 PM
Subject: Re: [PATCH] x86: do not enable efi boot for sgi uv machine

On Fri, May 23, 2014 at 06:14:55PM +0800, Dave Young wrote:
> 
> kexec/kdump uefi support depends on the 1:1 mapping scheme
> in 3.14 kernel but SGI reported that 1:1 mapping does not work on
> their UV system. thus there's below commit to switch back to
> old ioremap way for sgi uv machines.
> 
> So for kexec-tools before we got the 1:1 mapping support on those
> machines we should also use old way that means boot 2nd kernel
> without uefi.
> 
> Tested on a uv1 machine.
> 
> Here is the kernel commit to quirk out SGI UV:
> commit a5d90c923bcfb9632d998ed06e9569216ad695f3
> Author: Borislav Petkov <bp@suse.de>
> Date:   Tue Mar 4 17:02:17 2014 +0100
> 
>     x86/efi: Quirk out SGI UV
>     
>     Alex reported hitting the following BUG after the EFI 1:1 virtual
>     mapping work was merged,
>     
>      kernel BUG at arch/x86/mm/init_64.c:351!
>      invalid opcode: 0000 [#1] SMP
>      Call Trace:
>       [<ffffffff818aa71d>] init_extra_mapping_uc+0x13/0x15
>       [<ffffffff818a5e20>] uv_system_init+0x22b/0x124b
>       [<ffffffff8108b886>] ? clockevents_register_device+0x138/0x13d
>       [<ffffffff81028dbb>] ? setup_APIC_timer+0xc5/0xc7
>       [<ffffffff8108b620>] ? clockevent_delta2ns+0xb/0xd
>       [<ffffffff818a3a92>] ? setup_boot_APIC_clock+0x4a8/0x4b7
>       [<ffffffff8153d955>] ? printk+0x72/0x74
>       [<ffffffff818a1757>] native_smp_prepare_cpus+0x389/0x3d6
>       [<ffffffff818957bc>] kernel_init_freeable+0xb7/0x1fb
>       [<ffffffff81535530>] ? rest_init+0x74/0x74
>       [<ffffffff81535539>] kernel_init+0x9/0xff
>       [<ffffffff81541dfc>] ret_from_fork+0x7c/0xb0
>       [<ffffffff81535530>] ? rest_init+0x74/0x74
>     
>     Getting this thing to work with the new mapping scheme would need more
>     work, so automatically switch to the old memmap layout for SGI UV.
> 
> 
> Signed-off-by: Dave Young <dyoung@redhat.com>
> ---
>  kexec/arch/i386/x86-linux-setup.c |   15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> --- kexec-tools.orig/kexec/arch/i386/x86-linux-setup.c
> +++ kexec-tools/kexec/arch/i386/x86-linux-setup.c
> @@ -817,12 +817,25 @@ out:
>  	return;
>  }
>  
> +static int is_sgi_uv_machine(void)
> +{
> +	DIR *sgi_dir;
> +
> +	sgi_dir = opendir("/sys/firmware/sgi_uv");
> +	if (sgi_dir) {
> +		closedir(sgi_dir);
> +		return 1;
> +	}
> +
> +	return 0;
> +}
> +
>  void setup_linux_system_parameters(struct kexec_info *info,
>  				   struct x86_linux_param_header *real_mode)
>  {
>  	/* get subarch from running kernel */
>  	setup_subarch(real_mode);
> -	if (bzImage_support_efi_boot)
> +	if (bzImage_support_efi_boot && !is_sgi_uv_machine())
>  		setup_efi_info(info, real_mode);

Hi Dave,

I think instead of always falling back to old "noefi" method for SGI UV
machines, we should probably provide a config option to override default
behavior. Something like "--nouefi". And let user/distributions decide
in what cases to use that parameter.

Reason being, that at some point of time this limitation will be fixed.
And at that point of time if we modify kexec-tools, then it will stop
working with older kernels. And then same issue will arise that
kexec-tools is not working with older kernels.

If we just provide a way to override default, then distributions in their
scripts should know what kernels work what way and automatically use or
not use option accordingly.

Thanks
Vivek

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kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Borislav Petkov]

On Fri, May 23, 2014 at 09:47:08AM -0400, Dave Young wrote:
> Hi,
> 
> Vivek, replying with webmail, sorry for the formatting issue.
> 
> Another way is export the mapping scheme in sysfs. So if kernel boot
> with efi=old_map we can detect it as well. OTOH in future there's probably
> other quirk system.
> 
> So kexec-tools can switch to use old way if kernel use ioremap.
> 
> Adding Matt and Boris to cc, to see if they have idea.
> 
> Thanks
> Dave
> 
> ----- Original Message -----
> From: "Vivek Goyal" <vgoyal@redhat.com>
> To: "Dave Young" <dyoung@redhat.com>
> Cc: horms@verge.net.au, kexec@lists.infradead.org
> Sent: Friday, May 23, 2014 9:28:34 PM
> Subject: Re: [PATCH] x86: do not enable efi boot for sgi uv machine
> 
> On Fri, May 23, 2014 at 06:14:55PM +0800, Dave Young wrote:
> > 
> > kexec/kdump uefi support depends on the 1:1 mapping scheme
> > in 3.14 kernel but SGI reported that 1:1 mapping does not work on
> > their UV system. thus there's below commit to switch back to
> > old ioremap way for sgi uv machines.
> > 
> > So for kexec-tools before we got the 1:1 mapping support on those
> > machines we should also use old way that means boot 2nd kernel
> > without uefi.

Well, we did find the bug in a combined debug session and SGI will be
issuing a fix soon. I don't know whether any quirk will be needed for
systems which don't have the fix - I guess that's something for SGI
people to decide. CCed and leaving in the rest for reference.

@Alex, Russ: this is about using kexec on UEFI boxes.

> > 
> > Tested on a uv1 machine.
> > 
> > Here is the kernel commit to quirk out SGI UV:
> > commit a5d90c923bcfb9632d998ed06e9569216ad695f3
> > Author: Borislav Petkov <bp@suse.de>
> > Date:   Tue Mar 4 17:02:17 2014 +0100
> > 
> >     x86/efi: Quirk out SGI UV
> >     
> >     Alex reported hitting the following BUG after the EFI 1:1 virtual
> >     mapping work was merged,
> >     
> >      kernel BUG at arch/x86/mm/init_64.c:351!
> >      invalid opcode: 0000 [#1] SMP
> >      Call Trace:
> >       [<ffffffff818aa71d>] init_extra_mapping_uc+0x13/0x15
> >       [<ffffffff818a5e20>] uv_system_init+0x22b/0x124b
> >       [<ffffffff8108b886>] ? clockevents_register_device+0x138/0x13d
> >       [<ffffffff81028dbb>] ? setup_APIC_timer+0xc5/0xc7
> >       [<ffffffff8108b620>] ? clockevent_delta2ns+0xb/0xd
> >       [<ffffffff818a3a92>] ? setup_boot_APIC_clock+0x4a8/0x4b7
> >       [<ffffffff8153d955>] ? printk+0x72/0x74
> >       [<ffffffff818a1757>] native_smp_prepare_cpus+0x389/0x3d6
> >       [<ffffffff818957bc>] kernel_init_freeable+0xb7/0x1fb
> >       [<ffffffff81535530>] ? rest_init+0x74/0x74
> >       [<ffffffff81535539>] kernel_init+0x9/0xff
> >       [<ffffffff81541dfc>] ret_from_fork+0x7c/0xb0
> >       [<ffffffff81535530>] ? rest_init+0x74/0x74
> >     
> >     Getting this thing to work with the new mapping scheme would need more
> >     work, so automatically switch to the old memmap layout for SGI UV.
> > 
> > 
> > Signed-off-by: Dave Young <dyoung@redhat.com>
> > ---
> >  kexec/arch/i386/x86-linux-setup.c |   15 ++++++++++++++-
> >  1 file changed, 14 insertions(+), 1 deletion(-)
> > 
> > --- kexec-tools.orig/kexec/arch/i386/x86-linux-setup.c
> > +++ kexec-tools/kexec/arch/i386/x86-linux-setup.c
> > @@ -817,12 +817,25 @@ out:
> >  	return;
> >  }
> >  
> > +static int is_sgi_uv_machine(void)
> > +{
> > +	DIR *sgi_dir;
> > +
> > +	sgi_dir = opendir("/sys/firmware/sgi_uv");
> > +	if (sgi_dir) {
> > +		closedir(sgi_dir);
> > +		return 1;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> >  void setup_linux_system_parameters(struct kexec_info *info,
> >  				   struct x86_linux_param_header *real_mode)
> >  {
> >  	/* get subarch from running kernel */
> >  	setup_subarch(real_mode);
> > -	if (bzImage_support_efi_boot)
> > +	if (bzImage_support_efi_boot && !is_sgi_uv_machine())
> >  		setup_efi_info(info, real_mode);
> 
> Hi Dave,
> 
> I think instead of always falling back to old "noefi" method for SGI UV
> machines, we should probably provide a config option to override default
> behavior. Something like "--nouefi". And let user/distributions decide
> in what cases to use that parameter.
> 
> Reason being, that at some point of time this limitation will be fixed.
> And at that point of time if we modify kexec-tools, then it will stop
> working with older kernels. And then same issue will arise that
> kexec-tools is not working with older kernels.
> 
> If we just provide a way to override default, then distributions in their
> scripts should know what kernels work what way and automatically use or
> not use option accordingly.
> 
> Thanks
> Vivek
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Russ Anderson]

On Fri, May 23, 2014 at 05:54:11PM +0200, Borislav Petkov wrote:
> On Fri, May 23, 2014 at 09:47:08AM -0400, Dave Young wrote:
> > Hi,
> > 
> > Vivek, replying with webmail, sorry for the formatting issue.
> > 
> > Another way is export the mapping scheme in sysfs. So if kernel boot
> > with efi=old_map we can detect it as well. OTOH in future there's probably
> > other quirk system.
> > 
> > So kexec-tools can switch to use old way if kernel use ioremap.
> > 
> > Adding Matt and Boris to cc, to see if they have idea.
> > 
> > Thanks
> > Dave
> > 
> > ----- Original Message -----
> > From: "Vivek Goyal" <vgoyal@redhat.com>
> > To: "Dave Young" <dyoung@redhat.com>
> > Cc: horms@verge.net.au, kexec@lists.infradead.org
> > Sent: Friday, May 23, 2014 9:28:34 PM
> > Subject: Re: [PATCH] x86: do not enable efi boot for sgi uv machine
> > 
> > On Fri, May 23, 2014 at 06:14:55PM +0800, Dave Young wrote:
> > > 
> > > kexec/kdump uefi support depends on the 1:1 mapping scheme
> > > in 3.14 kernel but SGI reported that 1:1 mapping does not work on
> > > their UV system. thus there's below commit to switch back to
> > > old ioremap way for sgi uv machines.
> > > 
> > > So for kexec-tools before we got the 1:1 mapping support on those
> > > machines we should also use old way that means boot 2nd kernel
> > > without uefi.

Yes, the old workaround to allow the kdump kernel to boot was
to add the noefi bootline option, which also meant passing all
the memory ranges as kernel boot line options (since noefi meant
no EFI memory map info).  An ugly situation.  That is why we
want to get Boris' mapping changes working on SGI UV, so that
kexec/kdump work without ugly workarounds.


> Well, we did find the bug in a combined debug session and SGI will be
> issuing a fix soon. I don't know whether any quirk will be needed for
> systems which don't have the fix - I guess that's something for SGI
> people to decide. CCed and leaving in the rest for reference.
> 
> @Alex, Russ: this is about using kexec on UEFI boxes.

Thanks for the heads up.  Our bios made an assumption about
mapping that was valid with the old mapping scheme but not
with the new.  Fortunately the fix will work with both old
and new kernels, so the fix can be added in the next bios
update.  But we still have to be careful when removing the
quirk, to avoid someone trying a new kernel with old bios
and not being able to boot.


> > > Tested on a uv1 machine.
> > > 
> > > Here is the kernel commit to quirk out SGI UV:
> > > commit a5d90c923bcfb9632d998ed06e9569216ad695f3
> > > Author: Borislav Petkov <bp@suse.de>
> > > Date:   Tue Mar 4 17:02:17 2014 +0100
> > > 
> > >     x86/efi: Quirk out SGI UV
> > >     
> > >     Alex reported hitting the following BUG after the EFI 1:1 virtual
> > >     mapping work was merged,
> > >     
> > >      kernel BUG at arch/x86/mm/init_64.c:351!
> > >      invalid opcode: 0000 [#1] SMP
> > >      Call Trace:
> > >       [<ffffffff818aa71d>] init_extra_mapping_uc+0x13/0x15
> > >       [<ffffffff818a5e20>] uv_system_init+0x22b/0x124b
> > >       [<ffffffff8108b886>] ? clockevents_register_device+0x138/0x13d
> > >       [<ffffffff81028dbb>] ? setup_APIC_timer+0xc5/0xc7
> > >       [<ffffffff8108b620>] ? clockevent_delta2ns+0xb/0xd
> > >       [<ffffffff818a3a92>] ? setup_boot_APIC_clock+0x4a8/0x4b7
> > >       [<ffffffff8153d955>] ? printk+0x72/0x74
> > >       [<ffffffff818a1757>] native_smp_prepare_cpus+0x389/0x3d6
> > >       [<ffffffff818957bc>] kernel_init_freeable+0xb7/0x1fb
> > >       [<ffffffff81535530>] ? rest_init+0x74/0x74
> > >       [<ffffffff81535539>] kernel_init+0x9/0xff
> > >       [<ffffffff81541dfc>] ret_from_fork+0x7c/0xb0
> > >       [<ffffffff81535530>] ? rest_init+0x74/0x74
> > >     
> > >     Getting this thing to work with the new mapping scheme would need more
> > >     work, so automatically switch to the old memmap layout for SGI UV.
> > > 
> > > 
> > > Signed-off-by: Dave Young <dyoung@redhat.com>
> > > ---
> > >  kexec/arch/i386/x86-linux-setup.c |   15 ++++++++++++++-
> > >  1 file changed, 14 insertions(+), 1 deletion(-)
> > > 
> > > --- kexec-tools.orig/kexec/arch/i386/x86-linux-setup.c
> > > +++ kexec-tools/kexec/arch/i386/x86-linux-setup.c
> > > @@ -817,12 +817,25 @@ out:
> > >  	return;
> > >  }
> > >  
> > > +static int is_sgi_uv_machine(void)
> > > +{
> > > +	DIR *sgi_dir;
> > > +
> > > +	sgi_dir = opendir("/sys/firmware/sgi_uv");
> > > +	if (sgi_dir) {
> > > +		closedir(sgi_dir);
> > > +		return 1;
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > >  void setup_linux_system_parameters(struct kexec_info *info,
> > >  				   struct x86_linux_param_header *real_mode)
> > >  {
> > >  	/* get subarch from running kernel */
> > >  	setup_subarch(real_mode);
> > > -	if (bzImage_support_efi_boot)
> > > +	if (bzImage_support_efi_boot && !is_sgi_uv_machine())
> > >  		setup_efi_info(info, real_mode);
> > 
> > Hi Dave,
> > 
> > I think instead of always falling back to old "noefi" method for SGI UV
> > machines, we should probably provide a config option to override default
> > behavior. Something like "--nouefi". And let user/distributions decide
> > in what cases to use that parameter.
> > 
> > Reason being, that at some point of time this limitation will be fixed.
> > And at that point of time if we modify kexec-tools, then it will stop
> > working with older kernels. And then same issue will arise that
> > kexec-tools is not working with older kernels.
> > 
> > If we just provide a way to override default, then distributions in their
> > scripts should know what kernels work what way and automatically use or
> > not use option accordingly.
> > 
> > Thanks
> > Vivek
> > 
> > _______________________________________________
> > kexec mailing list
> > kexec@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kexec
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> Sent from a fat crate under my desk. Formatting is fine.
> --

-- 
Russ Anderson,  Kernel and Performance Software Team Manager
SGI - Silicon Graphics Inc          rja@sgi.com

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Alex Thorlton]

On Fri, May 23, 2014 at 11:19:30AM -0500, Russ Anderson wrote:
> On Fri, May 23, 2014 at 05:54:11PM +0200, Borislav Petkov wrote:
> > On Fri, May 23, 2014 at 09:47:08AM -0400, Dave Young wrote:
> > > Hi,
> > > 
> > > Vivek, replying with webmail, sorry for the formatting issue.
> > > 
> > > Another way is export the mapping scheme in sysfs. So if kernel boot
> > > with efi=old_map we can detect it as well. OTOH in future there's probably
> > > other quirk system.
> > > 
> > > So kexec-tools can switch to use old way if kernel use ioremap.

This sounds like a good approach to use, but I think we should still
have a way to force it to use the old way if necessary (can't think of a
use case for that off the top of my head, but I'm sure someone can :)

I think a sort of hybrid approach between detecting the mapping scheme,
and having a command-line option would probably be best:

- Detect which mapping method we used.
- Default to noefi if the old mapping method was used, default to
  efi if new mapping was used.
- Allow users to specify either --efi or --noefi when kexec'ing to
  override the suggested default, determined above.

Make sense?  We alway seems to run into trouble when we try to make
decisions on the user's behalf, and not allow them to have the final
say.

> > > Adding Matt and Boris to cc, to see if they have idea.
> > > Thanks
> > > Dave
> > > 
> > > ----- Original Message -----
> > > From: "Vivek Goyal" <vgoyal@redhat.com>
> > > To: "Dave Young" <dyoung@redhat.com>
> > > Cc: horms@verge.net.au, kexec@lists.infradead.org
> > > Sent: Friday, May 23, 2014 9:28:34 PM
> > > Subject: Re: [PATCH] x86: do not enable efi boot for sgi uv machine
> > > 
> > > On Fri, May 23, 2014 at 06:14:55PM +0800, Dave Young wrote:
> > > > 
> > > > kexec/kdump uefi support depends on the 1:1 mapping scheme
> > > > in 3.14 kernel but SGI reported that 1:1 mapping does not work on
> > > > their UV system. thus there's below commit to switch back to
> > > > old ioremap way for sgi uv machines.
> > > > 
> > > > So for kexec-tools before we got the 1:1 mapping support on those
> > > > machines we should also use old way that means boot 2nd kernel
> > > > without uefi.
> 
> Yes, the old workaround to allow the kdump kernel to boot was
> to add the noefi bootline option, which also meant passing all
> the memory ranges as kernel boot line options (since noefi meant
> no EFI memory map info).  An ugly situation.  That is why we
> want to get Boris' mapping changes working on SGI UV, so that
> kexec/kdump work without ugly workarounds.
> 
> 
> > Well, we did find the bug in a combined debug session and SGI will be
> > issuing a fix soon. I don't know whether any quirk will be needed for
> > systems which don't have the fix - I guess that's something for SGI
> > people to decide. CCed and leaving in the rest for reference.
> > 
> > @Alex, Russ: this is about using kexec on UEFI boxes.
> 
> Thanks for the heads up.  Our bios made an assumption about
> mapping that was valid with the old mapping scheme but not
> with the new.  Fortunately the fix will work with both old
> and new kernels, so the fix can be added in the next bios
> update.  But we still have to be careful when removing the
> quirk, to avoid someone trying a new kernel with old bios
> and not being able to boot.
> 
> 
> > > > Tested on a uv1 machine.
> > > > 
> > > > Here is the kernel commit to quirk out SGI UV:
> > > > commit a5d90c923bcfb9632d998ed06e9569216ad695f3
> > > > Author: Borislav Petkov <bp@suse.de>
> > > > Date:   Tue Mar 4 17:02:17 2014 +0100
> > > > 
> > > >     x86/efi: Quirk out SGI UV
> > > >     
> > > >     Alex reported hitting the following BUG after the EFI 1:1 virtual
> > > >     mapping work was merged,
> > > >     
> > > >      kernel BUG at arch/x86/mm/init_64.c:351!
> > > >      invalid opcode: 0000 [#1] SMP
> > > >      Call Trace:
> > > >       [<ffffffff818aa71d>] init_extra_mapping_uc+0x13/0x15
> > > >       [<ffffffff818a5e20>] uv_system_init+0x22b/0x124b
> > > >       [<ffffffff8108b886>] ? clockevents_register_device+0x138/0x13d
> > > >       [<ffffffff81028dbb>] ? setup_APIC_timer+0xc5/0xc7
> > > >       [<ffffffff8108b620>] ? clockevent_delta2ns+0xb/0xd
> > > >       [<ffffffff818a3a92>] ? setup_boot_APIC_clock+0x4a8/0x4b7
> > > >       [<ffffffff8153d955>] ? printk+0x72/0x74
> > > >       [<ffffffff818a1757>] native_smp_prepare_cpus+0x389/0x3d6
> > > >       [<ffffffff818957bc>] kernel_init_freeable+0xb7/0x1fb
> > > >       [<ffffffff81535530>] ? rest_init+0x74/0x74
> > > >       [<ffffffff81535539>] kernel_init+0x9/0xff
> > > >       [<ffffffff81541dfc>] ret_from_fork+0x7c/0xb0
> > > >       [<ffffffff81535530>] ? rest_init+0x74/0x74
> > > >     
> > > >     Getting this thing to work with the new mapping scheme would need more
> > > >     work, so automatically switch to the old memmap layout for SGI UV.
> > > > 
> > > > 
> > > > Signed-off-by: Dave Young <dyoung@redhat.com>
> > > > ---
> > > >  kexec/arch/i386/x86-linux-setup.c |   15 ++++++++++++++-
> > > >  1 file changed, 14 insertions(+), 1 deletion(-)
> > > > 
> > > > --- kexec-tools.orig/kexec/arch/i386/x86-linux-setup.c
> > > > +++ kexec-tools/kexec/arch/i386/x86-linux-setup.c
> > > > @@ -817,12 +817,25 @@ out:
> > > >  	return;
> > > >  }
> > > >  
> > > > +static int is_sgi_uv_machine(void)
> > > > +{
> > > > +	DIR *sgi_dir;
> > > > +
> > > > +	sgi_dir = opendir("/sys/firmware/sgi_uv");
> > > > +	if (sgi_dir) {
> > > > +		closedir(sgi_dir);
> > > > +		return 1;
> > > > +	}
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > >  void setup_linux_system_parameters(struct kexec_info *info,
> > > >  				   struct x86_linux_param_header *real_mode)
> > > >  {
> > > >  	/* get subarch from running kernel */
> > > >  	setup_subarch(real_mode);
> > > > -	if (bzImage_support_efi_boot)
> > > > +	if (bzImage_support_efi_boot && !is_sgi_uv_machine())
> > > >  		setup_efi_info(info, real_mode);
> > > 
> > > Hi Dave,
> > > 
> > > I think instead of always falling back to old "noefi" method for SGI UV
> > > machines, we should probably provide a config option to override default
> > > behavior. Something like "--nouefi". And let user/distributions decide
> > > in what cases to use that parameter.
> > > Reason being, that at some point of time this limitation will be fixed.
> > > And at that point of time if we modify kexec-tools, then it will stop
> > > working with older kernels. And then same issue will arise that
> > > kexec-tools is not working with older kernels.
> > > 
> > > If we just provide a way to override default, then distributions in their
> > > scripts should know what kernels work what way and automatically use or
> > > not use option accordingly.
> > > 
> > > Thanks
> > > Vivek
> > > 
> > > _______________________________________________
> > > kexec mailing list
> > > kexec@lists.infradead.org
> > > http://lists.infradead.org/mailman/listinfo/kexec
> > 
> > -- 
> > Regards/Gruss,
> >     Boris.
> > 
> > Sent from a fat crate under my desk. Formatting is fine.
> > --
> 
> -- 
> Russ Anderson,  Kernel and Performance Software Team Manager
> SGI - Silicon Graphics Inc          rja@sgi.com

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Dave Young]

On Fri, May 23, 2014 at 02:02:10PM -0500, Alex Thorlton wrote:
> On Fri, May 23, 2014 at 11:19:30AM -0500, Russ Anderson wrote:
> > On Fri, May 23, 2014 at 05:54:11PM +0200, Borislav Petkov wrote:
> > > On Fri, May 23, 2014 at 09:47:08AM -0400, Dave Young wrote:
> > > > Hi,
> > > > 
> > > > Vivek, replying with webmail, sorry for the formatting issue.
> > > > 
> > > > Another way is export the mapping scheme in sysfs. So if kernel boot
> > > > with efi=old_map we can detect it as well. OTOH in future there's probably
> > > > other quirk system.
> > > > 
> > > > So kexec-tools can switch to use old way if kernel use ioremap.
> 
> This sounds like a good approach to use, but I think we should still
> have a way to force it to use the old way if necessary (can't think of a
> use case for that off the top of my head, but I'm sure someone can :)
> 
> I think a sort of hybrid approach between detecting the mapping scheme,
> and having a command-line option would probably be best:
> 
> - Detect which mapping method we used.
> - Default to noefi if the old mapping method was used, default to
>   efi if new mapping was used.

Agree because the efi=old_map

> - Allow users to specify either --efi or --noefi when kexec'ing to
>   override the suggested default, determined above.

I can not think out of such a case, but who knows. I can work on a '--noefi'
patch. 

Thanks
Dave

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Dave Young]

> > Well, we did find the bug in a combined debug session and SGI will be
> > issuing a fix soon. I don't know whether any quirk will be needed for
> > systems which don't have the fix - I guess that's something for SGI
> > people to decide. CCed and leaving in the rest for reference.
> > 
> > @Alex, Russ: this is about using kexec on UEFI boxes.
> 
> Thanks for the heads up.  Our bios made an assumption about
> mapping that was valid with the old mapping scheme but not
> with the new.  Fortunately the fix will work with both old
> and new kernels, so the fix can be added in the next bios
> update.  But we still have to be careful when removing the
> quirk, to avoid someone trying a new kernel with old bios
> and not being able to boot.

The quirk will quirk out all uv system, will SGI people provide a patch
to only add quirk for old firmware version or just removing the quirk
after the update is out?

Thanks
Dave

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Alex Thorlton]

On Tue, May 27, 2014 at 11:28:16AM +0800, Dave Young wrote:
> > > Well, we did find the bug in a combined debug session and SGI will be
> > > issuing a fix soon. I don't know whether any quirk will be needed for
> > > systems which don't have the fix - I guess that's something for SGI
> > > people to decide. CCed and leaving in the rest for reference.
> > > 
> > > @Alex, Russ: this is about using kexec on UEFI boxes.
> > 
> > Thanks for the heads up.  Our bios made an assumption about
> > mapping that was valid with the old mapping scheme but not
> > with the new.  Fortunately the fix will work with both old
> > and new kernels, so the fix can be added in the next bios
> > update.  But we still have to be careful when removing the
> > quirk, to avoid someone trying a new kernel with old bios
> > and not being able to boot.
> 
> The quirk will quirk out all uv system, will SGI people provide a patch
> to only add quirk for old firmware version or just removing the quirk
> after the update is out?

Yes - I'm working on that now.  I'll make sure you're copied on the
patch when I do get it all worked out.

> Thanks
> Dave

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Vivek Goyal]

On Fri, May 23, 2014 at 11:19:30AM -0500, Russ Anderson wrote:

[..]
> 
> > Well, we did find the bug in a combined debug session and SGI will be
> > issuing a fix soon. I don't know whether any quirk will be needed for
> > systems which don't have the fix - I guess that's something for SGI
> > people to decide. CCed and leaving in the rest for reference.
> > 
> > @Alex, Russ: this is about using kexec on UEFI boxes.
> 
> Thanks for the heads up.  Our bios made an assumption about
> mapping that was valid with the old mapping scheme but not
> with the new.  Fortunately the fix will work with both old
> and new kernels, so the fix can be added in the next bios
> update.  But we still have to be careful when removing the
> quirk, to avoid someone trying a new kernel with old bios
> and not being able to boot.

Hi,

So is there is a way for kernel to know whether BIOS has fix or not?
IOW, I am wondering how would one remove quirk or how one can be
reasonably sure that kernel is not booting with Old BIOS.

Thanks
Vivek

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Vivek Goyal]

On Fri, May 23, 2014 at 09:47:08AM -0400, Dave Young wrote:
> Hi,
> 
> Vivek, replying with webmail, sorry for the formatting issue.
> 
> Another way is export the mapping scheme in sysfs. So if kernel boot
> with efi=old_map we can detect it as well. OTOH in future there's probably
> other quirk system.
> 
> So kexec-tools can switch to use old way if kernel use ioremap.

Exporting type of mapping being used in current kernel and automatically
deciding that whether to boot with efi or noefi sounds reasonable to me.
I am assuming that once type of mapping got fixed in first kernel boot
it can't be changed in subsequent kernel boots?

Thanks
Vivek

> 
> Adding Matt and Boris to cc, to see if they have idea.
> 
> Thanks
> Dave
> 
> ----- Original Message -----
> From: "Vivek Goyal" <vgoyal@redhat.com>
> To: "Dave Young" <dyoung@redhat.com>
> Cc: horms@verge.net.au, kexec@lists.infradead.org
> Sent: Friday, May 23, 2014 9:28:34 PM
> Subject: Re: [PATCH] x86: do not enable efi boot for sgi uv machine
> 
> On Fri, May 23, 2014 at 06:14:55PM +0800, Dave Young wrote:
> > 
> > kexec/kdump uefi support depends on the 1:1 mapping scheme
> > in 3.14 kernel but SGI reported that 1:1 mapping does not work on
> > their UV system. thus there's below commit to switch back to
> > old ioremap way for sgi uv machines.
> > 
> > So for kexec-tools before we got the 1:1 mapping support on those
> > machines we should also use old way that means boot 2nd kernel
> > without uefi.
> > 
> > Tested on a uv1 machine.
> > 
> > Here is the kernel commit to quirk out SGI UV:
> > commit a5d90c923bcfb9632d998ed06e9569216ad695f3
> > Author: Borislav Petkov <bp@suse.de>
> > Date:   Tue Mar 4 17:02:17 2014 +0100
> > 
> >     x86/efi: Quirk out SGI UV
> >     
> >     Alex reported hitting the following BUG after the EFI 1:1 virtual
> >     mapping work was merged,
> >     
> >      kernel BUG at arch/x86/mm/init_64.c:351!
> >      invalid opcode: 0000 [#1] SMP
> >      Call Trace:
> >       [<ffffffff818aa71d>] init_extra_mapping_uc+0x13/0x15
> >       [<ffffffff818a5e20>] uv_system_init+0x22b/0x124b
> >       [<ffffffff8108b886>] ? clockevents_register_device+0x138/0x13d
> >       [<ffffffff81028dbb>] ? setup_APIC_timer+0xc5/0xc7
> >       [<ffffffff8108b620>] ? clockevent_delta2ns+0xb/0xd
> >       [<ffffffff818a3a92>] ? setup_boot_APIC_clock+0x4a8/0x4b7
> >       [<ffffffff8153d955>] ? printk+0x72/0x74
> >       [<ffffffff818a1757>] native_smp_prepare_cpus+0x389/0x3d6
> >       [<ffffffff818957bc>] kernel_init_freeable+0xb7/0x1fb
> >       [<ffffffff81535530>] ? rest_init+0x74/0x74
> >       [<ffffffff81535539>] kernel_init+0x9/0xff
> >       [<ffffffff81541dfc>] ret_from_fork+0x7c/0xb0
> >       [<ffffffff81535530>] ? rest_init+0x74/0x74
> >     
> >     Getting this thing to work with the new mapping scheme would need more
> >     work, so automatically switch to the old memmap layout for SGI UV.
> > 
> > 
> > Signed-off-by: Dave Young <dyoung@redhat.com>
> > ---
> >  kexec/arch/i386/x86-linux-setup.c |   15 ++++++++++++++-
> >  1 file changed, 14 insertions(+), 1 deletion(-)
> > 
> > --- kexec-tools.orig/kexec/arch/i386/x86-linux-setup.c
> > +++ kexec-tools/kexec/arch/i386/x86-linux-setup.c
> > @@ -817,12 +817,25 @@ out:
> >  	return;
> >  }
> >  
> > +static int is_sgi_uv_machine(void)
> > +{
> > +	DIR *sgi_dir;
> > +
> > +	sgi_dir = opendir("/sys/firmware/sgi_uv");
> > +	if (sgi_dir) {
> > +		closedir(sgi_dir);
> > +		return 1;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> >  void setup_linux_system_parameters(struct kexec_info *info,
> >  				   struct x86_linux_param_header *real_mode)
> >  {
> >  	/* get subarch from running kernel */
> >  	setup_subarch(real_mode);
> > -	if (bzImage_support_efi_boot)
> > +	if (bzImage_support_efi_boot && !is_sgi_uv_machine())
> >  		setup_efi_info(info, real_mode);
> 
> Hi Dave,
> 
> I think instead of always falling back to old "noefi" method for SGI UV
> machines, we should probably provide a config option to override default
> behavior. Something like "--nouefi". And let user/distributions decide
> in what cases to use that parameter.
> 
> Reason being, that at some point of time this limitation will be fixed.
> And at that point of time if we modify kexec-tools, then it will stop
> working with older kernels. And then same issue will arise that
> kexec-tools is not working with older kernels.
> 
> If we just provide a way to override default, then distributions in their
> scripts should know what kernels work what way and automatically use or
> not use option accordingly.
> 
> Thanks
> Vivek
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

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Re: [PATCH] x86: do not enable efi boot for sgi uv machine

[Dave Young]

On Fri, May 23, 2014 at 11:54:27AM -0400, Vivek Goyal wrote:
> On Fri, May 23, 2014 at 09:47:08AM -0400, Dave Young wrote:
> > Hi,
> > 
> > Vivek, replying with webmail, sorry for the formatting issue.
> > 
> > Another way is export the mapping scheme in sysfs. So if kernel boot
> > with efi=old_map we can detect it as well. OTOH in future there's probably
> > other quirk system.
> > 
> > So kexec-tools can switch to use old way if kernel use ioremap.
> 
> Exporting type of mapping being used in current kernel and automatically
> deciding that whether to boot with efi or noefi sounds reasonable to me.
> I am assuming that once type of mapping got fixed in first kernel boot
> it can't be changed in subsequent kernel boots?

Right, 2nd kernel will continue to use the original mapping because we can
only call the firmware function once to enter virtual mode. 

Thanks
Dave

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