[PATCH]x86 efi: do not export efi runtime map in case old map

[PATCH]x86 efi: do not export efi runtime map in case old map

[Dave Young]

For ioremapped efi memory aka old_map the virt addresses are not persistant
across kexec reboot. kexec-tools will read the runtime maps from sysfs then
pass them to 2nd kernel and assuming kexec efi boot is ok. This will cause
kexec boot failure.

To address this issue do not export runtime maps in case efi old_map so
userspace can use no efi boot instead.

Signed-off-by: Dave Young <dyoung@redhat.com>
---
 arch/x86/platform/efi/efi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 3781dd3..4d36932 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -919,6 +919,9 @@ static void __init save_runtime_map(void)
 	void *tmp, *p, *q = NULL;
 	int count = 0;
 
+	if (efi_enabled(EFI_OLD_MEMMAP))
+		return;
+
 	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 		md = p;
 
-- 
1.8.3.1

Re: [PATCH]x86 efi: do not export efi runtime map in case old map

[Dave Young]

Ccing Simon.

Simon, appologize for not ccing you about this kernel patch. I see you have
applied the userspace patch for checking sysfs runtime existance.

The userspace patch depends on this patch but it is not harmful even without
this kernel patch. So applying the userspace patch before this one is still
safe.

On 05/30/14 at 11:20am, Dave Young wrote:
> 
> For ioremapped efi memory aka old_map the virt addresses are not persistant
> across kexec reboot. kexec-tools will read the runtime maps from sysfs then
> pass them to 2nd kernel and assuming kexec efi boot is ok. This will cause
> kexec boot failure.
> 
> To address this issue do not export runtime maps in case efi old_map so
> userspace can use no efi boot instead.
> 
> Signed-off-by: Dave Young <dyoung@redhat.com>
> ---
>  arch/x86/platform/efi/efi.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 3781dd3..4d36932 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -919,6 +919,9 @@ static void __init save_runtime_map(void)
>  	void *tmp, *p, *q = NULL;
>  	int count = 0;
>  
> +	if (efi_enabled(EFI_OLD_MEMMAP))
> +		return;
> +
>  	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
>  		md = p;
>  
> -- 
> 1.8.3.1
> 
> --
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Re: [PATCH]x86 efi: do not export efi runtime map in case old map

[Simon Horman]

On Fri, May 30, 2014 at 01:54:47PM +0800, Dave Young wrote:
> Ccing Simon.
> 
> Simon, appologize for not ccing you about this kernel patch. I see you have
> applied the userspace patch for checking sysfs runtime existance.
> 
> The userspace patch depends on this patch but it is not harmful even without
> this kernel patch. So applying the userspace patch before this one is still
> safe.

Thanks, I understand.

If the kernel side ends up being rejected or modified please
send an update for kexec-tools accordingly.

> 
> On 05/30/14 at 11:20am, Dave Young wrote:
> > 
> > For ioremapped efi memory aka old_map the virt addresses are not persistant
> > across kexec reboot. kexec-tools will read the runtime maps from sysfs then
> > pass them to 2nd kernel and assuming kexec efi boot is ok. This will cause
> > kexec boot failure.
> > 
> > To address this issue do not export runtime maps in case efi old_map so
> > userspace can use no efi boot instead.
> > 
> > Signed-off-by: Dave Young <dyoung@redhat.com>
> > ---
> >  arch/x86/platform/efi/efi.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> > index 3781dd3..4d36932 100644
> > --- a/arch/x86/platform/efi/efi.c
> > +++ b/arch/x86/platform/efi/efi.c
> > @@ -919,6 +919,9 @@ static void __init save_runtime_map(void)
> >  	void *tmp, *p, *q = NULL;
> >  	int count = 0;
> >  
> > +	if (efi_enabled(EFI_OLD_MEMMAP))
> > +		return;
> > +
> >  	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> >  		md = p;
> >  
> > -- 
> > 1.8.3.1
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at  http://www.tux.org/lkml/
> 

Re: [PATCH]x86 efi: do not export efi runtime map in case old map

[Dave Young]

On 05/30/14 at 03:08pm, Simon Horman wrote:
> On Fri, May 30, 2014 at 01:54:47PM +0800, Dave Young wrote:
> > Ccing Simon.
> > 
> > Simon, appologize for not ccing you about this kernel patch. I see you have
> > applied the userspace patch for checking sysfs runtime existance.
> > 
> > The userspace patch depends on this patch but it is not harmful even without
> > this kernel patch. So applying the userspace patch before this one is still
> > safe.
> 
> Thanks, I understand.
> 
> If the kernel side ends up being rejected or modified please
> send an update for kexec-tools accordingly.

Sure, will do

Thanks
Dave

Re: [PATCH]x86 efi: do not export efi runtime map in case old map

[Borislav Petkov]

On Fri, May 30, 2014 at 11:20:10AM +0800, Dave Young wrote:
> 
> For ioremapped efi memory aka old_map the virt addresses are not persistant
> across kexec reboot. kexec-tools will read the runtime maps from sysfs then
> pass them to 2nd kernel and assuming kexec efi boot is ok. This will cause
> kexec boot failure.
> 
> To address this issue do not export runtime maps in case efi old_map so
> userspace can use no efi boot instead.
> 
> Signed-off-by: Dave Young <dyoung@redhat.com>

Acked-by: Borislav Petkov <bp@suse.de>

-- 
Regards/Gruss,
    Boris.

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

Re: [PATCH]x86 efi: do not export efi runtime map in case old map

[Vivek Goyal]

On Fri, May 30, 2014 at 11:20:10AM +0800, Dave Young wrote:
> 
> For ioremapped efi memory aka old_map the virt addresses are not persistant
> across kexec reboot. kexec-tools will read the runtime maps from sysfs then
> pass them to 2nd kernel and assuming kexec efi boot is ok. This will cause
> kexec boot failure.
> 
> To address this issue do not export runtime maps in case efi old_map so
> userspace can use no efi boot instead.
> 
> Signed-off-by: Dave Young <dyoung@redhat.com>

Looks good to me.

Acked-by: Vivek Goyal <vgoyal@redhat.com>

Vivek

> ---
>  arch/x86/platform/efi/efi.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 3781dd3..4d36932 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -919,6 +919,9 @@ static void __init save_runtime_map(void)
>  	void *tmp, *p, *q = NULL;
>  	int count = 0;
>  
> +	if (efi_enabled(EFI_OLD_MEMMAP))
> +		return;
> +
>  	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
>  		md = p;
>  
> -- 
> 1.8.3.1

Re: [PATCH]x86 efi: do not export efi runtime map in case old map

[Matt Fleming]

On 30 May 2014 04:20, Dave Young <dyoung@redhat.com> wrote:
>
> For ioremapped efi memory aka old_map the virt addresses are not persistant
> across kexec reboot. kexec-tools will read the runtime maps from sysfs then
> pass them to 2nd kernel and assuming kexec efi boot is ok. This will cause
> kexec boot failure.
>
> To address this issue do not export runtime maps in case efi old_map so
> userspace can use no efi boot instead.
>
> Signed-off-by: Dave Young <dyoung@redhat.com>
> ---
>  arch/x86/platform/efi/efi.c | 3 +++
>  1 file changed, 3 insertions(+)

Thanks Dave, applied with acks.