Re: [kexec-lite PATCH V2] trampoline: Reset primary cpu endian to big-endian

2015-10-06 Thread Scott Wood 
On Wed, 2015-07-08 at 13:49 +1000, Samuel Mendoza-Jonas wrote:
> On 08/07/15 13:37, Scott Wood wrote:
> > On Wed, 2015-07-08 at 13:29 +1000, Samuel Mendoza-Jonas wrote:
> > > Older big-endian ppc64 kernels don't include the FIXUP_ENDIAN check,
> > > meaning if we kexec from a little-endian kernel the target kernel will
> > > fail to boot.
> > > Returning to big-endian before we enter the target kernel ensures that
> > > the target kernel can boot whether or not it includes FIXUP_ENDIAN.
> > > 
> > > Signed-off-by: Samuel Mendoza-Jonas 
> > > ---
> > > V2: As suggested by Anton take advantage of the rfid call and switch off
> > > MSR_LE and branch to the target kernel in the same step.
> > > 
> > >  kexec_trampoline.S | 11 +--
> > >  1 file changed, 9 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/kexec_trampoline.S b/kexec_trampoline.S
> > > index a3eb314..3751112 100644
> > > --- a/kexec_trampoline.S
> > > +++ b/kexec_trampoline.S
> > > @@ -88,8 +88,15 @@ start:
> > >  
> > >   li  r5,0
> > >  
> > > - mtctr   r4
> > > - bctr
> > > + mtsrr0  r4
> > > +
> > > + mfmsr   r5
> > > + clrrdi  r5,r5,1 /* Clear MSR_LE */
> > > + mtsrr1  r5
> > > +
> > > + li  r5,0
> > > +
> > > + rfid
> > 
> > Is kexec-lite meant to be specific to book3s-64?  The README just says "A 
> > simple kexec for flattened device tree platforms" and I see a 
> > __powerpc64__ 
> > ifdef in kexec_trampoline.S (but not in the above patch)...
> > 
> > -Scott
> > 
> 
> I believe that particular ifdef is to check if we're little-endian when 
> reading
> the device tree, but that's still a good point - I'll check with Anton.

It looks like this ended up going into main kexec, which means I get to find 
some way to distinguish book3s from book3e to avoid that rfid.  Yay.

-Scott

___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

Re: [kexec-lite PATCH V2] trampoline: Reset primary cpu endian to big-endian

2015-07-08 Thread Anton Blanchard 
Hi Scott,

 Is kexec-lite meant to be specific to book3s-64? 

It was originally built to test book3s-64 kexec. Likely some other
issues need fixing for other ppc sub arches, but it is nice to
have a very simple kexec.

Anton
___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

Re: [kexec-lite PATCH V2] trampoline: Reset primary cpu endian to big-endian

2015-07-07 Thread Samuel Mendoza-Jonas 
On 08/07/15 13:37, Scott Wood wrote:
 On Wed, 2015-07-08 at 13:29 +1000, Samuel Mendoza-Jonas wrote:
 Older big-endian ppc64 kernels don't include the FIXUP_ENDIAN check,
 meaning if we kexec from a little-endian kernel the target kernel will
 fail to boot.
 Returning to big-endian before we enter the target kernel ensures that
 the target kernel can boot whether or not it includes FIXUP_ENDIAN.

 Signed-off-by: Samuel Mendoza-Jonas sam...@au1.ibm.com
 ---
 V2: As suggested by Anton take advantage of the rfid call and switch off
 MSR_LE and branch to the target kernel in the same step.

  kexec_trampoline.S | 11 +--
  1 file changed, 9 insertions(+), 2 deletions(-)

 diff --git a/kexec_trampoline.S b/kexec_trampoline.S
 index a3eb314..3751112 100644
 --- a/kexec_trampoline.S
 +++ b/kexec_trampoline.S
 @@ -88,8 +88,15 @@ start:
  
   li  r5,0
  
 - mtctr   r4
 - bctr
 + mtsrr0  r4
 +
 + mfmsr   r5
 + clrrdi  r5,r5,1 /* Clear MSR_LE */
 + mtsrr1  r5
 +
 + li  r5,0
 +
 + rfid
 
 Is kexec-lite meant to be specific to book3s-64?  The README just says A 
 simple kexec for flattened device tree platforms and I see a __powerpc64__ 
 ifdef in kexec_trampoline.S (but not in the above patch)...
 
 -Scott
 

I believe that particular ifdef is to check if we're little-endian when reading
the device tree, but that's still a good point - I'll check with Anton.

-- 
---
LTC Ozlabs
IBM

___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

[kexec-lite PATCH V2] trampoline: Reset primary cpu endian to big-endian

2015-07-07 Thread Samuel Mendoza-Jonas 
Older big-endian ppc64 kernels don't include the FIXUP_ENDIAN check,
meaning if we kexec from a little-endian kernel the target kernel will
fail to boot.
Returning to big-endian before we enter the target kernel ensures that
the target kernel can boot whether or not it includes FIXUP_ENDIAN.

Signed-off-by: Samuel Mendoza-Jonas sam...@au1.ibm.com
---
V2: As suggested by Anton take advantage of the rfid call and switch off
MSR_LE and branch to the target kernel in the same step.

 kexec_trampoline.S | 11 +--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/kexec_trampoline.S b/kexec_trampoline.S
index a3eb314..3751112 100644
--- a/kexec_trampoline.S
+++ b/kexec_trampoline.S
@@ -88,8 +88,15 @@ start:
 
li  r5,0
 
-   mtctr   r4
-   bctr
+   mtsrr0  r4
+
+   mfmsr   r5
+   clrrdi  r5,r5,1 /* Clear MSR_LE */
+   mtsrr1  r5
+
+   li  r5,0
+
+   rfid
 
 . = KERNEL_ADDR_OFFSET
 kernel_addr:
-- 
2.4.5

___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

Re: [kexec-lite PATCH V2] trampoline: Reset primary cpu endian to big-endian

2015-07-07 Thread Scott Wood 
On Wed, 2015-07-08 at 13:29 +1000, Samuel Mendoza-Jonas wrote:
 Older big-endian ppc64 kernels don't include the FIXUP_ENDIAN check,
 meaning if we kexec from a little-endian kernel the target kernel will
 fail to boot.
 Returning to big-endian before we enter the target kernel ensures that
 the target kernel can boot whether or not it includes FIXUP_ENDIAN.
 
 Signed-off-by: Samuel Mendoza-Jonas sam...@au1.ibm.com
 ---
 V2: As suggested by Anton take advantage of the rfid call and switch off
 MSR_LE and branch to the target kernel in the same step.
 
  kexec_trampoline.S | 11 +--
  1 file changed, 9 insertions(+), 2 deletions(-)
 
 diff --git a/kexec_trampoline.S b/kexec_trampoline.S
 index a3eb314..3751112 100644
 --- a/kexec_trampoline.S
 +++ b/kexec_trampoline.S
 @@ -88,8 +88,15 @@ start:
  
   li  r5,0
  
 - mtctr   r4
 - bctr
 + mtsrr0  r4
 +
 + mfmsr   r5
 + clrrdi  r5,r5,1 /* Clear MSR_LE */
 + mtsrr1  r5
 +
 + li  r5,0
 +
 + rfid

Is kexec-lite meant to be specific to book3s-64?  The README just says A 
simple kexec for flattened device tree platforms and I see a __powerpc64__ 
ifdef in kexec_trampoline.S (but not in the above patch)...

-Scott

___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev