| Message ID | 1436326178-17021-1-git-send-email-sam.mj@au1.ibm.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
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.mj@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
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.mj@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.
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
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 <sam.mj@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. 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
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:
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.mj@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(-)