| Message ID | 20181205153918.29480-4-frankja@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | 390x: Add cross hypervisor and disk boot | expand |
On 05.12.18 16:39, Janosch Frank wrote: > LPAR and z/VM start in esam mode depending on the hardware, so we need > to switch to z/Arch and set 64 bit addressing. > > Under Qemu/KVM we already start out with both when being run with the > Qemu --kernel argument or we lack 64 bit when booting from disk > because of the initial psw specifying 31 bit for z/VM and lpar > compatibility. > > Signed-off-by: Janosch Frank <frankja@linux.ibm.com> > --- > s390x/cstart64.S | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/s390x/cstart64.S b/s390x/cstart64.S > index d382497..7886f35 100644 > --- a/s390x/cstart64.S > +++ b/s390x/cstart64.S > @@ -20,9 +20,17 @@ > * > * For KVM and TCG kernel boot we are in 64 bit z/Arch mode. > * When booting from disk the initial short psw is in 31 bit mode. > + * When running under LPAR or z/VM, we might start in 31 bit and esam mode. > */ > .globl start > start: > + /* Switch to z/Architecture mode and 64-bit */ > + slr %r0, %r0 # Set cpuid to zero > + lhi %r1, 2 # mode 2 = esame > + sigp %r1, %r0, 0x12 # sigp set arch > + bras %r13,0f # Jump over zero area > + .fill 16,4,0x0 # Zero area for lmh > +0: lmh %r0,%r15,0(%r13) # Clear high-order half of gprs > sam64 # Set addressing mode to 64 bit > /* setup stack */ > larl %r15, stackptr > Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/s390x/cstart64.S b/s390x/cstart64.S index d382497..7886f35 100644 --- a/s390x/cstart64.S +++ b/s390x/cstart64.S @@ -20,9 +20,17 @@ * * For KVM and TCG kernel boot we are in 64 bit z/Arch mode. * When booting from disk the initial short psw is in 31 bit mode. + * When running under LPAR or z/VM, we might start in 31 bit and esam mode. */ .globl start start: + /* Switch to z/Architecture mode and 64-bit */ + slr %r0, %r0 # Set cpuid to zero + lhi %r1, 2 # mode 2 = esame + sigp %r1, %r0, 0x12 # sigp set arch + bras %r13,0f # Jump over zero area + .fill 16,4,0x0 # Zero area for lmh +0: lmh %r0,%r15,0(%r13) # Clear high-order half of gprs sam64 # Set addressing mode to 64 bit /* setup stack */ larl %r15, stackptr
LPAR and z/VM start in esam mode depending on the hardware, so we need to switch to z/Arch and set 64 bit addressing. Under Qemu/KVM we already start out with both when being run with the Qemu --kernel argument or we lack 64 bit when booting from disk because of the initial psw specifying 31 bit for z/VM and lpar compatibility. Signed-off-by: Janosch Frank <frankja@linux.ibm.com> --- s390x/cstart64.S | 8 ++++++++ 1 file changed, 8 insertions(+)