From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Date: Tue, 15 Mar 2016 18:44:23 +0000 Subject: Re: [PATCH] powerpc: enable 64-bit mode Message-Id: <56E85807.5050903@suse.de> List-Id: References: <1458047717-25052-1-git-send-email-lvivier@redhat.com> <56E857C2.2020404@redhat.com> In-Reply-To: <56E857C2.2020404@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Thomas Huth , Laurent Vivier , kvm@vger.kernel.org, kvm-ppc@vger.kernel.org Cc: drjones@redhat.com, dgibson@redhat.com, pbonzini@redhat.com On 15.03.16 19:43, Thomas Huth wrote: > On 15.03.2016 14:15, Laurent Vivier wrote: >> When they are started, processors are in 32-bit mode, >> as we are testing ppc64 processors, enable the 64bit mode >> on starting. >> >> Signed-off-by: Laurent Vivier >> --- >> powerpc/cstart64.S | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> >> diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S >> index c87e3d6..634b854 100644 >> --- a/powerpc/cstart64.S >> +++ b/powerpc/cstart64.S >> @@ -18,6 +18,15 @@ >> .globl start >> start: >> FIXUP_ENDIAN >> + >> + /* enable 64-bit mode */ >> + mfmsr r11 >> + li r12,-1 >> + rldicr r12,r12,0,0 > > Nice idea to set the highest bit, I didn't know that one yet :-) > >> + or r11,r11,r12 >> + mtmsrd r11 >> + isync > > Looks good! > > Reviewed-by: Thomas Huth > > > PS: As far as I can see, the C code has already been compiled for 64 > bits ... how did that work if it has been run in 32-bit mode so far?? And why would we enter a 64bit CPU without MSR_SF set? Alex