| Message ID | 20230404101434.172721-1-thuth@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [kvm-unit-tests] s390x/snippets: Fix compilation with Clang 15 | expand |
On Tue, 4 Apr 2023 12:14:34 +0200 Thomas Huth <thuth@redhat.com> wrote: > Clang complains: > > s390x/snippets/c/cstart.S:22:13: error: invalid operand for instruction > lghi %r15, stackptr > ^ > Let's load the address with "larl" instead, like we already do > it in s390x/cstart64.S. For this we should also switch to 64-bit > mode first, then we also don't have to clear r15 right in front > of this anymore. > > Changing the code here triggered another problem: initial_cr0 > must be aligned on a double-word boundary, otherwise the lctlg > instruction will fail with an specification exception. This was > just working by accident so far - add an ".align 8" now to avoid > the problem. > > Signed-off-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > --- > s390x/snippets/c/cstart.S | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/s390x/snippets/c/cstart.S b/s390x/snippets/c/cstart.S > index a7d4cd42..c80ccfed 100644 > --- a/s390x/snippets/c/cstart.S > +++ b/s390x/snippets/c/cstart.S > @@ -15,12 +15,12 @@ start: > larl %r1, initial_cr0 > lctlg %c0, %c0, 0(%r1) > /* XOR all registers with themselves to clear them fully. */ > - .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 > + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14 > xgr \i,\i > .endr > - /* 0x3000 is the stack page for now */ > - lghi %r15, stackptr > sam64 > + /* 0x3000 is the stack page for now */ > + larl %r15, stackptr > brasl %r14, main > /* > * If main() returns, we stop the CPU with the code below. We also > @@ -37,6 +37,7 @@ exit: > xgr %r0, %r0 > sigp %r2, %r0, SIGP_STOP > > + .align 8 > initial_cr0: > /* enable AFP-register control, so FP regs (+BFP instr) can be used */ > .quad 0x0000000000040000
On 4/4/23 12:14, Thomas Huth wrote: > Clang complains: > > s390x/snippets/c/cstart.S:22:13: error: invalid operand for instruction > lghi %r15, stackptr > ^ > Let's load the address with "larl" instead, like we already do > it in s390x/cstart64.S. For this we should also switch to 64-bit > mode first, then we also don't have to clear r15 right in front > of this anymore. > > Changing the code here triggered another problem: initial_cr0 > must be aligned on a double-word boundary, otherwise the lctlg > instruction will fail with an specification exception. This was > just working by accident so far - add an ".align 8" now to avoid > the problem. > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > s390x/snippets/c/cstart.S | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/s390x/snippets/c/cstart.S b/s390x/snippets/c/cstart.S > index a7d4cd42..c80ccfed 100644 > --- a/s390x/snippets/c/cstart.S > +++ b/s390x/snippets/c/cstart.S > @@ -15,12 +15,12 @@ start: > larl %r1, initial_cr0 > lctlg %c0, %c0, 0(%r1) > /* XOR all registers with themselves to clear them fully. */ > - .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 > + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14 Eh, I would have left that in, it doesn't hurt us after all. Reviewed-by: Janosch Frank <frankja@linux.ibm.com> > xgr \i,\i > .endr > - /* 0x3000 is the stack page for now */ > - lghi %r15, stackptr > sam64 > + /* 0x3000 is the stack page for now */ > + larl %r15, stackptr > brasl %r14, main > /* > * If main() returns, we stop the CPU with the code below. We also > @@ -37,6 +37,7 @@ exit: > xgr %r0, %r0 > sigp %r2, %r0, SIGP_STOP > > + .align 8 > initial_cr0: > /* enable AFP-register control, so FP regs (+BFP instr) can be used */ > .quad 0x0000000000040000
Quoting Thomas Huth (2023-04-04 12:14:34) > Clang complains: > > s390x/snippets/c/cstart.S:22:13: error: invalid operand for instruction > lghi %r15, stackptr > ^ > Let's load the address with "larl" instead, like we already do > it in s390x/cstart64.S. For this we should also switch to 64-bit > mode first, then we also don't have to clear r15 right in front > of this anymore. > > Changing the code here triggered another problem: initial_cr0 > must be aligned on a double-word boundary, otherwise the lctlg > instruction will fail with an specification exception. This was > just working by accident so far - add an ".align 8" now to avoid > the problem. > > Signed-off-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
diff --git a/s390x/snippets/c/cstart.S b/s390x/snippets/c/cstart.S index a7d4cd42..c80ccfed 100644 --- a/s390x/snippets/c/cstart.S +++ b/s390x/snippets/c/cstart.S @@ -15,12 +15,12 @@ start: larl %r1, initial_cr0 lctlg %c0, %c0, 0(%r1) /* XOR all registers with themselves to clear them fully. */ - .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14 xgr \i,\i .endr - /* 0x3000 is the stack page for now */ - lghi %r15, stackptr sam64 + /* 0x3000 is the stack page for now */ + larl %r15, stackptr brasl %r14, main /* * If main() returns, we stop the CPU with the code below. We also @@ -37,6 +37,7 @@ exit: xgr %r0, %r0 sigp %r2, %r0, SIGP_STOP + .align 8 initial_cr0: /* enable AFP-register control, so FP regs (+BFP instr) can be used */ .quad 0x0000000000040000
Clang complains: s390x/snippets/c/cstart.S:22:13: error: invalid operand for instruction lghi %r15, stackptr ^ Let's load the address with "larl" instead, like we already do it in s390x/cstart64.S. For this we should also switch to 64-bit mode first, then we also don't have to clear r15 right in front of this anymore. Changing the code here triggered another problem: initial_cr0 must be aligned on a double-word boundary, otherwise the lctlg instruction will fail with an specification exception. This was just working by accident so far - add an ".align 8" now to avoid the problem. Signed-off-by: Thomas Huth <thuth@redhat.com> --- s390x/snippets/c/cstart.S | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)