On Tue, 4 Apr 2023 12:14:34 +0200 Thomas Huth <thuth@xxxxxxxxxx> 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@xxxxxxxxxx> Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> > --- > 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
