On 2/20/20 1:00 PM, Pierre Morel wrote: > If we use multiple source of interrupts, for example, using SCLP > console to print information while using I/O interrupts, we need > to have a re-entrant register saving interruption handling. > > Instead of saving at a static memory address, let's save the base > registers and the floating point registers on the stack. > > Note that we keep the static register saving to recover from the > RESET tests. > > Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx> > --- > s390x/cstart64.S | 23 +++++++++++++++++++++-- > 1 file changed, 21 insertions(+), 2 deletions(-) > > diff --git a/s390x/cstart64.S b/s390x/cstart64.S > index 9af6bb3..45da523 100644 > --- a/s390x/cstart64.S > +++ b/s390x/cstart64.S > @@ -118,6 +118,25 @@ memsetxc: > lmg %r0, %r15, GEN_LC_SW_INT_GRS > .endm > > +/* Save registers on the stack, so we can have stacked interrupts. */ > + .macro SAVE_IRQ_REGS > + slgfi %r15, 15 * 8 > + stmg %r0, %r14, 0(%r15) So this is just making some space on the stack and storing r0 - r14, right? Same is done for the floating point registers below. Could you add a comment above slgfi and stmg and explain what they do? A few words are enough. > + slgfi %r15, 16 * 8 > + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 > + std \i, \i * 8(%r15) > + .endr > + .endm > + > + .macro RESTORE_IRQ_REGS > + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 > + ld \i, \i * 8(%r15) > + .endr > + algfi %r15, 16 * 8 > + lmg %r0, %r14, 0(%r15) > + algfi %r15, 15 * 8 > + .endm > + > .section .text > /* > * load_reset calling convention: > @@ -182,9 +201,9 @@ mcck_int: > lpswe GEN_LC_MCCK_OLD_PSW > > io_int: > - SAVE_REGS > + SAVE_IRQ_REGS > brasl %r14, handle_io_int > - RESTORE_REGS > + RESTORE_IRQ_REGS > lpswe GEN_LC_IO_OLD_PSW > > svc_int: >
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