On 2020-04-27 10:59, David Hildenbrand wrote:
On 24.04.20 12:45, 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.
So the primary reason is to print during I/O interrupts (which we
already do, but usually never trigger - handle_io_int())
Instead of saving at a static memory address, let's save the base
registers and the floating point registers on the stack.
".. in case of I/O interrupts".
OK
Note that we keep the static register saving to recover from the
RESET tests.
and for all other types of interrupts.
OK
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
s390x/cstart64.S | 34 ++++++++++++++++++++++++++++++++--
1 file changed, 32 insertions(+), 2 deletions(-)
diff --git a/s390x/cstart64.S b/s390x/cstart64.S
index 9af6bb3..ba2e67c 100644
--- a/s390x/cstart64.S
+++ b/s390x/cstart64.S
@@ -118,6 +118,36 @@ memsetxc:
lmg %r0, %r15, GEN_LC_SW_INT_GRS
.endm
+/* Save registers on the stack (r15), so we can have stacked interrupts. */
+ .macro SAVE_IRQ_REGS
s/SAVE_IRQ_REGS/SAVE_REGS_STACK/ ?
Same for the other macro.
OK
+ /* Allocate a stack frame for 15 integer registers */
not integers. sizeof(int) == 4.
hum, yes, I just do not know from where I took the word "integer" here!.
"doublewords" should be the right s390x speak.
in fact they are named general registers in the POP.
(which indeed are doublewords :) )
+ slgfi %r15, 15 * 8
+ /* Store all registers from r0 to r14 on the stack */
+ stmg %r0, %r14, 0(%r15)
+ /* Allocate a stack frame for 16 floating point registers */
+ /* The size of a FP register is the size of an integer */
+ slgfi %r15, 16 * 8
+ /* Save fp register on stack: offset to SP is multiple of reg number */
+ .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
What about the FPC?
Seems I forgot it.
I will update.
Thanks.
Regards,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
