On 2020-04-22 09:47, Janosch Frank wrote:
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.
OK, thanks
Regards,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
