Re: [kvm-unit-tests PATCH v4 1/9] s390x: saving regs for interrupts

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On 2019-12-12 10:24, Janosch Frank wrote:
On 12/11/19 4:46 PM, Pierre Morel wrote:
If we use multiple source of interrupts, for exemple, using SCLP

s/exemple/example/

OK, thanks


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 | 25 +++++++++++++++++++++++--
  1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/s390x/cstart64.S b/s390x/cstart64.S
index 86dd4c4..ff05f9b 100644
--- a/s390x/cstart64.S
+++ b/s390x/cstart64.S
@@ -118,6 +118,25 @@ memsetxc:
  	lmg	%r0, %r15, GEN_LC_SW_INT_GRS
  	.endm
+	.macro SAVE_IRQ_REGS

Maybe add comments to the start of the macros like:
"Save registers on the stack, so we can have stacked interrupts."

OK.


+	slgfi   %r15, 15 * 8
+	stmg    %r0, %r14, 0(%r15)
+	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
+	lgr     %r2, %r15

What's that doing?

Passing a parameter to the saved registers to the handler.
makes me think that since I reworked the interrupt handler to add registration the parameter disappeared...

I will remove this line and come back with a new series at the time we need to access the registers.


+	.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:
@@ -154,6 +173,8 @@ diag308_load_reset:
  	lpswe	GEN_LC_SW_INT_PSW
  1:	br	%r14
+
+

Still not fixed

sorry I did not see this

Thanks for review,
Regards,
Pierre


--
Pierre Morel
IBM Lab Boeblingen




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