[kvm-unit-tests GIT PULL v2 06/14] s390x: define a macro for the stack frame size

Nico Boehr
2023-04-04T11:37:17Z

From: Marc Hartmayer <mhartmay@linux.ibm.com>

Define and use a macro for the stack frame size. While at it, fix
whitespace in the `gs_handler_asm` block.

Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Co-developed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20230307091051.13945-7-mhartmay@linux.ibm.com
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
s390x/Makefile | 2 +-
lib/s390x/asm-offsets.c | 1 +
s390x/cstart64.S | 2 +-
s390x/flat.lds.S | 4 +++-
s390x/macros.S | 4 ++--
s390x/snippets/c/flat.lds.S | 6 ++++--
s390x/gs.c | 38 +++++++++++++++++++++----------------
7 files changed, 34 insertions(+), 23 deletions(-)

diff --git a/s390x/Makefile b/s390x/Makefile
index 6732b48..ab146eb 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -162,7 +162,7 @@ $(SNIPPET_DIR)/c/%.gbin: $(SNIPPET_DIR)/c/%.o $(snippet_lib) $(FLATLIBS) $(SNIPP
$(OBJCOPY) -I binary -O elf64-s390 -B "s390:64-bit" $< $@

lds-autodepend-flags = -MMD -MF $(dir $*).$(notdir $*).d -MT $@
-%.lds: %.lds.S
+%.lds: %.lds.S $(asm-offsets)
$(CPP) $(lds-autodepend-flags) $(CPPFLAGS) -P -C -o $@ $<

.SECONDEXPANSION:
diff --git a/lib/s390x/asm-offsets.c b/lib/s390x/asm-offsets.c
index f612f32..188dd2e 100644
--- a/lib/s390x/asm-offsets.c
+++ b/lib/s390x/asm-offsets.c
@@ -87,6 +87,7 @@ int main(void)
OFFSET(STACK_FRAME_INT_GRS0, stack_frame_int, grs0);
OFFSET(STACK_FRAME_INT_GRS1, stack_frame_int, grs1);
DEFINE(STACK_FRAME_INT_SIZE, sizeof(struct stack_frame_int));
+ DEFINE(STACK_FRAME_SIZE, sizeof(struct stack_frame));

return 0;
}
diff --git a/s390x/cstart64.S b/s390x/cstart64.S
index 6f83da2..468ace3 100644
--- a/s390x/cstart64.S
+++ b/s390x/cstart64.S
@@ -38,7 +38,7 @@ start:
/* setup stack */
larl %r15, stackptr
/* Clear first stack frame */
- xc 0(160,%r15), 0(%r15)
+ xc 0(STACK_FRAME_SIZE,%r15), 0(%r15)
/* setup initial PSW mask + control registers*/
larl %r1, initial_psw
lpswe 0(%r1)
diff --git a/s390x/flat.lds.S b/s390x/flat.lds.S
index 952f6cd..0cb7e38 100644
--- a/s390x/flat.lds.S
+++ b/s390x/flat.lds.S
@@ -1,3 +1,5 @@
+#include <asm/asm-offsets.h>
+
SECTIONS
{
.lowcore : {
@@ -44,6 +46,6 @@ SECTIONS
/*
* stackptr set with initial stack frame preallocated
*/
- stackptr = . - 160;
+ stackptr = . - STACK_FRAME_SIZE;
stacktop = .;
}
diff --git a/s390x/macros.S b/s390x/macros.S
index 13cff29..e2a56a3 100644
--- a/s390x/macros.S
+++ b/s390x/macros.S
@@ -21,14 +21,14 @@
/* Save the stack address in GR2 which is the first function argument */
lgr %r2, %r15
/* Allocate stack space for called C function, as specified in s390 ELF ABI */
- slgfi %r15, 160
+ slgfi %r15, STACK_FRAME_SIZE
/*
* Save the address of the interrupt stack into the back chain
* of the called function.
*/
stg %r2, STACK_FRAME_INT_BACKCHAIN(%r15)
brasl %r14, \c_func
- algfi %r15, 160
+ algfi %r15, STACK_FRAME_SIZE
RESTORE_REGS_STACK
lpswe \old_psw
.endm
diff --git a/s390x/snippets/c/flat.lds.S b/s390x/snippets/c/flat.lds.S
index 9e5eb66..468b5f1 100644
--- a/s390x/snippets/c/flat.lds.S
+++ b/s390x/snippets/c/flat.lds.S
@@ -1,3 +1,5 @@
+#include <asm/asm-offsets.h>
+
SECTIONS
{
.lowcore : {
@@ -18,9 +20,9 @@ SECTIONS
. = 0x4000;
/*
* The stack grows down from 0x4000 to 0x2000, we pre-allocoate
- * a frame via the -160.
+ * a frame via the -STACK_FRAME_SIZE.
*/
- stackptr = . - 160;
+ stackptr = . - STACK_FRAME_SIZE;
stacktop = .;
/* Start text 0x4000 */
.text : {
diff --git a/s390x/gs.c b/s390x/gs.c
index 4993eb8..9ae893e 100644
--- a/s390x/gs.c
+++ b/s390x/gs.c
@@ -9,6 +9,7 @@
* Janosch Frank <frankja@linux.ibm.com>
*/
#include <libcflat.h>
+#include <asm/asm-offsets.h>
#include <asm/page.h>
#include <asm/facility.h>
#include <asm/interrupt.h>
@@ -35,22 +36,27 @@ static inline unsigned long load_guarded(unsigned long *p)

/* guarded-storage event handler and finally it calls gs_handler */
extern void gs_handler_asm(void);
- asm(".globl gs_handler_asm\n"
- "gs_handler_asm:\n"
- " lgr %r14,%r15\n" /* Save current stack address in r14 */
- " aghi %r15,-320\n" /* Allocate stack frame */
- " stmg %r0,%r13,192(%r15)\n" /* Store regs to save area */
- " stg %r14,312(%r15)\n"
- " la %r2,160(%r15)\n" /* Store gscb address in this_cb */
- " .insn rxy,0xe30000000049,0,160(%r15)\n" /* stgsc */
- " lg %r14,24(%r2)\n" /* Get GSEPLA from GSCB*/
- " lg %r14,40(%r14)\n" /* Get GSERA from GSEPL*/
- " stg %r14,304(%r15)\n" /* Store GSERA in r14 of reg save area */
- " brasl %r14,gs_handler\n" /* Jump to gs_handler */
- " lmg %r0,%r15,192(%r15)\n" /* Restore regs */
- " aghi %r14, 6\n" /* Add lgg instr len to GSERA */
- " br %r14\n" /* Jump to next instruction after lgg */
- " .size gs_handler_asm,.-gs_handler_asm\n");
+ asm ( ".macro STGSC args:vararg\n"
+ " .insn rxy,0xe30000000049,\\args\n"
+ " .endm\n"
+ " .globl gs_handler_asm\n"
+ "gs_handler_asm:\n"
+ " lgr %r14,%r15\n" /* Save current stack address in r14 */
+ ".Lgs_handler_frame = 16*8+32+" xstr(STACK_FRAME_SIZE) "\n"
+ " aghi %r15,-(.Lgs_handler_frame)\n" /* Allocate stack frame */
+ " stmg %r0,%r13,192(%r15)\n" /* Store regs to save area */
+ " stg %r14,312(%r15)\n"
+ " la %r2," xstr(STACK_FRAME_SIZE) "(%r15)\n" /* Store gscb address in this_cb */
+ " STGSC %r0," xstr(STACK_FRAME_SIZE) "(%r15)\n"
+ " lg %r14,24(%r2)\n" /* Get GSEPLA from GSCB*/
+ " lg %r14,40(%r14)\n" /* Get GSERA from GSEPL*/
+ " stg %r14,304(%r15)\n" /* Store GSERA in r14 of reg save area */
+ " brasl %r14,gs_handler\n" /* Jump to gs_handler */
+ " lmg %r0,%r15,192(%r15)\n" /* Restore regs */
+ " aghi %r14, 6\n" /* Add lgg instr len to GSERA */
+ " br %r14\n" /* Jump to next instruction after lgg */
+ ".size gs_handler_asm,.-gs_handler_asm\n"
+ );

void gs_handler(struct gs_cb *this_cb)
{
--
2.39.2