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

[Nico Boehr <nrb@linux.ibm.com>]

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