samples: add s390 support for ftrace direct call samples

Add s390 support for ftrace direct call samples, which also enables
ftrace direct call selftests within ftrace selftests.
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20211012133802.2460757-5-hca@linux.ibm.comSigned-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/Kconfig

@@ -193,6 +193,7 @@ config S390
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
+	select HAVE_SAMPLE_FTRACE_DIRECT
 	select HAVE_SOFTIRQ_ON_OWN_STACK
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_VIRT_CPU_ACCOUNTING

samples/ftrace/ftrace-direct-modify.c

@@ -2,6 +2,7 @@
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/ftrace.h>
+#include <asm/asm-offsets.h>
 
 void my_direct_func1(void)
 {
@@ -18,6 +19,8 @@ extern void my_tramp2(void *);
 
 static unsigned long my_ip = (unsigned long)schedule;
 
+#ifdef CONFIG_X86_64
+
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"
 "	.type		my_tramp1, @function\n"
@@ -41,6 +44,47 @@ asm (
 "	.popsection\n"
 );
 
+#endif /* CONFIG_X86_64 */
+
+#ifdef CONFIG_S390
+
+asm (
+"	.pushsection	.text, \"ax\", @progbits\n"
+"	.type		my_tramp1, @function\n"
+"	.globl		my_tramp1\n"
+"   my_tramp1:"
+"	lgr		%r1,%r15\n"
+"	stmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
+"	stg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
+"	aghi		%r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
+"	stg		%r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
+"	brasl		%r14,my_direct_func1\n"
+"	aghi		%r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
+"	lmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
+"	lg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
+"	lgr		%r1,%r0\n"
+"	br		%r1\n"
+"	.size		my_tramp1, .-my_tramp1\n"
+"	.type		my_tramp2, @function\n"
+"	.globl		my_tramp2\n"
+"   my_tramp2:"
+"	lgr		%r1,%r15\n"
+"	stmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
+"	stg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
+"	aghi		%r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
+"	stg		%r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
+"	brasl		%r14,my_direct_func2\n"
+"	aghi		%r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
+"	lmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
+"	lg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
+"	lgr		%r1,%r0\n"
+"	br		%r1\n"
+"	.size		my_tramp2, .-my_tramp2\n"
+"	.popsection\n"
+);
+
+#endif /* CONFIG_S390 */
+
 static unsigned long my_tramp = (unsigned long)my_tramp1;
 static unsigned long tramps[2] = {
 	(unsigned long)my_tramp1,

samples/ftrace/ftrace-direct-too.c

@@ -3,6 +3,7 @@
 
 #include <linux/mm.h> /* for handle_mm_fault() */
 #include <linux/ftrace.h>
+#include <asm/asm-offsets.h>
 
 void my_direct_func(struct vm_area_struct *vma,
 			unsigned long address, unsigned int flags)
@@ -13,6 +14,8 @@ void my_direct_func(struct vm_area_struct *vma,
 
 extern void my_tramp(void *);
 
+#ifdef CONFIG_X86_64
+
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"
 "	.type		my_tramp, @function\n"
@@ -33,6 +36,31 @@ asm (
 "	.popsection\n"
 );
 
+#endif /* CONFIG_X86_64 */
+
+#ifdef CONFIG_S390
+
+asm (
+"	.pushsection	.text, \"ax\", @progbits\n"
+"	.type		my_tramp, @function\n"
+"	.globl		my_tramp\n"
+"   my_tramp:"
+"	lgr		%r1,%r15\n"
+"	stmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
+"	stg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
+"	aghi		%r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
+"	stg		%r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
+"	brasl		%r14,my_direct_func\n"
+"	aghi		%r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
+"	lmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
+"	lg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
+"	lgr		%r1,%r0\n"
+"	br		%r1\n"
+"	.size		my_tramp, .-my_tramp\n"
+"	.popsection\n"
+);
+
+#endif /* CONFIG_S390 */
 
 static int __init ftrace_direct_init(void)
 {

samples/ftrace/ftrace-direct.c

@@ -3,6 +3,7 @@
 
 #include <linux/sched.h> /* for wake_up_process() */
 #include <linux/ftrace.h>
+#include <asm/asm-offsets.h>
 
 void my_direct_func(struct task_struct *p)
 {
@@ -11,6 +12,8 @@ void my_direct_func(struct task_struct *p)
 
 extern void my_tramp(void *);
 
+#ifdef CONFIG_X86_64
+
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"
 "	.type		my_tramp, @function\n"
@@ -27,6 +30,31 @@ asm (
 "	.popsection\n"
 );
 
+#endif /* CONFIG_X86_64 */
+
+#ifdef CONFIG_S390
+
+asm (
+"	.pushsection	.text, \"ax\", @progbits\n"
+"	.type		my_tramp, @function\n"
+"	.globl		my_tramp\n"
+"   my_tramp:"
+"	lgr		%r1,%r15\n"
+"	stmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
+"	stg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
+"	aghi		%r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
+"	stg		%r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
+"	brasl		%r14,my_direct_func\n"
+"	aghi		%r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
+"	lmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
+"	lg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
+"	lgr		%r1,%r0\n"
+"	br		%r1\n"
+"	.size		my_tramp, .-my_tramp\n"
+"	.popsection\n"
+);
+
+#endif /* CONFIG_S390 */
 
 static int __init ftrace_direct_init(void)
 {