[PATCH 4/4] samples: add s390 support for ftrace direct call samples

Heiko Carstens
2021-10-12T13:39:10Z

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>
---
arch/s390/Kconfig | 1 +
samples/ftrace/ftrace-direct-modify.c | 44 +++++++++++++++++++++++++++
samples/ftrace/ftrace-direct-too.c | 28 +++++++++++++++++
samples/ftrace/ftrace-direct.c | 28 +++++++++++++++++
4 files changed, 101 insertions(+)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 908da6f1aa0d..f615c3f65f5a 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -192,6 +192,7 @@ 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
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index 5b9a09957c6e..690e4a9ff333 100644
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/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,
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index 3f0079c9bd6f..6e0de725bf22 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/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)
{
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index a2729d1ef17f..a30aa42ec76a 100644
--- a/samples/ftrace/ftrace-direct.c
+++ b/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)
{
--
2.25.1