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authorVasily Gorbik <gor@linux.ibm.com>2019-11-22 18:22:06 +0100
committerVasily Gorbik <gor@linux.ibm.com>2019-11-30 10:52:47 +0100
commit7868249fbbc8125b82b83d99d33b23897ae7d9ab (patch)
tree1168e658e094e7ee81d017d0a477f38f4f5a72a4 /arch/s390/lib
parent4ac24c092b4eef69b2436ee4d478500dc886e8b5 (diff)
s390/test_unwind: add CALL_ON_STACK tests
Add CALL_ON_STACK helper testing. Tests make sure that we can unwind from switched stack to original one up to task pt_regs (nodat -> task stack). UWM_SWITCH_STACK could not be used together with UWM_THREAD because get_stack_info explicitly restricts unwinding to task stack if task != current. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/lib')
-rw-r--r--arch/s390/lib/test_unwind.c26
1 files changed, 19 insertions, 7 deletions
diff --git a/arch/s390/lib/test_unwind.c b/arch/s390/lib/test_unwind.c
index 2839f8cb691d..687a6922beda 100644
--- a/arch/s390/lib/test_unwind.c
+++ b/arch/s390/lib/test_unwind.c
@@ -43,7 +43,7 @@ static noinline int test_unwind(struct task_struct *task, struct pt_regs *regs,
int ret = 0;
char *bt;
- bt = kmalloc(BT_BUF_SIZE, GFP_KERNEL);
+ bt = kmalloc(BT_BUF_SIZE, GFP_ATOMIC);
if (!bt) {
pr_err("failed to allocate backtrace buffer\n");
return -ENOMEM;
@@ -98,11 +98,12 @@ struct unwindme {
};
/* Values of unwindme.flags. */
-#define UWM_DEFAULT 0x0
-#define UWM_THREAD 0x1 /* Unwind a separate task. */
-#define UWM_REGS 0x2 /* Pass regs to test_unwind(). */
-#define UWM_SP 0x4 /* Pass sp to test_unwind(). */
-#define UWM_CALLER 0x8 /* Unwind starting from caller. */
+#define UWM_DEFAULT 0x0
+#define UWM_THREAD 0x1 /* Unwind a separate task. */
+#define UWM_REGS 0x2 /* Pass regs to test_unwind(). */
+#define UWM_SP 0x4 /* Pass sp to test_unwind(). */
+#define UWM_CALLER 0x8 /* Unwind starting from caller. */
+#define UWM_SWITCH_STACK 0x10 /* Use CALL_ON_STACK. */
static __always_inline unsigned long get_psw_addr(void)
{
@@ -146,7 +147,16 @@ static noinline int unwindme_func3(struct unwindme *u)
/* This function must appear in the backtrace. */
static noinline int unwindme_func2(struct unwindme *u)
{
- return unwindme_func3(u);
+ int rc;
+
+ if (u->flags & UWM_SWITCH_STACK) {
+ preempt_disable();
+ rc = CALL_ON_STACK(unwindme_func3, S390_lowcore.nodat_stack, 1, u);
+ preempt_enable();
+ return rc;
+ } else {
+ return unwindme_func3(u);
+ }
}
/* This function must follow unwindme_func2 in the backtrace. */
@@ -215,9 +225,11 @@ do { \
TEST(UWM_DEFAULT);
TEST(UWM_SP);
TEST(UWM_REGS);
+ TEST(UWM_SWITCH_STACK);
TEST(UWM_SP | UWM_REGS);
TEST(UWM_CALLER | UWM_SP);
TEST(UWM_CALLER | UWM_SP | UWM_REGS);
+ TEST(UWM_CALLER | UWM_SP | UWM_REGS | UWM_SWITCH_STACK);
TEST(UWM_THREAD);
TEST(UWM_THREAD | UWM_SP);
TEST(UWM_THREAD | UWM_CALLER | UWM_SP);