Hi Florian,
On 8/9/22 4:33 PM, Florian Weimer wrote:
diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
index a54d4d05a058..acb1bf1f06b3 100644
--- a/tools/testing/selftests/kvm/rseq_test.c
+++ b/tools/testing/selftests/kvm/rseq_test.c
@@ -9,6 +9,7 @@
#include <string.h>
#include <signal.h>
#include <syscall.h>
+#include <dlfcn.h>
#include <sys/ioctl.h>
#include <sys/sysinfo.h>
#include <asm/barrier.h>
I'm surprised that there isn't a Makefile update to link with -ldl
(still required for glibc 2.33 and earlier).
In next revision, I will add '-ldl' into tools/testing/selftests/kvm/Makefile.
@@ -36,6 +37,8 @@ static __thread volatile struct rseq __rseq = {
*/
#define NR_TASK_MIGRATIONS 100000
+static bool __rseq_ownership;
+static volatile struct rseq *__rseq_info;
static pthread_t migration_thread;
static cpu_set_t possible_mask;
static int min_cpu, max_cpu;
@@ -49,11 +52,33 @@ static void guest_code(void)
GUEST_SYNC(0);
}
+static void sys_rseq_ownership(void)
+{
+ long *offset;
+ unsigned int *size, *flags;
+
+ offset = dlsym(RTLD_NEXT, "__rseq_offset");
+ size = dlsym(RTLD_NEXT, "__rseq_size");
+ flags = dlsym(RTLD_NEXT, "__rseq_flags");
+
+ if (offset && size && *size && flags) {
+ __rseq_ownership = false;
+ __rseq_info = (struct rseq *)((uintptr_t)__builtin_thread_pointer() +
+ *offset);
__builtin_thread_pointer doesn't work on all architectures/GCC versions.
Is this a problem for selftests?
It's a problem as the test case is running on all architectures. I think I
need introduce our own __builtin_thread_pointer() for where it's not
supported: (1) PowerPC (2) x86 without GCC 11
Please let me know if I still have missed cases where __buitin_thread_pointer()
isn't supported?
Thanks,
Gavin
