diff options
Diffstat (limited to 'tools/testing/selftests/kvm/rseq_test.c')
| -rw-r--r-- | tools/testing/selftests/kvm/rseq_test.c | 58 |
1 files changed, 28 insertions, 30 deletions
diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c index a54d4d05a058..fac248a43666 100644 --- a/tools/testing/selftests/kvm/rseq_test.c +++ b/tools/testing/selftests/kvm/rseq_test.c @@ -20,15 +20,7 @@ #include "processor.h" #include "test_util.h" -static __thread volatile struct rseq __rseq = { - .cpu_id = RSEQ_CPU_ID_UNINITIALIZED, -}; - -/* - * Use an arbitrary, bogus signature for configuring rseq, this test does not - * actually enter an rseq critical section. - */ -#define RSEQ_SIG 0xdeadbeef +#include "../rseq/rseq.c" /* * Any bug related to task migration is likely to be timing-dependent; perform @@ -49,12 +41,16 @@ static void guest_code(void) GUEST_SYNC(0); } -static void sys_rseq(int flags) +/* + * We have to perform direct system call for getcpu() because it's + * not available until glic 2.29. + */ +static void sys_getcpu(unsigned *cpu) { int r; - r = syscall(__NR_rseq, &__rseq, sizeof(__rseq), flags, RSEQ_SIG); - TEST_ASSERT(!r, "rseq failed, errno = %d (%s)", errno, strerror(errno)); + r = syscall(__NR_getcpu, cpu, NULL, NULL); + TEST_ASSERT(!r, "getcpu failed, errno = %d (%s)", errno, strerror(errno)); } static int next_cpu(int cpu) @@ -101,7 +97,7 @@ static void *migration_worker(void *__rseq_tid) atomic_inc(&seq_cnt); /* - * Ensure the odd count is visible while sched_getcpu() isn't + * Ensure the odd count is visible while getcpu() isn't * stable, i.e. while changing affinity is in-progress. */ smp_wmb(); @@ -142,10 +138,10 @@ static void *migration_worker(void *__rseq_tid) * check completes. * * 3. To ensure the read-side makes efficient forward progress, - * e.g. if sched_getcpu() involves a syscall. Stalling the - * read-side means the test will spend more time waiting for - * sched_getcpu() to stabilize and less time trying to hit - * the timing-dependent bug. + * e.g. if getcpu() involves a syscall. Stalling the read-side + * means the test will spend more time waiting for getcpu() + * to stabilize and less time trying to hit the timing-dependent + * bug. * * Because any bug in this area is likely to be timing-dependent, * run with a range of delays at 1us intervals from 1us to 10us @@ -218,7 +214,9 @@ int main(int argc, char *argv[]) calc_min_max_cpu(); - sys_rseq(0); + r = rseq_register_current_thread(); + TEST_ASSERT(!r, "rseq_register_current_thread failed, errno = %d (%s)", + errno, strerror(errno)); /* * Create and run a dummy VM that immediately exits to userspace via @@ -238,9 +236,9 @@ int main(int argc, char *argv[]) /* * Verify rseq's CPU matches sched's CPU. Ensure migration - * doesn't occur between sched_getcpu() and reading the rseq - * cpu_id by rereading both if the sequence count changes, or - * if the count is odd (migration in-progress). + * doesn't occur between getcpu() and reading the rseq cpu_id + * by rereading both if the sequence count changes, or if the + * count is odd (migration in-progress). */ do { /* @@ -250,13 +248,13 @@ int main(int argc, char *argv[]) snapshot = atomic_read(&seq_cnt) & ~1; /* - * Ensure reading sched_getcpu() and rseq.cpu_id - * complete in a single "no migration" window, i.e. are - * not reordered across the seq_cnt reads. + * Ensure calling getcpu() and reading rseq.cpu_id complete + * in a single "no migration" window, i.e. are not reordered + * across the seq_cnt reads. */ smp_rmb(); - cpu = sched_getcpu(); - rseq_cpu = READ_ONCE(__rseq.cpu_id); + sys_getcpu(&cpu); + rseq_cpu = rseq_current_cpu_raw(); smp_rmb(); } while (snapshot != atomic_read(&seq_cnt)); @@ -267,9 +265,9 @@ int main(int argc, char *argv[]) /* * Sanity check that the test was able to enter the guest a reasonable * number of times, e.g. didn't get stalled too often/long waiting for - * sched_getcpu() to stabilize. A 2:1 migration:KVM_RUN ratio is a - * fairly conservative ratio on x86-64, which can do _more_ KVM_RUNs - * than migrations given the 1us+ delay in the migration task. + * getcpu() to stabilize. A 2:1 migration:KVM_RUN ratio is a fairly + * conservative ratio on x86-64, which can do _more_ KVM_RUNs than + * migrations given the 1us+ delay in the migration task. */ TEST_ASSERT(i > (NR_TASK_MIGRATIONS / 2), "Only performed %d KVM_RUNs, task stalled too much?\n", i); @@ -278,7 +276,7 @@ int main(int argc, char *argv[]) kvm_vm_free(vm); - sys_rseq(RSEQ_FLAG_UNREGISTER); + rseq_unregister_current_thread(); return 0; } |