LAM enabling is only allowed when the process has single thread.
LAM mode is inherited into child thread.
Trying to enable LAM after spawning a thread has to fail.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
tools/testing/selftests/x86/lam.c | 92 +++++++++++++++++++++++++++++++
1 file changed, 92 insertions(+)
diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c
index a8c91829b616..eb0e46905bf9 100644
--- a/tools/testing/selftests/x86/lam.c
+++ b/tools/testing/selftests/x86/lam.c
@@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -12,6 +13,7 @@
#include <sys/stat.h>
#include <fcntl.h>
#include <inttypes.h>
+#include <sched.h>
#include <sys/uio.h>
#include <linux/io_uring.h>
@@ -50,6 +52,8 @@
#define PAGE_SIZE (4 << 10)
+#define STACK_SIZE 65536
+
#define barrier() ({ \
__asm__ __volatile__("" : : : "memory"); \
})
@@ -731,6 +735,75 @@ static int handle_inheritance(struct testcases *test)
return 0;
}
+static int thread_fn_get_lam(void *arg)
+{
+ return get_lam();
+}
+
+static int thread_fn_set_lam(void *arg)
+{
+ struct testcases *test = arg;
+
+ return set_lam(test->lam);
+}
+
+static int handle_thread(struct testcases *test)
+{
+ char stack[STACK_SIZE];
+ int ret, child_ret;
+ int lam = 0;
+ pid_t pid;
+
+ /* Set LAM mode in parent process */
+ if (!test->later) {
+ lam = test->lam;
+ if (set_lam(lam) != 0)
+ return 1;
+ }
+
+ pid = clone(thread_fn_get_lam, stack + STACK_SIZE,
+ SIGCHLD | CLONE_FILES | CLONE_FS | CLONE_VM, NULL);
+ if (pid < 0) {
+ perror("Clone failed.");
+ return 1;
+ }
+
+ waitpid(pid, &child_ret, 0);
+ ret = WEXITSTATUS(child_ret);
+
+ if (lam != ret)
+ return 1;
+
+ if (test->later) {
+ if (set_lam(test->lam) != 0)
+ return 1;
+ }
+
+ return 0;
+}
+
+static int handle_thread_enable(struct testcases *test)
+{
+ char stack[STACK_SIZE];
+ int ret, child_ret;
+ int lam = test->lam;
+ pid_t pid;
+
+ pid = clone(thread_fn_set_lam, stack + STACK_SIZE,
+ SIGCHLD | CLONE_FILES | CLONE_FS | CLONE_VM, test);
+ if (pid < 0) {
+ perror("Clone failed.");
+ return 1;
+ }
+
+ waitpid(pid, &child_ret, 0);
+ ret = WEXITSTATUS(child_ret);
+
+ if (lam != ret)
+ return 1;
+
+ return 0;
+}
static void run_test(struct testcases *test, int count)
{
int i, ret = 0;
@@ -846,6 +919,25 @@ static struct testcases inheritance_cases[] = {
.test_func = handle_inheritance,
.msg = "FORK: LAM_U57, child process should get LAM mode same as parent\n",
},
+ {
+ .expected = 0,
+ .lam = LAM_U57_BITS,
+ .test_func = handle_thread,
+ .msg = "THREAD: LAM_U57, child thread should get LAM mode same as parent\n",
+ },
+ {
+ .expected = 1,
+ .lam = LAM_U57_BITS,
+ .test_func = handle_thread_enable,
+ .msg = "THREAD: [NEGATIVE] Enable LAM in child.\n",
+ },
+ {
+ .expected = 1,
+ .later = 1,
+ .lam = LAM_U57_BITS,
+ .test_func = handle_thread,
+ .msg = "THREAD: [NEGATIVE] Enable LAM in parent after thread created.\n",
+ },
{
.expected = 0,
.lam = LAM_U57_BITS,
--
2.39.1
