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Subject[PATCH RFC PKS/PMEM 02/58] x86/pks/test: Add testing for global option
Date
From: Ira Weiny <ira.weiny@intel.com>

Now that PKS can be enabled globaly (for all threads) add a test which
spawns a thread and tests the same PKS functionality.

The test enables/disables PKS in 1 thread while attempting to access the
page in another thread. We use the same test array as in the 'local'
PKS testing.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
arch/x86/mm/fault.c | 4 ++
lib/pks/pks_test.c | 128 +++++++++++++++++++++++++++++++++++++++++---
2 files changed, 124 insertions(+), 8 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 4b4ff9efa298..4c74f52fbc23 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1108,6 +1108,10 @@ static int spurious_kernel_fault_check(unsigned long error_code, pte_t *pte,
if (global_pkey_is_enabled(pte, is_write, irq_state))
return 1;

+ /*
+ * NOTE: This must be after the global_pkey_is_enabled() call
+ * to allow the fixup code to be tested.
+ */
if (handle_pks_testing(error_code, irq_state))
return 1;

diff --git a/lib/pks/pks_test.c b/lib/pks/pks_test.c
index 286c8b8457da..dfddccbe4cb6 100644
--- a/lib/pks/pks_test.c
+++ b/lib/pks/pks_test.c
@@ -154,7 +154,8 @@ static void check_exception(irqentry_state_t *irq_state)
}

/* Check the exception state */
- if (!check_pkrs(test_armed_key, PKEY_DISABLE_ACCESS)) {
+ if (!check_pkrs(test_armed_key,
+ PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE)) {
pr_err(" FAIL: PKRS cache and MSR\n");
test_exception_ctx->pass = false;
}
@@ -308,24 +309,29 @@ static int test_it(struct pks_test_ctx *ctx, struct pks_access_test *test, void
return ret;
}

-static int run_access_test(struct pks_test_ctx *ctx,
- struct pks_access_test *test,
- void *ptr)
+static void set_protection(int pkey, enum pks_access_mode mode, bool global)
{
- switch (test->mode) {
+ switch (mode) {
case PKS_TEST_NO_ACCESS:
- pks_mknoaccess(ctx->pkey, false);
+ pks_mknoaccess(pkey, global);
break;
case PKS_TEST_RDWR:
- pks_mkrdwr(ctx->pkey, false);
+ pks_mkrdwr(pkey, global);
break;
case PKS_TEST_RDONLY:
- pks_mkread(ctx->pkey, false);
+ pks_mkread(pkey, global);
break;
default:
pr_err("BUG in test invalid mode\n");
break;
}
+}
+
+static int run_access_test(struct pks_test_ctx *ctx,
+ struct pks_access_test *test,
+ void *ptr)
+{
+ set_protection(ctx->pkey, test->mode, false);

return test_it(ctx, test, ptr);
}
@@ -516,6 +522,110 @@ static void run_exception_test(void)
pass ? "PASS" : "FAIL");
}

+struct shared_data {
+ struct mutex lock;
+ struct pks_test_ctx *ctx;
+ void *kmap_addr;
+ struct pks_access_test *test;
+};
+
+static int thread_main(void *d)
+{
+ struct shared_data *data = d;
+ struct pks_test_ctx *ctx = data->ctx;
+
+ while (!kthread_should_stop()) {
+ mutex_lock(&data->lock);
+ /*
+ * wait for the main thread to hand us the page
+ * We should be spinning so hopefully we will not have gotten
+ * the global value from a schedule in.
+ */
+ if (data->kmap_addr) {
+ if (test_it(ctx, data->test, data->kmap_addr))
+ ctx->pass = false;
+ data->kmap_addr = NULL;
+ }
+ mutex_unlock(&data->lock);
+ }
+
+ return 0;
+}
+
+static void run_thread_access_test(struct shared_data *data,
+ struct pks_test_ctx *ctx,
+ struct pks_access_test *test,
+ void *ptr)
+{
+ set_protection(ctx->pkey, test->mode, true);
+
+ pr_info("checking... mode %s; write %s\n",
+ get_mode_str(test->mode), test->write ? "TRUE" : "FALSE");
+
+ mutex_lock(&data->lock);
+ data->test = test;
+ data->kmap_addr = ptr;
+ mutex_unlock(&data->lock);
+
+ while (data->kmap_addr) {
+ msleep(10);
+ }
+}
+
+static void run_global_test(void)
+{
+ struct task_struct *other_task;
+ struct pks_test_ctx *ctx;
+ struct shared_data data;
+ bool pass = true;
+ void *ptr;
+ int i;
+
+ pr_info(" ***** BEGIN: global pkey checking\n");
+
+ /* Set up context, data pgae, and thread */
+ ctx = alloc_ctx("global pkey test");
+ if (IS_ERR(ctx)) {
+ pr_err(" FAIL: no context\n");
+ pass = false;
+ goto result;
+ }
+ ptr = alloc_test_page(ctx->pkey);
+ if (!ptr) {
+ pr_err(" FAIL: no vmalloc page\n");
+ pass = false;
+ goto free_context;
+ }
+ other_task = kthread_run(thread_main, &data, "PKRS global test");
+ if (IS_ERR(other_task)) {
+ pr_err(" FAIL: Failed to start thread\n");
+ pass = false;
+ goto free_page;
+ }
+
+ memset(&data, 0, sizeof(data));
+ mutex_init(&data.lock);
+ data.ctx = ctx;
+
+ /* Start testing */
+ ctx->pass = true;
+
+ for (i = 0; i < ARRAY_SIZE(pkey_test_ary); i++) {
+ run_thread_access_test(&data, ctx, &pkey_test_ary[i], ptr);
+ }
+
+ kthread_stop(other_task);
+ pass = ctx->pass;
+
+free_page:
+ vfree(ptr);
+free_context:
+ free_ctx(ctx);
+result:
+ pr_info(" ***** END: global pkey checking : %s\n",
+ pass ? "PASS" : "FAIL");
+}
+
static void run_all(void)
{
struct pks_test_ctx *ctx[PKS_NUM_KEYS];
@@ -538,6 +648,8 @@ static void run_all(void)
}

run_exception_test();
+
+ run_global_test();
}

static void crash_it(void)
--
2.28.0.rc0.12.gb6a658bd00c9
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