[PATCH for_v23 13/16] selftests/x86/sgx: Add a test of the vDSO exception reporting mechanism

[Sean Christopherson <sean.j.christopherson@intel.com>]

Add a sub-test to verify that an exception on EENTER is correctly
reported.  Although the type of exception doesn't truly matter, e.g. a
page fault (#PF) is no more or less interesting than a general protection
fault (#GP), use an unaligned TCS to trigger a #GP to avoid errors on
platforms that report EPCM related #PFs as #GPs, e.g. SGX1 systems.

Suggested-by: Cedric Xing <cedric.xing@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 tools/testing/selftests/x86/sgx/defines.h | 4 ++++
 tools/testing/selftests/x86/sgx/main.c    | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/tools/testing/selftests/x86/sgx/defines.h b/tools/testing/selftests/x86/sgx/defines.h
index 3ff73a9d9b93..ab9671b8a993 100644
--- a/tools/testing/selftests/x86/sgx/defines.h
+++ b/tools/testing/selftests/x86/sgx/defines.h
@@ -36,4 +36,8 @@ typedef uint64_t u64;
 #include "../../../../../arch/x86/kernel/cpu/sgx/arch.h"
 #include "../../../../../arch/x86/include/uapi/asm/sgx.h"
 
+#define ENCLU_EENTER	2
+
+#define GP_VECTOR 13
+
 #endif /* TYPES_H */
diff --git a/tools/testing/selftests/x86/sgx/main.c b/tools/testing/selftests/x86/sgx/main.c
index 93b8d7781782..2676570493f2 100644
--- a/tools/testing/selftests/x86/sgx/main.c
+++ b/tools/testing/selftests/x86/sgx/main.c
@@ -321,6 +321,12 @@ static void test_vdso_no_exit_handler(struct sgx_secs *secs)
 	sgx_call((void *)&MAGIC, &result, 0, 0, 0, 0, (void *)secs->base,
 		 &exception, NULL);
 	ASSERT_EQ(result, MAGIC);
+
+	/* Verify a #GP is reported if the TCS isn't 4k aligned. */
+	sgx_call((void *)&MAGIC, &result, 0, 0, 0, 0,
+		 (void *)(secs->base | 0xfff), &exception, NULL);
+	ASSERT_EQ(exception.trapnr, GP_VECTOR);
+	ASSERT_EQ(exception.leaf, ENCLU_EENTER);
 }
 
 int main(int argc, char *argv[], char *envp[])
-- 
2.22.0