efi_selftest: check executing in EL2
UEFI binaries should be executed in EL2 or EL1 even if U-Boot is started
in EL3. Provide a unit test.
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/lib/efi_selftest/Makefile b/lib/efi_selftest/Makefile
index 17fbfad..d78bf7d 100644
--- a/lib/efi_selftest/Makefile
+++ b/lib/efi_selftest/Makefile
@@ -51,6 +51,7 @@
efi_selftest_watchdog.o
obj-$(CONFIG_EFI_ECPT) += efi_selftest_ecpt.o
+obj-$(CONFIG_ARM64) += efi_selftest_el.o
obj-$(CONFIG_NETDEVICES) += efi_selftest_snp.o
obj-$(CONFIG_EFI_HTTP_PROTOCOL) += efi_selftest_http.o
obj-$(CONFIG_EFI_HTTP_PROTOCOL) += efi_selftest_ipconfig.o
diff --git a/lib/efi_selftest/efi_selftest_el.c b/lib/efi_selftest/efi_selftest_el.c
new file mode 100644
index 0000000..f9941ca
--- /dev/null
+++ b/lib/efi_selftest/efi_selftest_el.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Check current exception level on ARMv8.
+ */
+#include <efi_loader.h>
+#include <efi_selftest.h>
+
+/**
+ * current_exception_level()
+ *
+ * Return: current exception level, 0 - 3
+ */
+static unsigned int current_exception_level(void)
+{
+ unsigned long el;
+
+ asm volatile (
+ "MRS %0, CurrentEL"
+ : "=r" (el) : : );
+
+ return (el >> 2) & 0x3;
+}
+
+/**
+ * execute() - execute test
+ *
+ * Check that the exception level is not EL3.
+ */
+static int execute(void)
+{
+ unsigned int el = current_exception_level();
+
+ efi_st_printf("Exception level EL%u\n", el);
+ if (el != 1 && el != 2) {
+ efi_st_error("EL1 or EL2 expected");
+ return EFI_ST_FAILURE;
+ }
+
+ return EFI_ST_SUCCESS;
+}
+
+EFI_UNIT_TEST(el) = {
+ .name = "exception level",
+ .phase = EFI_EXECUTE_BEFORE_BOOTTIME_EXIT,
+ .execute = execute,
+};