efi_loader: refactor switch to non-secure mode
Refactor the switch from supervisor to hypervisor to a new function called
at the beginning of do_bootefi().
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/arm/cpu/armv7/exception_level.c b/arch/arm/cpu/armv7/exception_level.c
new file mode 100644
index 0000000..274f03d
--- /dev/null
+++ b/arch/arm/cpu/armv7/exception_level.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Switch to non-secure mode
+ *
+ * Copyright (c) 2018 Heinrich Schuchardt
+ *
+ * This module contains the ARMv7 specific code required for leaving the
+ * secure mode before booting an operating system.
+ */
+
+#include <common.h>
+#include <bootm.h>
+#include <asm/armv7.h>
+#include <asm/secure.h>
+#include <asm/setjmp.h>
+
+/**
+ * entry_non_secure() - entry point when switching to non-secure mode
+ *
+ * When switching to non-secure mode switch_to_non_secure_mode() calls this
+ * function passing a jump buffer. We use this jump buffer to restore the
+ * original stack and register state.
+ *
+ * @non_secure_jmp: jump buffer for restoring stack and registers
+ */
+static void entry_non_secure(struct jmp_buf_data *non_secure_jmp)
+{
+ dcache_enable();
+ debug("Reached non-secure mode\n");
+
+ /* Restore stack and registers saved in switch_to_non_secure_mode() */
+ longjmp(non_secure_jmp, 1);
+}
+
+/**
+ * switch_to_non_secure_mode() - switch to non-secure mode
+ *
+ * Operating systems may expect to run in non-secure mode. Here we check if
+ * we are running in secure mode and switch to non-secure mode if necessary.
+ */
+void switch_to_non_secure_mode(void)
+{
+ static bool is_nonsec;
+ struct jmp_buf_data non_secure_jmp;
+
+ if (armv7_boot_nonsec() && !is_nonsec) {
+ if (setjmp(&non_secure_jmp))
+ return;
+ dcache_disable(); /* flush cache before switch to HYP */
+ armv7_init_nonsec();
+ is_nonsec = true;
+ secure_ram_addr(_do_nonsec_entry)(entry_non_secure,
+ (uintptr_t)&non_secure_jmp,
+ 0, 0);
+ }
+}