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/Makefile b/arch/arm/cpu/armv7/Makefile
index 4f4647c90ac1f7d291676b05c07c648c492db108..8c955d0d528483f576c74ab642e28e924fe8c8cf 100644 (file)
--- a/arch/arm/cpu/armv7/Makefile
+++ b/arch/arm/cpu/armv7/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_SYS_ARM_MPU) += mpu_v7r.o
 
 ifneq ($(CONFIG_SPL_BUILD),y)
 obj-$(CONFIG_EFI_LOADER) += sctlr.o
+obj-$(CONFIG_ARMV7_NONSEC) += exception_level.o
 endif
 
 ifneq ($(CONFIG_SKIP_LOWLEVEL_INIT),y)

diff --git a/arch/arm/cpu/armv7/exception_level.c b/arch/arm/cpu/armv7/exception_level.c
new file mode 100644 (file)
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);
+       }
+}

diff --git a/arch/arm/cpu/armv8/Makefile b/arch/arm/cpu/armv8/Makefile
index 4c4b13c9e7599cfc7dce35bdb02480d37419b54c..a5f54330e38e9675a4ce1908329e1587129c707f 100644 (file)
--- a/arch/arm/cpu/armv8/Makefile
+++ b/arch/arm/cpu/armv8/Makefile
@@ -14,6 +14,7 @@ ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_ARMV8_SPL_EXCEPTION_VECTORS) += exceptions.o
 else
 obj-y  += exceptions.o
+obj-y  += exception_level.o
 endif
 obj-y  += cache.o
 obj-y  += tlb.o

diff --git a/arch/arm/cpu/armv8/exception_level.c b/arch/arm/cpu/armv8/exception_level.c
new file mode 100644 (file)
index 0000000..57824eb
--- /dev/null
+++ b/arch/arm/cpu/armv8/exception_level.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Switch to non-secure mode
+ *
+ * Copyright (c) 2018 Heinrich Schuchardt
+ *
+ * This module contains the ARMv8 specific code required to adjust the exception
+ * level before booting an operating system.
+ */
+
+#include <common.h>
+#include <bootm.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
+ *
+ * Exception level EL3 is meant to be used by the secure monitor only (ARM
+ * trusted firmware being one embodiment). The operating system shall be
+ * started at exception level EL2. So here we check the exception level
+ * and switch it if necessary.
+ */
+void switch_to_non_secure_mode(void)
+{
+       struct jmp_buf_data non_secure_jmp;
+
+       /* On AArch64 we need to make sure we call our payload in < EL3 */
+       if (current_el() == 3) {
+               if (setjmp(&non_secure_jmp))
+                       return;
+               dcache_disable();       /* flush cache before switch to EL2 */
+
+               /* Move into EL2 and keep running there */
+               armv8_switch_to_el2((uintptr_t)&non_secure_jmp, 0, 0, 0,
+                                   (uintptr_t)entry_non_secure, ES_TO_AARCH64);
+       }
+}

diff --git a/cmd/bootefi.c b/cmd/bootefi.c
index bcdd29ebed03615d45bd4b8f48b6c53aed92b57c..ee685d8644e5449aec25a232623911ce9a7d291a 100644 (file)
--- a/cmd/bootefi.c
+++ b/cmd/bootefi.c
@@ -5,8 +5,9 @@
  *  Copyright (c) 2016 Alexander Graf
  */
 
-#include <charset.h>
 #include <common.h>
+#include <bootm.h>
+#include <charset.h>
 #include <command.h>
 #include <dm.h>
 #include <efi_loader.h>
@@ -21,11 +22,6 @@
 #include <asm-generic/unaligned.h>
 #include <linux/linkage.h>
 
-#ifdef CONFIG_ARMV7_NONSEC
-#include <asm/armv7.h>
-#include <asm/secure.h>
-#endif
-
 DECLARE_GLOBAL_DATA_PTR;
 
 static struct efi_device_path *bootefi_image_path;
@@ -151,34 +147,6 @@ static efi_status_t efi_do_enter(
        return ret;
 }
 
-#ifdef CONFIG_ARM64
-static efi_status_t efi_run_in_el2(EFIAPI efi_status_t (*entry)(
-                       efi_handle_t image_handle, struct efi_system_table *st),
-                       efi_handle_t image_handle, struct efi_system_table *st)
-{
-       /* Enable caches again */
-       dcache_enable();
-
-       return efi_do_enter(image_handle, st, entry);
-}
-#endif
-
-#ifdef CONFIG_ARMV7_NONSEC
-static bool is_nonsec;
-
-static efi_status_t efi_run_in_hyp(EFIAPI efi_status_t (*entry)(
-                       efi_handle_t image_handle, struct efi_system_table *st),
-                       efi_handle_t image_handle, struct efi_system_table *st)
-{
-       /* Enable caches again */
-       dcache_enable();
-
-       is_nonsec = true;
-
-       return efi_do_enter(image_handle, st, entry);
-}
-#endif
-
 /*
  * efi_carve_out_dt_rsv() - Carve out DT reserved memory ranges
  *
@@ -358,39 +326,6 @@ static efi_status_t do_bootefi_exec(void *efi,
                goto err_prepare;
        }
 
-#ifdef CONFIG_ARM64
-       /* On AArch64 we need to make sure we call our payload in < EL3 */
-       if (current_el() == 3) {
-               smp_kick_all_cpus();
-               dcache_disable();       /* flush cache before switch to EL2 */
-
-               /* Move into EL2 and keep running there */
-               armv8_switch_to_el2((ulong)entry,
-                                   (ulong)&image_obj->header,
-                                   (ulong)&systab, 0, (ulong)efi_run_in_el2,
-                                   ES_TO_AARCH64);
-
-               /* Should never reach here, efi exits with longjmp */
-               while (1) { }
-       }
-#endif
-
-#ifdef CONFIG_ARMV7_NONSEC
-       if (armv7_boot_nonsec() && !is_nonsec) {
-               dcache_disable();       /* flush cache before switch to HYP */
-
-               armv7_init_nonsec();
-               secure_ram_addr(_do_nonsec_entry)(
-                                       efi_run_in_hyp,
-                                       (uintptr_t)entry,
-                                       (uintptr_t)&image_obj->header,
-                                       (uintptr_t)&systab);
-
-               /* Should never reach here, efi exits with longjmp */
-               while (1) { }
-       }
-#endif
-
        ret = efi_do_enter(&image_obj->header, &systab, entry);
 
 err_prepare:
@@ -476,6 +411,8 @@ static int do_bootefi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
        /* Allow unaligned memory access */
        allow_unaligned();
 
+       switch_to_non_secure_mode();
+
        /* Initialize EFI drivers */
        r = efi_init_obj_list();
        if (r != EFI_SUCCESS) {

diff --git a/common/bootm.c b/common/bootm.c
index 7c7505f09204cdd10019b42f08bd8405f5026fed..3adbceaa38e381c62f569fa1ecdff8852756d8b8 100644 (file)
--- a/common/bootm.c
+++ b/common/bootm.c
@@ -912,6 +912,16 @@ static const void *boot_get_kernel(cmd_tbl_t *cmdtp, int flag, int argc,
 
        return buf;
 }
+
+/**
+ * switch_to_non_secure_mode() - switch to non-secure mode
+ *
+ * This routine is overridden by architectures requiring this feature.
+ */
+void __weak switch_to_non_secure_mode(void)
+{
+}
+
 #else /* USE_HOSTCC */
 
 void memmove_wd(void *to, void *from, size_t len, ulong chunksz)

diff --git a/include/bootm.h b/include/bootm.h
index dbd6f49c2df41eccf8f1d822b2960cf05b24dc2d..e2cc6d4b99a59b4fb51de8fc6ad953bbc736fa24 100644 (file)
--- a/include/bootm.h
+++ b/include/bootm.h
@@ -82,4 +82,9 @@ int bootm_decomp_image(int comp, ulong load, ulong image_start, int type,
  */
 void board_quiesce_devices(void);
 
+/**
+ * switch_to_non_secure_mode() - switch to non-secure mode
+ */
+void switch_to_non_secure_mode(void);
+
 #endif