[imm_rom_ext] Mint CDI_0 certs in immutable rom ext

Since CDI_0 attests the integrity of rom_ext, this PR moves the UDS & CDI_0
stage to the immutable rom_ext part, which will be executed before mutable
rom_ext, to establish root trust in hardware.

SKU owners can choose whether the immutability should be enforced using the
`CREATOR_SW_CFG_IMMUTABLE_ROM_EXT_EN` OTP field.

Change-Id: If971654a27ea32eaf74d20d385e48801d28e1da5
Signed-off-by: Yi-Hsuan Deng <[email protected]>

sw/device/silicon_creator/imm_rom_ext/BUILD

@@ -8,4 +8,21 @@ cc_library(
     name = "main_lib",
     srcs = ["imm_rom_ext.c"],
     hdrs = ["imm_rom_ext.h"],
+    deps = [
+        "//hw/top_earlgrey/ip_autogen/flash_ctrl:flash_ctrl_c_regs",
+        "//sw/device/lib/arch:device",
+        "//sw/device/lib/base:macros",
+        "//sw/device/silicon_creator/lib:dbg_print",
+        "//sw/device/silicon_creator/lib:epmp_state",
+        "//sw/device/silicon_creator/lib:manifest",
+        "//sw/device/silicon_creator/lib:shutdown",
+        "//sw/device/silicon_creator/lib/base:boot_measurements",
+        "//sw/device/silicon_creator/lib/base:sec_mmio",
+        "//sw/device/silicon_creator/lib/base:static_critical",
+        "//sw/device/silicon_creator/lib/cert:dice_chain",
+        "//sw/device/silicon_creator/lib/drivers:pinmux",
+        "//sw/device/silicon_creator/lib/drivers:rnd",
+        "//sw/device/silicon_creator/lib/drivers:uart",
+        "//sw/device/silicon_creator/rom_ext:rom_ext_manifest",
+    ],
 )

sw/device/silicon_creator/imm_rom_ext/e2e/boot_message/BUILD

@@ -0,0 +1,26 @@
+# Copyright lowRISC contributors (OpenTitan project).
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+load(
+    "//rules/opentitan:defs.bzl",
+    "fpga_params",
+    "opentitan_test",
+)
+
+package(default_visibility = ["//visibility:public"])
+
+opentitan_test(
+    name = "boot_test",
+    srcs = ["boot_test.c"],
+    exec_env = {
+        "//hw/top_earlgrey:fpga_cw310_rom_ext": None,
+        "//hw/top_earlgrey:fpga_cw340_rom_ext": None,
+    },
+    fpga = fpga_params(
+        exit_success = "\nIMM_ROM_EXT v",
+    ),
+    deps = [
+        "//sw/device/lib/testing/test_framework:ottf_main",
+    ],
+)

sw/device/silicon_creator/imm_rom_ext/e2e/boot_message/boot_test.c

@@ -0,0 +1,9 @@
+// Copyright lowRISC contributors (OpenTitan project).
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#include "sw/device/lib/testing/test_framework/ottf_main.h"
+
+OTTF_DEFINE_TEST_CONFIG();
+
+bool test_main(void) { return true; }

sw/device/silicon_creator/imm_rom_ext/imm_rom_ext.c

@@ -4,7 +4,57 @@
 
 #include "sw/device/silicon_creator/imm_rom_ext/imm_rom_ext.h"
 
+#include "sw/device/lib/arch/device.h"
+#include "sw/device/lib/base/macros.h"
+#include "sw/device/silicon_creator/lib/base/boot_measurements.h"
+#include "sw/device/silicon_creator/lib/base/sec_mmio.h"
+#include "sw/device/silicon_creator/lib/cert/dice_chain.h"
+#include "sw/device/silicon_creator/lib/dbg_print.h"
+#include "sw/device/silicon_creator/lib/drivers/pinmux.h"
+#include "sw/device/silicon_creator/lib/drivers/rnd.h"
+#include "sw/device/silicon_creator/lib/drivers/uart.h"
+#include "sw/device/silicon_creator/lib/epmp_state.h"
+#include "sw/device/silicon_creator/lib/shutdown.h"
+#include "sw/device/silicon_creator/rom_ext/rom_ext_manifest.h"
+
+OT_WARN_UNUSED_RESULT
+static rom_error_t imm_rom_ext_start(void) {
+  // Check the ePMP state.
+  HARDENED_RETURN_IF_ERROR(epmp_state_check());
+  // Check sec_mmio expectations.
+  // We don't check the counters since we don't want to tie ROM_EXT to a
+  // specific ROM version.
+  sec_mmio_check_values(rnd_uint32());
+
+  // Initialize Immutable ROM EXT.
+  sec_mmio_next_stage_init();
+  // Configure UART0 as stdout.
+  pinmux_init_uart0_tx();
+  uart_init(kUartNCOValue);
+
+  dbg_printf("IMM_ROM_EXT v0.1\r\n");
+
+  // Establish our identity.
+  const manifest_t *rom_ext = rom_ext_manifest();
+  HARDENED_RETURN_IF_ERROR(dice_chain_init());
+  // TODO: Move UDS cert check to mutable ROM_EXT.
+  HARDENED_RETURN_IF_ERROR(dice_chain_attestation_silicon());
+  HARDENED_RETURN_IF_ERROR(
+      dice_chain_attestation_creator(&boot_measurements.rom_ext, rom_ext));
+
+  // Write the DICE certs to flash if they have been updated.
+  HARDENED_RETURN_IF_ERROR(dice_chain_flush_flash());
+
+  return kErrorOk;
+}
+
 void imm_rom_ext_main(void) {
-  // TODO(opentitan#24368): Implement this.
+  rom_error_t error = imm_rom_ext_start();
+  if (launder32(error) != kErrorOk) {
+    shutdown_finalize(error);
+  }
+  HARDENED_CHECK_EQ(error, kErrorOk);
+
+  // Go back to ROM / Mutable ROM_EXT.
   return;
 }

sw/device/silicon_creator/lib/drivers/pinmux.c

@@ -169,6 +169,8 @@ static void configure_output(pinmux_output_t output) {
       output.outsel);
 }
 
+void pinmux_init_uart0_tx(void) { configure_output(kOutputUart0); }
+
 void pinmux_init(void) {
   uint32_t bootstrap_dis =
       otp_read32(OTP_CTRL_PARAM_OWNER_SW_CFG_ROM_BOOTSTRAP_DIS_OFFSET);

sw/device/silicon_creator/lib/drivers/pinmux.h

@@ -23,6 +23,11 @@ extern "C" {
  */
 void pinmux_init(void);
 
+/**
+ * Initialize the pinmux with output UART0 only.
+ */
+void pinmux_init_uart0_tx(void);
+
 /**
  * Read the SW_STRAP value.
  *

sw/device/silicon_creator/lib/drivers/pinmux_unittest.cc

@@ -125,5 +125,13 @@ TEST_F(InitTest, WithoutBootstrap) {
   pinmux_init();
 }
 
+TEST_F(InitTest, Uart0TxOnly) {
+  // The outputs that will be configured.
+  EXPECT_ABS_WRITE32(RegOutSel(kTopEarlgreyPinmuxMioOutIoc4),
+                     kTopEarlgreyPinmuxOutselUart0Tx);
+
+  pinmux_init_uart0_tx();
+}
+
 }  // namespace
 }  // namespace pinmux_unittest

sw/device/silicon_creator/rom_ext/BUILD

@@ -33,6 +33,18 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "rom_ext_manifest",
+    srcs = ["rom_ext_manifest.c"],
+    hdrs = ["rom_ext_manifest.h"],
+    target_compatible_with = [OPENTITAN_CPU],
+    deps = [
+        "//hw/top_earlgrey/sw/autogen:top_earlgrey",
+        "//sw/device/lib/base:macros",
+        "//sw/device/silicon_creator/lib:manifest",
+    ],
+)
+
 dual_cc_library(
     name = "rom_ext_boot_policy_ptrs",
     srcs = dual_inputs(
@@ -207,6 +219,7 @@ cc_library(
         ":rescue",
         ":rom_ext_boot_policy",
         ":rom_ext_boot_policy_ptrs",
+        ":rom_ext_manifest",
         ":sigverify_keys",
         "//hw/ip/sram_ctrl/data:sram_ctrl_c_regs",
         "//hw/top_earlgrey/ip_autogen/flash_ctrl:flash_ctrl_c_regs",
@@ -220,9 +233,11 @@ cc_library(
         "//sw/device/silicon_creator/lib:boot_data",
         "//sw/device/silicon_creator/lib:boot_log",
         "//sw/device/silicon_creator/lib:dbg_print",
+        "//sw/device/silicon_creator/lib:epmp_state",
         "//sw/device/silicon_creator/lib:manifest",
         "//sw/device/silicon_creator/lib:manifest_def",
         "//sw/device/silicon_creator/lib:shutdown",
+        "//sw/device/silicon_creator/lib/base:boot_measurements",
         "//sw/device/silicon_creator/lib/base:chip",
         "//sw/device/silicon_creator/lib/base:sec_mmio",
         "//sw/device/silicon_creator/lib/base:static_critical",

sw/device/silicon_creator/rom_ext/rom_ext.c

@@ -46,6 +46,7 @@
 #include "sw/device/silicon_creator/rom_ext/rescue.h"
 #include "sw/device/silicon_creator/rom_ext/rom_ext_boot_policy.h"
 #include "sw/device/silicon_creator/rom_ext/rom_ext_boot_policy_ptrs.h"
+#include "sw/device/silicon_creator/rom_ext/rom_ext_manifest.h"
 #include "sw/device/silicon_creator/rom_ext/sigverify_keys.h"
 
 #include "flash_ctrl_regs.h"                          // Generated.
@@ -140,17 +141,6 @@ static uint32_t rom_ext_current_slot(void) {
   return side;
 }
 
-OT_WARN_UNUSED_RESULT
-const manifest_t *rom_ext_manifest(void) {
-  uint32_t pc = 0;
-  asm("auipc %[pc], 0;" : [pc] "=r"(pc));
-  const uint32_t kFlashHalf = TOP_EARLGREY_FLASH_CTRL_MEM_SIZE_BYTES / 2;
-  // Align the PC to the current flash side.  The ROM_EXT must be the first
-  // entity in each flash side, so this alignment is the manifest address.
-  pc &= ~(kFlashHalf - 1);
-  return (const manifest_t *)pc;
-}
-
 void rom_ext_check_rom_expectations(void) {
   // Check the ePMP state.
   SHUTDOWN_IF_ERROR(epmp_state_check());
@@ -619,11 +609,8 @@ static rom_error_t rom_ext_start(boot_data_t *boot_data, boot_log_t *boot_log) {
   dbg_printf("Starting ROM_EXT %u.%u\r\n", self->version_major,
              self->version_minor);
 
-  // Establish our identity.
+  // Prepare dice chain builder for CDI_1.
   HARDENED_RETURN_IF_ERROR(dice_chain_init());
-  HARDENED_RETURN_IF_ERROR(dice_chain_attestation_silicon());
-  HARDENED_RETURN_IF_ERROR(
-      dice_chain_attestation_creator(&boot_measurements.rom_ext, self));
 
   // Initialize the boot_log in retention RAM.
   const chip_info_t *rom_chip_info = (const chip_info_t *)_rom_chip_info_start;

sw/device/silicon_creator/rom_ext/rom_ext_manifest.c

@@ -0,0 +1,23 @@
+// Copyright lowRISC contributors (OpenTitan project).
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#include "sw/device/silicon_creator/rom_ext/rom_ext_manifest.h"
+
+#include "sw/device/silicon_creator/lib/manifest.h"
+
+#include "hw/top_earlgrey/sw/autogen/top_earlgrey.h"  // Generated.
+
+enum {
+  kFlashHalf = TOP_EARLGREY_FLASH_CTRL_MEM_SIZE_BYTES / 2,
+};
+
+const manifest_t *rom_ext_manifest(void) {
+  uintptr_t pc = 0;
+  asm("auipc %[pc], 0;" : [pc] "=r"(pc));
+
+  // Align the PC to the current flash side.  The ROM_EXT must be the first
+  // entity in each flash side, so this alignment is the manifest address.
+  pc &= ~((uintptr_t)kFlashHalf - 1);
+  return (const manifest_t *)pc;
+}

sw/device/silicon_creator/rom_ext/rom_ext_manifest.h

@@ -0,0 +1,25 @@
+// Copyright lowRISC contributors (OpenTitan project).
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#ifndef OPENTITAN_SW_DEVICE_SILICON_CREATOR_ROM_EXT_ROM_EXT_MANIFEST_H_
+#define OPENTITAN_SW_DEVICE_SILICON_CREATOR_ROM_EXT_ROM_EXT_MANIFEST_H_
+
+#include "sw/device/lib/base/macros.h"
+#include "sw/device/silicon_creator/lib/manifest.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif  // __cplusplus
+
+/**
+ * Return the pointer to rom_ext manifest on the active flash bank.
+ */
+OT_WARN_UNUSED_RESULT
+const manifest_t *rom_ext_manifest(void);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif  // __cplusplus
+
+#endif  // OPENTITAN_SW_DEVICE_SILICON_CREATOR_ROM_EXT_ROM_EXT_MANIFEST_H_