Fix chip info in the ROM/ROM_EXT

rules/autogen.bzl

@@ -184,7 +184,7 @@ autogen_chip_info_src = rule(
     } | stamp_attr(-1, "//rules:stamp_flag"),
 )
 
-def autogen_chip_info(name):
+def autogen_chip_info(name, deps = []):
     """Generates a cc_library named `name` that defines chip info."""
 
     # Generate a C source file that defines the chip info struct. This is an
@@ -198,10 +198,10 @@ def autogen_chip_info(name):
     native.cc_library(
         name = name,
         srcs = [chip_info_src_target],
-        hdrs = ["//sw/device/silicon_creator/lib:chip_info.h"],
-        deps = [
-            "//sw/device/lib/base:macros",
-        ],
+        deps = deps,
+        # Make sure to participate in linking so that the symbol is not discarded
+        # (since it is not meant to be directly used).
+        alwayslink = True,
     )
 
 def _cryptotest_hjson_external(ctx):

sw/device/lib/testing/test_rom/test_rom.c

@@ -155,7 +155,8 @@ bool rom_test_main(void) {
   }
 
   // Print the chip version information
-  LOG_INFO("kChipInfo: scm_revision=%x", kChipInfo.scm_revision);
+  chip_info_t *chip_info = (chip_info_t *)&_chip_info_start;
+  LOG_INFO("kChipInfo: scm_revision=%x", chip_info->scm_revision);
 
   // Skip sram_init for test_rom
   dif_rstmgr_reset_info_bitfield_t reset_reasons;

sw/device/silicon_creator/lib/BUILD

@@ -352,7 +352,18 @@ filegroup(
     ],
 )
 
-autogen_chip_info(name = "chip_info")
+cc_library(
+    name = "chip_info",
+    hdrs = ["chip_info.h"],
+)
+
+autogen_chip_info(
+    name = "chip_info_data",
+    deps = [
+        ":chip_info",
+        "//sw/device/lib/base:macros",
+    ],
+)
 
 dual_cc_library(
     name = "shutdown",

sw/device/silicon_creator/lib/chip_info.h

@@ -51,10 +51,9 @@ enum {
 };
 
 /**
- * Extern declaration for the `kChipInfo` instance placed at the end of ROM.
- *
- * The actual definition is in an auto-generated file.
+ * The chip information is placed at the end of ROM and is accessible using
+ * the following symbol.
  */
-extern const chip_info_t kChipInfo;
+extern const char _chip_info_start[];
 
 #endif  // OPENTITAN_SW_DEVICE_SILICON_CREATOR_LIB_CHIP_INFO_H_

sw/device/silicon_creator/lib/shutdown.c

@@ -413,10 +413,11 @@ SHUTDOWN_FUNC(NO_MODIFIERS, shutdown_report_error(rom_error_t reason)) {
 
   // Print the error message and the raw life cycle state as reported by the
   // hardware.
+  const chip_info_t *rom_chip_info = (const chip_info_t *)_chip_info_start;
   shutdown_print(kShutdownLogPrefixBootFault, redacted_error);
   shutdown_print(kShutdownLogPrefixLifecycle, raw_state);
   shutdown_print(kShutdownLogPrefixVersion,
-                 kChipInfo.scm_revision.scm_revision_high);
+                 rom_chip_info->scm_revision.scm_revision_high);
 }
 
 SHUTDOWN_FUNC(NO_MODIFIERS, shutdown_software_escalate(void)) {

sw/device/silicon_creator/rom/BUILD

@@ -123,6 +123,8 @@ cc_library(
         "//sw/device/lib/base:hardened",
         "//sw/device/lib/base:multibits",
         "//sw/device/silicon_creator/lib/base:chip",
+        # This embeds the chip info into the binary.
+        "//sw/device/silicon_creator/lib:chip_info_data",
     ],
     alwayslink = True,
 )

sw/device/silicon_creator/rom/e2e/BUILD

@@ -472,3 +472,16 @@ opentitan_test(
         "//sw/device/silicon_creator/lib/drivers:rstmgr",
     ],
 )
+
+opentitan_test(
+    name = "rom_e2e_chip_info",
+    srcs = ["chip_info_test.c"],
+    exec_env = {
+        "//hw/top_earlgrey:fpga_cw310_rom_with_fake_keys": None,
+        "//hw/top_earlgrey:fpga_cw340_rom_with_fake_keys": None,
+    },
+    deps = [
+        "//sw/device/lib/testing/test_framework:ottf_main",
+        "//sw/device/silicon_creator/lib:chip_info",
+    ],
+)

sw/device/silicon_creator/rom/e2e/chip_info_test.c

@@ -0,0 +1,21 @@
+// 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/lib/chip_info.h"
+
+#include <stdbool.h>
+
+#include "sw/device/lib/testing/test_framework/ottf_main.h"
+
+OTTF_DEFINE_TEST_CONFIG();
+
+bool test_main(void) {
+  chip_info_t *chip_info = (chip_info_t *)&_chip_info_start;
+  LOG_INFO("Chip Info");
+  LOG_INFO("  Version: %x", chip_info->version);
+  LOG_INFO("   SCM lo: %x", chip_info->scm_revision.scm_revision_low);
+  LOG_INFO("   SCM hi: %x", chip_info->scm_revision.scm_revision_high);
+
+  return chip_info->version == kChipInfoVersion1;
+}

sw/device/silicon_creator/rom/rom.c

@@ -244,9 +244,10 @@ static rom_error_t rom_init(void) {
 
   // Initialize boot_log
   boot_log_t *boot_log = &retention_sram_get()->creator.boot_log;
+  const chip_info_t *rom_chip_info = (const chip_info_t *)_chip_info_start;
   memset(boot_log, 0, sizeof(*boot_log));
   boot_log->identifier = kBootLogIdentifier;
-  boot_log->chip_version = kChipInfo.scm_revision;
+  boot_log->chip_version = rom_chip_info->scm_revision;
   boot_log->retention_ram_initialized =
       reset_reasons & reset_mask ? kHardenedBoolTrue : kHardenedBoolFalse;
 

util/rom_chip_info.py

@@ -34,6 +34,7 @@ def generate_chip_info_c_source(scm_revision: int) -> str:
 
 #include "sw/device/lib/base/macros.h"
 
+OT_USED
 OT_SECTION(".chip_info")
 const chip_info_t kChipInfo = {{
   .scm_revision = (chip_info_scm_revision_t){{