[silicon_creator] Use linker symbol to access the chip_info

Some places were using a symbol provided by chip_info.h but
this symbol might not be present in the binary. Instead, the
expected way to access the symbol is to use the linker provided
one which uses a fixed address.

Signed-off-by: Amaury Pouly <[email protected]>

Author: pamaury

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/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;