[keymgr_dpe, sw] backport

This commit backport relevant changes implemented on the master.
All changes were implemented in the `keymgr` drivers.

Relevant git commit hashes:
- 9dcbb05
- 4afe7cd
- ab8c166
- b10d2fe
- e587303
- 068c37e

Signed-off-by: Raphael Roth <rroth@lowrisc.org>

Author: rroth-lowrisc

sw/device/lib/crypto/drivers/keymgr_dpe.c

@@ -9,7 +9,6 @@
 #include "sw/device/lib/base/bitfield.h"
 #include "sw/device/lib/base/hardened_memory.h"
 #include "sw/device/lib/base/memory.h"
-#include "sw/device/lib/crypto/drivers/entropy.h"
 #include "sw/device/lib/crypto/impl/status.h"
 
 #include "hw/top/keymgr_dpe_regs.h"
@@ -74,7 +73,7 @@ static status_t keymgr_dpe_key_gen_start(
   abs_mmio_write32(kBase + KEYMGR_DPE_START_REG_OFFSET,
                    1 << KEYMGR_DPE_START_EN_BIT);
 
-  return OTCRYPTO_OK;
+  return LAUNDERED_OTCRYPTO_OK;
 }
 
 /**
@@ -107,7 +106,7 @@ static status_t keymgr_dpe_wait_until_done(void) {
   // be possible.
   // The `IDLE` status is left unhandled because the keymgr should never be
   // idle after an operation has been started by the caller.
-  switch (status) {
+  switch (launder32(status)) {
     case KEYMGR_DPE_OP_STATUS_STATUS_VALUE_DONE_SUCCESS:
       HARDENED_CHECK_EQ(launder32(status),
                         KEYMGR_DPE_OP_STATUS_STATUS_VALUE_DONE_SUCCESS);
@@ -122,11 +121,11 @@ static status_t keymgr_dpe_wait_until_done(void) {
                         KEYMGR_DPE_OP_STATUS_STATUS_VALUE_DONE_ERROR);
       return OTCRYPTO_RECOV_ERR;
     }
+    default:
+      // Should be unreachable.
+      HARDENED_TRAP();
+      return OTCRYPTO_FATAL_ERR;
   }
-
-  // Should be unreachable.
-  HARDENED_TRAP();
-  return OTCRYPTO_FATAL_ERR;
 }
 
 /**
@@ -188,8 +187,7 @@ static status_t keymgr_dpe_wait_until_done(void) {
 status_t keymgr_dpe_generate_key_sw(
     const keymgr_dpe_diversification_t diversification,
     keymgr_dpe_output_t *key) {
-  // Ensure that the entropy complex has been initialized and keymgr is idle.
-  HARDENED_TRY(entropy_complex_check());
+  // Ensure the keymgr dpe is idle
   HARDENED_TRY(keymgr_dpe_is_idle());
 
   // Set the control register to generate a software-visible key.
@@ -221,9 +219,7 @@ status_t keymgr_dpe_generate_key_sw(
 
 status_t keymgr_dpe_generate_key_aes(
     keymgr_dpe_diversification_t diversification) {
-  // Ensure that the entropy complex has been initialized and keymgr dpe is
-  // idle.
-  HARDENED_TRY(entropy_complex_check());
+  // Ensure the keymgr dpe is idle
   HARDENED_TRY(keymgr_dpe_is_idle());
 
   // Set the control register to generate an AES key.
@@ -240,9 +236,7 @@ status_t keymgr_dpe_generate_key_aes(
 
 status_t keymgr_dpe_generate_key_kmac(
     keymgr_dpe_diversification_t diversification) {
-  // Ensure that the entropy complex has been initialized and keymgr dpe is
-  // idle.
-  HARDENED_TRY(entropy_complex_check());
+  // Ensure the keymgr dpe is idle
   HARDENED_TRY(keymgr_dpe_is_idle());
 
   // Set the control register to generate a KMAC key.
@@ -258,9 +252,7 @@ status_t keymgr_dpe_generate_key_kmac(
 
 status_t keymgr_dpe_generate_key_otbn(
     keymgr_dpe_diversification_t diversification) {
-  // Ensure that the entropy complex has been initialized and keymgr dpe is
-  // idle.
-  HARDENED_TRY(entropy_complex_check());
+  // Ensure the keymgr dpe is idle
   HARDENED_TRY(keymgr_dpe_is_idle());
 
   // Set the control register to generate an OTBN key.
@@ -285,9 +277,7 @@ status_t keymgr_dpe_generate_key_otbn(
  * @param slot Value to write to the SIDELOAD_CLEAR register.
  */
 static status_t keymgr_dpe_sideload_clear(uint32_t slot) {
-  // Ensure that the entropy complex has been initialized and keymgr dpe is
-  // idle.
-  HARDENED_TRY(entropy_complex_check());
+  // Ensure the keymgr dpe is idle
   HARDENED_TRY(keymgr_dpe_is_idle());
 
   // Set SIDELOAD_CLEAR to begin continuously clearing the requested slot.