Support secure/non-secure flash IAP for Cortex-M23/M33

hal/TARGET_FLASH_CMSIS_ALGO/flash_common_algo.c

@@ -17,6 +17,13 @@
 #include "flash_api.h"
 #include "flash_data.h"
 #include "mbed_critical.h"
+#include "mbed_toolchain.h"
+
+#ifndef __DOMAIN_NS
+
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
+#include <arm_cmse.h>
+#endif
 
 #define MBED_FLASH_ALGO_ERASE   1UL
 #define MBED_FLASH_ALGO_PROGRAM 2UL
@@ -82,20 +89,62 @@ static int32_t flash_algo_uninit(flash_t *obj, uint32_t address, uint32_t functi
     return ((flash_algo_jump_t)(((uint32_t)&jump_to_flash_algo) | 1))(&arguments);
 }
 
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
+/* Check if address range [start_addr, end_addr] is in non-secure flash
+ *
+ *  @param obj          The flash object
+ *  @param start_addr   Start address to check
+ *  @param end_addr     End address to check. Could be the same as start_addr to just check start_addr
+ *                      for e.g. flash_erase_sector.
+ *  @return             0 for success, -1 for error
+ */ 
+static int32_t flash_check_nonsecure(flash_t *obj, uint32_t start_addr, uint32_t end_addr)
+{
+    /* Check if end address wraps around */
+    if (end_addr < start_addr) {
+        return -1;
+    }
+
+    /* Check if start address is in non-secure flash */
+    if ((start_addr < obj->target_config_ns->flash_start) ||
+        (start_addr >= (obj->target_config_ns->flash_start + obj->target_config_ns->flash_size))) {
+        return -1;
+    }
+
+    /* Check if end address is in non-secure flash */
+    if (end_addr != start_addr) {
+        if ((end_addr < obj->target_config_ns->flash_start) ||
+            (end_addr >= (obj->target_config_ns->flash_start + obj->target_config_ns->flash_size))) {
+            return -1;
+        }
+    }
+
+    return 0;
+}
+#endif
 
-int32_t flash_init(flash_t *obj)
+MBED_NONSECURE_ENTRY int32_t flash_init(flash_t *obj)
 {
     flash_set_target_config(obj);
     return 0;
 }
 
-int32_t flash_free(flash_t *obj)
+MBED_NONSECURE_ENTRY int32_t flash_free(flash_t *obj)
 {
     return 0;
 }
 
-int32_t flash_erase_sector(flash_t *obj, uint32_t address)
+MBED_NONSECURE_ENTRY int32_t flash_erase_sector(flash_t *obj, uint32_t address)
 {
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
+    if (cmse_nonsecure_caller()) {
+        // Confine non-secure access to non-secure flash
+        if (flash_check_nonsecure(obj, address, address)) {
+            return -1;
+        }
+    }
+#endif
+
     core_util_critical_section_enter();
     flash_algo_init(obj, address, MBED_FLASH_ALGO_ERASE);
 
@@ -114,9 +163,17 @@ int32_t flash_erase_sector(flash_t *obj, uint32_t address)
     return ret ? -1 : 0;
 }
 
-
-int32_t flash_program_page(flash_t *obj, uint32_t address, const uint8_t *data, uint32_t size)
+MBED_NONSECURE_ENTRY int32_t flash_program_page(flash_t *obj, uint32_t address, const uint8_t *data, uint32_t size)
 {
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
+    if (cmse_nonsecure_caller()) {
+        // Confine non-secure access to non-secure flash
+        if (flash_check_nonsecure(obj, address, address + size - 1)) {
+            return -1;
+        }
+    }
+#endif
+
     core_util_critical_section_enter();
     flash_algo_init(obj, address, MBED_FLASH_ALGO_PROGRAM);
 
@@ -135,9 +192,26 @@ int32_t flash_program_page(flash_t *obj, uint32_t address, const uint8_t *data,
     return ret ? -1 : 0;
 }
 
-
-uint32_t flash_get_sector_size(const flash_t *obj, uint32_t address)
+MBED_NONSECURE_ENTRY uint32_t flash_get_sector_size(const flash_t *obj, uint32_t address)
 {
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
+    if (cmse_nonsecure_caller()) {
+        const sector_info_t *sectors = obj->target_config_ns->sectors;
+
+        if (address >= obj->target_config_ns->flash_start + obj->target_config_ns->flash_size) {
+            return MBED_FLASH_INVALID_SIZE;
+        }
+
+        int sector_index = obj->target_config_ns->sector_info_count - 1;
+        for (; sector_index >= 0; sector_index--) {
+            if (address >= sectors[sector_index].start) {
+                return sectors[sector_index].size;
+            }
+        }
+        return MBED_FLASH_INVALID_SIZE;
+    }
+#endif
+
     const sector_info_t *sectors = obj->target_config->sectors;
 
     if (address >= obj->target_config->flash_start + obj->target_config->flash_size) {
@@ -153,17 +227,37 @@ uint32_t flash_get_sector_size(const flash_t *obj, uint32_t address)
     return MBED_FLASH_INVALID_SIZE;
 }
 
-uint32_t flash_get_page_size(const flash_t *obj)
+MBED_NONSECURE_ENTRY uint32_t flash_get_page_size(const flash_t *obj)
 {
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
+    if (cmse_nonsecure_caller()) {
+        return obj->target_config_ns->page_size;
+    }
+#endif
+
     return obj->target_config->page_size;
 }
 
-uint32_t flash_get_start_address(const flash_t *obj)
+MBED_NONSECURE_ENTRY uint32_t flash_get_start_address(const flash_t *obj)
 {
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
+    if (cmse_nonsecure_caller()) {
+        return obj->target_config_ns->flash_start;
+    }
+#endif
+
     return obj->target_config->flash_start;
 }
 
-uint32_t flash_get_size(const flash_t *obj)
+MBED_NONSECURE_ENTRY uint32_t flash_get_size(const flash_t *obj)
 {
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
+    if (cmse_nonsecure_caller()) {
+        return obj->target_config_ns->flash_size;
+    }
+#endif
+
     return obj->target_config->flash_size;
 }
+
+#endif  // #ifndef __DOMAIN_NS

hal/TARGET_FLASH_CMSIS_ALGO/flash_data.h

@@ -47,9 +47,18 @@ typedef struct {
 } flash_target_config_t;
 
 /** Target flash configuration
+ *  For targets not supporting TrustZone, its flash_set_target_config must define target_config.
+ *  For targets supporting TrustZone, it has the following requirements:
+ *  -# Flash IAP H/W can only configure to secure. It can access both secure/non-secure flash.
+ *  -# Flash IAP port is for secure build only. It exports secure functions for non-secure build.
+ *  -# In Flash IAP port, flash_set_target_config must define both target_config/target_config_ns for secure/non-secure flash respectively.
+ *  -# Non-secure application can access its non-secure flash only through secure flash IAP functions. It cannot access secure flash.
  */
 struct flash_s {
-    const flash_target_config_t *target_config;
+    const flash_target_config_t *target_config; /**< Normal/secure flash configuration structure for targets not supporting/supporting TrustZone */
+#if defined(__CORTEX_M23) || defined(__CORTEX_M33)
+    const flash_target_config_t *target_config_ns; /**< Non-secure flash configuration structure for targets supporting TrustZone */
+#endif
     const flash_algo_t *flash_algo;
 };
 

platform/mbed_toolchain.h

@@ -412,6 +412,27 @@
 #define EXTERN extern
 #endif
 
+/** MBED_NONSECURE_ENTRY
+ *  Declare a function that can be called from non-secure world or secure world
+ *
+ *  @code
+ *  #include "mbed_toolchain.h"
+ *
+ *  MBED_NONSECURE_ENTRY void foo() {
+ *
+ *  }
+ *  @endcode
+ */
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3L)
+#if defined (__ICCARM__)
+#define MBED_NONSECURE_ENTRY       __cmse_nonsecure_entry
+#else
+#define MBED_NONSECURE_ENTRY       __attribute__((cmse_nonsecure_entry))
+#endif
+#else
+#define MBED_NONSECURE_ENTRY
+#endif
+
 #endif
 
 /** @}*/