diff options
Diffstat (limited to 'common/system.c')
| -rw-r--r-- | common/system.c | 53 |
1 files changed, 37 insertions, 16 deletions
diff --git a/common/system.c b/common/system.c index 5a3e9f9e03..346496c087 100644 --- a/common/system.c +++ b/common/system.c @@ -225,32 +225,53 @@ void system_disable_jump(void) disable_jump = 1; #ifdef CONFIG_MPU - /* - * Lock down memory to prevent code execution from data areas. - * - * TODO(crosbug.com/p/16904): Also lock down the image which isn't - * running (RO if RW, or vice versa), so a bad or malicious jump can't - * execute code from that image. - */ if (system_is_locked()) { + int ret; + int enable_mpu = 0; + enum system_image_copy_t copy; + + CPRINTF("[%T MPU type: %08x]\n", mpu_get_type()); /* - * Protect memory from code execution + * Protect RAM from code execution */ - int mpu_error = mpu_protect_ram(); - if (mpu_error == EC_SUCCESS) { - mpu_enable(); + ret = mpu_protect_ram(); + if (ret == EC_SUCCESS) { + enable_mpu = 1; CPRINTF("[%T RAM locked. Exclusion %08x-%08x]\n", &__iram_text_start, &__iram_text_end); } else { - CPRINTF("[%T Failed to lock RAM (%d). mpu_type:%08x]\n", - mpu_error, mpu_get_type()); + CPRINTF("[%T Failed to lock RAM (%d)]\n", ret); } + /* - * Protect the other image from code execution - * TODO: https://chromium-review.googlesource.com/#/c/169050/ + * Protect inactive image (ie. RO if running RW, vice versa) + * from code execution. */ + switch (system_get_image_copy()) { + case SYSTEM_IMAGE_RO: + ret = mpu_lock_rw_flash(); + copy = SYSTEM_IMAGE_RW; + break; + case SYSTEM_IMAGE_RW: + ret = mpu_lock_ro_flash(); + copy = SYSTEM_IMAGE_RO; + break; + default: + copy = SYSTEM_IMAGE_UNKNOWN; + ret = !EC_SUCCESS; + } + if (ret == EC_SUCCESS) { + enable_mpu = 1; + CPRINTF("[%T %s image locked]\n", image_names[copy]); + } else { + CPRINTF("[%T Failed to lock %s image (%d)]\n", + image_names[copy], ret); + } + + if (enable_mpu) + mpu_enable(); } else { - CPRINTF("[%T RAM not locked]\n"); + CPRINTF("[%T System is unlocked. Skip MPU configuration\n"); } #endif } |