MA-16203 Load boot/dtbo image to fixed memory

Only limited heap memory is available on imx8q platforms due
to some memory is reserved for m4 image. Commit cd67414 will
free avb verify data and thus help decrease the heap memory
consumption.

But when the device is locked, avb will try to verify one slot
first, it will continue to verify another if the first slot
returns failure. Function load_full_partition() will alloc memory
to load boot/dtbo images from heap (which is a big and continuous
memory region), this memory will be freed if the first slot returns
verify failure. but because part of the continous memory region
will be used in following verify process, even total available memory
is enough, u-boot can't find a continous memory region to load the
boot/dtbo image for another slot and will return error "Failed to
allocate memory".

Instead, this commit use fixed memory region start from 96MB offset of
CONFIG_FASTBOOT_BUF_ADDR to load the boot/dtbo images.

Test: slot verify and A/B slot switch.

Change-Id: Ifc83bed5a6be37196c0fd109d942eaf9b07b6a74
Signed-off-by: Ji Luo <ji.luo@nxp.com>

1 files changed, 27 insertions, 8 deletions

diff --git a/lib/avb/libavb/avb_slot_verify.c b/lib/avb/libavb/avb_slot_verify.c
index f682007a5e..0f09c21790 100644
--- a/lib/avb/libavb/avb_slot_verify.c
+++ b/lib/avb/libavb/avb_slot_verify.c
@@ -47,6 +47,22 @@
 /* Maximum size of a vbmeta image - 64 KiB. */
 #define VBMETA_MAX_SIZE (64 * 1024)
 
+/* Set the image load addr start from 96MB offset of CONFIG_FASTBOOT_BUF_ADDR */
+#define PARTITION_LOAD_ADDR_START (CONFIG_FASTBOOT_BUF_ADDR + (96 * 1024 * 1024))
+
+/* Load dtbo/boot partition to fixed address instead of heap memory. */
+static void *image_addr_top = (void *)PARTITION_LOAD_ADDR_START;
+static void *alloc_partition_addr(int size)
+{
+  void *ptr = image_addr_top;
+  image_addr_top = image_addr_top + ROUND(size, ARCH_DMA_MINALIGN);
+  return ptr;
+}
+static void free_partition_addr(int size)
+{
+  image_addr_top = (void *)(image_addr_top - ROUND(size, ARCH_DMA_MINALIGN));
+}
+
 /* Helper function to see if we should continue with verification in
  * allow_verification_error=true mode if something goes wrong. See the
  * comments for the avb_slot_verify() function for more information.
@@ -111,7 +127,7 @@ static AvbSlotVerifyResult load_full_partition(AvbOps* ops,
 
   /* Allocate and copy the partition. */
   if (!*out_image_preloaded) {
-    *out_image_buf = avb_malloc(image_size);
+    *out_image_buf = (void *)alloc_partition_addr(image_size);
     if (*out_image_buf == NULL) {
       return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
     }
@@ -412,8 +428,10 @@ out:
   }
 
 fail:
+  /* Now the image_buf is not allocated by malloc(), we should not free.
+   * Instead, we should reset the image_addr_top.*/
   if (image_buf != NULL && !image_preloaded) {
-    avb_free(image_buf);
+    free_partition_addr(image_size);
   }
   return ret;
 }
@@ -425,6 +443,7 @@ static AvbSlotVerifyResult load_requested_partitions(
     AvbSlotVerifyData* slot_data) {
   AvbSlotVerifyResult ret;
   uint8_t* image_buf = NULL;
+    uint64_t image_size;
   bool image_preloaded = false;
   size_t n;
 
@@ -437,7 +456,6 @@ static AvbSlotVerifyResult load_requested_partitions(
   for (n = 0; requested_partitions[n] != NULL; n++) {
     char part_name[AVB_PART_NAME_MAX_SIZE];
     AvbIOResult io_ret;
-    uint64_t image_size;
     AvbPartitionData* loaded_partition;
 
     if (!avb_str_concat(part_name,
@@ -491,9 +509,10 @@ static AvbSlotVerifyResult load_requested_partitions(
   ret = AVB_SLOT_VERIFY_RESULT_OK;
 
 out:
-  /* Free the current buffer if any. */
+  /* Now the image_buf is not allocated by malloc(), we should not free.
+   * Instead, we should reset the image_addr_top.*/
   if (image_buf != NULL && !image_preloaded) {
-    avb_free(image_buf);
+    free_partition_addr(image_size);
   }
   /* Buffers that are already saved in slot_data will be handled by the caller
    * even on failure. */
@@ -1338,10 +1357,10 @@ void avb_slot_verify_data_free(AvbSlotVerifyData* data) {
       if (loaded_partition->partition_name != NULL) {
         avb_free(loaded_partition->partition_name);
       }
-      if (loaded_partition->data != NULL && !loaded_partition->preloaded) {
-        avb_free(loaded_partition->data);
-      }
     }
+    /* partition data is not loaded to heap memory, so we just reset the
+     * image_addr_top here. */
+    image_addr_top = (void *)PARTITION_LOAD_ADDR_START;
     avb_free(data->loaded_partitions);
   }
   avb_free(data);