Commit 152cca07 authored by Fabio Utzig's avatar Fabio Utzig Committed by Fabio Utzig
Browse files

bootutil: fix scratch status offset calculation 



Update `boot_status_off` to take into consideration that scratch only
has to store status for one swap of sectors, thus requiring much less
flash space than what is required in the primary slot.

This commits does a bit of refactoring on the functions that return
parts of trailer size to make the code clearer.

Signed-off-by: default avatarFabio Utzig <utzig@apache.org>
parent b3039fd6

boot/bootutil/src/bootutil_misc.c

+55 −13
Original line number Diff line number Diff line
@@ -94,18 +94,15 @@ out: 
}

#endif



uint32_t

boot_status_sz(uint32_t min_write_sz)

{

    return /* state for all sectors */

           BOOT_STATUS_MAX_ENTRIES * BOOT_STATUS_STATE_COUNT * min_write_sz;

}



uint32_t

boot_trailer_sz(uint32_t min_write_sz)

/*

 * Amount of space used to save information required when doing a swap,

 * or while a swap is under progress, but not the status of sector swap

 * progress itself.

 */

static inline uint32_t

boot_trailer_info_sz(void)

{

    return /* state for all sectors */

           boot_status_sz(min_write_sz)           +

    return (

#ifdef MCUBOOT_ENC_IMAGES

           /* encryption keys */

#  if MCUBOOT_SWAP_SAVE_ENCTLV
@@ -116,9 +113,46 @@ boot_trailer_sz(uint32_t min_write_sz) 
#endif

           /* swap_type + copy_done + image_ok + swap_size */

           BOOT_MAX_ALIGN * 4                     +

           BOOT_MAGIC_SZ;

           BOOT_MAGIC_SZ

           );

}



/*

 * Amount of space used to maintain progress information for a single swap

 * operation.

 */

static inline uint32_t

boot_status_entry_sz(uint32_t min_write_sz)

{

    return BOOT_STATUS_STATE_COUNT * min_write_sz;

}



uint32_t

boot_status_sz(uint32_t min_write_sz)

{

    return BOOT_STATUS_MAX_ENTRIES * boot_status_entry_sz(min_write_sz);

}



uint32_t

boot_trailer_sz(uint32_t min_write_sz)

{

    return boot_status_sz(min_write_sz) + boot_trailer_info_sz();

}



#if MCUBOOT_SWAP_USING_SCRATCH

/*

 * Similar to `boot_trailer_sz` but this function returns the space used to

 * store status in the scratch partition. The scratch partition only stores

 * status during the swap of the last sector from primary/secondary (which

 * is the first swap operation) and thus only requires space for one swap.

 */

static uint32_t

boot_scratch_trailer_sz(uint32_t min_write_sz)

{

    return boot_status_entry_sz(min_write_sz) + boot_trailer_info_sz();

}

#endif



int

boot_status_entries(int image_index, const struct flash_area *fap)

{
@@ -142,7 +176,15 @@ boot_status_off(const struct flash_area *fap) 


    elem_sz = flash_area_align(fap);



#if MCUBOOT_SWAP_USING_SCRATCH

    if (fap->fa_id == FLASH_AREA_IMAGE_SCRATCH) {

        off_from_end = boot_scratch_trailer_sz(elem_sz);

    } else {

#endif

        off_from_end = boot_trailer_sz(elem_sz);

#if MCUBOOT_SWAP_USING_SCRATCH

    }

#endif



    assert(off_from_end <= flash_area_get_size(fap));

    return flash_area_get_size(fap) - off_from_end;

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