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[nrf noup] boot: zephyr: decompression: Fix issues with ARM thumb filter
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fixup! [nrf noup] zephyr: Add support for ARM thumb filter

Fixes some issues with the ARM filter implementation which has
been updated to support jump instructions that are staggered into
2 different data chunks, and whereby the final portion of data was
not ran through the filter

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
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@nordicjm
nordicjm committed Oct 22, 2024
1 parent 29646ac commit 690c58e
Showing 1 changed file with 120 additions and 34 deletions.
154 changes: 120 additions & 34 deletions boot/zephyr/decompression.c
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,14 @@
#define EXPECTED_SIG_TLV IMAGE_TLV_ED25519
#endif

#define DECOMP_BUF_SIZE CONFIG_BOOT_DECOMPRESSION_BUFFER_SIZE
#if defined(CONFIG_NRF_COMPRESS_ARM_THUMB)
#define DECOMP_BUF_EXTRA_SIZE 2
#else
#define DECOMP_BUF_EXTRA_SIZE 0
#endif
#define DECOMP_BUF_ALLOC_SIZE (DECOMP_BUF_SIZE + DECOMP_BUF_EXTRA_SIZE)

/* Number of times that consumed data by decompression system can be 0 in a row before aborting */
#define OFFSET_ZERO_CHECK_TIMES 3

Expand Down Expand Up @@ -317,11 +325,6 @@ int bootutil_img_hash_decompress(struct enc_key_data *enc_state, int image_index
BOOT_LOG_ERR("Decompression error: %d", rc);
rc = BOOT_EBADSTATUS;
goto finish;
} else if (current_size != offset_arm_thumb) {
BOOT_LOG_ERR("Decompression expected offset mismatch: %d vs %d",
current_size, offset_arm_thumb);
rc = BOOT_EBADSTATUS;
goto finish;
}

bootutil_sha_update(&sha_ctx, output_arm_thumb, output_size_arm_thumb);
Expand Down Expand Up @@ -863,7 +866,7 @@ int boot_copy_region_decompress(struct boot_loader_state *state, const struct fl
struct nrf_compress_implementation *compression_lzma = NULL;
struct nrf_compress_implementation *compression_arm_thumb = NULL;
struct image_header *hdr;
TARGET_STATIC uint8_t decomp_buf[CONFIG_BOOT_DECOMPRESSION_BUFFER_SIZE] __attribute__((aligned(4)));
TARGET_STATIC uint8_t decomp_buf[DECOMP_BUF_ALLOC_SIZE] __attribute__((aligned(4)));
TARGET_STATIC struct image_header modified_hdr;

hdr = boot_img_hdr(state, BOOT_SECONDARY_SLOT);
Expand Down Expand Up @@ -950,6 +953,10 @@ int boot_copy_region_decompress(struct boot_loader_state *state, const struct fl
while (pos < hdr->ih_img_size) {
uint32_t copy_size = hdr->ih_img_size - pos;
uint32_t tmp_off = 0;
#if defined(CONFIG_NRF_COMPRESS_ARM_THUMB)
uint8_t excess_data_buffer[DECOMP_BUF_EXTRA_SIZE];
bool excess_data_buffer_full = false;
#endif

if (copy_size > buf_size) {
copy_size = buf_size;
Expand Down Expand Up @@ -985,8 +992,8 @@ int boot_copy_region_decompress(struct boot_loader_state *state, const struct fl
last_packet = true;
}

rc = compression_lzma->decompress(NULL, &buf[tmp_off], chunk_size, last_packet, &offset,
&output, &output_size);
rc = compression_lzma->decompress(NULL, &buf[tmp_off], chunk_size, last_packet,
&offset, &output, &output_size);

if (rc) {
BOOT_LOG_ERR("Decompression error: %d", rc);
Expand All @@ -996,42 +1003,55 @@ int boot_copy_region_decompress(struct boot_loader_state *state, const struct fl

/* Copy data to secondary buffer for writing out */
while (output_size > 0) {
uint32_t data_size = (sizeof(decomp_buf) - decomp_buf_size);
uint32_t data_size = (DECOMP_BUF_SIZE - decomp_buf_size);

if (data_size > output_size) {
data_size = output_size;
}

memcpy(&decomp_buf[decomp_buf_size], &output[compression_buffer_pos], data_size);
#if defined(CONFIG_NRF_COMPRESS_ARM_THUMB)
if (hdr->ih_flags & IMAGE_F_COMPRESSED_ARM_THUMB_FLT) {
memcpy(&decomp_buf[decomp_buf_size + DECOMP_BUF_EXTRA_SIZE],
&output[compression_buffer_pos], data_size);
} else
#endif
{
memcpy(&decomp_buf[decomp_buf_size], &output[compression_buffer_pos],
data_size);
}

compression_buffer_pos += data_size;

decomp_buf_size += data_size;
output_size -= data_size;

/* Write data out from secondary buffer when it is full */
if (decomp_buf_size == sizeof(decomp_buf)) {
if (decomp_buf_size == DECOMP_BUF_SIZE) {
#if defined(CONFIG_NRF_COMPRESS_ARM_THUMB)
if (hdr->ih_flags & IMAGE_F_COMPRESSED_ARM_THUMB_FLT) {
/* Run this through the ARM thumb filter */
uint32_t offset_arm_thumb = 0;
uint32_t output_size_arm_thumb = 0;
uint32_t filter_writeback_pos = 0;
uint32_t processed_size = 0;
uint8_t *output_arm_thumb = NULL;

while (processed_size < sizeof(decomp_buf)) {
uint32_t current_size = sizeof(decomp_buf);
/* Run this through the ARM thumb filter */
while (processed_size < DECOMP_BUF_SIZE) {
uint32_t offset_arm_thumb = 0;
uint32_t output_size_arm_thumb = 0;
uint8_t *output_arm_thumb = NULL;
uint32_t current_size = DECOMP_BUF_SIZE;
bool arm_thumb_last_packet = false;

if (current_size > CONFIG_NRF_COMPRESS_CHUNK_SIZE) {
current_size = CONFIG_NRF_COMPRESS_CHUNK_SIZE;
}

if (last_packet && (processed_size + current_size) ==
sizeof(decomp_buf)) {
if (last_packet && (processed_size + current_size) == DECOMP_BUF_SIZE
&& output_size == 0) {
arm_thumb_last_packet = true;
}

rc = compression_arm_thumb->decompress(NULL,
&decomp_buf[processed_size],
&decomp_buf[processed_size +
DECOMP_BUF_EXTRA_SIZE],
current_size,
arm_thumb_last_packet,
&offset_arm_thumb,
Expand All @@ -1044,25 +1064,70 @@ int boot_copy_region_decompress(struct boot_loader_state *state, const struct fl
goto finish;
}

memcpy(&decomp_buf[processed_size], output_arm_thumb, current_size);
memcpy(&decomp_buf[filter_writeback_pos], output_arm_thumb,
output_size_arm_thumb);
filter_writeback_pos += output_size_arm_thumb;
processed_size += current_size;
}
}

rc = flash_area_write(fap_dst, (off_dst + hdr->ih_hdr_size + write_pos),
decomp_buf, sizeof(decomp_buf));
if (excess_data_buffer_full == true)
{
/* Restore extra data removed from previous iteration to the write
* buffer
*/
memmove(&decomp_buf[DECOMP_BUF_EXTRA_SIZE], decomp_buf,
filter_writeback_pos);
memcpy(decomp_buf, excess_data_buffer, DECOMP_BUF_EXTRA_SIZE);
excess_data_buffer_full = false;
filter_writeback_pos += DECOMP_BUF_EXTRA_SIZE;
}

if (rc != 0) {
BOOT_LOG_ERR(
"Flash write failed at offset: 0x%x, size: 0x%x, area: %d, rc: %d",
(off_dst + hdr->ih_hdr_size + write_pos), sizeof(decomp_buf),
fap_dst->fa_id, rc);
rc = BOOT_EFLASH;
goto finish;
}
if ((filter_writeback_pos % sizeof(uint32_t)) != 0)
{
/* Since there are an extra 2 bytes here, remove them and stash for
* later usage to prevent flash write issues with non-word boundary
* writes
*/
memcpy(excess_data_buffer, &decomp_buf[filter_writeback_pos -
DECOMP_BUF_EXTRA_SIZE],
DECOMP_BUF_EXTRA_SIZE);
excess_data_buffer_full = true;
filter_writeback_pos -= DECOMP_BUF_EXTRA_SIZE;
}

rc = flash_area_write(fap_dst, (off_dst + hdr->ih_hdr_size + write_pos),
decomp_buf, filter_writeback_pos);

if (rc != 0) {
BOOT_LOG_ERR(
"Flash write failed at offset: 0x%x, size: 0x%x, area: %d, rc: %d",
(off_dst + hdr->ih_hdr_size + write_pos), DECOMP_BUF_SIZE,
fap_dst->fa_id, rc);
rc = BOOT_EFLASH;
goto finish;
}

write_pos += filter_writeback_pos;
decomp_buf_size = 0;
filter_writeback_pos = 0;
} else
#endif
{
rc = flash_area_write(fap_dst, (off_dst + hdr->ih_hdr_size + write_pos),
decomp_buf, DECOMP_BUF_SIZE);

if (rc != 0) {
BOOT_LOG_ERR(
"Flash write failed at offset: 0x%x, size: 0x%x, area: %d, rc: %d",
(off_dst + hdr->ih_hdr_size + write_pos), DECOMP_BUF_SIZE,
fap_dst->fa_id, rc);
rc = BOOT_EFLASH;
goto finish;
}

write_pos += sizeof(decomp_buf);
decomp_buf_size = 0;
write_pos += DECOMP_BUF_SIZE;
decomp_buf_size = 0;
}
}
}

Expand All @@ -1072,6 +1137,27 @@ int boot_copy_region_decompress(struct boot_loader_state *state, const struct fl
pos += copy_size;
}

#if defined(CONFIG_NRF_COMPRESS_ARM_THUMB)
if (hdr->ih_flags & IMAGE_F_COMPRESSED_ARM_THUMB_FLT && decomp_buf_size > 0) {
/* Extra data that has not been written out that needs ARM thumb filter applied */
uint32_t offset_arm_thumb = 0;
uint32_t output_size_arm_thumb = 0;
uint8_t *output_arm_thumb = NULL;

rc = compression_arm_thumb->decompress(NULL, &decomp_buf[DECOMP_BUF_EXTRA_SIZE],
decomp_buf_size, true, &offset_arm_thumb,
&output_arm_thumb, &output_size_arm_thumb);

if (rc) {
BOOT_LOG_ERR("Decompression error: %d", rc);
rc = BOOT_EBADSTATUS;
goto finish;
}

memcpy(decomp_buf, output_arm_thumb, output_size_arm_thumb);
}
#endif

/* Clean up decompression system */
(void)compression_lzma->deinit(NULL);
(void)compression_arm_thumb->deinit(NULL);
Expand Down

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