On Mon, Aug 08, 2022 at 08:56:48AM +0200, Ahmad Fatoum wrote:
> FIT image contents are often compressed, but we got by so far, because
> a compressed initramfs is usually meant to be decompressed by the kernel
> (and so has compression = "none") and arm32 kernels had their own
> decompresser embedded. On ARM64, bootloader is responsible for
> uncompressing kernel, so we should properly process the compression
> property we so far ignored.
>
> The decompression isn't as efficient as one would hope for, because
> the FIT format only describes length of the compressed data. We thus
> have two options:
>
> - define an output size up-front, e.g. by guessing the uncompressed
> buffer size for decompression or hardcoding it (e.g. U-Boot's
> CONFIG_SYS_BOOTM_LEN).
>
> - Uncompress to a file descriptor
>
> We choose the second one to play it safe, but it comes with worse
> performance because of extra memory copies. Intention is to go with
> first option for the kernel image: We know how much size we can spare
> for the kernel image and can have bootm_load_os uncompress there
> directly without intermittent memory copies. This would involve slight
> change to the barebox decompresser API to align it with the kernel's,
> which allows to have it accept and observe an output buffer size.
> So far, we had the kernel PREBOOT API, which lacks such a parameter,
> but that's an optimization for another day.
>
> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
> ---
> common/image-fit.c | 38 +++++++++++++++++++++++++++++++++++---
> include/uncompress.h | 6 ++++++
> lib/uncompress.c | 40 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 81 insertions(+), 3 deletions(-)
>
> diff --git a/common/image-fit.c b/common/image-fit.c
> index 507a857cadb4..e692fcdaa737 100644
> --- a/common/image-fit.c
> +++ b/common/image-fit.c
> @@ -21,6 +21,7 @@
> #include <linux/err.h>
> #include <stringlist.h>
> #include <rsa.h>
> +#include <uncompress.h>
> #include <image-fit.h>
>
> #define FDT_MAX_DEPTH 32
> @@ -559,6 +560,11 @@ int fit_get_image_address(struct fit_handle *handle, void *configuration,
> return ret;
> }
>
> +static void fit_uncompress_error_fn(char *x)
> +{
> + pr_err("%s\n", x);
> +}
> +
> /**
> * fit_open_image - Open an image in a FIT image
> * @handle: The FIT image handle
> @@ -581,8 +587,10 @@ int fit_open_image(struct fit_handle *handle, void *configuration,
> unsigned long *outsize)
> {
> struct device_node *image;
> - const char *unit = name, *type = NULL, *desc= "(no description)";
> - const void *data;
> + const char *unit = name, *type = NULL, *compression = NULL,
> + *desc= "(no description)";
> + struct property *dataprop;
> + const void *data = NULL;
> int data_len;
> int ret = 0;
>
> @@ -599,7 +607,9 @@ int fit_open_image(struct fit_handle *handle, void *configuration,
> return -EINVAL;
> }
>
> - data = of_get_property(image, "data", &data_len);
> + dataprop = of_find_property(image, "data", &data_len);
> + if (dataprop)
> + data = of_property_get_value(dataprop);
> if (!data) {
> pr_err("data not found\n");
> return -EINVAL;
> @@ -613,6 +623,28 @@ int fit_open_image(struct fit_handle *handle, void *configuration,
> if (ret < 0)
> return ret;
>
> + of_property_read_string(image, "compression", &compression);
> + if (compression && strcmp(compression, "none") != 0) {
> + if (!IS_ENABLED(CONFIG_UNCOMPRESS)) {
> + pr_err("image has compression = \"%s\", but support not compiled in\n");
> + return -ENOSYS;
> + }
> + if (!dataprop->value) {
> + void *uc_data;
> +
> + data_len = uncompress_buf_to_buf(data, data_len, &uc_data,
> + fit_uncompress_error_fn);
> + if (data_len < 0) {
> + pr_err("data couldn't be decompressed\n");
> + return data_len;
> + }
> +
> + /* associate buffer with FIT, so it's not leaked */
> + data = dataprop->value = uc_data;
> + dataprop->length = data_len;
Why are you fiddling with struct property fields directly?
of_get_property() and of_set_property() should do what you want.
Sascha
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