Re: [PATCH v5 1/1] soc: qcom: mdt_loader: Enhance split binary detection

Bjorn Andersson
2023-04-10T21:48:46Z

On Mon, Apr 10, 2023 at 10:14:32AM -0700, Gokul krishna Krishnakumar wrote:
> It may be that the offset of the first program header lies inside the mdt's
> filesize, in this case the loader would incorrectly assume that the bins
> were not split. The loading would then continue on to fail for split bins.
> This change updates the logic used by the mdt loader to understand whether
> the firmware images are split or not. It figures this out by checking if
> each programs header's segment lies within the file or not.
>
> Signed-off-by: Gokul krishna Krishnakumar <quic_gokukris@quicinc.com>
> Signed-off-by: Melody Olvera <quic_molvera@quicinc.com>

Please read Documentation/process/submitting-patches.rst section about
Developer's Certificate of Origin 1.1, then apply that for each person
in the S-o-b chain from the top. Finally consider how Melody's name can
be the last one in this list, while the patch is coming from you.

> ---
> V5: Removes extra empty lines from V4.

That's nice, but what about the other changes I asked for?

Regards,
Bjorn

>
> V4: Removes the unneceessary change in qcom_mdt_read_metadata(), the
> exisiting check holds good in case the hash segment is in the loaded image.
>
> V3 is separated out from [1] and includes
> changes addressing comments from that patch set.
>
> [1] https://lore.kernel.org/all/20230306231202.12223-5-quic_molvera@quicinc.com/
> ---
> drivers/soc/qcom/mdt_loader.c | 25 +++++++++++++++++++++++--
> 1 file changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/soc/qcom/mdt_loader.c b/drivers/soc/qcom/mdt_loader.c
> index 33dd8c315eb7..814646ce41e5 100644
> --- a/drivers/soc/qcom/mdt_loader.c
> +++ b/drivers/soc/qcom/mdt_loader.c
> @@ -258,6 +258,26 @@ int qcom_mdt_pas_init(struct device *dev, const struct firmware *fw,
> }
> EXPORT_SYMBOL_GPL(qcom_mdt_pas_init);
>
> +static bool qcom_mdt_bins_are_split(const struct firmware *fw, const char* fw_name)
> +{
> + const struct elf32_phdr *phdrs;
> + const struct elf32_hdr *ehdr;
> + uint64_t seg_start, seg_end;
> + int i;
> +
> + ehdr = (struct elf32_hdr *)fw->data;
> + phdrs = (struct elf32_phdr *)(ehdr + 1);
> +
> + for (i = 0; i < ehdr->e_phnum; i++) {
> + seg_start = phdrs[i].p_offset;
> + seg_end = phdrs[i].p_offset + phdrs[i].p_filesz;
> + if (seg_start > fw->size || seg_end > fw->size)
> + return true;
> + }
> +
> + return false;
> +}
> +
> static int __qcom_mdt_load(struct device *dev, const struct firmware *fw,
> const char *fw_name, int pas_id, void *mem_region,
> phys_addr_t mem_phys, size_t mem_size,
> @@ -270,6 +290,7 @@ static int __qcom_mdt_load(struct device *dev, const struct firmware *fw,
> phys_addr_t min_addr = PHYS_ADDR_MAX;
> ssize_t offset;
> bool relocate = false;
> + bool is_split;
> void *ptr;
> int ret = 0;
> int i;
> @@ -277,6 +298,7 @@ static int __qcom_mdt_load(struct device *dev, const struct firmware *fw,
> if (!fw || !mem_region || !mem_phys || !mem_size)
> return -EINVAL;
>
> + is_split = qcom_mdt_bins_are_split(fw, fw_name);
> ehdr = (struct elf32_hdr *)fw->data;
> phdrs = (struct elf32_phdr *)(ehdr + 1);
>
> @@ -330,8 +352,7 @@ static int __qcom_mdt_load(struct device *dev, const struct firmware *fw,
>
> ptr = mem_region + offset;
>
> - if (phdr->p_filesz && phdr->p_offset < fw->size &&
> - phdr->p_offset + phdr->p_filesz <= fw->size) {
> + if (phdr->p_filesz && !is_split) {
> /* Firmware is large enough to be non-split */
> if (phdr->p_offset + phdr->p_filesz > fw->size) {
> dev_err(dev, "file %s segment %d would be truncated\n",
> --
> 2.39.2
>