Thanks Bjorn for the review comments.
On 3/15/2023 7:12 PM, Bjorn Andersson wrote:
On Mon, Mar 06, 2023 at 03:11:59PM -0800, Melody Olvera wrote:
From: Gokul Krishna Krishnakumar <quic_gokukris@xxxxxxxxxxx>
When booting with split binaries, 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 and fail for split bins.
Can you please be more explicit about the scenario you're having
problems with?
In this scenario below, the first pheader end address is < mdt file size
but the next pheader lies outside the mdt file size. The
_qcom_mdt_load() would continue on to load the firmware as a single
image which leads to load error. By checking if all the pheaders lie
inside the file size, we will be able to fix this issue.
fw = cdsp_dtb.mdt phdr->p_filesz = 148 phdr->p_offset 0 fw->size 4044
fw = cdsp_dtb.mdt phdr->p_filesz = 512 phdr->p_offset 148 fw->size 4044
fw = cdsp_dtb.mdt phdr->p_filesz = 3896 phdr->p_offset 4096 fw->size 4044
Is the problem that the first segment is represented in both the .mdt
and .b01, but different? Or is it that you find the hash in both .mdt
abd .b01, but only one of them is valid?
This change updates the logic used
by the mdt loader to understand whether the firmware images are split or not
by checking if each programs header's segment lies within the file or not.
Signed-off-by: Gokul Krishna Krishnakumar <quic_gokukris@xxxxxxxxxxx>
Signed-off-by: Melody Olvera <quic_molvera@xxxxxxxxxxx>
---
drivers/soc/qcom/mdt_loader.c | 64 +++++++++++++++++++----------------
1 file changed, 35 insertions(+), 29 deletions(-)
diff --git a/drivers/soc/qcom/mdt_loader.c b/drivers/soc/qcom/mdt_loader.c
index 33dd8c315eb7..3aadce299c02 100644
--- a/drivers/soc/qcom/mdt_loader.c
+++ b/drivers/soc/qcom/mdt_loader.c
@@ -31,6 +31,26 @@ static bool mdt_phdr_valid(const struct elf32_phdr *phdr)
return true;
}
+static bool qcom_mdt_bins_are_split(const struct firmware *fw)
+{
+ 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 ssize_t mdt_load_split_segment(void *ptr, const struct elf32_phdr *phdrs,
unsigned int segment, const char *fw_name,
struct device *dev)
@@ -167,23 +187,13 @@ void *qcom_mdt_read_metadata(const struct firmware *fw, size_t *data_len,
/* Copy ELF header */
memcpy(data, fw->data, ehdr_size);
The existing code handles 3 cases:
- if (ehdr_size + hash_size == fw->size) {
1) File is split, but hash resides with the ELF header in the .mdt
- /* Firmware is split and hash is packed following the ELF header */
- hash_offset = phdrs[0].p_filesz;
- memcpy(data + ehdr_size, fw->data + hash_offset, hash_size);
- } else if (phdrs[hash_segment].p_offset + hash_size <= fw->size) {
2) The hash segment exists in a segment of its own, but in the loaded
image.
- /* Hash is in its own segment, but within the loaded file */
+
+ if (qcom_mdt_bins_are_split(fw)) {
+ ret = mdt_load_split_segment(data + ehdr_size, phdrs, hash_segment, fw_name, dev);
+ } else {
hash_offset = phdrs[hash_segment].p_offset;
memcpy(data + ehdr_size, fw->data + hash_offset, hash_size);
- } else {
3) The image is split, and the hash segment resides in it's own file.
Afaict the updated logic maintains #2 and #3, but drops #1. Please
review the git history to see if you can determine which target this
case exists with - and ask for someone to specifically verify your
change there.
Perhaps all your change is doing is removing case #1, in which case this
should be clear in the commit message; and we need to validate that your
new assumptions holds.
- /* Hash is in its own segment, beyond the loaded file */
- ret = mdt_load_split_segment(data + ehdr_size, phdrs, hash_segment, fw_name, dev);
For some reason you reversed the condition and got this out of the else
(seems like an unnecessary change)...but in the process you lost the
error handling below.
Yes, Updating the patch to remove this unnecessary change in the
qcom_mdt_read_metadat().
- if (ret) {
- kfree(data);
- return ERR_PTR(ret);
- }
}
-
*data_len = ehdr_size + hash_size;
return data;
@@ -270,6 +280,7 @@ 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 +288,7 @@ 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);
ehdr = (struct elf32_hdr *)fw->data;
phdrs = (struct elf32_phdr *)(ehdr + 1);
@@ -330,22 +342,16 @@ 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) {
- /* 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",
- fw_name, i);
- ret = -EINVAL;
- break;
+ if (phdr->p_filesz) {
If you just change the condition (phr->p_filesz && !issplit), then your
patch becomes easier to read.
Done.
V3: only make change in the __qcom_mdt_load() and not in the
qcom_mdt_read_metadata().
Regards,
Bjorn
+ if (!is_split) {
+ /* Firmware is large enough to be non-split */
+ memcpy(ptr, fw->data + phdr->p_offset, phdr->p_filesz);
+ } else {
+ /* Firmware not large enough, load split-out segments */
+ ret = mdt_load_split_segment(ptr, phdrs, i, fw_name, dev);
+ if (ret)
+ break;
}
-
- memcpy(ptr, fw->data + phdr->p_offset, phdr->p_filesz);
- } else if (phdr->p_filesz) {
- /* Firmware not large enough, load split-out segments */
- ret = mdt_load_split_segment(ptr, phdrs, i, fw_name, dev);
- if (ret)
- break;
}
if (phdr->p_memsz > phdr->p_filesz)
--
2.25.1
Thanks,
Gokul
