soc: qcom: mdt_loader: Allow hash to reside in any segment

It's been observed that some firmware found on Qualcomm SM8450 devices
carries the hash segment as the last segment in the ELF. Extend the
support to allow picking the hash from any segment in the MDT/MBN.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220128025513.97188-5-bjorn.andersson@linaro.org

drivers/soc/qcom/mdt_loader.c

@@ -126,9 +126,11 @@ void *qcom_mdt_read_metadata(const struct firmware *fw, size_t *data_len,
 {
 	const struct elf32_phdr *phdrs;
 	const struct elf32_hdr *ehdr;
+	unsigned int hash_segment = 0;
 	size_t hash_offset;
 	size_t hash_size;
 	size_t ehdr_size;
+	unsigned int i;
 	ssize_t ret;
 	void *data;
 
@@ -141,11 +143,20 @@ void *qcom_mdt_read_metadata(const struct firmware *fw, size_t *data_len,
 	if (phdrs[0].p_type == PT_LOAD)
 		return ERR_PTR(-EINVAL);
 
-	if ((phdrs[1].p_flags & QCOM_MDT_TYPE_MASK) != QCOM_MDT_TYPE_HASH)
+	for (i = 1; i < ehdr->e_phnum; i++) {
+		if ((phdrs[i].p_flags & QCOM_MDT_TYPE_MASK) == QCOM_MDT_TYPE_HASH) {
+			hash_segment = i;
+			break;
+		}
+	}
+
+	if (!hash_segment) {
+		dev_err(dev, "no hash segment found in %s\n", fw_name);
 		return ERR_PTR(-EINVAL);
+	}
 
 	ehdr_size = phdrs[0].p_filesz;
-	hash_size = phdrs[1].p_filesz;
+	hash_size = phdrs[hash_segment].p_filesz;
 
 	data = kmalloc(ehdr_size + hash_size, GFP_KERNEL);
 	if (!data)
@@ -158,13 +169,13 @@ void *qcom_mdt_read_metadata(const struct firmware *fw, size_t *data_len,
 		/* 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[1].p_offset + hash_size <= fw->size) {
+	} else if (phdrs[hash_segment].p_offset + hash_size <= fw->size) {
 		/* Hash is in its own segment, but within the loaded file */
-		hash_offset = phdrs[1].p_offset;
+		hash_offset = phdrs[hash_segment].p_offset;
 		memcpy(data + ehdr_size, fw->data + hash_offset, hash_size);
 	} else {
 		/* Hash is in its own segment, beyond the loaded file */
-		ret = mdt_load_split_segment(data + ehdr_size, phdrs, 1, fw_name, dev);
+		ret = mdt_load_split_segment(data + ehdr_size, phdrs, hash_segment, fw_name, dev);
 		if (ret) {
 			kfree(data);
 			return ERR_PTR(ret);