Update Linux to v5.10.157

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.157.tar.xz

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I7b30d9e98d8c465d6b44de8e7433b4a40b3289ba
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 1372f40..a4dd500 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -793,6 +793,8 @@
 		  size_t offset, u32 opt_flags)
 {
 	struct firmware *fw = NULL;
+	struct cred *kern_cred = NULL;
+	const struct cred *old_cred;
 	bool nondirect = false;
 	int ret;
 
@@ -809,6 +811,18 @@
 	if (ret <= 0) /* error or already assigned */
 		goto out;
 
+	/*
+	 * We are about to try to access the firmware file. Because we may have been
+	 * called by a driver when serving an unrelated request from userland, we use
+	 * the kernel credentials to read the file.
+	 */
+	kern_cred = prepare_kernel_cred(NULL);
+	if (!kern_cred) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	old_cred = override_creds(kern_cred);
+
 	ret = fw_get_filesystem_firmware(device, fw->priv, "", NULL);
 
 	/* Only full reads can support decompression, platform, and sysfs. */
@@ -834,6 +848,9 @@
 	} else
 		ret = assign_fw(fw, device);
 
+	revert_creds(old_cred);
+	put_cred(kern_cred);
+
  out:
 	if (ret < 0) {
 		fw_abort_batch_reqs(fw);