On 2/22/21 10:21 PM, Tom Rini wrote:
On Mon, Feb 22, 2021 at 07:18:51PM +0000, Niko Mauno wrote:
By declaring board-specific board_fdt_chosen_bootargs() the kernel
command line arguments can be adjusted before injecting to flat dt
chosen node.
Signed-off-by: Niko Mauno <niko.ma...@vaisala.com>
---
common/fdt_support.c | 12 +++++++++++-
include/fdt_support.h | 10 ++++++++++
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/common/fdt_support.c b/common/fdt_support.c
index 08d540bfc8..4379507e30 100644
--- a/common/fdt_support.c
+++ b/common/fdt_support.c
@@ -269,6 +269,15 @@ int fdt_initrd(void *fdt, ulong initrd_start, ulong
initrd_end)
return 0;
}
+/**
+ * board_fdt_chosen_bootargs - boards may override this function to use
+ * alternative kernel command line arguments
+ */
+__weak char *board_fdt_chosen_bootargs(void)
+{
+ return env_get("bootargs");
+}
+
int fdt_chosen(void *fdt)
{
int nodeoffset;
@@ -286,7 +295,8 @@ int fdt_chosen(void *fdt)
if (nodeoffset < 0)
return nodeoffset;
- str = env_get("bootargs");
+ str = board_fdt_chosen_bootargs();
+
if (str) {
err = fdt_setprop(fdt, nodeoffset, "bootargs", str,
strlen(str) + 1);
What's this look like in practice? I'm very wary about changing "set
bootargs to what you pass to the kernel" logic that's been there for
forever and a constant of every platform. Thanks!
Hi Tom,
Effectively this change as such should introduce no changes to
prevalent "bootargs" logic when an overriding
board_fdt_chosen_bootargs() is not defined. Our motivation for proposing
this change is that it provides us with a means to introduce an entry
point where we can append rootfs specific dm-verity kernel command line
metrics (such as described in
https://www.kernel.org/doc/html/latest/admin-guide/device-mapper/verity.html)
by reading a property from within a kernel tier FIT image header, in
order to facilitate secure boot process all the way to root filesystem.
-Niko
