arch: riscv: support kernel command line forcing when no DTB passed

CONFIG_CMDLINE_FORCE doesn't work on RISC-V when no DTB is passed into
the kernel.  This is because the code that forces the kernel command
line only runs if a valid DTB is present at boot.  During debugging,
it's useful to have the ability to force kernel command lines even
when no DTB is present.  This patch adds support for doing so.

Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org (open list)
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index fc8006a042ebc0af6c88ccf9341bc702800ce0fe..6e079e94b6386277ae80e5a542fc70a80a4b3e73 100644 (file)
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -149,7 +149,14 @@ asmlinkage void __init setup_vm(void)
 
 void __init parse_dtb(unsigned int hartid, void *dtb)
 {
-       early_init_dt_scan(__va(dtb));
+       if (!early_init_dt_scan(__va(dtb)))
+               return;
+
+       pr_err("No DTB passed to the kernel\n");
+#ifdef CONFIG_CMDLINE_FORCE
+       strlcpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+       pr_info("Forcing kernel command line to: %s\n", boot_command_line);
+#endif
 }
 
 static void __init setup_bootmem(void)