[PATCH] openrisc: Add support for external initrd images

[Stafford Horne]

In OpenRISC we set the initrd_start and initrd_end based on the symbols
we setup in vmlinux.lds.S.  However, this is not needed if we use the
generic linker description in INIT_DATA_SECTION.

Removing our own initrd setup reduces code, but also the generic code
supports loading external initrd images.  A bootloader can load a rootfs
image into memory and we can configure devicetree to load it with:

        chosen {
                bootargs = "earlycon";
                stdout-path = "uart0:115200";
                linux,initrd-start = < 0x08000100 >;
                linux,initrd-end = < 0x08200000 >;
        };

Reported-by: Mateusz Holenko <mhole...@antmicro.com>
Signed-off-by: Stafford Horne <sho...@gmail.com>
---
 arch/openrisc/kernel/setup.c       |  8 +++++---
 arch/openrisc/kernel/vmlinux.lds.S | 12 ------------
 2 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/arch/openrisc/kernel/setup.c b/arch/openrisc/kernel/setup.c
index 8aa438e1f51f..b18e775f8be3 100644
--- a/arch/openrisc/kernel/setup.c
+++ b/arch/openrisc/kernel/setup.c
@@ -292,13 +292,15 @@ void __init setup_arch(char **cmdline_p)
        init_mm.brk = (unsigned long)_end;
 
 #ifdef CONFIG_BLK_DEV_INITRD
-       initrd_start = (unsigned long)&__initrd_start;
-       initrd_end = (unsigned long)&__initrd_end;
        if (initrd_start == initrd_end) {
+               printk(KERN_INFO "Initial ramdisk not found\n");
                initrd_start = 0;
                initrd_end = 0;
+       } else {
+               printk(KERN_INFO "Initial ramdisk at: 0x%p (%lu bytes)\n",
+                      (void *)(initrd_start), initrd_end - initrd_start);
+               initrd_below_start_ok = 1;
        }
-       initrd_below_start_ok = 1;
 #endif
 
        /* setup memblock allocator */
diff --git a/arch/openrisc/kernel/vmlinux.lds.S 
b/arch/openrisc/kernel/vmlinux.lds.S
index 60449fd7f16f..22fbc5fb24b3 100644
--- a/arch/openrisc/kernel/vmlinux.lds.S
+++ b/arch/openrisc/kernel/vmlinux.lds.S
@@ -96,18 +96,6 @@ SECTIONS
 
         __init_end = .;
 
-       . = ALIGN(PAGE_SIZE);
-       .initrd                 : AT(ADDR(.initrd) - LOAD_OFFSET)
-       {
-               __initrd_start = .;
-               *(.initrd)
-               __initrd_end = .;
-               FILL (0);
-                . = ALIGN (PAGE_SIZE);
-       }
-
-        __vmlinux_end = .;            /* last address of the physical file */
-
        BSS_SECTION(0, 0, 0x20)
 
         _end = .;
-- 
2.26.2