MIPS: ZBOOT: copy appended dtb to the end of the kernel

Instead of rewriting the arguments, just move the appended dtb to where
the decompressed kernel expects it. This eliminates the need for special
casing vmlinuz.bin appended dtb files.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: John Crispin <john@phrozen.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Alban Bedel <albeu@free.fr>
Cc: Daniel Gimpelevich <daniel@gimpelevich.san-francisco.ca.us>
Cc: Antony Pavlov <antonynpavlov@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13698/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 3953bb1..b0b0a4d 100644 (file)
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2884,10 +2884,10 @@ choice
                  the documented boot protocol using a device tree.
 
        config MIPS_RAW_APPENDED_DTB
-               bool "vmlinux.bin"
+               bool "vmlinux.bin or vmlinuz.bin"
                help
                  With this option, the boot code will look for a device tree binary
-                 DTB) appended to raw vmlinux.bin (without decompressor).
+                 DTB) appended to raw vmlinux.bin or vmlinuz.bin.
                  (e.g. cat vmlinux.bin <filename>.dtb > vmlinux_w_dtb).
 
                  This is meant as a backward compatibility convenience for those
@@ -2899,24 +2899,6 @@ choice
                  look like a DTB header after a reboot if no actual DTB is appended
                  to vmlinux.bin.  Do not leave this option active in a production kernel
                  if you don't intend to always append a DTB.
-
-       config MIPS_ZBOOT_APPENDED_DTB
-               bool "vmlinuz.bin"
-               depends on SYS_SUPPORTS_ZBOOT
-               help
-                 With this option, the boot code will look for a device tree binary
-                 DTB) appended to raw vmlinuz.bin (with decompressor).
-                 (e.g. cat vmlinuz.bin <filename>.dtb > vmlinuz_w_dtb).
-
-                 This is meant as a backward compatibility convenience for those
-                 systems with a bootloader that can't be upgraded to accommodate
-                 the documented boot protocol using a device tree.
-
-                 Beware that there is very little in terms of protection against
-                 this option being confused by leftover garbage in memory that might
-                 look like a DTB header after a reboot if no actual DTB is appended
-                 to vmlinuz.bin.  Do not leave this option active in a production kernel
-                 if you don't intend to always append a DTB.
 endchoice
 
 choice

diff --git a/arch/mips/boot/compressed/decompress.c b/arch/mips/boot/compressed/decompress.c
index 080cd53..fdf99e9 100644 (file)
--- a/arch/mips/boot/compressed/decompress.c
+++ b/arch/mips/boot/compressed/decompress.c
@@ -14,6 +14,7 @@
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
+#include <linux/libfdt.h>
 
 #include <asm/addrspace.h>
 
@@ -36,6 +37,8 @@ extern void puthex(unsigned long long val);
 #define puthex(val) do {} while (0)
 #endif
 
+extern char __appended_dtb[];
+
 void error(char *x)
 {
        puts("\n\n");
@@ -114,6 +117,20 @@ void decompress_kernel(unsigned long boot_heap_start)
        __decompress((char *)zimage_start, zimage_size, 0, 0,
                   (void *)VMLINUX_LOAD_ADDRESS_ULL, 0, 0, error);
 
+       if (IS_ENABLED(CONFIG_MIPS_RAW_APPENDED_DTB) &&
+           fdt_magic((void *)&__appended_dtb) == FDT_MAGIC) {
+               unsigned int image_size, dtb_size;
+
+               dtb_size = fdt_totalsize((void *)&__appended_dtb);
+
+               /* last four bytes is always image size in little endian */
+               image_size = le32_to_cpup((void *)&__image_end - 4);
+
+               /* copy dtb to where the booted kernel will expect it */
+               memcpy((void *)VMLINUX_LOAD_ADDRESS_ULL + image_size,
+                      __appended_dtb, dtb_size);
+       }
+
        /* FIXME: should we flush cache here? */
        puts("Now, booting the kernel...\n");
 }

diff --git a/arch/mips/boot/compressed/head.S b/arch/mips/boot/compressed/head.S
index c580e85..409cb48 100644 (file)
--- a/arch/mips/boot/compressed/head.S
+++ b/arch/mips/boot/compressed/head.S
@@ -25,22 +25,6 @@ start:
        move    s2, a2
        move    s3, a3
 
-#ifdef CONFIG_MIPS_ZBOOT_APPENDED_DTB
-       PTR_LA  t0, __appended_dtb
-#ifdef CONFIG_CPU_BIG_ENDIAN
-       li      t1, 0xd00dfeed
-#else
-       li      t1, 0xedfe0dd0
-#endif
-       lw      t2, (t0)
-       bne     t1, t2, not_found
-        nop
-
-       move    s1, t0
-       PTR_LI  s0, -2
-not_found:
-#endif
-
        /* Clear BSS */
        PTR_LA  a0, _edata
        PTR_LA  a2, _end