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| author |   John Williams <john.williams@petalogix.com> | 2009-06-22 14:02:09 +1000 |
|---|---|---|
| committer |   Michal Simek <monstr@monstr.eu> | 2009-07-27 07:39:53 +0200 |
| commit | 909964ec89ba466d75d53250d5738d1891cc1a3d (patch) | |
| tree | 5b0b2ce13b2d82e9193dd0398535f634d8c4d8e7 /arch/microblaze/kernel/head.S | |
| parent | microblaze: remove duplicated #include (diff) | |
| download | linux-dev-909964ec89ba466d75d53250d5738d1891cc1a3d.tar.xz linux-dev-909964ec89ba466d75d53250d5738d1891cc1a3d.zip | |
microblaze: Final support for statically linked DTB
If r7 is zero at kernel boot, or does not point to a valid DTB, then
we fall back to a DTB (assumed to be) linked statically in the kernel, instead
of blindly copying bogus cruft into the kernel DTB memory region
Signed-off-by: John Williams <john.williams@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
Diffstat (limited to 'arch/microblaze/kernel/head.S')
| -rw-r--r-- | arch/microblaze/kernel/head.S | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S index e568d6ec621b..815bcaae99c3 100644 --- a/arch/microblaze/kernel/head.S +++ b/arch/microblaze/kernel/head.S @@ -31,6 +31,7 @@ #include <linux/linkage.h> #include <asm/thread_info.h> #include <asm/page.h> +#include <asm/prom.h> /* for OF_DT_HEADER */ #ifdef CONFIG_MMU #include <asm/setup.h> /* COMMAND_LINE_SIZE */ @@ -54,11 +55,16 @@ ENTRY(_start) andi r1, r1, ~2 mts rmsr, r1 -/* save fdt to kernel location */ -/* r7 stores pointer to fdt blob */ - beqi r7, no_fdt_arg +/* r7 may point to an FDT, or there may be one linked in. + if it's in r7, we've got to save it away ASAP. + We ensure r7 points to a valid FDT, just in case the bootloader + is broken or non-existent */ + beqi r7, no_fdt_arg /* NULL pointer? don't copy */ + lw r11, r0, r7 /* Does r7 point to a */ + rsubi r11, r11, OF_DT_HEADER /* valid FDT? */ + bnei r11, no_fdt_arg /* No - get out of here */ or r11, r0, r0 /* incremment */ - ori r4, r0, TOPHYS(_fdt_start) /* save bram context */ + ori r4, r0, TOPHYS(_fdt_start) ori r3, r0, (0x4000 - 4) _copy_fdt: lw r12, r7, r11 /* r12 = r7 + r11 */ @@ -67,6 +73,7 @@ _copy_fdt: bgtid r3, _copy_fdt /* loop for all entries */ addik r3, r3, -4 /* descrement loop */ no_fdt_arg: + add r7, r0, r0 /* Clear r7, just to be sure */ #ifdef CONFIG_MMU |