Commit 1da8f179 authored by Jonas Gorski's avatar Jonas Gorski Committed by Ralf Baechle
Browse files

MIPS: Add support for vmlinux.bin appended dtb 



Add support for detecting a vmlinux.bin appended dtb and overriding
the boot arguments to match the UHI interface.

Due to the PERCPU section being empty for !SMP, but still modifying
the current address by aligning it to the page size, do not define
it for !SMP builds to allow __appended_dtb to still point to
the actual end of the data.

Signed-off-by: default avatarJonas Gorski <jogo@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Cc: John Crispin <blogic@openwrt.org>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: James Hartley <James.Hartley@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/9739/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 01306aea

arch/mips/Kconfig

+27 −0
Original line number Diff line number Diff line
@@ -2677,6 +2677,33 @@ config USE_OF 
config BUILTIN_DTB

	bool



choice

	prompt "Kernel appended dtb support" if OF

	default MIPS_NO_APPENDED_DTB



	config MIPS_NO_APPENDED_DTB

		bool "None"

		help

		  Do not enable appended dtb support.



	config MIPS_RAW_APPENDED_DTB

		bool "vmlinux.bin"

		help

		  With this option, the boot code will look for a device tree binary

		  DTB) appended to raw vmlinux.bin (without decompressor).

		  (e.g. cat vmlinux.bin <filename>.dtb > vmlinux_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 vmlinux.bin.  Do not leave this option active in a production kernel

		  if you don't intend to always append a DTB.

endchoice



endmenu



config LOCKDEP_SUPPORT

arch/mips/kernel/head.S

+16 −0
Original line number Diff line number Diff line
@@ -94,6 +94,22 @@ NESTED(kernel_entry, 16, sp) # kernel entry point 
	jr	t0

0:



#ifdef CONFIG_MIPS_RAW_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		a1, t0

	PTR_LI		a0, -2

not_found:

#endif

	PTR_LA		t0, __bss_start		# clear .bss

	LONG_S		zero, (t0)

	PTR_LA		t1, __bss_stop - LONGSIZE

arch/mips/kernel/vmlinux.lds.S

+7 −1
Original line number Diff line number Diff line
@@ -125,8 +125,14 @@ SECTIONS 
	.exit.data : {

		EXIT_DATA

	}



#ifdef CONFIG_SMP

	PERCPU_SECTION(1 << CONFIG_MIPS_L1_CACHE_SHIFT)

#endif

#ifdef CONFIG_MIPS_RAW_APPENDED_DTB

	__appended_dtb = .;

	/* leave space for appended DTB */

	. += 0x100000;

#endif

	/*

	 * Align to 64K in attempt to eliminate holes before the

	 * .bss..swapper_pg_dir section at the start of .bss.  This

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