113 lines
3.4 KiB
Diff
113 lines
3.4 KiB
Diff
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From 1da8f1798e307fb8422753984339beb00025f97d Mon Sep 17 00:00:00 2001
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From: Jonas Gorski <jogo@openwrt.org>
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Date: Sun, 12 Apr 2015 12:24:58 +0200
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Subject: [PATCH] MIPS: Add support for vmlinux.bin appended dtb
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Add support for detecting a vmlinux.bin appended dtb and overriding
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the boot arguments to match the UHI interface.
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Due to the PERCPU section being empty for !SMP, but still modifying
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the current address by aligning it to the page size, do not define
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it for !SMP builds to allow __appended_dtb to still point to
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the actual end of the data.
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Signed-off-by: Jonas Gorski <jogo@openwrt.org>
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Cc: linux-mips@linux-mips.org
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Cc: devicetree@vger.kernel.org
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Cc: John Crispin <blogic@openwrt.org>
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Cc: Kevin Cernekee <cernekee@gmail.com>
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Cc: Florian Fainelli <f.fainelli@gmail.com>
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Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
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Cc: Markos Chandras <markos.chandras@imgtec.com>
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Cc: Andrew Bresticker <abrestic@chromium.org>
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Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
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Cc: Paul Burton <paul.burton@imgtec.com>
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Cc: James Hartley <James.Hartley@imgtec.com>
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Patchwork: https://patchwork.linux-mips.org/patch/9739/
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Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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---
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arch/mips/Kconfig | 27 +++++++++++++++++++++++++++
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arch/mips/kernel/head.S | 16 ++++++++++++++++
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arch/mips/kernel/vmlinux.lds.S | 8 +++++++-
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3 files changed, 50 insertions(+), 1 deletion(-)
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -2702,6 +2702,33 @@ config BOOT_RAW
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+choice
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+ prompt "Kernel appended dtb support" if OF
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+ default MIPS_NO_APPENDED_DTB
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+
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+ config MIPS_NO_APPENDED_DTB
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+ bool "None"
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+ help
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+ Do not enable appended dtb support.
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+
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+ config MIPS_RAW_APPENDED_DTB
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+ bool "vmlinux.bin"
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+ help
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+ With this option, the boot code will look for a device tree binary
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+ DTB) appended to raw vmlinux.bin (without decompressor).
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+ (e.g. cat vmlinux.bin <filename>.dtb > vmlinux_w_dtb).
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+
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+ This is meant as a backward compatibility convenience for those
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+ systems with a bootloader that can't be upgraded to accommodate
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+ the documented boot protocol using a device tree.
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+
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+ Beware that there is very little in terms of protection against
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+ this option being confused by leftover garbage in memory that might
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+ look like a DTB header after a reboot if no actual DTB is appended
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+ to vmlinux.bin. Do not leave this option active in a production kernel
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+ if you don't intend to always append a DTB.
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+endchoice
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+
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endmenu
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config LOCKDEP_SUPPORT
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--- a/arch/mips/kernel/head.S
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+++ b/arch/mips/kernel/head.S
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@@ -100,6 +100,22 @@ NESTED(kernel_entry, 16, sp) # kernel
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jr t0
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0:
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+#ifdef CONFIG_MIPS_RAW_APPENDED_DTB
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+ PTR_LA t0, __appended_dtb
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+
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+#ifdef CONFIG_CPU_BIG_ENDIAN
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+ li t1, 0xd00dfeed
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+#else
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+ li t1, 0xedfe0dd0
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+#endif
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+ lw t2, (t0)
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+ bne t1, t2, not_found
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+ nop
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+
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+ move a1, t0
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+ PTR_LI a0, -2
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+not_found:
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+#endif
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PTR_LA t0, __bss_start # clear .bss
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LONG_S zero, (t0)
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PTR_LA t1, __bss_stop - LONGSIZE
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--- a/arch/mips/kernel/vmlinux.lds.S
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+++ b/arch/mips/kernel/vmlinux.lds.S
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@@ -125,8 +125,14 @@ SECTIONS
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.exit.data : {
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EXIT_DATA
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}
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-
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+#ifdef CONFIG_SMP
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PERCPU_SECTION(1 << CONFIG_MIPS_L1_CACHE_SHIFT)
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+#endif
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+#ifdef CONFIG_MIPS_RAW_APPENDED_DTB
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+ __appended_dtb = .;
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+ /* leave space for appended DTB */
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+ . += 0x100000;
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+#endif
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/*
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* Align to 64K in attempt to eliminate holes before the
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* .bss..swapper_pg_dir section at the start of .bss. This
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