kernel: re-apply 300-arch-arm-force-ZRELADDR-on-arch-qcom.patch on 4.9 (FS#549)

Fixes memory corruption issues. See commit bdcba36442 for more
details.

Signed-off-by: Felix Fietkau <nbd@nbd.name>

target/linux/ipq806x/config-4.9

@@ -56,7 +56,6 @@ CONFIG_ARM_THUMB=y
 CONFIG_ARM_UNWIND=y
 CONFIG_ARM_VIRT_EXT=y
 CONFIG_AT803X_PHY=y
-CONFIG_AUTO_ZRELADDR=y
 # CONFIG_B53 is not set
 # CONFIG_BINFMT_FLAT is not set
 CONFIG_BLK_DEV_LOOP=y

target/linux/ipq806x/patches-4.9/300-arch-arm-force-ZRELADDR-on-arch-qcom.patch

@@ -0,0 +1,62 @@
+From b12e230f09d4481424e6a5d7e2ae566b6954e83f Mon Sep 17 00:00:00 2001
+From: Mathieu Olivari <mathieu@codeaurora.org>
+Date: Wed, 29 Apr 2015 15:21:46 -0700
+Subject: [PATCH] HACK: arch: arm: force ZRELADDR on arch-qcom
+
+ARCH_QCOM is using the ARCH_MULTIPLATFORM option, as now recommended
+on most ARM architectures. This automatically calculate ZRELADDR by
+masking PHYS_OFFSET with 0xf8000000.
+
+However, on IPQ806x, the first ~20MB of RAM is reserved for the hardware
+network accelerators, and the bootloader removes this section from the
+layout passed from the ATAGS (when used).
+
+For newer bootloader, when DT is used, this is not a problem, we just
+reserve this memory in the device tree. But if the bootloader doesn't
+have DT support, then ATAGS have to be used. In this case, the ARM
+decompressor will position the kernel in this low mem, which will not be
+in the RAM section mapped by the bootloader, which means the kernel will
+freeze in the middle of the boot process trying to map the memory.
+
+As a work around, this patch allows disabling AUTO_ZRELADDR when
+ARCH_QCOM is selected. It makes the zImage usage possible on bootloaders
+which don't support device-tree, which is the case on certain early
+IPQ806x based designs.
+
+Signed-off-by: Mathieu Olivari <mathieu@codeaurora.org>
+---
+ arch/arm/Kconfig                 | 2 +-
+ arch/arm/Makefile                | 2 ++
+ arch/arm/mach-qcom/Makefile.boot | 1 +
+ 3 files changed, 4 insertions(+), 1 deletion(-)
+ create mode 100644 arch/arm/mach-qcom/Makefile.boot
+
+--- a/arch/arm/Kconfig
++++ b/arch/arm/Kconfig
+@@ -332,7 +332,7 @@ config ARCH_MULTIPLATFORM
+ 	depends on MMU
+ 	select ARM_HAS_SG_CHAIN
+ 	select ARM_PATCH_PHYS_VIRT
+-	select AUTO_ZRELADDR
++	select AUTO_ZRELADDR if !ARCH_QCOM
+ 	select CLKSRC_OF
+ 	select COMMON_CLK
+ 	select GENERIC_CLOCKEVENTS
+--- a/arch/arm/Makefile
++++ b/arch/arm/Makefile
+@@ -251,9 +251,11 @@ MACHINE  := arch/arm/mach-$(word 1,$(mac
+ else
+ MACHINE  :=
+ endif
++ifeq ($(CONFIG_ARCH_QCOM),)
+ ifeq ($(CONFIG_ARCH_MULTIPLATFORM),y)
+ MACHINE  :=
+ endif
++endif
+ 
+ machdirs := $(patsubst %,arch/arm/mach-%/,$(machine-y))
+ platdirs := $(patsubst %,arch/arm/plat-%/,$(sort $(plat-y)))
+--- /dev/null
++++ b/arch/arm/mach-qcom/Makefile.boot
+@@ -0,0 +1 @@
++zreladdr-y+= 0x42208000