ARM: 6748/1: ignore mdesc->boot_params if out of range
The initial MMU table created in head.S contains a 1 MB mapping at the
start of memory to let the early kernel boot code access the boot params
specified by mdesc->boot_params.
When using CONFIG_ARM_PATCH_PHYS_VIRT it is possible for the kernel to
have a different idea of where the start of memory is at run time, making
the compile-time determined mdesc->boot_params pointing to a memory area
which is not mapped. Any access to the boot params in that case will
fault and silently hang the kernel at that point. It is therefore a
better idea to simply ignore mdesc->boot_params in that case and give
the kernel a chance to print some diagnostic on the console later.
If the bootloader provides a valid pointer in r2 to the kernel then this
is used instead of mdesc->boot_params, and an explicit mapping is already
created in the initial MMU table for it. It is therefore a good idea to
use that facility when using a relocated kernel.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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