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ARM: 6748/1: ignore mdesc->boot_params if out of range

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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>
This commit is contained in:
Nicolas Pitre 2011-02-21 06:57:33 +01:00 committed by Russell King
parent dce72dd08c
commit 3572bea8cb
1 changed files with 19 additions and 2 deletions
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21
arch/arm/kernel/setup.c
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@ -839,8 +839,25 @@ void __init setup_arch(char **cmdline_p)
if (__atags_pointer)
tags = phys_to_virt(__atags_pointer);
else if (mdesc->boot_params)
tags = phys_to_virt(mdesc->boot_params);
else if (mdesc->boot_params) {
#ifdef CONFIG_MMU
/*
* We still are executing with a minimal MMU mapping created
* with the presumption that the machine default for this
* is located in the first MB of RAM. Anything else will
* fault and silently hang the kernel at this point.
*/
if (mdesc->boot_params < PHYS_OFFSET ||
mdesc->boot_params >= PHYS_OFFSET + SZ_1M) {
printk(KERN_WARNING
"Default boot params at physical 0x%08lx out of reach\n",
mdesc->boot_params);
} else
#endif
{
tags = phys_to_virt(mdesc->boot_params);
}
}
#if defined(CONFIG_DEPRECATED_PARAM_STRUCT)
/*