pl08x_pre_boundary() was unsafe with addresses towards the top of
memory space:
boundary = ((addr >> PL08X_BOUNDARY_SHIFT) + 1)
<< PL08X_BOUNDARY_SHIFT;
This can overflow a 32-bit number, producing zero. When it does:
if (boundary < addr + len)
return boundary - addr;
else
return len;
results in (boundary - addr) returning either a large positive value.
Also if addr + len overflows, this calculation also fails.
We can fix this trivially as the only thing we're actually interested
in is the value of the least significant PL08X_BOUNDARY_SHIFT bits:
boundary_len = PL08X_BOUNDARY_SIZE -
(addr & (PL08X_BOUNDARY_SIZE - 1));
gives us the number of bytes before 'addr' becomes a multiple of
PL08X_BOUNDARY_SIZE. We can then just take the min() of the two
calculated lengths.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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