Robin Getz wrote:
On Thu 3 May 2007 07:03, Greg Ungerer pondered:
Robin Getz wrote:
On Wed 2 May 2007 07:32, Greg Ungerer pondered:
Robin Getz wrote:
I was trying to understand why we don't want to do the same checking on
noMMU?
The problem is on systems that have RAM mapped at high physical
addresses. TASK_SIZE may well be a numerically smaller number
than the address range that RAM sits in. So this test fails when
it shouldn't.
So, then this is a problem only on one or two architectures, not all
noMMU platforms?
Its not an architecture problem. It can effect any board that
has RAM mapped at a large numerical addresses (larger than TASK_SIZE).
So it can effect any non-MMU platform.
Depending on how TASK_SIZE is defined - it looks like everyone else forces it
to end of memory, except 68k[nommu].
asm-arm/memory.h:#define TASK_SIZE (CONFIG_DRAM_SIZE)
asm-blackfin/processor.h:#define TASK_SIZE (memory_end)
asm-frv/mem-layout.h:#define TASK_SIZE __UL(0xFFFFFFFFUL)
asm-m68k/processor.h:#define TASK_SIZE (0xF0000000UL)
asm-m68k/processor.h:#define TASK_SIZE (0x0E000000)
asm-m68k/processor.h:#define TASK_SIZE (0x0E000000UL)
asm-m68knommu/processor.h:#define TASK_SIZE (0xF0000000UL)
Probably too:
asm-sh/processor.h:#define TASK_SIZE 0x7c000000UL
which has some parts with MMU.
There have been others out of tree that have it like this to.
I'm happy to learn we are doing something wrong, but I think that we just
copied the arm/frv setup.
That is one way to handle it. Have you followed all the other
uses of TASK_SIZE and verified it is not a problem?
Regards
Greg
------------------------------------------------------------------------
Greg Ungerer -- Chief Software Dude EMAIL: [email protected]
SnapGear -- a Secure Computing Company PHONE: +61 7 3435 2888
825 Stanley St, FAX: +61 7 3891 3630
Woolloongabba, QLD, 4102, Australia WEB: http://www.SnapGear.com
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