MIPS: Make TASK_SIZE reflect proper size for both 32 and 64 bit processes.
The TASK_SIZE macro should reflect the size of a user process virtual address space. Previously for 64-bit kernels, this was not the case. The immediate cause of pain was in hugetlbfs/inode.c:hugetlb_get_unmapped_area() where 32-bit processes trying to mmap a huge page would be served a page with an address outside of the 32-bit address range. But there are other uses of TASK_SIZE in the kernel as well that would like an accurate value. The new definition is nice because it now makes TASK_SIZE and TASK_SIZE_OF() yield the same value for any given process. For 32-bit kernels there should be no change, although I did factor out some code in asm/processor.h that became identical for the 32-bit and 64-bit cases. __UA_LIMIT is now set to ~((1 << SEGBITS) - 1) for 64-bit kernels. This should eliminate the possibility of getting a AddressErrorException in the kernel for addresses that pass the access_ok() test. With the patch applied, I can still run o32, n32 and n64 processes, and have an o32 shell fork/exec both n32 and n64 processes. Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com> To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/1701/
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