Messages in this thread | | | Date | Tue, 2 Oct 2012 16:39:39 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH 10/36] AArch64: MMU definitions |
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On Tue, Oct 02, 2012 at 01:43:04AM +0100, Jon Masters wrote: > On 07/06/2012 05:05 PM, Catalin Marinas wrote: > > > +/* > > + * PAGE_OFFSET - the virtual address of the start of the kernel image. > > + * VA_BITS - the maximum number of bits for virtual addresses. > > + * TASK_SIZE - the maximum size of a user space task. > > + * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area. > > + * The module space lives between the addresses given by TASK_SIZE > > + * and PAGE_OFFSET - it must be within 128MB of the kernel text. > > + */ > > +#define PAGE_OFFSET UL(0xffffffc000000000) > > +#define MODULES_END (PAGE_OFFSET) > > +#define MODULES_VADDR (MODULES_END - SZ_64M) > > +#define VA_BITS (39) > > +#define TASK_SIZE_64 (UL(1) << VA_BITS) > > Pedantic nit pick. Shouldn't that "it must be within 128MB of the kernel > text" be "within 128MB of the *end* of the kernel text"? The point being > that on AArch64 unconditional branches are encoded as imm26+1 (27 bits) > and so you're going with -64MB to ensure that you're within the range.
I read it to be within 128MB of any part of the kernel text but I can change it to "end of" if that's clearer.
-- Catalin
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