Re: [RFC][PATCH] allow bigger PAGE_OFFSET with PAE

William Lee Irwin III
2003-01-07T23:28:41Z

> Also, this gets the kernel's pagetables right, but neglects
> userspace's for now. pgd_alloc() needs to be fixed to allocate
> another PMD, if the split isn't PMD-alighed.

Um, that should be automatic when USER_PTRS_PER_PGD is increased.

I see the following:

$ grep -n TASK_SIZE include/asm-i386/*.h
include/asm-i386/a.out.h:22:#define STACK_TOP TASK_SIZE
include/asm-i386/elf.h:60:#define ELF_ET_DYN_BASE (TASK_SIZE / 3 * 2)
include/asm-i386/pgtable.h:68:#define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE)
include/asm-i386/processor.h:277:#define TASK_SIZE (PAGE_OFFSET)
include/asm-i386/processor.h:282:#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 3))

... which sounds like you need to round up in an overflow-safe fashion
in the macro.

Bill