kernel.git/include/asm-x86/pgtable_64.h, branch linux-2.6.25.y

Revert "x86: fix pmd_bad and pud_bad to support huge pages"

2008-03-03T18:02:44Z

This reverts commit cded932b75ab0a5f9181ee3da34a0a488d1a14fd. Arjan bisected down a boot-time hang to this, saying: ".. it prevents the kernel to finish booting on my (Penryn based) laptop. The boot stops right after freeing the init memory." and while it's not clear exactly what triggers it, at this stage we're better off just reverting it while Ingo tries to figure out what went wrong. Requested-by: Arjan van de Ven Cc: Hans Rosenfeld Cc: Nish Aravamudan Acked-by: Ingo Molnar Signed-off-by: Linus Torvalds

x86: fix pmd_bad and pud_bad to support huge pages

2008-02-29T17:55:39Z

I recently stumbled upon a problem in the support for huge pages. If a program using huge pages does not explicitly unmap them, they remain mapped (and therefore, are lost) after the program exits. I observed that the free huge page count in /proc/meminfo decreased when running my program, and it did not increase after the program exited. After running the program a few times, no more huge pages could be allocated. The reason for this seems to be that the x86 pmd_bad and pud_bad consider pmd/pud entries having the PSE bit set invalid. I think there is nothing wrong with this bit being set, it just indicates that the lowest level of translation has been reached. This bit has to be (and is) checked after the basic validity of the entry has been checked, like in this fragment from follow_page() in mm/memory.c: if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) goto no_page_table; if (pmd_huge(*pmd)) { BUG_ON(flags & FOLL_GET); page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); goto out; } Note that this code currently doesn't work as intended if the pmd refers to a huge page, the pmd_huge() check can not be reached if the page is huge. Extending pmd_bad() (and, for future 1GB page support, pud_bad()) to allow for the PSE bit being set fixes this. For similar reasons, allowing the NX bit being set is necessary, too. I have seen huge pages having the NX bit set in their pmd entry, which would cause the same problem. Signed-Off-By: Hans Rosenfeld Signed-off-by: Ingo Molnar

x86: add pgd_large() on 64-bit, for consistency

2008-02-19T15:18:32Z

In order to have it at all levels, add pgd_large() which only returns 0. Signed-off-by: H. Peter Anvin Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

x86: zap invalid and unused pmds in early boot

2008-02-18T19:54:14Z

The early boot code maps KERNEL_TEXT_SIZE (currently 40MB) starting from __START_KERNEL_map. The kernel itself only needs _text to _end mapped in the high alias. On relocatible kernels the ASM setup code adjusts the compile time created high mappings to the relocation. This creates invalid pmd entries for negative offsets: 0xffffffff80000000 -> pmd entry: ffffffffff2001e3 It points outside of the physical address space and is marked present. This starts at the virtual address __START_KERNEL_map and goes up to the point where the first valid physical address (0x0) is mapped. Zap the mappings before _text and after _end right away in early boot. This removes also the invalid entries. Furthermore it simplifies the range check for high aliases. Signed-off-by: Thomas Gleixner Acked-by: H. Peter Anvin Signed-off-by: Ingo Molnar

x86: add pgtable accessor functions for gbpages

2008-02-04T15:48:09Z

Signed-off-by: Andi Kleen Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

x86: remove now unused clear_kernel_mapping

2008-02-04T15:48:08Z

Signed-off-by: Andi Kleen Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

x86: use the same pgd_list for PAE and 64-bit

2008-01-30T12:34:11Z

Use a standard list threaded through page->lru for maintaining the pgd list on PAE. This is the same as 64-bit, and seems saner than using a non-standard list via page->index. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

x86: clean up lookup_address() declarations

2008-01-30T12:34:04Z

Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

x86: clean up arch/x86/mm/pageattr.c

2008-01-30T12:34:04Z

do some leftover cleanups in the now unified arch/x86/mm/pageattr.c file. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

x86: introduce native_set_pte_atomic() on 64-bit too

2008-01-30T12:34:01Z

Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner