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    SubjectRe: [PATCH 00 of 10] x86: unify asm/pgtable.h

    * Ingo Molnar <mingo@elte.hu> wrote:

    >
    > * Ingo Molnar <mingo@elte.hu> wrote:
    >
    > > > >>> #define __PAGE_KERNEL_EXEC \
    > > > >>> - (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL)
    > > > >>> + (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
    > > > >>>
    > > > >
    > > > > This shouldn't be necessary. The old 64-bit code defined everything
    > > > > without _PAGE_GLOBAL, but then used a MAKE_GLOBAL() macro to OR it
    > > > > in later. This seemed a bit roundabout to me, so I just put it in
    > > > > from the outset.
    > >
    > > actually, this is wrong.
    > >
    > > a couple of places use __PAGE_* values, which you've now changed to
    > > include the _PAGE_GLOBAL flag.
    >
    > yep, fixing this resolves the crash.

    but then it crashes init:

    init[1]: segfault at ffffffffff600400 ip ffffffffff600400 sp
    7fff81bedda8 error5printk: 7740690 messages suppressed.

    because you changed __PAGE_KERNEL_VSYSCALL as well, from:

    #define __PAGE_KERNEL_VSYSCALL \
    (_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)

    to:

    #define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RO | _PAGE_USER)

    but __PAGE_KERNEL_RO is an NX one, so the vsyscall cannot execute
    instructions.

    so this wants to be:

    #define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RX | _PAGE_USER)

    this was the last bug and the resulting kernel boots fine. 3 nasty bugs
    in one patch :-/

    Ingo

    ---------------->
    Subject: x86: move all asm/pgtable constants into one place, fix
    From: Ingo Molnar <mingo@elte.hu>

    fix.

    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    ---
    include/asm-x86/pgtable.h | 22 +++++++++++-----------
    1 file changed, 11 insertions(+), 11 deletions(-)

    Index: linux-x86.q/include/asm-x86/pgtable.h
    ===================================================================
    --- linux-x86.q.orig/include/asm-x86/pgtable.h
    +++ linux-x86.q/include/asm-x86/pgtable.h
    @@ -68,27 +68,27 @@ extern unsigned long long __PAGE_KERNEL,
    #endif /* __ASSEMBLER__ */
    #else
    #define __PAGE_KERNEL_EXEC \
    - (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL)
    + (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
    #define __PAGE_KERNEL (__PAGE_KERNEL_EXEC | _PAGE_NX)
    #endif

    #define __PAGE_KERNEL_RO (__PAGE_KERNEL & ~_PAGE_RW)
    #define __PAGE_KERNEL_RX (__PAGE_KERNEL_EXEC & ~_PAGE_RW)
    #define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL | _PAGE_PCD | _PAGE_PWT)
    -#define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RO | _PAGE_USER)
    +#define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RX | _PAGE_USER)
    #define __PAGE_KERNEL_VSYSCALL_NOCACHE (__PAGE_KERNEL_VSYSCALL | _PAGE_PCD | _PAGE_PWT)
    #define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE)
    #define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC | _PAGE_PSE)

    -#define PAGE_KERNEL __pgprot(__PAGE_KERNEL)
    -#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO)
    -#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC)
    -#define PAGE_KERNEL_RX __pgprot(__PAGE_KERNEL_RX)
    -#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE)
    -#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE)
    -#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC)
    -#define PAGE_KERNEL_VSYSCALL __pgprot(__PAGE_KERNEL_VSYSCALL)
    -#define PAGE_KERNEL_VSYSCALL_NOCACHE __pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE)
    +#define PAGE_KERNEL __pgprot(__PAGE_KERNEL | _PAGE_GLOBAL)
    +#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO | _PAGE_GLOBAL)
    +#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC | _PAGE_GLOBAL)
    +#define PAGE_KERNEL_RX __pgprot(__PAGE_KERNEL_RX | _PAGE_GLOBAL)
    +#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE | _PAGE_GLOBAL)
    +#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE | _PAGE_GLOBAL)
    +#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC | _PAGE_GLOBAL)
    +#define PAGE_KERNEL_VSYSCALL __pgprot(__PAGE_KERNEL_VSYSCALL | _PAGE_GLOBAL)
    +#define PAGE_KERNEL_VSYSCALL_NOCACHE __pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE | _PAGE_GLOBAL)

    /* xwr */
    #define __P000 PAGE_NONE

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      Last update: 2008-01-09 01:47    [W:0.027 / U:0.024 seconds]
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