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    Subject[PATCH 3/5] x86-64: Work around gold bug 13023
    Date
    Gold has trouble assigning numbers to the location counter inside of
    an output section description. The bug was triggered by
    9fd67b4ed0714ab718f1f9bd14c344af336a6df7, which consolidated all of
    the vsyscall sections into a single section. The workaround is IMO
    still nicer than the old way of doing it.

    This produces an apparently valid kernel image and passes my vdso
    tests on both GNU ld version 2.21.51.0.6-2.fc15 20110118 and GNU
    gold (version 2.21.51.0.6-2.fc15 20110118) 1.10 as distributed by
    Fedora 15.

    Signed-off-by: Andy Lutomirski <luto@mit.edu>
    Reported-by: Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>
    ---
    arch/x86/kernel/vmlinux.lds.S | 16 ++++++++++------
    1 files changed, 10 insertions(+), 6 deletions(-)

    diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
    index e79fb39..8f3a265 100644
    --- a/arch/x86/kernel/vmlinux.lds.S
    +++ b/arch/x86/kernel/vmlinux.lds.S
    @@ -158,10 +158,12 @@ SECTIONS
    __vvar_page = .;

    .vvar : AT(ADDR(.vvar) - LOAD_OFFSET) {
    + /* work around gold bug 13023 */
    + __vvar_beginning_hack = .;

    - /* Place all vvars at the offsets in asm/vvar.h. */
    -#define EMIT_VVAR(name, offset) \
    - . = offset; \
    + /* Place all vvars at the offsets in asm/vvar.h. */
    +#define EMIT_VVAR(name, offset) \
    + . = __vvar_beginning_hack + offset; \
    *(.vvar_ ## name)
    #define __VVAR_KERNEL_LDS
    #include <asm/vvar.h>
    @@ -184,15 +186,17 @@ SECTIONS

    . = VSYSCALL_ADDR;
    .vsyscall : AT(VLOAD(.vsyscall)) {
    + /* work around gold bug 13023 */
    + __vsyscall_beginning_hack = .;
    *(.vsyscall_0)

    - . = 1024;
    + . = __vsyscall_beginning_hack + 1024;
    *(.vsyscall_1)

    - . = 2048;
    + . = __vsyscall_beginning_hack + 2048;
    *(.vsyscall_2)

    - . = 4096; /* Pad the whole page. */
    + . = __vsyscall_beginning_hack + 4096; /* Pad the whole page. */
    } :user =0xcc
    . = ALIGN(__vsyscall_0 + PAGE_SIZE, PAGE_SIZE);

    --
    1.7.6


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