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    Subject[PATCH] allow placing exception table in .rodata (and do so on x86)
    This is since the table is really a set of pointers, i.e. misplaced in
    .text.

    Quite likely other architectures would want to follow.

    Signed-off-by: Jan Beulich <jbeulich@novell.com>

    ---
    arch/x86/include/asm/sections.h | 2 +-
    arch/x86/kernel/vmlinux.lds.S | 5 +++--
    arch/x86/mm/init_64.c | 6 +++---
    include/asm-generic/vmlinux.lds.h | 5 +++++
    4 files changed, 12 insertions(+), 6 deletions(-)

    --- 2.6.39-rc5/arch/x86/include/asm/sections.h
    +++ 2.6.39-rc5-extable-in-rodata/arch/x86/include/asm/sections.h
    @@ -5,7 +5,7 @@
    #include <asm/uaccess.h>

    extern char __brk_base[], __brk_limit[];
    -extern struct exception_table_entry __stop___ex_table[];
    +extern const char __stop_notes[];

    #if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
    extern char __end_rodata_hpage_align[];
    --- 2.6.39-rc5/arch/x86/kernel/vmlinux.lds.S
    +++ 2.6.39-rc5-extable-in-rodata/arch/x86/kernel/vmlinux.lds.S
    @@ -20,6 +20,8 @@
    #define LOAD_OFFSET __START_KERNEL_map
    #endif

    +#define EXCEPTION_TABLE_RO EXCEPTION_TABLE(16)
    +
    #include <asm-generic/vmlinux.lds.h>
    #include <asm/asm-offsets.h>
    #include <asm/thread_info.h>
    @@ -114,8 +116,7 @@ SECTIONS
    } :text = 0x9090

    NOTES :text :note
    -
    - EXCEPTION_TABLE(16) :text = 0x9090
    + text_continues : {} :text /* switch back to regular text... */

    #if defined(CONFIG_DEBUG_RODATA)
    /* .text should occupy whole number of pages */
    --- 2.6.39-rc5/arch/x86/mm/init_64.c
    +++ 2.6.39-rc5-extable-in-rodata/arch/x86/mm/init_64.c
    @@ -741,7 +741,7 @@ int kernel_set_to_readonly;
    void set_kernel_text_rw(void)
    {
    unsigned long start = PFN_ALIGN(_text);
    - unsigned long end = PFN_ALIGN(__stop___ex_table);
    + unsigned long end = PFN_ALIGN(_etext);

    if (!kernel_set_to_readonly)
    return;
    @@ -760,7 +760,7 @@ void set_kernel_text_rw(void)
    void set_kernel_text_ro(void)
    {
    unsigned long start = PFN_ALIGN(_text);
    - unsigned long end = PFN_ALIGN(__stop___ex_table);
    + unsigned long end = PFN_ALIGN(_etext);

    if (!kernel_set_to_readonly)
    return;
    @@ -780,7 +780,7 @@ void mark_rodata_ro(void)
    unsigned long rodata_start =
    ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
    unsigned long end = (unsigned long) &__end_rodata_hpage_align;
    - unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
    + unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop_notes);
    unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
    unsigned long data_start = (unsigned long) &_sdata;

    --- 2.6.39-rc5/include/asm-generic/vmlinux.lds.h
    +++ 2.6.39-rc5-extable-in-rodata/include/asm-generic/vmlinux.lds.h
    @@ -226,6 +226,7 @@
    *(.rodata1) \
    } \
    \
    + EXCEPTION_TABLE_RO \
    BUG_TABLE \
    \
    JUMP_TABLE \
    @@ -459,6 +460,10 @@
    VMLINUX_SYMBOL(__stop___ex_table) = .; \
    }

    +#ifndef EXCEPTION_TABLE_RO
    +#define EXCEPTION_TABLE_RO
    +#endif
    +
    /*
    * Init task
    */




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