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    Subject[PATCH 3/4] kernel linker stripts: accomodate function and data sections
    Date
    gcc -ffunction-sections -fdata-sections places each function foo
    into separate section .text.foo, and every data object bar into
    separate section .data.bar, .rodata.bar or .bss.bar.

    Kernel linker scripts were not ready for this and linker heuristics
    for orphaned sections were not good enough to result in bootable
    kernel.

    This fix adds *(.text.*), *(.data.*) etc patterns
    directly after corresponding *(.text), *(.data) etc patterns
    in all kernel linker scripts. Boot scripts will be handled
    in the next fix.

    include/asm-generic/vmlinux.lds.h is a little bit more complicated.
    It needs to avoid collecting special kernel sections
    by using more restrictive patterns like *(.text.[A-Za-z0-9_$^]*)
    instead of simplistic *(.text.*): special kernel sections like
    .text..page_aligned contain double dots and won't be accidentally
    matched by them.

    Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
    Acked-by: Sam Ravnborg <sam@ravnborg.org>
    ---
    arch/frv/kernel/vmlinux.lds.S | 1 -
    arch/ia64/scripts/check-segrel.lds | 4 ++--
    arch/m68knommu/kernel/vmlinux.lds.S | 1 +
    arch/mips/lasat/image/romscript.normal | 1 +
    arch/parisc/kernel/vmlinux.lds.S | 1 +
    arch/sh/kernel/vsyscall/vsyscall.lds.S | 2 +-
    arch/x86/kernel/acpi/realmode/wakeup.lds.S | 1 +
    arch/x86/kernel/vmlinux.lds.S | 1 +
    include/asm-generic/vmlinux.lds.h | 18 +++++++++++++++++-
    9 files changed, 25 insertions(+), 5 deletions(-)

    diff --git a/arch/frv/kernel/vmlinux.lds.S b/arch/frv/kernel/vmlinux.lds.S
    index 8b973f3..9949f1a 100644
    --- a/arch/frv/kernel/vmlinux.lds.S
    +++ b/arch/frv/kernel/vmlinux.lds.S
    @@ -114,7 +114,6 @@ SECTIONS

    .sbss : { *(.sbss .sbss.*) }
    .bss : { *(.bss .bss.*) }
    - .bss..stack : { *(.bss) }

    __bss_stop = .;
    _end = . ;
    diff --git a/arch/ia64/scripts/check-segrel.lds b/arch/ia64/scripts/check-segrel.lds
    index 85a0d54..1e23df4 100644
    --- a/arch/ia64/scripts/check-segrel.lds
    +++ b/arch/ia64/scripts/check-segrel.lds
    @@ -1,9 +1,9 @@
    SECTIONS {
    . = SIZEOF_HEADERS;
    - .rodata : { *(.rodata) } :ro
    + .rodata : { *(.rodata) *(.rodata.*) } :ro
    .note : { *(.note*) }
    . = 0xa0000;
    - .data : { *(.data) } :dat
    + .data : { *(.data) *(.data.*) } :dat
    /DISCARD/ : { *(*) }
    }
    PHDRS {
    diff --git a/arch/m68knommu/kernel/vmlinux.lds.S b/arch/m68knommu/kernel/vmlinux.lds.S
    index a91b271..c095a5b 100644
    --- a/arch/m68knommu/kernel/vmlinux.lds.S
    +++ b/arch/m68knommu/kernel/vmlinux.lds.S
    @@ -169,6 +169,7 @@ SECTIONS {
    . = ALIGN(4);
    _sbss = . ;
    *(.bss)
    + *(.bss.*)
    *(COMMON)
    . = ALIGN(4) ;
    _ebss = . ;
    diff --git a/arch/mips/lasat/image/romscript.normal b/arch/mips/lasat/image/romscript.normal
    index 0864c96..408e5ad 100644
    --- a/arch/mips/lasat/image/romscript.normal
    +++ b/arch/mips/lasat/image/romscript.normal
    @@ -12,6 +12,7 @@ SECTIONS
    .data ALIGN(0x10) :
    {
    *(.data)
    + *(.data.*)
    }
    _image_start = ADDR(.data);
    _image_size = SIZEOF(.data);
    diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S
    index d64a6bb..56d472c 100644
    --- a/arch/parisc/kernel/vmlinux.lds.S
    +++ b/arch/parisc/kernel/vmlinux.lds.S
    @@ -112,6 +112,7 @@ SECTIONS
    }
    .bss : {
    *(.bss)
    + *(.bss.*)
    *(COMMON)
    }
    __bss_stop = .;
    diff --git a/arch/sh/kernel/vsyscall/vsyscall.lds.S b/arch/sh/kernel/vsyscall/vsyscall.lds.S
    index 6d59ee7..19ee0cb 100644
    --- a/arch/sh/kernel/vsyscall/vsyscall.lds.S
    +++ b/arch/sh/kernel/vsyscall/vsyscall.lds.S
    @@ -35,7 +35,7 @@ SECTIONS
    */
    . = 0x400;

    - .text : { *(.text) } :text =0x90909090
    + .text : { *(.text) *(.text.*) } :text =0x90909090
    .note : { *(.note.*) } :text :note
    .eh_frame_hdr : { *(.eh_frame_hdr ) } :text :eh_frame_hdr
    .eh_frame : {
    diff --git a/arch/x86/kernel/acpi/realmode/wakeup.lds.S b/arch/x86/kernel/acpi/realmode/wakeup.lds.S
    index 060fff8..38f18e8 100644
    --- a/arch/x86/kernel/acpi/realmode/wakeup.lds.S
    +++ b/arch/x86/kernel/acpi/realmode/wakeup.lds.S
    @@ -42,6 +42,7 @@ SECTIONS
    .bss : {
    __bss_start = .;
    *(.bss)
    + *(.bss.*)
    __bss_end = .;
    }

    diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
    index d0bb522..eb5b2a6 100644
    --- a/arch/x86/kernel/vmlinux.lds.S
    +++ b/arch/x86/kernel/vmlinux.lds.S
    @@ -307,6 +307,7 @@ SECTIONS
    __bss_start = .;
    *(.bss..page_aligned)
    *(.bss)
    + *(.bss.*)
    . = ALIGN(4);
    __bss_stop = .;
    }
    diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
    index 030a954..079895a 100644
    --- a/include/asm-generic/vmlinux.lds.h
    +++ b/include/asm-generic/vmlinux.lds.h
    @@ -146,9 +146,22 @@
    #define TRACE_SYSCALLS()
    #endif

    +/* .data.foo are generated by gcc itself with -fdata-sections,
    + * whereas double-dot sections (like .data..percpu) are generated
    + * by kernel's magic macros.
    + *
    + * arch/.../vmlinux.lds.S decides where to place various double-dot sections
    + * as needed by its arch, here DATA_DATA needs to be careful and collect
    + * only .data and .data.foo sections, skipping .data..foo
    + *
    + * Same goes for .text, .bss and .rodata. In case of .rodata, various
    + * .rodata.foo sections are generated by gcc even without -fdata-sections
    + */
    +
    /* .data section */
    #define DATA_DATA \
    *(.data) \
    + *(.data.[A-Za-z0-9_$^]*) \
    *(.ref.data) \
    DEV_KEEP(init.data) \
    DEV_KEEP(exit.data) \
    @@ -212,7 +225,8 @@
    . = ALIGN((align)); \
    .rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \
    VMLINUX_SYMBOL(__start_rodata) = .; \
    - *(.rodata) *(.rodata.*) \
    + *(.rodata) \
    + *(.rodata.[A-Za-z0-9_$^]*) \
    *(__vermagic) /* Kernel version magic */ \
    *(__markers_strings) /* Markers: strings */ \
    *(__tracepoints_strings)/* Tracepoints: strings */ \
    @@ -379,6 +393,7 @@
    ALIGN_FUNCTION(); \
    *(.text.hot) \
    *(.text) \
    + *(.text.[A-Za-z0-9_$^]*) \
    *(.ref.text) \
    DEV_KEEP(init.text) \
    DEV_KEEP(exit.text) \
    @@ -512,6 +527,7 @@
    *(.bss..page_aligned) \
    *(.dynbss) \
    *(.bss) \
    + *(.bss.[A-Za-z0-9_$^]*) \
    *(COMMON) \
    }

    --
    1.6.2.4


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