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    SubjectRe: [PATCH v3 1/3] Make section names compatible with -ffunction-sections -fdata-sections
    On Sat, Apr 25, 2009 at 10:10:38PM -0400, Tim Abbott wrote:
    > On Fri, 24 Apr 2009, Sam Ravnborg wrote:
    > > This patch touches far too many files.
    > > We should try to work out a method so we are in better control
    > > of the section names, so renaming in the end is a simple patch
    > > touching only a few files.
    > OK, I'm now planning to implement this approach.
    > > > -.section .text.head, "ax"
    > > > +.section .text..head, "ax"
    > >
    > > Use __HEAD (from include/linux/init.h)
    > > Same goes for all other uses of .text.head.
    > I notice that __HEAD uses .head.text, while some architectures use
    > .text.head. It looks like this is just an inconsistency across
    > architectures that will be removed as a consequence of this cleanup work
    > (no architecture uses both .head.text and .text.head).
    Correct - this is implied by the introduction of __HEAD.
    For users of the old naming schme (like i386) you need to adjust the
    linker script too.

    > One challenge with this approach is that many linker scripts use these
    > section names in more complex ways than just squashing HEAD_TEXT at the
    > start of the text section. For example, the the linker scripts for x86
    > and ia64 have code like:
    > .text.head : AT(ADDR(.text.head) - LOAD_OFFSET) {
    > _text = .; /* Text and read-only data */
    > *(.text.head)
    > } :text = 0x9090
    > which can't user either the __HEAD macro (which is the full .section line)
    > or the HEAD_TEXT macro (which is the *(.head.text)).

    The simple way to deal wi8th this is to accept some duplication of naming
    in order to keep readability.
    So I suggest you to use:

    .head.text : AT(ADDR(.head.text) - LOAD_OFFSET) {
    _text = .; /* Text and read-only data */
    } :text = 0x9090

    We need to be carefull about keeping some sort of readability
    of these linker macro files.

    I was not specific in my last mail about this - but I assume you have
    understood that the naming ".head.text" was selected so it is compatible
    wiht -ffunction-sections. In other words no need for any ugly ".." here.

    We should try to be as consistent as possible across architectures here
    so it is better to toach a few additiona files rather than adding macros
    and the like to accept there sub-optimal section naming.


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