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    SubjectRe: Portable assmbler code - newline (was Re: [PATCH] kernel/modsign_certificate.S: use real contents instead of macro GLOBAL())
    On 10/25/2013 01:10 PM, Vineet Gupta wrote:
    > On 10/25/2013 01:11 AM, Geert Uytterhoeven wrote:
    >> On Thu, Oct 24, 2013 at 7:28 PM, Vineet Gupta <vineetg76@gmail.com> wrote:
    >>>> +CC linux-arch
    >>>>
    >>>> On 10/24/2013 11:33 AM, Richard Weinberger wrote:
    >>>>>> On Thu, Oct 24, 2013 at 7:31 AM, Chen Gang <gang.chen@asianux.com> wrote:
    >>>>>>>>>> For some architectures, tool chain is not smart enough to recognize the
    >>>>>>>>>> macro with multiple lines (e.g. arc tool chain), and for common ".S"
    >>>>>>>>>> file, this kind of macro is also rarely used.
    >>>>>> Does not "not smart enough" mean than the said toolchain is broken/buggy
    >>>>>> or is the kernel using an unsupported notation?
    >>>>>>
    >>>>
    >>>> IMHO this is not broken - rather the code is not fully portable - given that gas
    >>>> ports of arches have differnet notions of what to treat as comment and what newline.
    >>>>
    >>>> Looking as binutils/gas/config, I can see that avr, cris,...are likely broken in
    >>>> the same way as ARC is.
    >>>>
    >>>> Historically ARC has had ';' as comment char, which Joern relatively recently
    >>>> augmented to have '#' as well. However there's legacy codebase which relies on ';'
    >>>> being a comment and we can't change that fact.
    >>>>
    >>>> So can we introduce an ARCH over-ridable newline annotation in linkage.h and other
    >>>> places after auditing. Since asm/linkage.h preempts linux/linkage.h by way of
    >>>> #include it shd be pretty strightforward.
    >>>>
    >>>> Something like below. I can send the formal patch if people think the approach is OK.
    >> By what are you gonna override __ARCH_NL on ARC?
    >> I'm afraid cpp will still turn it into a single line.
    >>
    >
    > Eh ! My untested patch was broken but not because of what you mentioned.
    >
    > For ARC, the ; negating the newline annotation. So the following works (backquote
    > is new line for ARC)
    >
    > diff --git a/arch/arc/include/asm/linkage.h b/arch/arc/include/asm/linkage.h
    > index 0283e9e44e0d..b3eea2999322 100644
    > --- a/arch/arc/include/asm/linkage.h
    > +++ b/arch/arc/include/asm/linkage.h
    > @@ -9,6 +9,8 @@
    > #ifndef __ASM_LINKAGE_H
    > #define __ASM_LINKAGE_H
    >
    > +#define __ARCH_NL `
    > +
    > #ifdef __ASSEMBLY__
    >
    >
    > diff --git a/include/linux/linkage.h b/include/linux/linkage.h
    > index d3e8ad23a8e0..969e70ad231a 100644
    > --- a/include/linux/linkage.h
    > +++ b/include/linux/linkage.h
    > @@ -6,6 +6,10 @@
    > #include <linux/export.h>
    > #include <asm/linkage.h>
    >
    > +#ifndef __ARCH_NL
    > +#define __ARCH_NL ;
    > +#endif
    > +
    > #ifdef __cplusplus
    > #define CPP_ASMLINKAGE extern "C"
    > #else
    > @@ -75,7 +79,7 @@
    >
    > #ifndef ENTRY
    > #define ENTRY(name) \
    > - .globl name; \
    > + .globl name __ARCH_NL \
    > ALIGN; \

    Do we also need consider about "ALIGN;"?

    > name:
    > #endif
    >

    For next-20130927 tree, do we also need consider about WEAK, ENDPROC?


    I am not quite sure about it, but I will try. Now, I am just analyzing
    another issue -- maybe the last issue for allmodconfig under arc, which
    may be related with this patch, the errors are:

    1 Building modules, stage 2.
    2 MODPOST 2994 modules
    3 ERROR: "__st_r13_to_r20" [sound/usb/snd-usbmidi-lib.ko] undefined!
    4 ERROR: "__ld_r13_to_r15" [sound/usb/snd-usbmidi-lib.ko] undefined!
    5 ERROR: "__st_r13_to_r18" [sound/usb/snd-usbmidi-lib.ko] undefined!
    6 ERROR: "__ld_r13_to_r14_ret" [sound/usb/snd-usbmidi-lib.ko] undefined!
    7 ERROR: "__ld_r13_to_r22" [sound/usb/snd-usbmidi-lib.ko] undefined!
    8 ERROR: "__ld_r13_to_r15_ret" [sound/usb/snd-usbmidi-lib.ko] undefined!
    9 ERROR: "__ld_r13_to_r16" [sound/usb/snd-usbmidi-lib.ko] undefined!
    10 ERROR: "__ld_r13_to_r18_ret" [sound/usb/snd-usbmidi-lib.ko] undefined!
    11 ERROR: "__ld_r13_to_r24_ret" [sound/usb/snd-usbmidi-lib.ko] undefined!
    ...
    ...

    28095 ERROR: "__st_r13_to_r17" [arch/arc/oprofile/oprofile.ko] undefined!
    28096 ERROR: "__st_r13_to_r22" [arch/arc/oprofile/oprofile.ko] undefined!
    28097 ERROR: "__ld_r13_to_r19_ret" [Documentation/filesystems/configfs/configfs_example_macros.ko] undefined!
    28098 ERROR: "__st_r13_to_r19" [Documentation/filesystems/configfs/configfs_example_macros.ko] undefined!
    28099 ERROR: "__ld_r13_to_r14_ret" [Documentation/filesystems/configfs/configfs_example_macros.ko] undefined!
    28100 ERROR: "__ld_r13_to_r19_ret" [Documentation/filesystems/configfs/configfs_example_explicit.ko] undefined!
    28101 ERROR: "__st_r13_to_r19" [Documentation/filesystems/configfs/configfs_example_explicit.ko] undefined!
    28102 ERROR: "__ld_r13_to_r14_ret" [Documentation/filesystems/configfs/configfs_example_explicit.ko] undefined!
    28103 ERROR: "__ld_r13_to_r14_ret" [Documentation/connector/cn_test.ko] undefined!
    28104 make[1]: *** [__modpost] Error 1
    28105 make: *** [modules] Error 2


    Thanks.
    --
    Chen Gang


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