Portable assmbler code - newline (was Re: [PATCH] kernel/modsign_certificate.S:use real contents instead of macro GLOBAL())
From: Vineet Gupta
Date: Thu Oct 24 2013 - 13:29:05 EST
On 10/24/2013 11:33 AM, Richard Weinberger wrote:
> On Thu, Oct 24, 2013 at 7:31 AM, Chen Gang <gang.chen@xxxxxxxxxxx> 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.
diff --git a/include/linux/linkage.h b/include/linux/linkage.h
index d3e8ad23a8e0..4188c632f2b8 100644
@@ -6,6 +6,10 @@
#define CPP_ASMLINKAGE extern "C"
@@ -75,7 +79,7 @@
#define ENTRY(name) \
- .globl name; \
+ .globl name; __ARCH_NL \
@@ -83,7 +87,7 @@
#define WEAK(name) \
- .weak name; \
+ .weak name; __ARCH_NL \
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