[PATCH 0/2] kbuild: cleanup asm-offset generation, and make it work with clang

[PATCH 0/2] kbuild: cleanup asm-offset generation, and make it work with clang

[Masahiro Yamada]

1/2 is a trivial cleanup of sed script
2/2 imports clang work-around from U-Boot.


Jeroen Hofstee (1):
  kbuild: fix asm-offset generation to work with clang

Masahiro Yamada (1):
  kbuild: consolidate redundant sed script ASM offset generation

 include/linux/kbuild.h | 6 +++---
 scripts/Makefile.lib   | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

-- 
2.7.4

[PATCH 1/2] kbuild: consolidate redundant sed script ASM offset generation

[Masahiro Yamada]

This part ended up in redundant code after touched by multiple
people.

[1] Commit 3234282f33b2 ("x86, asm: Fix CFI macro invocations to
deal with shortcomings in gas") added parentheses for defined
expressions to support old gas for x86.

[2] Commit a22dcdb0032c ("x86, asm: Fix ancient-GAS workaround")
split the pattern into two to avoid parentheses for non-numeric
expressions.

[3] Commit 95a2f6f72d37 ("Partially revert patch that encloses
asm-offset.h numbers in brackets") removed parentheses from numeric
expressions as well because parentheses in MN10300 assembly have a
special meaning (pointer access).

Apparently, there is a conflict between [1] and [3].  After all,
[3] took precedence, and a long time has passed since then.

Now, merge the two patterns again because the first one is covered
by the other.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 scripts/Makefile.lib | 1 -
 1 file changed, 1 deletion(-)

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index e36427a..9c20690 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -415,7 +415,6 @@ cmd_xzmisc = (cat $(filter-out FORCE,$^) | \
 # Default sed regexp - multiline due to syntax constraints
 define sed-offsets
 	"/^->/{s:->#\(.*\):/* \1 */:; \
-	s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
 	s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
 	s:->::; p;}"
 endef
-- 
2.7.4

Re: [PATCH 1/2] kbuild: consolidate redundant sed script ASM offset generation

[Matthias Kaehlcke]

El Fri, Apr 14, 2017 at 02:50:02PM +0900 Masahiro Yamada ha dit:

> This part ended up in redundant code after touched by multiple
> people.
> 
> [1] Commit 3234282f33b2 ("x86, asm: Fix CFI macro invocations to
> deal with shortcomings in gas") added parentheses for defined
> expressions to support old gas for x86.
> 
> [2] Commit a22dcdb0032c ("x86, asm: Fix ancient-GAS workaround")
> split the pattern into two to avoid parentheses for non-numeric
> expressions.
> 
> [3] Commit 95a2f6f72d37 ("Partially revert patch that encloses
> asm-offset.h numbers in brackets") removed parentheses from numeric
> expressions as well because parentheses in MN10300 assembly have a
> special meaning (pointer access).
> 
> Apparently, there is a conflict between [1] and [3].  After all,
> [3] took precedence, and a long time has passed since then.
> 
> Now, merge the two patterns again because the first one is covered
> by the other.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>

Thanks

Matthias

Re: [PATCH 1/2] kbuild: consolidate redundant sed script ASM offset generation

[David Howells]

Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

> This part ended up in redundant code after touched by multiple
> people.
> 
> [1] Commit 3234282f33b2 ("x86, asm: Fix CFI macro invocations to
> deal with shortcomings in gas") added parentheses for defined
> expressions to support old gas for x86.
> 
> [2] Commit a22dcdb0032c ("x86, asm: Fix ancient-GAS workaround")
> split the pattern into two to avoid parentheses for non-numeric
> expressions.
> 
> [3] Commit 95a2f6f72d37 ("Partially revert patch that encloses
> asm-offset.h numbers in brackets") removed parentheses from numeric
> expressions as well because parentheses in MN10300 assembly have a
> special meaning (pointer access).
> 
> Apparently, there is a conflict between [1] and [3].  After all,
> [3] took precedence, and a long time has passed since then.

There's a conflict between [1] and various assembly code formats.  Some
formats define, say,

	mov	4,r1

to move the number 4 into register r1, and:

	mov	(4),r1

to move the contents of the memory at address 4 into r1.  Therefore, you
cannot simply wrap numeric operands in brackets.  What might work is adding a
'+' on the front, e.g.:

	mov	+(4),r1

David

Re: [PATCH 1/2] kbuild: consolidate redundant sed script ASM offset generation

[Masahiro Yamada]

Hi David,


2017-04-18 18:57 GMT+09:00 David Howells <dhowells@redhat.com>:
> Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
>
>> This part ended up in redundant code after touched by multiple
>> people.
>>
>> [1] Commit 3234282f33b2 ("x86, asm: Fix CFI macro invocations to
>> deal with shortcomings in gas") added parentheses for defined
>> expressions to support old gas for x86.
>>
>> [2] Commit a22dcdb0032c ("x86, asm: Fix ancient-GAS workaround")
>> split the pattern into two to avoid parentheses for non-numeric
>> expressions.
>>
>> [3] Commit 95a2f6f72d37 ("Partially revert patch that encloses
>> asm-offset.h numbers in brackets") removed parentheses from numeric
>> expressions as well because parentheses in MN10300 assembly have a
>> special meaning (pointer access).
>>
>> Apparently, there is a conflict between [1] and [3].  After all,
>> [3] took precedence, and a long time has passed since then.
>
> There's a conflict between [1] and various assembly code formats.  Some
> formats define, say,
>
>         mov     4,r1
>
> to move the number 4 into register r1, and:
>
>         mov     (4),r1
>
> to move the contents of the memory at address 4 into r1.  Therefore, you
> cannot simply wrap numeric operands in brackets.  What might work is adding a
> '+' on the front, e.g.:
>
>         mov     +(4),r1
>
> David


OK, thanks for this info.

But, nobody has raised a flag about the reverted [1].
(perhaps, nobody cares about the old gas any more?)
So, I think this patch will be OK.


BTW, do you still maintain mn10300?

(Before, I worked for Panasonic, i.e. former Matsushita)



-- 
Best Regards
Masahiro Yamada

Re: [PATCH 1/2] kbuild: consolidate redundant sed script ASM offset generation

[David Howells]

Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

> BTW, do you still maintain mn10300?

Kind of.  I don't really have working hardware any more, though.

David

Re: [PATCH 1/2] kbuild: consolidate redundant sed script ASM offset generation

[Masahiro Yamada]

Hi David,

2017-04-18 22:15 GMT+09:00 David Howells <dhowells@redhat.com>:
> Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
>
>> BTW, do you still maintain mn10300?
>
> Kind of.  I don't really have working hardware any more, though.
>
> David

Thanks for maintaining this.



-- 
Best Regards
Masahiro Yamada

[PATCH 2/2] kbuild: fix asm-offset generation to work with clang

[Masahiro Yamada]

From: Jeroen Hofstee <jeroen@myspectrum.nl>

KBuild abuses the asm statement to write to a file and
clang chokes about these invalid asm statements. Hack it
even more by fooling this is actual valid asm code.

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
[masahiro:
 Import Jeroen's work for U-Boot:
 http://patchwork.ozlabs.org/patch/375026/
 Tweak sed script a little to drop garbage '#' for GCC case, like
 #define NR_PAGEFLAGS 23 /* __NR_PAGEFLAGS       # */ ]
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

---

 include/linux/kbuild.h | 6 +++---
 scripts/Makefile.lib   | 5 +++--
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/linux/kbuild.h b/include/linux/kbuild.h
index 22a7219..4e80f3a 100644
--- a/include/linux/kbuild.h
+++ b/include/linux/kbuild.h
@@ -2,14 +2,14 @@
 #define __LINUX_KBUILD_H
 
 #define DEFINE(sym, val) \
-        asm volatile("\n->" #sym " %0 " #val : : "i" (val))
+	asm volatile("\n.ascii \"->" #sym " %0 " #val "\"" : : "i" (val))
 
-#define BLANK() asm volatile("\n->" : : )
+#define BLANK() asm volatile("\n.ascii \"->\"" : : )
 
 #define OFFSET(sym, str, mem) \
 	DEFINE(sym, offsetof(struct str, mem))
 
 #define COMMENT(x) \
-	asm volatile("\n->#" x)
+	asm volatile("\n.ascii \"->#" x "\"")
 
 #endif
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 9c20690..a050859 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -414,9 +414,10 @@ cmd_xzmisc = (cat $(filter-out FORCE,$^) | \
 
 # Default sed regexp - multiline due to syntax constraints
 define sed-offsets
-	"/^->/{s:->#\(.*\):/* \1 */:; \
+	's:^\.ascii *"\(.*\)".*:\1:; \
+	/^->/{s:->#\(.*\):/* \1 */:; \
 	s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
-	s:->::; p;}"
+	s:->::; p;}'
 endef
 
 # Use filechk to avoid rebuilds when a header changes, but the resulting file
-- 
2.7.4

Re: [PATCH 2/2] kbuild: fix asm-offset generation to work with clang

[Matthias Kaehlcke]

El Fri, Apr 14, 2017 at 02:50:03PM +0900 Masahiro Yamada ha dit:

> From: Jeroen Hofstee <jeroen@myspectrum.nl>
> 
> KBuild abuses the asm statement to write to a file and
> clang chokes about these invalid asm statements. Hack it
> even more by fooling this is actual valid asm code.
> 
> Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
> [masahiro:
>  Import Jeroen's work for U-Boot:
>  http://patchwork.ozlabs.org/patch/375026/
>  Tweak sed script a little to drop garbage '#' for GCC case, like
>  #define NR_PAGEFLAGS 23 /* __NR_PAGEFLAGS       # */ ]
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>

I tested with x86 and arm64. Please note that two more changes are
needed to avoid breaking frv and um:

https://patchwork.kernel.org/patch/9660473/
https://patchwork.kernel.org/patch/9660503/

Maybe these should be part of your patch set? I only sent them out
separately to avoid cross posting with my initial patch for this issue
being a RFC.

Cheers

Matthias