Re: [PATCH v4 05/13] Compiler Attributes: naked was fixed in gcc 4.6
Hi,
On 08.09.2018 14:24, Miguel Ojeda wrote:
> Commit 9c695203a7dd ("compiler-gcc.h: gcc-4.5 needs noclone
> and noinline on __naked functions") added noinline and noclone
> as a workaround for a gcc 4.5 bug, which was resolved in 4.6.0.
>
> Since now the minimum gcc supported version is 4.6,
> we can clean it up.
>
> See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44290
> and https://godbolt.org/z/h6NMIL
>
> Cc: Rasmus Villemoes
> Cc: Luc Van Oostenryck
> Cc: Eli Friedman
> Cc: Christopher Li
> Cc: Kees Cook
> Cc: Ingo Molnar
> Cc: Geert Uytterhoeven
> Cc: Arnd Bergmann
> Cc: Greg Kroah-Hartman
> Cc: Masahiro Yamada
> Cc: Joe Perches
> Cc: Dominique Martinet
> Cc: Nick Desaulniers
> Cc: Linus Torvalds
> Cc: linux-spa...@vger.kernel.org
> Signed-off-by: Miguel Ojeda
> ---
> include/linux/compiler-gcc.h | 8 +---
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index 76f4907ef707..4cd5e9264bce 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -77,14 +77,8 @@
> * to trace naked functions because then mcount is called without
> * stack and frame pointer being set up and there is no chance to
> * restore the lr register to the value before mcount was called.
I think this is also no longer required since GCC 4.6 and newer only
have the new mcount interface:
https://lore.kernel.org/lkml/20180826214022.4889-1-ste...@agner.ch/T/#u
That said, I am not sure whether it is a good idea to enable tracing for
naked functions even with the mcount interface.
--
Stefan
> - *
> - * The asm() bodies of naked functions often depend on standard calling
> - * conventions, therefore they must be noinline and noclone.
> - *
> - * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
> - * See GCC PR44290.
> */
> -#define __naked __attribute__((__naked__)) noinline __noclone
> notrace
> +#define __naked __attribute__((__naked__)) notrace
>
> #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix),
> __COUNTER__)
Re: [PATCH v4 05/13] Compiler Attributes: naked was fixed in gcc 4.6
Hi,
On 08.09.2018 14:24, Miguel Ojeda wrote:
> Commit 9c695203a7dd ("compiler-gcc.h: gcc-4.5 needs noclone
> and noinline on __naked functions") added noinline and noclone
> as a workaround for a gcc 4.5 bug, which was resolved in 4.6.0.
>
> Since now the minimum gcc supported version is 4.6,
> we can clean it up.
>
> See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44290
> and https://godbolt.org/z/h6NMIL
>
> Cc: Rasmus Villemoes
> Cc: Luc Van Oostenryck
> Cc: Eli Friedman
> Cc: Christopher Li
> Cc: Kees Cook
> Cc: Ingo Molnar
> Cc: Geert Uytterhoeven
> Cc: Arnd Bergmann
> Cc: Greg Kroah-Hartman
> Cc: Masahiro Yamada
> Cc: Joe Perches
> Cc: Dominique Martinet
> Cc: Nick Desaulniers
> Cc: Linus Torvalds
> Cc: linux-spa...@vger.kernel.org
> Signed-off-by: Miguel Ojeda
> ---
> include/linux/compiler-gcc.h | 8 +---
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index 76f4907ef707..4cd5e9264bce 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -77,14 +77,8 @@
> * to trace naked functions because then mcount is called without
> * stack and frame pointer being set up and there is no chance to
> * restore the lr register to the value before mcount was called.
I think this is also no longer required since GCC 4.6 and newer only
have the new mcount interface:
https://lore.kernel.org/lkml/20180826214022.4889-1-ste...@agner.ch/T/#u
That said, I am not sure whether it is a good idea to enable tracing for
naked functions even with the mcount interface.
--
Stefan
> - *
> - * The asm() bodies of naked functions often depend on standard calling
> - * conventions, therefore they must be noinline and noclone.
> - *
> - * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
> - * See GCC PR44290.
> */
> -#define __naked __attribute__((__naked__)) noinline __noclone
> notrace
> +#define __naked __attribute__((__naked__)) notrace
>
> #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix),
> __COUNTER__)
[PATCH v4 05/13] Compiler Attributes: naked was fixed in gcc 4.6
Commit 9c695203a7dd ("compiler-gcc.h: gcc-4.5 needs noclone
and noinline on __naked functions") added noinline and noclone
as a workaround for a gcc 4.5 bug, which was resolved in 4.6.0.
Since now the minimum gcc supported version is 4.6,
we can clean it up.
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44290
and https://godbolt.org/z/h6NMIL
Cc: Rasmus Villemoes
Cc: Luc Van Oostenryck
Cc: Eli Friedman
Cc: Christopher Li
Cc: Kees Cook
Cc: Ingo Molnar
Cc: Geert Uytterhoeven
Cc: Arnd Bergmann
Cc: Greg Kroah-Hartman
Cc: Masahiro Yamada
Cc: Joe Perches
Cc: Dominique Martinet
Cc: Nick Desaulniers
Cc: Linus Torvalds
Cc: linux-spa...@vger.kernel.org
Signed-off-by: Miguel Ojeda
---
include/linux/compiler-gcc.h | 8 +---
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 76f4907ef707..4cd5e9264bce 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -77,14 +77,8 @@
* to trace naked functions because then mcount is called without
* stack and frame pointer being set up and there is no chance to
* restore the lr register to the value before mcount was called.
- *
- * The asm() bodies of naked functions often depend on standard calling
- * conventions, therefore they must be noinline and noclone.
- *
- * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
- * See GCC PR44290.
*/
-#define __naked__attribute__((__naked__)) noinline __noclone
notrace
+#define __naked__attribute__((__naked__)) notrace
#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
--
2.17.1
[PATCH v4 05/13] Compiler Attributes: naked was fixed in gcc 4.6
Commit 9c695203a7dd ("compiler-gcc.h: gcc-4.5 needs noclone
and noinline on __naked functions") added noinline and noclone
as a workaround for a gcc 4.5 bug, which was resolved in 4.6.0.
Since now the minimum gcc supported version is 4.6,
we can clean it up.
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44290
and https://godbolt.org/z/h6NMIL
Cc: Rasmus Villemoes
Cc: Luc Van Oostenryck
Cc: Eli Friedman
Cc: Christopher Li
Cc: Kees Cook
Cc: Ingo Molnar
Cc: Geert Uytterhoeven
Cc: Arnd Bergmann
Cc: Greg Kroah-Hartman
Cc: Masahiro Yamada
Cc: Joe Perches
Cc: Dominique Martinet
Cc: Nick Desaulniers
Cc: Linus Torvalds
Cc: linux-spa...@vger.kernel.org
Signed-off-by: Miguel Ojeda
---
include/linux/compiler-gcc.h | 8 +---
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 76f4907ef707..4cd5e9264bce 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -77,14 +77,8 @@
* to trace naked functions because then mcount is called without
* stack and frame pointer being set up and there is no chance to
* restore the lr register to the value before mcount was called.
- *
- * The asm() bodies of naked functions often depend on standard calling
- * conventions, therefore they must be noinline and noclone.
- *
- * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
- * See GCC PR44290.
*/
-#define __naked__attribute__((__naked__)) noinline __noclone
notrace
+#define __naked__attribute__((__naked__)) notrace
#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
--
2.17.1
