| Message ID | 20180104184334.16571-4-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jan 04, 2018 at 06:43:18PM +0000, Marc Zyngier wrote: > So far, we've been lucky enough that none of the include files > that asm-offsets.c requires include asm-offsets.h. This is > about to change, and would introduce a nasty circular dependency... > > Let's now guard the inclusion of asm-offsets.h so that it never > gets pulled from asm-offsets.c. The same issue exists between > bounce.c and include/generated/bounds.h, and is worked around > by using the existing guard symbol. > > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > --- > arch/arm64/include/asm/asm-offsets.h | 2 ++ > arch/arm64/kernel/asm-offsets.c | 2 ++ > 2 files changed, 4 insertions(+) > > diff --git a/arch/arm64/include/asm/asm-offsets.h b/arch/arm64/include/asm/asm-offsets.h > index d370ee36a182..7d6531a81eb3 100644 > --- a/arch/arm64/include/asm/asm-offsets.h > +++ b/arch/arm64/include/asm/asm-offsets.h > @@ -1 +1,3 @@ > +#if !defined(__GENERATING_ASM_OFFSETS_H) && !defined(__GENERATING_BOUNDS_H) I don't understand why we need to check __GENERATING_BOUNDS_H here? What is the interaction between asm-offsets and bounds? Thanks, -Christoffer
On 15/01/18 08:34, Christoffer Dall wrote: > On Thu, Jan 04, 2018 at 06:43:18PM +0000, Marc Zyngier wrote: >> So far, we've been lucky enough that none of the include files >> that asm-offsets.c requires include asm-offsets.h. This is >> about to change, and would introduce a nasty circular dependency... >> >> Let's now guard the inclusion of asm-offsets.h so that it never >> gets pulled from asm-offsets.c. The same issue exists between >> bounce.c and include/generated/bounds.h, and is worked around >> by using the existing guard symbol. >> >> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >> --- >> arch/arm64/include/asm/asm-offsets.h | 2 ++ >> arch/arm64/kernel/asm-offsets.c | 2 ++ >> 2 files changed, 4 insertions(+) >> >> diff --git a/arch/arm64/include/asm/asm-offsets.h b/arch/arm64/include/asm/asm-offsets.h >> index d370ee36a182..7d6531a81eb3 100644 >> --- a/arch/arm64/include/asm/asm-offsets.h >> +++ b/arch/arm64/include/asm/asm-offsets.h >> @@ -1 +1,3 @@ >> +#if !defined(__GENERATING_ASM_OFFSETS_H) && !defined(__GENERATING_BOUNDS_H) > > I don't understand why we need to check __GENERATING_BOUNDS_H here? > What is the interaction between asm-offsets and bounds? bound.c ends up including asm-offsets.h as well once you start adding the dependency between it and alternatives.h. See the report there: https://www.spinics.net/lists/arm-kernel/msg623723.html which this check addresses. Thanks, M.
On Mon, Jan 15, 2018 at 9:42 AM, Marc Zyngier <marc.zyngier@arm.com> wrote: > On 15/01/18 08:34, Christoffer Dall wrote: >> On Thu, Jan 04, 2018 at 06:43:18PM +0000, Marc Zyngier wrote: >>> So far, we've been lucky enough that none of the include files >>> that asm-offsets.c requires include asm-offsets.h. This is >>> about to change, and would introduce a nasty circular dependency... >>> >>> Let's now guard the inclusion of asm-offsets.h so that it never >>> gets pulled from asm-offsets.c. The same issue exists between >>> bounce.c and include/generated/bounds.h, and is worked around >>> by using the existing guard symbol. >>> >>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >>> --- >>> arch/arm64/include/asm/asm-offsets.h | 2 ++ >>> arch/arm64/kernel/asm-offsets.c | 2 ++ >>> 2 files changed, 4 insertions(+) >>> >>> diff --git a/arch/arm64/include/asm/asm-offsets.h b/arch/arm64/include/asm/asm-offsets.h >>> index d370ee36a182..7d6531a81eb3 100644 >>> --- a/arch/arm64/include/asm/asm-offsets.h >>> +++ b/arch/arm64/include/asm/asm-offsets.h >>> @@ -1 +1,3 @@ >>> +#if !defined(__GENERATING_ASM_OFFSETS_H) && !defined(__GENERATING_BOUNDS_H) >> >> I don't understand why we need to check __GENERATING_BOUNDS_H here? >> What is the interaction between asm-offsets and bounds? > > bound.c ends up including asm-offsets.h as well once you start adding > the dependency between it and alternatives.h. See the report there: > > https://www.spinics.net/lists/arm-kernel/msg623723.html > > which this check addresses. > Ah, I see. Thanks, -Christoffer
diff --git a/arch/arm64/include/asm/asm-offsets.h b/arch/arm64/include/asm/asm-offsets.h index d370ee36a182..7d6531a81eb3 100644 --- a/arch/arm64/include/asm/asm-offsets.h +++ b/arch/arm64/include/asm/asm-offsets.h @@ -1 +1,3 @@ +#if !defined(__GENERATING_ASM_OFFSETS_H) && !defined(__GENERATING_BOUNDS_H) #include <generated/asm-offsets.h> +#endif diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 742887330101..5ab8841af382 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -18,6 +18,8 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#define __GENERATING_ASM_OFFSETS_H 1 + #include <linux/sched.h> #include <linux/mm.h> #include <linux/dma-mapping.h>
So far, we've been lucky enough that none of the include files that asm-offsets.c requires include asm-offsets.h. This is about to change, and would introduce a nasty circular dependency... Let's now guard the inclusion of asm-offsets.h so that it never gets pulled from asm-offsets.c. The same issue exists between bounce.c and include/generated/bounds.h, and is worked around by using the existing guard symbol. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/arm64/include/asm/asm-offsets.h | 2 ++ arch/arm64/kernel/asm-offsets.c | 2 ++ 2 files changed, 4 insertions(+)