| Message ID | 20130716110721.GD24642@n2100.arm.linux.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 07/16/2013 03:07 PM, Russell King - ARM Linux wrote: > On Tue, Jul 16, 2013 at 02:47:45PM +0400, Alexander Kartashov wrote: >> On 07/16/2013 02:36 PM, Russell King - ARM Linux wrote: >>> shmget() doesn't allocate space in the process for the SHM region. It >>> merely creates the shm memory and returns an identifier for it which can >>> later be used by shmat() to map it. >> Thank you for the correction, I meant shmat() in that comment indeed. >> I'm sorry for the inconvenience. > Right, so it appears that there's a difference between shmat() with an > address and with a NULL address, because the enforcement is done by two > completely different bits of code in unrelated parts of the kernel. > > I notice Sparc32 seems to have a fix for this along the lines of the > (untested) patch below, so let's do the same on ARM. Please test this > and let me know if this solves your problem. > > Thanks. > > arch/arm/include/asm/shmparam.h | 8 ++++---- > 1 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/arm/include/asm/shmparam.h b/arch/arm/include/asm/shmparam.h > index a5223b3..843db59 100644 > --- a/arch/arm/include/asm/shmparam.h > +++ b/arch/arm/include/asm/shmparam.h > @@ -1,16 +1,16 @@ > #ifndef _ASMARM_SHMPARAM_H > #define _ASMARM_SHMPARAM_H > > +#include <asm/cachetype.h> > + > /* > * This should be the size of the virtually indexed cache/ways, > * or page size, whichever is greater since the cache aliases > * every size/ways bytes. > */ > -#define SHMLBA (4 * PAGE_SIZE) /* attach addr a multiple of this */ > +#define SHMLBA (cache_is_vipt_aliasing() ? (4 * PAGE_SIZE) : PAGE_SIZE) This change breaks compilation: arch/arm/mm/copypage-v6.c:23:5: warning: "cacheid_is" is not defined [-Wundef] arch/arm/mm/copypage-v6.c:23:5: error: missing binary operator before token "(" make[1]: *** [arch/arm/mm/copypage-v6.o] Error 1 make: *** [arch/arm/mm] Error 2 The lines in trouble is #if SHMLBA > 16384 #error FIX ME #endif > > -/* > - * Enforce SHMLBA in shmat > - */ > +/* Enforce SHMLBA in shmat */ > #define __ARCH_FORCE_SHMLBA > > #endif /* _ASMARM_SHMPARAM_H */
Dear Russell, I'm sorry for the delayed response. On 07/16/2013 05:12 PM, Alexander Kartashov wrote: > The lines in trouble is > > #if SHMLBA > 16384 > #error FIX ME > #endif Nevertheless, removing these lines fixes both the compilation and shared memory alignment issue. Thank you.
diff --git a/arch/arm/include/asm/shmparam.h b/arch/arm/include/asm/shmparam.h index a5223b3..843db59 100644 --- a/arch/arm/include/asm/shmparam.h +++ b/arch/arm/include/asm/shmparam.h @@ -1,16 +1,16 @@ #ifndef _ASMARM_SHMPARAM_H #define _ASMARM_SHMPARAM_H +#include <asm/cachetype.h> + /* * This should be the size of the virtually indexed cache/ways, * or page size, whichever is greater since the cache aliases * every size/ways bytes. */ -#define SHMLBA (4 * PAGE_SIZE) /* attach addr a multiple of this */ +#define SHMLBA (cache_is_vipt_aliasing() ? (4 * PAGE_SIZE) : PAGE_SIZE) -/* - * Enforce SHMLBA in shmat - */ +/* Enforce SHMLBA in shmat */ #define __ARCH_FORCE_SHMLBA #endif /* _ASMARM_SHMPARAM_H */