Anton Blanchard wrote: > Hi, > > >>I've got a ppc64 box running 2.6.14. 64-bit kernel, 32-bit userspace. >>It has a ~86KB chunk of memory near the top of the process address >>space, and I'm not sure who's setting it up and what the purpose is. In >>/proc/<pid>/maps it looks like this: >> >>fffea000-fffff000 rw-p fffea000 00:00 0 >> >>Can anyone enlighten me as to what this is for and who is allocating it? > > > Looks like your process stack. BTW we leave the top page > (0xfffff000 - 0xffffffff) unmapped mostly because of test cases that > expect > > *(unsigned long *)-1UL > > to fail.
Doh. Of course, that's almost certainly it. For some background, we're running an emulator that uses a null pointer value of 0xffff0000 and we want any accesses to that address to trap. Do you anticipate any issues with the following change? -#define TASK_SIZE_USER32 (0x0000000100000000UL - (1*PAGE_SIZE)) +#define TASK_SIZE_USER32 (0x00000000FFFF0000UL - (1*PAGE_SIZE)) Thanks, Chris _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
