On Mon, 2008-07-07 at 17:17 -0500, Nathan Lynch wrote: > Benjamin Herrenschmidt wrote: > > On Thu, 2008-07-03 at 19:19 -0700, Roland McGrath wrote: > > > Why not just use ELF_HWCAP for this? It looks like powerpc only has 3 > > > bits > > > left there (keeping it to 32), but 3 is not 0. If not that, why not use > > > dsocaps? That is, some magic in the vDSO, which glibc already supports on > > > all machines where it uses the vDSO. (For how it works, see the use in > > > arch/x86/vdso/vdso32/note.S for CONFIG_XEN.) > > > > Well, we use strings to represent the platforms already (ie, the actual > > CPU microarchitecture). Fitting those into bits would be annoying, it > > makes sense to have AT_BASE_PLATFORM to be the "base" variant of > > AT_PLATFORM. > > > > _However_ there is a bug in that this patch adds an entry without > > bumping the number of entries in the cached array (ie. > > AT_VECTOR_SIZE_BASE needs to be updated). > > Ugh, yes. I was hoping to work this in such a way that AT_VECTOR_SIZE > (and thus the size of mm_struct) increases only for architectures that > implement AT_BASE_PLATFORM... would it be wrong to account for it in > AT_VECTOR_SIZE_ARCH?
Yes. The later is for things added from ARCH_DLINFO. Since the code for AT_BASE_PLATFORM is in the generic binfmt_elf, it would be asking for trouble to not account for it in the base AT_VECTOR_SIZE. Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev