Messages in this thread | | | Subject | Re: [PATCH] arm64: Enable CONFIG_COMPAT also for 64k page size | From | Alexander Graf <> | Date | Wed, 11 Mar 2015 08:08:41 -0500 |
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> Am 11.03.2015 um 07:47 schrieb Arnd Bergmann <arnd@arndb.de>: > >> On Wednesday 11 March 2015 06:24:16 Alexander Graf wrote: >> So after recompiling all of the distribution with newer binutils we now >> have an openSUSE Factory tree that has 64k aligned 32bit binaries. >> >> Unfortunately however, the 32bit glibc has a bogus mmap() implementation >> that hard codes 4k page size. >> >> With the patch below applied to glibc, I can successfully run 32bit user >> space on Seattle with 64k PAGE_SIZE though. So I guess we'll need to fix >> up glibc next. >> >> Do you know of anyone who's fluent enough in 32bit ARM assembly to >> convert the hard coded assumptions in there to instead use a variable >> that takes the actual host page size into account? > > I believe this is a kernel bug, and the kernel API for 32-bit emulation > should always take the pgoff argument in 4KB units instead of PAGE_SIZE > units, see the implementation of sys_mmap2 in > arch/powerpc/kernel/sys_ppc32.c. > > All user space programs that call mmap2 still need to make sure that > their arguments are PAGE_SIZE aligned, but the libc need not care > about this here.
Awesome, that makes my life a lot easier. Let me cook up a patch that fixes the compat mmap call later today :).
Alex
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