> Date: Wed, 10 Aug 2016 00:31:06 -0700
> From: Philip Guenther <[email protected]>
>
> So it looks like relro wasn't working for me on mips64...because I
> couldn't count zeros correctly: 0x1000 != 0x10000, resulting in it
> aligning on subpage size and protecting the relro area altered the .data
> and .bss segments too. Setting COMMONPAGESIZE to 0x4000 == 16K, the
> advertised page size on loongson appears to have everything working.
>
> Also, since mips64 doesn't have a real hardware NX bit, splitting the
> .text and .rodata segments doesn't actually get us anything from a
> protection standpoint. So, unset PAD_NO to smoosh them back together.
> What I'm not sure is if the pmap would be happier with them separate: the
> workaround for the "R4000 EOP" bug applies to PROT_EXEC pages only, so
> maybe it would be better to keep them separate for that? Anyone?
Hmm, doesn' Loongsoon actually have a NX bit? Perhaps in later
generations? In any case I'd keep them separate. Keeps the number of
variations between platfforms down a bit.
> I'm going to leave the loongon doing the full build overnight, but it
> looks like it's happy with the critical parts of a partial build...
>
>
> Philip
>
>
> Index: ld/ldmain.c
> ===================================================================
> RCS file: /data/src/openbsd/src/gnu/usr.bin/binutils-2.17/ld/ldmain.c,v
> retrieving revision 1.10
> diff -u -p -r1.10 ldmain.c
> --- ld/ldmain.c 10 Aug 2016 02:58:44 -0000 1.10
> +++ ld/ldmain.c 10 Aug 2016 07:16:41 -0000
> @@ -299,7 +299,7 @@ main (int argc, char **argv)
> link_info.new_dtags = FALSE;
> link_info.combreloc = TRUE;
> link_info.eh_frame_hdr = FALSE;
> -#if defined(__mips64__) || defined(__m88k__)
> +#if defined(__m88k__)
> link_info.relro = FALSE;
> #else
> link_info.relro = TRUE;
> Index: ld/emulparams/elf64btsmip_obsd.sh
> ===================================================================
> RCS file:
> /data/src/openbsd/src/gnu/usr.bin/binutils-2.17/ld/emulparams/elf64btsmip_obsd.sh,v
> retrieving revision 1.3
> diff -u -p -r1.3 elf64btsmip_obsd.sh
> --- ld/emulparams/elf64btsmip_obsd.sh 10 Aug 2016 02:58:44 -0000 1.3
> +++ ld/emulparams/elf64btsmip_obsd.sh 10 Aug 2016 07:04:26 -0000
> @@ -1,7 +1,9 @@
> . ${srcdir}/emulparams/elf64btsmip.sh
> MAXPAGESIZE=0x10000
> -COMMONPAGESIZE=0x1000
> +COMMONPAGESIZE=0x4000
> TEXT_START_ADDR="0x10000000"
> . ${srcdir}/emulparams/elf_obsd.sh
> # XXX causes GOT oflows
> NO_PAD_CDTOR=y
> +# No nx bit, so don't bother to pad between .text and .rodata
> +unset PAD_RO
> Index: ld/emulparams/elf64ltsmip_obsd.sh
> ===================================================================
> RCS file:
> /data/src/openbsd/src/gnu/usr.bin/binutils-2.17/ld/emulparams/elf64ltsmip_obsd.sh,v
> retrieving revision 1.3
> diff -u -p -r1.3 elf64ltsmip_obsd.sh
> --- ld/emulparams/elf64ltsmip_obsd.sh 10 Aug 2016 02:58:44 -0000 1.3
> +++ ld/emulparams/elf64ltsmip_obsd.sh 10 Aug 2016 07:04:16 -0000
> @@ -1,7 +1,9 @@
> . ${srcdir}/emulparams/elf64ltsmip.sh
> MAXPAGESIZE=0x10000
> -COMMONPAGESIZE=0x1000
> +COMMONPAGESIZE=0x4000
> TEXT_START_ADDR="0x10000000"
> . ${srcdir}/emulparams/elf_obsd.sh
> # XXX causes GOT oflows
> NO_PAD_CDTOR=y
> +# No nx bit, so don't bother to pad between .text and .rodata
> +unset PAD_RO
>
>
