> On Jan 5, 2023, at 8:53 AM, Christos Zoulas <chris...@zoulas.com> wrote: > > Hello, > > Our dynamic linker ld_elf.so in map_object.c currently can only handle 2 > PT_LOAD segments (one for text and one for data); the kernel elf loader does > not have this limitation, it can load multiple PT_LOAD segment. The following > patch (from FreeBSD) removes this limitation from the dynamic linker. The > reason I made this patch now is that the latest binutils (2.39) for amd64 > sets a maxinum pagesize of 2Mb, and when using relocation read only binaries > (ld -z relro) this will cause the binaries to have an extra 2Mbytes for > alignment. This can be fixed by building binutils to set a separate code > segment by default (ld -z separate-code). Binutils then sets the maximum page > size to 4Kb. Setting this option creates 4 PT_LOAD segments, two for text > (r--, r-x) and two for data (r--, rw-), which also improves security. This is > the default for linux on x86 and the patch also makes it the default for > NetBSD x86. The patch also adds -z noseparate-code to the kernel builds so > that we don't need to fix the boot loaders. I am planning to commit this > soon, so please let me know if you hsve any objections. > > Best, > > christos<separate-code.diff>
Is this ld.elf_so change also going to be put into NetBSD 10? (Seems like it could / should be?). That way, the configuration changes for the toolchain (which you will presumable want to upstream) can match against NetBSD 10 for the new defaults. -- thorpej
