On Tue, May 14, 2019 at 01:24:37PM -0700, Nick Desaulniers wrote: > On Tue, May 14, 2019 at 11:11 AM Kees Cook <keesc...@chromium.org> wrote: > > > > On Mon, May 13, 2019 at 04:50:05PM -0700, Nick Desaulniers wrote: > > > On Mon, May 13, 2019 at 4:29 PM Nathan Chancellor > > > <natechancel...@gmail.com> wrote: > > > > > > > > On Mon, May 13, 2019 at 03:21:09PM -0700, 'Nick Desaulniers' via Clang > > > > Built Linux wrote: > > > > > With CONFIG_LKDTM=y and make OBJCOPY=llvm-objcopy, llvm-objcopy > > > > > errors: > > > > > llvm-objcopy: error: --set-section-flags=.text conflicts with > > > > > --rename-section=.text=.rodata > > > > > > > > > > Rather than support setting flags then renaming sections vs renaming > > > > > then setting flags, it's simpler to just change both at the same time > > > > > via --rename-section. > > I'm not sure I want to call it a bug in the initial implementation. I've > filed: > https://sourceware.org/bugzilla/show_bug.cgi?id=24554 for > clarification. Jordan, I hope you can participate in any discussion > there?
Based on the hint from Alan Modra, it seems PROGBITS/NOBITS can be controlled with the presence/absence of the "load" section flag. This appears to work for both BFD and LLVM: $ objcopy --rename-section .text=.rodata,alloc,readonly,load rodata.o rodata_objcopy.o $ readelf -WS rodata_objcopy.o | grep \.rodata [ 1] .rodata PROGBITS 0000000000000000 000040 000002 00 A 0 0 16 $ llvm-objcopy --rename-section .text=.rodata,alloc,readonly,load rodata.o rodata_objcopy.o $ readelf -WS rodata_objcopy.o | grep \.rodata [ 1] .rodata PROGBITS 0000000000000000 000040 000002 00 A 0 0 16 So, that's an easy change that could be folded into the original version of this patch (no need for my two-phase work-around). -- Kees Cook
