[llvmlinux] Rebasing llvmlinux kernel patches to more current kernels

[Sedat Dilek]

On Sun, Apr 10, 2016 at 9:08 PM, Renato Golin <renato.golin at linaro.org> wrote:
> On 10 April 2016 at 19:51, Sedat Dilek <sedat.dilek at gmail.com> wrote:
>> This solution is wonderful for the ARM world, but I am living in the
>> Linux/x86 world.
>
> This problem is completely irrelevant for x86, AFAIK, so, you should be fine.
>

No, it's not.

With CONFIG_FUNCTION_TRACER=y I see in my logs...

+ ld -m elf_x86_64 --build-id --build-id -o .tmp_vmlinux1 -T
./arch/x86/kernel/vmlinux.lds arch/x86/kernel/head_64.o
arch/x86/kernel/head64.o arch/x86/kernel/head.o init/built-in.o
--start-group usr/built-in.o arch/x86/built-in.o kernel/built-in.o
certs/built-in.o mm/built-in.o fs/built-in.o ipc/built-in.o
security/built-in.o crypto/built-in.o block/built-in.o lib/lib.a
arch/x86/lib/lib.a lib/built-in.o arch/x86/lib/built-in.o
drivers/built-in.o sound/built-in.o firmware/built-in.o
arch/x86/pci/built-in.o arch/x86/power/built-in.o
arch/x86/video/built-in.o arch/x86/ras/built-in.o net/built-in.o
virt/built-in.o --end-group
arch/x86/kernel/head64.o: In function `early_make_pgtable':
arch/x86/kernel/head64.c:(.init.text+0x1f): undefined reference to `_mcount'
arch/x86/kernel/head64.c:(.init.text+0x51): undefined reference to `_mcount'
arch/x86/kernel/head64.c:(.init.text+0x60): undefined reference to `_mcount'
arch/x86/kernel/head64.c:(.init.text+0xdc): undefined reference to `_mcount'
arch/x86/kernel/head64.c:(.init.text+0x110): undefined reference to `_mcount'
arch/x86/kernel/head64.o:arch/x86/kernel/head64.c:(.init.text+0x162):
more undefined references to `_mcount' follow
+ on_exit

Some explanations from PaX see [1].

>> As usually I need a backport for "clang-stable" aka v3.8.0.
>
> If you need anything back-ported to point releases, please send an
> email to the LLVM list and copy Tom Stellard (tom at stellard.net) and
> the code owner, if any (check file CODE_OWNERS.TXT).
>

That will be done when the issue is solved for X86.

- Sedat -

[1] https://lists.linuxfoundation.org/pipermail/llvmlinux/2013-July/000429.html