On Fri, Feb 28, 2020 at 07:51:21AM +0100, Sedat Dilek wrote:

On Fri, Feb 28, 2020 at 1:22 AM Kees Cook [off-list ref] wrote:

quoted

This series depends on tip/x86/boot (where recent .eh_frame fixes[3]
landed), and has a minor conflict[4] with the ARM tree (related to
the earlier mentioned bug). As it uses refactorings in the asm-generic
linker script, and makes changes to kbuild, I think the cleanest place
for this series to land would also be through -tip. Once again (like
my READ_IMPLIES_EXEC series), I'm looking to get maintainer Acks so
this can go all together with the least disruption. Splitting it up by
architecture seems needlessly difficult.

Hi Kees,

is this an updated version of what you have in your
kees/linux.git#linker/orphans/x86-arm Git branch?

Hi; yes indeed.

Especially, I saw a difference in [2] and "[PATCH 4/9] x86/boot: Warn
on orphan section placement"

[ arch/x86/boot/compressed/Makefile ]

+KBUILD_LDFLAGS += --no-ld-generated-unwind-info

Can you comment on why this KBUILD_LDFLAGS was added/needed?

It looks like the linker decided to add .eh_frame sections even when all
the .o files lacked it. Adding this flag solved it (which I prefer over
adding it to DISCARD).

I like when people offer their work in a Git branch.
Do you plan to do that?

Since it was based on a -tip sub-branch I didn't push a
copy, but since you asked here it is:
https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=orphans/tip/x86/boot

And this email can serve as a "ping" to the arch maintainers too...
does this all look okay to you? I think it'd be a nice improvement. :)

Thanks!

-Kees

Thanks.

Regards,
- Sedat -

[1] https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=linker/orphans/x86-arm
[2] https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?h=linker/orphans/x86-arm&id=e43aa77956c40b9b6db0b37b3780423aa2e661ad

quoted

H.J. Lu (1):
  Add RUNTIME_DISCARD_EXIT to generic DISCARDS

Kees Cook (8):
  scripts/link-vmlinux.sh: Delay orphan handling warnings until final
    link
  vmlinux.lds.h: Add .gnu.version* to DISCARDS
  x86/build: Warn on orphan section placement
  x86/boot: Warn on orphan section placement
  arm64/build: Use common DISCARDS in linker script
  arm64/build: Warn on orphan section placement
  arm/build: Warn on orphan section placement
  arm/boot: Warn on orphan section placement

 arch/arm/Makefile                             |  4 ++++
 arch/arm/boot/compressed/Makefile             |  2 ++
 arch/arm/boot/compressed/vmlinux.lds.S        | 17 ++++++--------
 .../arm/{kernel => include/asm}/vmlinux.lds.h | 22 ++++++++++++++-----
 arch/arm/kernel/vmlinux-xip.lds.S             |  5 ++---
 arch/arm/kernel/vmlinux.lds.S                 |  5 ++---
 arch/arm64/Makefile                           |  4 ++++
 arch/arm64/kernel/vmlinux.lds.S               | 13 +++++------
 arch/x86/Makefile                             |  4 ++++
 arch/x86/boot/compressed/Makefile             |  3 ++-
 arch/x86/boot/compressed/vmlinux.lds.S        | 13 +++++++++++
 arch/x86/kernel/vmlinux.lds.S                 |  7 ++++++
 include/asm-generic/vmlinux.lds.h             | 11 ++++++++--
 scripts/link-vmlinux.sh                       |  6 +++++
 14 files changed, 85 insertions(+), 31 deletions(-)
 rename arch/arm/{kernel => include/asm}/vmlinux.lds.h (92%)

-- 
Kees Cook

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