On Sat, Feb 29, 2020 at 2:20 AM Quentin Perret <qperret@xxxxxxxxxx> wrote: > > The current norm on Android and many other systems is for vendors to > introduce significant changes to their downstream kernels, and to > contribute very little (if any) code back upstream. The Generic Kernel > Image (GKI) project in Android attempts to improve the status-quo by > having a unique kernel for all android devices of the same architecture, > regardless of the SoC vendor. The key idea is to make all interested > parties agree on a common solution, and contribute their code upstream > to make it available to use by the wider community. > > The kernel-to-drivers ABI on Android devices varies significantly from > one vendor kernel to another today because of changes to exported > symbols, dependencies on vendor symbols, and surely other things. The > first step for GKI is to try and put some order into this by agreeing on > one version of the ABI that works for everybody. > > For practical reasons, we need to reduce the ABI surface to a subset of > the exported symbols, simply to make the problem realistically solvable, > but there is currently no upstream support for this use-case. > > As such, this series attempts to improve the situation by enabling users > to specify a symbol 'whitelist' at compile time. Any symbol specified in > this whitelist will be kept exported when CONFIG_TRIM_UNUSED_KSYMS is > set, even if it has no in-tree user. The whitelist is defined as a > simple text file, listing symbols, one per line. Series, applied to linux-kbuild. Thanks. > v6: > - made permission checks on the whitelist file more robust (Masahiro) > - better style/identation in Makefile (Masahiro) > > v5: > - made sure to be POSIX-compliant (+ tested with dash and posh) > - added failure path if the whitelist path is incorrect (Matthias, > Nicolas) > - collected Acked-By (and other) tags from Nicolas and Matthias > > v4: > - removed [[]] bash-specific pattern from the scripts (Nicolas) > - use $CONFIG_SHELL consistently in all patches (Masahiro) > - added shortlog for initial generation of autoksyms.h (Masahiro) > - added comment on how 'eval' expands the whitelist path (Masahiro) > > v3: > - added a cover letter to explain why this is in fact an attempt to > help upstream in the long term (Christoph) > - made path relative to the kernel source tree (Matthias) > - made the Kconfig help text less confusing (Jessica) > - added patch 02 and 03 to optimize build time when a whitelist is > provided > > v2: > - make sure to quote the whitelist path properly (Nicolas) > > Quentin Perret (3): > kbuild: allow symbol whitelisting with TRIM_UNUSED_KSYMS > kbuild: split adjust_autoksyms.sh in two parts > kbuild: generate autoksyms.h early > > Makefile | 7 +++-- > init/Kconfig | 13 ++++++++++ > scripts/adjust_autoksyms.sh | 24 +++-------------- > scripts/gen_autoksyms.sh | 52 +++++++++++++++++++++++++++++++++++++ > 4 files changed, 74 insertions(+), 22 deletions(-) > create mode 100755 scripts/gen_autoksyms.sh > > -- > 2.25.1.481.gfbce0eb801-goog > -- Best Regards Masahiro Yamada
