RISC-V: Fix the VDSO symbol generaton for binutils-2.35+

Browse source

We were relying on GNU ld's ability to re-link executable files in order
to extract our VDSO symbols.  This behavior was deemed a bug as of
binutils-2.35 (specifically the binutils-gdb commit a87e1817a4 ("Have
the linker fail if any attempt to link in an executable is made."), but
as that has been backported to at least Debian's binutils-2.34 in may
manifest in other places.

The previous version of this was a bit of a mess: we were linking a
static executable version of the VDSO, containing only a subset of the
input symbols, which we then linked into the kernel.  This worked, but
certainly wasn't a supported path through the toolchain.  Instead this
new version parses the textual output of nm to produce a symbol table.
Both rely on near-zero addresses being linkable, but as we rely on weak
undefined symbols being linkable elsewhere I don't view this as a major
issue.

Fixes: e2c0cdfba7 ("RISC-V: User-facing API")
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

...

This commit is contained in:

Palmer Dabbelt 2020-10-23 21:50:47 -07:00

parent 1074dd44c5

commit c2c81bb2f6

No known key found for this signature in database

GPG key ID: 2E1319F35FBB1889

3 changed files with 16 additions and 9 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

1

arch/riscv/kernel/vdso/.gitignore vendored

View file

18

arch/riscv/kernel/vdso/Makefile

View file

6

arch/riscv/kernel/vdso/so2s.sh Executable file

View file