On Mon, Dec 2, 2024, at 02:34, Greg Ungerer wrote:
Arnd, ping...
Sorry I hadn't realized you were waiting for me.
On 6/11/24 08:04, Greg Ungerer wrote:
On 5/11/24 21:46, Geert Uytterhoeven wrote:
On Mon, Nov 13, 2023 at 2:32 PM Greg Ungerer <gerg@xxxxxxxxxxxxxx> wrote:
Use the kernels own generic lib/muldi3.c implementation of muldi3 for
68K machines. Some 68K CPUs support 64bit multiplies so move the arch
specific umul_ppmm() macro into a header file that is included by
lib/muldi3.c. That way it can take advantage of the single instruction
when available.
There does not appear to be any existing mechanism for the generic
lib/muldi3.c code to pick up an external arch definition of umul_ppmm().
Create an arch specific libgcc.h that can optionally be included by
the system include/linux/libgcc.h to allow for this.
Somewhat oddly there is also a similar definition of umul_ppmm() in
the non-architecture code in lib/crypto/mpi/longlong.h for a wide range
or machines. Its presence ends up complicating the include setup and
means not being able to use something like compiler.h instead. Actually
there is a few other defines of umul_ppmm() macros spread around in
various architectures, but not directly usable for the m68k case.
Signed-off-by: Greg Ungerer <gerg@xxxxxxxxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
arch/Kconfig | 8 +++
arch/m68k/Kconfig | 2 +
arch/m68k/include/asm/libgcc.h | 20 +++++++
arch/m68k/lib/Makefile | 2 +-
arch/m68k/lib/muldi3.c | 97 ----------------------------------
include/linux/libgcc.h | 4 ++
6 files changed, 35 insertions(+), 98 deletions(-)
create mode 100644 arch/m68k/include/asm/libgcc.h
delete mode 100644 arch/m68k/lib/muldi3.c
I had this in my local tree for about a year.
Is it fine to queue this in the m68k tree, or does this need a broader
coverage?
I am still in favor of it :-)
Would be good to get some feedback on the common code changes, like the change
to libgcc.h.
Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
This looks fine to me, nice cleanup. My instinct at first was
to add an asm-generic/libgcc.h as a fallback in place of
the Kconfig symbol and move the common macro there, but there
really isn't much benefit to that over your version. Either way,
please merge this through the m68k tree.
Arnd
