Re: Patches to fix building m68k with CPUFLAGS

To: port-m68k%netbsd.org@localhost, port-amiga%netbsd.org@localhost
Subject: Re: Patches to fix building m68k with CPUFLAGS
From: Jake Hamby <jake.hamby%gmail.com@localhost>
Date: Sun, 19 Jul 2020 10:38:24 -0700
Oops, I meant "changes to *not* add CPUFLAGS to AFLAGS (for m68k). At
least it looks like Gmail didn't word wrap my patches, but it did word
wrap the text I put at the top (because I tried to add my own line
breaks, something I won't do this time).

BTW, here's the GitHub repo where I'm keeping my local fork of the
src. I didn't want to deal with CVS, and this is a nice way to avoid
doing so. https://github.com/jhamby/netbsd-src

Best regards,
Jake

On Sun, Jul 19, 2020 at 10:35 AM Jake Hamby <jake.hamby%gmail.com@localhost> wrote:
>
> Hi all,
>
> I've been spending some time getting reacquainted with NetBSD/amiga, thanks to
> emulation, and I just fixed some annoying bugs that were preventing anyone from
> setting CPUFLAGS in their NetBSD build (e.g. to optimize for m68060 or m68040.
> I also switched my build to use GCC 8.4.0 and binutils 2.34.
>
> The biggest problem with CPUFLAGS had to do with a whitespace bug in
> external/gpl3/gcc/dist/gcc/config/m68k/m68k.h (and in "gcc.old"),
> which is the last
> patch in the email. The bug is still in GCC, so the fix can be
> upstreamed right away.
> The changes to now add CPUFLAGS to AFLAGS are because GAS doesn't
> recognize, e.g. "-m68020-60", so we can't ever pass CPUFLAGS directly (on m68k).
>
> The patch to libgcc/config/m68k/lb1sf68.S (in gcc and gcc.old) is
> because otherwise
> the linker fails trying to handle unsupported 16-bit relocations. I'm
> not sure if wrapping
> the unworking code with !defined("__ELF__") is the correct fix, or if
> this is a bug
> that's specific to NetBSD. Either way, it got me past the build break.
>
> As for switching to the new GCC and binutils, I'm still testing that.
> I'm seeing some
> kernel panics in UVM, but I think they may be related to instability
> in NetBSD-current.
> I'll have to build a kernel with GCC 7 and compare, and also with the
> older binutils.
> I wanted to email the list with the patches I have so far, since I
> know a lot of people
> are blocked from making builds for their 68060 or 68040 because CPUFLAGS
> has been broken on m68k. If the mailing list breaks any of the patches, I also
> put a PR at: https://github.com/NetBSD/src/pull/13
>
> I'll delete the GitHub PR after the patches get merged. Thanks for reviewing!
>
> Subject: [PATCH 1/2] Switch m68k to new GCC and binutils, fix CPUFLAGS.
>
> - Change m68k build to use GCC 8.4.0 and binutils 2.34.
> - Update binutils config files to define TARGET_BYTES_BIG_ENDIAN.
> - Fix libgcc/config/m68k/lb1sf68.S to work around linker error
>   when using CPUFLAGS (normally masked by default CPU options).
> - Don't add CPUFLAGS to AFLAGS, to fix several build failures:
>   - Amiga kernel locore.s uses opcodes not present in 68040/060
>   - Amiga bootblocks use custom make rule that calls gas directly,
>     and gas doesn't understand all m68k CPUFLAGS recognized by GCC.
>   - m68060 kernel support package also doesn't like CPUFLAGS.
> ---
>  external/gpl3/binutils.old/usr.bin/gas/arch/m68k/config.h | 2 +-
>  external/gpl3/binutils/usr.bin/gas/arch/m68k/config.h     | 2 +-
>  external/gpl3/gcc.old/dist/libgcc/config/m68k/lb1sf68.S   | 4 ++--
>  external/gpl3/gcc/dist/libgcc/config/m68k/lb1sf68.S       | 4 ++--
>  share/mk/bsd.own.mk                                       | 5 +----
>  share/mk/bsd.sys.mk                                       | 4 ++++
>  6 files changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/external/gpl3/binutils.old/usr.bin/gas/arch/m68k/config.h
> b/external/gpl3/binutils.old/usr.bin/gas/arch/m68k/config.h
> index 63afe83d1be4..181f0bbe08fc 100644
> --- a/external/gpl3/binutils.old/usr.bin/gas/arch/m68k/config.h
> +++ b/external/gpl3/binutils.old/usr.bin/gas/arch/m68k/config.h
> @@ -298,7 +298,7 @@
>  #define TARGET_ALIAS "m68k--netbsdelf"
>
>  /* Define as 1 if big endian. */
> -/* #undef TARGET_BYTES_BIG_ENDIAN */
> +#define TARGET_BYTES_BIG_ENDIAN 1
>
>  /* Canonical target. */
>  #define TARGET_CANONICAL "m68k--netbsdelf"
> diff --git a/external/gpl3/binutils/usr.bin/gas/arch/m68k/config.h
> b/external/gpl3/binutils/usr.bin/gas/arch/m68k/config.h
> index eddab29535cb..c4087fdff09c 100644
> --- a/external/gpl3/binutils/usr.bin/gas/arch/m68k/config.h
> +++ b/external/gpl3/binutils/usr.bin/gas/arch/m68k/config.h
> @@ -317,7 +317,7 @@
>  #define TARGET_ALIAS "m68k--netbsdelf"
>
>  /* Define as 1 if big endian. */
> -/* #undef TARGET_BYTES_BIG_ENDIAN */
> +#define TARGET_BYTES_BIG_ENDIAN 1
>
>  /* Canonical target. */
>  #define TARGET_CANONICAL "m68k--netbsdelf"
> diff --git a/external/gpl3/gcc.old/dist/libgcc/config/m68k/lb1sf68.S
> b/external/gpl3/gcc.old/dist/libgcc/config/m68k/lb1sf68.S
> index 0c367428ceff..472f4d94a9da 100644
> --- a/external/gpl3/gcc.old/dist/libgcc/config/m68k/lb1sf68.S
> +++ b/external/gpl3/gcc.old/dist/libgcc/config/m68k/lb1sf68.S
> @@ -172,7 +172,7 @@ see the files COPYING3 and COPYING.RUNTIME
> respectively.  If not, see
>   /* ISA C has no bra.l instruction, and since this assembly file
>     gets assembled into multiple object files, we avoid the
>     bra instruction entirely.  */
> -#if defined (__mcoldfire__) && !defined (__mcfisab__)
> +#if defined (__ELF__) || (defined (__mcoldfire__) && !defined (__mcfisab__))
>   lea \addr-.-8,a0
>   jmp pc@(a0)
>  #else
> @@ -211,7 +211,7 @@ see the files COPYING3 and COPYING.RUNTIME
> respectively.  If not, see
>   /* ISA C has no bra.l instruction, and since this assembly file
>     gets assembled into multiple object files, we avoid the
>     bra instruction entirely.  */
> -#if defined (__mcoldfire__) && !defined (__mcfisab__)
> +#if defined (__ELF__) || (defined (__mcoldfire__) && !defined (__mcfisab__))
>   lea \addr-.-8,a0
>   jmp pc@(a0)
>  #else
> diff --git a/external/gpl3/gcc/dist/libgcc/config/m68k/lb1sf68.S
> b/external/gpl3/gcc/dist/libgcc/config/m68k/lb1sf68.S
> index 3784f4323961..2b3ff490a2a1 100644
> --- a/external/gpl3/gcc/dist/libgcc/config/m68k/lb1sf68.S
> +++ b/external/gpl3/gcc/dist/libgcc/config/m68k/lb1sf68.S
> @@ -172,7 +172,7 @@ see the files COPYING3 and COPYING.RUNTIME
> respectively.  If not, see
>   /* ISA C has no bra.l instruction, and since this assembly file
>     gets assembled into multiple object files, we avoid the
>     bra instruction entirely.  */
> -#if defined (__mcoldfire__) && !defined (__mcfisab__)
> +#if defined (__ELF__) || (defined (__mcoldfire__) && !defined (__mcfisab__))
>   lea \addr-.-8,a0
>   jmp pc@(a0)
>  #else
> @@ -211,7 +211,7 @@ see the files COPYING3 and COPYING.RUNTIME
> respectively.  If not, see
>   /* ISA C has no bra.l instruction, and since this assembly file
>     gets assembled into multiple object files, we avoid the
>     bra instruction entirely.  */
> -#if defined (__mcoldfire__) && !defined (__mcfisab__)
> +#if defined (__ELF__) || (defined (__mcoldfire__) && !defined (__mcfisab__))
>   lea \addr-.-8,a0
>   jmp pc@(a0)
>  #else
> diff --git a/share/mk/bsd.own.mk b/share/mk/bsd.own.mk
> index 3d4850e22e52..efaadde72aaa 100644
> --- a/share/mk/bsd.own.mk
> +++ b/share/mk/bsd.own.mk
> @@ -63,9 +63,6 @@ TOOLCHAIN_MISSING?= no
>  #
>  # What GCC is used?
>  #
> -.if ${MACHINE_CPU} == "m68k"
> -HAVE_GCC?= 7
> -.endif
>  HAVE_GCC?= 8
>
>  #
> @@ -163,7 +160,7 @@ EXTERNAL_GDB_SUBDIR= /does/not/exist
>      ${MACHINE_ARCH} == "powerpc64" || ${MACHINE_ARCH} == "powerpc" || \
>      ${MACHINE_CPU} == "aarch64" || ${MACHINE_CPU} == "arm" || \
>      ${MACHINE_ARCH} == "hppa" || ${MACHINE_ARCH} == "sparc64" || \
> -    ${MACHINE} == "sun2" || ${MACHINE} == "alpha"
> +    ${MACHINE_CPU} == "m68k" || ${MACHINE} == "alpha"
>  HAVE_BINUTILS?= 234
>  .else
>  HAVE_BINUTILS?= 231
> diff --git a/share/mk/bsd.sys.mk b/share/mk/bsd.sys.mk
> index 758ab3485d4a..ba7f0f4d3cbc 100644
> --- a/share/mk/bsd.sys.mk
> +++ b/share/mk/bsd.sys.mk
> @@ -234,7 +234,11 @@ CPUFLAGS+= -Wa,--fatal-warnings
>  #CPUFLAGS+= -mno-abicalls -fno-PIC
>  #.endif
>  CFLAGS+= ${CPUFLAGS}
> +
> +# GNU assembler doesn't like some m68k flags, esp. for kernel locore.s, etc.
> +.if ${MACHINE_CPU} != "m68k"
>  AFLAGS+= ${CPUFLAGS}
> +.endif
>
>  .if ${KCOV:U0} > 0
>  KCOVFLAGS= -fsanitize-coverage=trace-pc,trace-cmp
>
> Subject: [PATCH 2/2] Insert missing whitespace for assembler flag rules.
>
> Fixes assembler errors like "unrecognized option -m68040-mcpu=68040".
> ---
>  external/gpl3/gcc/dist/gcc/config/m68k/m68k.h | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/external/gpl3/gcc/dist/gcc/config/m68k/m68k.h
> b/external/gpl3/gcc/dist/gcc/config/m68k/m68k.h
> index 506fa4e50e76..8c688a4156cc 100644
> --- a/external/gpl3/gcc/dist/gcc/config/m68k/m68k.h
> +++ b/external/gpl3/gcc/dist/gcc/config/m68k/m68k.h
> @@ -36,9 +36,9 @@ along with GCC; see the file COPYING3.  If not see
>     and .arch directives.  */
>
>  #define ASM_CPU_SPEC "\
> -%{m68851}%{mno-68851} %{m68881}%{mno-68881} %{msoft-float:-mno-float} \
> -%{m68020-40:-m68040}%{m68020-60:-m68040}\
> -%{mcpu=*:-mcpu=%*}%{march=*:-march=%*}\
> + %{m68851} %{mno-68851} %{m68881} %{mno-68881} %{msoft-float:-mno-float}\
> + %{m68020-40:-m68040} %{m68020-60:-m68040}\
> + %{mcpu=*:-mcpu=%*} %{march=*:-march=%*}\
>  "
>  #define ASM_PCREL_SPEC "%{" FPIE_OR_FPIC_SPEC ":--pcrel} \
>   %{mpcrel:%{" NO_FPIE_AND_FPIC_SPEC ":--pcrel}} \
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