Re: [PATCH 08/10] m68k: Add <asm/archhash.h>

From: George Spelvin
Date: Wed May 25 2016 - 04:20:01 EST

> With my comment above, you wouldn't need this, but I'm gonna comment anyway.
> We don't use special GCCs to target specific CPU variants. Hence inside the
> kernel, you should check the config symbols, to see if support for 68000 or
> 68010 (which isn't supported by the kernel yet) is enabled.

Do you remember some earlier discussion about the m68k Makefile and old
GCC versions? In particular, lines like:

cpuflags-$(CONFIG_M525x) := $(call cc-option,-mcpu=5253,-m5200)
cpuflags-$(CONFIG_M5249) := $(call cc-option,-mcpu=5249,-m5200)
cpuflags-$(CONFIG_M520x) := $(call cc-option,-mcpu=5208,-m5200)
cpuflags-$(CONFIG_M5206e) := $(call cc-option,-mcpu=5206e,-m5200)
cpuflags-$(CONFIG_M5206) := $(call cc-option,-mcpu=5206,-m5200)

The problem is that whether MULU.L exists depends on the targeted
architecture, and *that* depends on this Makefile trickery, not
just CONFIG symbols...

Oh, f*** me.

I misremembered. That problem exists, but only for DIVU.L. As I said in
the comments (which I wrote *after* deciding I needed this approach), all
ColdFire have MULU.L. It's DIVU.L that's missing from some early ones.

You're absolutely right. MULU.L support can be done perfectly from
CONFIG_ options.

Improved patch coming in a few minutes. My sincere apologies.