Hi Christoph,
On Mon, Jul 5, 2021 at 7:58 AM Christoph Hellwig <hch@xxxxxx> wrote:
m68knommu already does not distinguish between kernel and user address
spaces. Stop defining set_fs() and thus uaccess_kernel() to avoid
confusion.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Thanks for your patch!
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -32,7 +32,7 @@ config M68K
select NO_DMA if !MMU && !COLDFIRE
select OLD_SIGACTION
select OLD_SIGSUSPEND3
- select SET_FS
+ select SET_FS if MMU
Probably this should be
select SET_FS if CPU_HAS_ADDRESS_SPACES
instead. Classic m68k (except for good old 68000) has address spaces,
Coldfire has not.
Which brought my attention to a problem with support for embedded
68EC020 cores: MCPU32 does not select CPU_HAS_ADDRESS_SPACES, but
it also does not select GENERIC_CSUM. The latter means it will use
arch/m68k/lib/checksum.c, which does contain moves instructions, thus
assuming separate address spaces. Fortunately MCPU32 is no longer
used since commit a3595962d82495f5 ("m68knommu: remove obsolete 68360
support"), so it can be removed, too.
I guess we want to simplify
config GENERIC_CSUM
default y if !CPU_HAS_ADDRESS_SPACES
which would allow us to get rid of the ifndef CONFIG_GENERIC_CSUM in
arch/m68k/lib/Makefile, in favor of lib-$(CPU_HAS_ADDRESS_SPACES).
--- a/arch/m68k/include/asm/segment.h
+++ b/arch/m68k/include/asm/segment.h
@@ -2,19 +2,20 @@
#ifndef _M68K_SEGMENT_H
#define _M68K_SEGMENT_H
-/* define constants */
/* Address spaces (FC0-FC2) */
#define USER_DATA (1)
+#define USER_PROGRAM (2)
+#define SUPER_DATA (5)
+#define SUPER_PROGRAM (6)
+#define CPU_SPACE (7)
+
+#ifdef CONFIG_MMU
#ifndef __USER_DS
#define __USER_DS (USER_DATA)
#endif
-#define USER_PROGRAM (2)
-#define SUPER_DATA (5)
#ifndef __KERNEL_DS
#define __KERNEL_DS (SUPER_DATA)
#endif
-#define SUPER_PROGRAM (6)
-#define CPU_SPACE (7)
#ifndef __ASSEMBLY__
Just below this is the existing handling for !CPU_HAS_ADDRESS_SPACES.
Probably the [sg]et_fs() definitions there should be made dummies,
reducing the need to add a rather large number of #ifdefs.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
