Patch series "sort out the flush_icache_range mess", v2.

flush_icache_range is mostly used for kernel address, except for the
following cases:

 - the nommu brk and mmap implementations

 - the read_code helper that is only used for binfmt_flat,
   binfmt_elf_fdpic, and binfmt_aout including the broken
   ia32 compat version

 - binfmt_flat itself

none of which really are used by a typical MMU enabled kernel, as a.out
can only be build for alpha and m68k to start with.

But strangely enough commit ae92ef8a ("PATCH] flush icache in
correct context") added a "set_fs(KERNEL_DS)" around the
flush_icache_range call in the module loader, because apparently m68k
assumed user pointers.

This series first cleans up the cacheflush implementations, largely by
switching as much as possible to the asm-generic version after a few
preparations, then moves the misnamed current flush_icache_user_range to
a new name, to finally introduce a real flush_icache_user_range to be
used for the above use cases to flush the instruction cache for a
userspace address range.  The last patch then drops the set_fs in the
module code and moves it into the m68k implementation.

This patch (of 29):

The arguments passed look bogus, try to fix them to something that seems
to make sense.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Aurelien Jacquiot <jacquiot.aurelien@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200515143646.3857579-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200515143646.3857579-2-hch@lst.deSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>