microblaze: Do loop unrolling for optimized memset implementation

Align implementation with memcpy and memmove where also remaining bytes are
copied via final switch case instead of using simple implementations which
loop. But this alignment has much stronger reason and definitely aligning
implementation is not the key point here. It is just good to have in mind
that the same technique is used already there.

In GCC 10, now -ftree-loop-distribute-patterns optimization is on at O2.
This optimization causes GCC to convert the while loop in memset.c into a
call to memset.
So this optimization is transforming a loop in a memset/memcpy into a call
to the function itself. This makes the memset implementation as recursive.
"-freestanding" option will disable the built-in library function but it
has been added in generic library implementation.

In default microblaze kernel defconfig we have CONFIG_OPT_LIB_FUNCTION
enabled so it will always pick optimized version of memset which is target
specific so we are replacing the while() loop with switch case to avoid
recursive memset call.

Issue with freestanding was already discussed in connection to commit
33d0f96ffd73 ("lib/string.c: Use freestanding environment") and also this
is topic in glibc and gcc.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56888
http://patchwork.ozlabs.org/project/glibc/patch/20191121021040.14554-1-sandra@codesourcery.com/

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mahesh Bodapati <mbodapat@xilinx.com>
Link: https://lore.kernel.org/r/10a432e269a6d3349cf458e4f5792522779cba0d.1645797329.git.michal.simek@xilinx.com

microblaze: Use simple memset implementation from lib/string.c

On microblaze systems which are not using OPT_LIB_FUNCTION only simple
memset is used. This function is already implemented in lib/string.c that's
why it should be used instead.
This change is done in respect of issue fixed by commit 33d0f96ffd73
("lib/string.c: Use freestanding environment") where gcc-10.x moved
-ftree-loop-distribute-patterns optimization is to O2 optimization level.
This optimization causes GCC to convert the while loop in memset.c into a
call to memset. So This optimization is transforming a loop in a
memset/memcpy into a call to the function itself. This makes the memset
implementation as recursive.

Based on fix above -ffreestanding was used and it needs to be used on
Microblaze too but the patch is not adding this flag it removes simple
implementation to cause that generic implementation is used where this flag
is already setup.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mahesh Bodapati <mbodapat@xilinx.com>
Link: https://lore.kernel.org/r/4a143e7654f72ee893dcea9769946e17d3570b16.1645797329.git.michal.simek@xilinx.com

microblaze: add 'fallthrough' to memcpy/memset/memmove

Fix "fallthrough" warnings in microblaze memcpy/memset/memmove
library functions.

CC arch/microblaze/lib/memcpy.o
../arch/microblaze/lib/memcpy.c: In function 'memcpy':
../arch/microblaze/lib/memcpy.c:70:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
70 | --c;
../arch/microblaze/lib/memcpy.c:71:3: note: here
71 | case 2:
../arch/microblaze/lib/memcpy.c:73:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
73 | --c;
../arch/microblaze/lib/memcpy.c:74:3: note: here
74 | case 3:
../arch/microblaze/lib/memcpy.c:178:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
178 | *dst++ = *src++;
../arch/microblaze/lib/memcpy.c:179:2: note: here
179 | case 2:
../arch/microblaze/lib/memcpy.c:180:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
180 | *dst++ = *src++;
../arch/microblaze/lib/memcpy.c:181:2: note: here
181 | case 1:
CC arch/microblaze/lib/memset.o
../arch/microblaze/lib/memset.c: In function 'memset':
../arch/microblaze/lib/memset.c:71:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
71 | --n;
../arch/microblaze/lib/memset.c:72:3: note: here
72 | case 2:
../arch/microblaze/lib/memset.c:74:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
74 | --n;
../arch/microblaze/lib/memset.c:75:3: note: here
75 | case 3:
CC arch/microblaze/lib/memmove.o
../arch/microblaze/lib/memmove.c: In function 'memmove':
../arch/microblaze/lib/memmove.c:92:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
92 | --c;
../arch/microblaze/lib/memmove.c:93:3: note: here
93 | case 2:
../arch/microblaze/lib/memmove.c:95:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
95 | --c;
../arch/microblaze/lib/memmove.c:96:3: note: here
96 | case 1:
../arch/microblaze/lib/memmove.c:203:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
203 | *--dst = *--src;
../arch/microblaze/lib/memmove.c:204:2: note: here
204 | case 3:
../arch/microblaze/lib/memmove.c:205:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
205 | *--dst = *--src;
../arch/microblaze/lib/memmove.c:206:2: note: here
206 | case 2:
../arch/microblaze/lib/memmove.c:207:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
207 | *--dst = *--src;
../arch/microblaze/lib/memmove.c:208:2: note: here
208 | case 1:

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michal Simek <monstr@monstr.eu>
Link: https://lore.kernel.org/r/20210421022041.10689-1-rdunlap@infradead.org
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

microblaze: Do not use module.h in files which are not modules

Based on the patch:
"lib: reduce the use of module.h wherever possible"
(sha1: 8bc3bcc93a2b4e47d5d410146f6546bca6171663)
fix all microblaze files which are not modules.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

microblaze: Separate library optimized functions

memcpy/memmove/memset

Signed-off-by: Michal Simek <monstr@monstr.eu>

microblaze: Adding likely macros

On the base on GCOV analytics is helpful to add likely/unlikely
macros.

Signed-off-by: Michal Simek <monstr@monstr.eu>

tree-wide: fix assorted typos all over the place

That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

microblaze_v8: supported function for memory - kernel/lib

Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: John Linn <john.linn@xilinx.com>
Acked-by: John Williams <john.williams@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>