linux/arch
Michal Simek 95fee37be4 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
33d0f96ffd ("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
2022-04-21 10:54:20 +02:00
..
alpha Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
arc
arm ARM fixes for 5.18-rc1: 2022-04-03 10:17:48 -07:00
arm64 SoC: fixes for 5.18, part 1 2022-04-01 13:21:19 -07:00
csky
h8300 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
hexagon
ia64 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
m68k Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
microblaze microblaze: Do loop unrolling for optimized memset implementation 2022-04-21 10:54:20 +02:00
mips - build fix for gpio 2022-04-02 12:14:38 -07:00
nios2
openrisc
parisc Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
powerpc Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
riscv RISC-V Patches for the 5.18 Merge Window, Part 2 2022-04-01 13:31:57 -07:00
s390 * Only do MSR filtering for MSRs accessed by rdmsr/wrmsr 2022-04-02 12:09:02 -07:00
sh Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
sparc Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
um Kbuild fixes for v5.18 2022-04-02 12:33:31 -07:00
x86 A set of x86 fixes and updates: 2022-04-03 12:15:47 -07:00
xtensa Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
.gitignore
Kconfig Networking fixes for 5.18-rc1 and rethook patches. 2022-03-31 11:23:31 -07:00