linux.git/arch/arc/kernel/unwind.c, branch v6.16

ARC: unwind: Use built-in sort swap to reduce code size and improve performance

2025-06-09T16:18:12+00:00

The custom swap function used in sort() was identical to the default
built-in sort swap. Remove the custom swap function and passes NULL to
sort(), allowing it to use the default swap function.

This change reduces code size and improves performance, particularly when
CONFIG_MITIGATION_RETPOLINE is enabled. With RETPOLINE mitigation, indirect
function calls incur significant overhead, and using the default swap
function avoids this cost.

$ ./scripts/bloat-o-meter ./unwind.o.old ./unwind.o.new
add/remove: 0/1 grow/shrink: 0/1 up/down: 0/-22 (-22)
Function                                     old     new   delta
init_unwind_hdr.constprop                    544     540      -4
swap_eh_frame_hdr_table_entries               18       -     -18
Total: Before=4410, After=4388, chg -0.50%

Signed-off-by: Yu-Chun Lin 
Signed-off-by: Vineet Gupta

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23+00:00

asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-specific in that header.

auto-generated by the following:

for i in `git grep -l -w asm/unaligned.h`; do
	sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i
done
for i in `git grep -l -w asm-generic/unaligned.h`; do
	sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i
done
git mv include/asm-generic/unaligned.h include/linux/unaligned.h
git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h
sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild
sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h

module: replace module_layout with module_memory

2023-03-09T20:55:15+00:00

module_layout manages different types of memory (text, data, rodata, etc.)
in one allocation, which is problematic for some reasons:

1. It is hard to enable CONFIG_STRICT_MODULE_RWX.
2. It is hard to use huge pages in modules (and not break strict rwx).
3. Many archs uses module_layout for arch-specific data, but it is not
   obvious how these data are used (are they RO, RX, or RW?)

Improve the scenario by replacing 2 (or 3) module_layout per module with
up to 7 module_memory per module:

        MOD_TEXT,
        MOD_DATA,
        MOD_RODATA,
        MOD_RO_AFTER_INIT,
        MOD_INIT_TEXT,
        MOD_INIT_DATA,
        MOD_INIT_RODATA,

and allocating them separately. This adds slightly more entries to
mod_tree (from up to 3 entries per module, to up to 7 entries per
module). However, this at most adds a small constant overhead to
__module_address(), which is expected to be fast.

Various archs use module_layout for different data. These data are put
into different module_memory based on their location in module_layout.
IOW, data that used to go with text is allocated with MOD_MEM_TYPE_TEXT;
data that used to go with data is allocated with MOD_MEM_TYPE_DATA, etc.

module_memory simplifies quite some of the module code. For example,
ARCH_WANTS_MODULES_DATA_IN_VMALLOC is a lot cleaner, as it just uses a
different allocator for the data. kernel/module/strict_rwx.c is also
much cleaner with module_memory.

Signed-off-by: Song Liu 
Cc: Luis Chamberlain 
Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Guenter Roeck 
Cc: Christophe Leroy 
Reviewed-by: Thomas Gleixner 
Reviewed-by: Christophe Leroy 
Reviewed-by: Luis Chamberlain 
Signed-off-by: Luis Chamberlain

arc: use swap() to make code cleaner

2021-12-29T03:49:44+00:00

Use the macro 'swap()' defined in 'include/linux/minmax.h' to avoid
opencoding it.

Signed-off-by: Yihao Han 
Signed-off-by: Vineet Gupta

arc: Prefer unsigned int to bare use of unsigned

2021-08-04T01:58:33+00:00

Fix checkpatch warnings:
    WARNING: Prefer 'unsigned int' to bare use of 'unsigned'

Signed-off-by: Jinchao Wang 
Signed-off-by: Vineet Gupta

ARC: treewide: avoid the pointer addition with NULL pointer

2021-03-22T17:05:43+00:00

Signed-off-by: dean.yang_cp 
Acked-by: Vineet Gupta 
Signed-off-by: Vineet Gupta

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

arc: remove #ifndef CONFIG_AS_CFI_SIGNAL_FRAME

2020-04-13T05:27:10+00:00

CONFIG_AS_CFI_SIGNAL_FRAME is never defined for ARC.

Suggested-by: Nick Desaulniers 
Signed-off-by: Masahiro Yamada 
Signed-off-by: Vineet Gupta

treewide: Use sizeof_field() macro

2019-12-09T18:36:44+00:00

Replace all the occurrences of FIELD_SIZEOF() with sizeof_field() except
at places where these are defined. Later patches will remove the unused
definition of FIELD_SIZEOF().

This patch is generated using following script:

EXCLUDE_FILES="include/linux/stddef.h|include/linux/kernel.h"

git grep -l -e "\bFIELD_SIZEOF\b" | while read file;
do

	if [[ "$file" =~ $EXCLUDE_FILES ]]; then
		continue
	fi
	sed -i  -e 's/\bFIELD_SIZEOF\b/sizeof_field/g' $file;
done

Signed-off-by: Pankaj Bharadiya 
Link: https://lore.kernel.org/r/20190924105839.110713-3-pankaj.laxminarayan.bharadiya@intel.com
Co-developed-by: Kees Cook 
Signed-off-by: Kees Cook 
Acked-by: David Miller  # for net

Merge tag 'Wimplicit-fallthrough-5.3-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

2019-08-29T16:28:25+00:00

Pull fallthrough fixes from Gustavo A. R. Silva:
 "Fix fall-through warnings on arc and nds32 for multiple
  configurations"

* tag 'Wimplicit-fallthrough-5.3-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  nds32: Mark expected switch fall-throughs
  ARC: unwind: Mark expected switch fall-through