The patch titled
Subject: lib: crc32: constify crc32 lookup table
has been removed from the -mm tree. Its filename was
lib-crc32-constify-crc32-lookup-table.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Daniel Borkmann <dborkman@xxxxxxxxxx>
Subject: lib: crc32: constify crc32 lookup table
Commit 8f243af42ade ("sections: fix const sections for crc32 table")
removed the compile-time generated crc32 tables from the RO sections,
because it conflicts with the definition of __cacheline_aligned which puts
all such aligned data into .data..cacheline_aligned section optimized for
wasting less space, and can cause alignment issues when used in
combination with const with some gcc versions like 4.7.0 due to a gcc bug
[1].
Given that most gcc versions should have the fix by now, we can just use
____cacheline_aligned, which only aligns the data but doesn't move it into
specific sections as opposed to __cacheline_aligned. In case of gcc
versions having the mentioned bug, the alignment attribute will have no
effect, but the data will still be made RO.
After patch tables are in RO:
$ nm -v lib/crc32.o | grep -1 -E "crc32c?table"
0000000000000000 t arch_local_irq_enable
0000000000000000 r crc32ctable_le
0000000000000000 t crc32_exit
--
0000000000000960 t test_buf
0000000000002000 r crc32table_be
0000000000004000 r crc32table_le
000000001d1056e5 A __crc_crc32_be
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52181
Signed-off-by: Daniel Borkmann <dborkman@xxxxxxxxxx>
Cc: Joe Mario <jmario@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/gen_crc32table.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff -puN lib/gen_crc32table.c~lib-crc32-constify-crc32-lookup-table lib/gen_crc32table.c
--- a/lib/gen_crc32table.c~lib-crc32-constify-crc32-lookup-table
+++ a/lib/gen_crc32table.c
@@ -109,7 +109,7 @@ int main(int argc, char** argv)
if (CRC_LE_BITS > 1) {
crc32init_le();
- printf("static u32 __cacheline_aligned "
+ printf("static const u32 ____cacheline_aligned "
"crc32table_le[%d][%d] = {",
LE_TABLE_ROWS, LE_TABLE_SIZE);
output_table(crc32table_le, LE_TABLE_ROWS,
@@ -119,7 +119,7 @@ int main(int argc, char** argv)
if (CRC_BE_BITS > 1) {
crc32init_be();
- printf("static u32 __cacheline_aligned "
+ printf("static const u32 ____cacheline_aligned "
"crc32table_be[%d][%d] = {",
BE_TABLE_ROWS, BE_TABLE_SIZE);
output_table(crc32table_be, LE_TABLE_ROWS,
@@ -128,7 +128,7 @@ int main(int argc, char** argv)
}
if (CRC_LE_BITS > 1) {
crc32cinit_le();
- printf("static u32 __cacheline_aligned "
+ printf("static const u32 ____cacheline_aligned "
"crc32ctable_le[%d][%d] = {",
LE_TABLE_ROWS, LE_TABLE_SIZE);
output_table(crc32ctable_le, LE_TABLE_ROWS,
_
Patches currently in -mm which might be from dborkman@xxxxxxxxxx are
origin.patch
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