From: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Subject: lib: fix bitmap_parse() on 64-bit big endian archs
Commit 2d6261583be0 ("lib: rework bitmap_parse()") does not take into
account order of halfwords on 64-bit big endian architectures. As result
(at least) Receive Packet Steering, IRQ affinity masks and runtime kernel
test "test_bitmap" get broken on s390.
[andriy.shevchenko@xxxxxxxxxxxxxxx: convert infinite while loop to a for loop]
Link: http://lkml.kernel.org/r/20200609140535.87160-1-andriy.shevchenko@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1591634471-17647-1-git-send-email-agordeev@xxxxxxxxxxxxx
Fixes: 2d6261583be0 ("lib: rework bitmap_parse()")
Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Cc: Yury Norov <yury.norov@xxxxxxxxx>
Cc: Amritha Nambiar <amritha.nambiar@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Cc: "Tobin C . Harding" <tobin@xxxxxxxxxx>
Cc: Vineet Gupta <vineet.gupta1@xxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/bitmap.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/lib/bitmap.c~lib-fix-bitmap_parse-on-64-bit-big-endian-archs
+++ a/lib/bitmap.c
@@ -741,8 +741,9 @@ int bitmap_parse(const char *start, unsi
int chunks = BITS_TO_U32(nmaskbits);
u32 *bitmap = (u32 *)maskp;
int unset_bit;
+ int chunk;
- while (1) {
+ for (chunk = 0; ; chunk++) {
end = bitmap_find_region_reverse(start, end);
if (start > end)
break;
@@ -750,7 +751,11 @@ int bitmap_parse(const char *start, unsi
if (!chunks--)
return -EOVERFLOW;
- end = bitmap_get_x32_reverse(start, end, bitmap++);
+#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
+ end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]);
+#else
+ end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]);
+#endif
if (IS_ERR(end))
return PTR_ERR(end);
}
_
