On 3/10/25 12:17 PM, Quentin Schulz wrote:
Hi Marek,
Hi,
On 3/8/25 9:12 PM, Marek Vasut wrote:
Fix the following conversion overflow errors. The input field is already
limited to 3/2/1 bits using the bitwise and, move the parenthesis around
to avoid the bogus warning:
"
fs/exfat/utf.c: In function ‘utf8_to_wchar’:
fs/exfat/utf.c:165:23: warning: overflow in conversion from ‘int’ to
‘wchar_t’ {aka ‘short unsigned int’} changes value from ‘(int)(short
unsigned int)*input << 18 & 1835008’ to ‘0’ [-Woverflow]
165 | *wc = ((wchar_t) input[0] & 0x07) << 18;
| ^
fs/exfat/utf.c:170:23: warning: overflow in conversion from ‘int’ to
‘wchar_t’ {aka ‘short unsigned int’} changes value from ‘(int)(short
unsigned int)*input << 24 & 50331648’ to ‘0’ [-Woverflow]
170 | *wc = ((wchar_t) input[0] & 0x03) << 24;
| ^
fs/exfat/utf.c:175:23: warning: overflow in conversion from ‘int’ to
‘wchar_t’ {aka ‘short unsigned int’} changes value from ‘(int)(short
unsigned int)*input << 30 & 1073741824’ to ‘0’ [-Woverflow]
175 | *wc = ((wchar_t) input[0] & 0x01) << 30;
| ^
"
Since this doesn't seem to be U-Boot-specific, any chance to open a Pull
Request on the project so we may be able to not carry this patch when
upgrading (yes, the last commit in the branch was two years ago, but it
seems the maintainer is still active on issues).
Considering that wchar_t is an unsigned short int and that USHRT_MAX is
0xffff (so 2B or 16b)...
In fact, this error does not even appear in upstream , because upstream
does not use -fshort-wchar compiler flag . U-Boot does use this compiler
flags since 4a85663ec7ed ("kbuild: Enable -fshort-wchar") .
So I wonder if this might be the right fix here instead:
diff --git a/fs/exfat/Makefile b/fs/exfat/Makefile
index 550c0683d65..8ca112cf0e9 100644
--- a/fs/exfat/Makefile
+++ b/fs/exfat/Makefile
@@ -1,6 +1,9 @@
# SPDX-License-Identifier: GPL-2.0+
#
+# The utf.o does really need 32bit wchar_t
+CFLAGS_REMOVE_utf.o := -fshort-wchar
+
obj-$(CONFIG_FS_EXFAT) += \
cluster.o \
io.o \
