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see warnings: | drivers/misc/eeprom/idt_89hpesx.c:570:5: error: format specifies type | 'unsigned char' but the argument has type 'u16' (aka 'unsigned short') | [-Werror,-Wformat] memaddr); - | drivers/misc/eeprom/idt_89hpesx.c:579:5: error: format specifies type | 'unsigned char' but the argument has type 'u16' (aka 'unsigned short') | [-Werror,-Wformat] memaddr); - | drivers/misc/eeprom/idt_89hpesx.c:814:4: error: format specifies type | 'unsigned short' but the argument has type 'unsigned int' | [-Werror,-Wformat] CSR_REAL_ADDR(csraddr)); There's an ongoing movement to eventually enable the -Wformat flag for clang. See: https://github.com/ClangBuiltLinux/linux/issues/378 The format specifier for idt_89hpesx.c:570 and 579 was `0x%02hhx`. The part we care about `%hhx` describes a single byte format, wherein the leftmost byte of our u16 type (of which memaddr is) is truncated. example: ``` uint16_t x = 0xbabe; printf("%hhx\n", x); // output is: be // we lost 'ba' ``` There exists a similar issue at idt_89hpesx.c:814 which involves the CSR_REAL_ADDR macro. This macro returns a u16 but due to default argument promotion for variadic functions (printf-like) actually provides an int to the dev_err method. My proposed solution is to expand the width of the format specifier to fully encompass the provided argument (which is promoted to an int, see below). I opted for '%x' as this specifies an unsigned hexadecimal integer which, with a guarantee, can represent all the values of a u16. As per C11 6.3.1.1: (https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1548.pdf) `If an int can represent all values of the original type ..., the value is converted to an int; otherwise, it is converted to an unsigned int. These are called the integer promotions.` Link: https://github.com/ClangBuiltLinux/linux/issues/378 Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Justin Stitt <justinstitt@google.com> Link: https://lore.kernel.org/r/20220701232031.2639134-1-justinstitt@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.