From ffff4913c7e22cc2bd5570df73e0e154bf111215 Mon Sep 17 00:00:00 2001 From: Justin Stitt Date: Fri, 1 Jul 2022 16:20:31 -0700 Subject: [PATCH] eeprom: idt_89hpesx: fix clang -Wformat warnings 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 Signed-off-by: Justin Stitt Link: https://lore.kernel.org/r/20220701232031.2639134-1-justinstitt@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/misc/eeprom/idt_89hpesx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/misc/eeprom/idt_89hpesx.c b/drivers/misc/eeprom/idt_89hpesx.c index b0cff4b152da8..42eac114edd74 100644 --- a/drivers/misc/eeprom/idt_89hpesx.c +++ b/drivers/misc/eeprom/idt_89hpesx.c @@ -566,7 +566,7 @@ static int idt_eeprom_read_byte(struct idt_89hpesx_dev *pdev, u16 memaddr, eeseq.memaddr = cpu_to_le16(memaddr); ret = pdev->smb_write(pdev, &smbseq); if (ret != 0) { - dev_err(dev, "Failed to init eeprom addr 0x%02hhx", + dev_err(dev, "Failed to init eeprom addr 0x%02x", memaddr); break; } @@ -575,7 +575,7 @@ static int idt_eeprom_read_byte(struct idt_89hpesx_dev *pdev, u16 memaddr, smbseq.bytecnt = EEPROM_RD_CNT; ret = pdev->smb_read(pdev, &smbseq); if (ret != 0) { - dev_err(dev, "Failed to read eeprom data 0x%02hhx", + dev_err(dev, "Failed to read eeprom data 0x%02x", memaddr); break; } @@ -810,7 +810,7 @@ static int idt_csr_read(struct idt_89hpesx_dev *pdev, u16 csraddr, u32 *data) smbseq.bytecnt = CSR_RD_CNT; ret = pdev->smb_read(pdev, &smbseq); if (ret != 0) { - dev_err(dev, "Failed to read csr 0x%04hx", + dev_err(dev, "Failed to read csr 0x%04x", CSR_REAL_ADDR(csraddr)); goto err_mutex_unlock; } -- 2.30.2