来源：HTTPS://WWW.KERNEL.ORG/DOC/DOCUMENTATION/PRINTK-FORMATS.TXT If variable is of Type, use printk format specifier: --------------------------------------------------------- int %d or %x unsigned int %u or %x long %ld or %lx unsigned long %lu or %lx long long %lld or %llx unsigned long long %llu or %llx size_t %zu or %zx ssize_t %zd or %zx s32 %d or %x u32 %u or %x s64 %lld or %llx u64 %llu or %llx If is dependent on a config option for its size (e.g., sector_t, blkcnt_t) or is architecture-dependent for its size (e.g., tcflag_t), use a format specifier of its largest possible type and explicitly cast to it. Example: printk("test: sector number/total blocks: %llu/%llu ", (unsigned long long)sector, (unsigned long long)blockcount); Reminder: sizeof() result is of type size_t. The kernel's printf does not support %n. For obvious reasons, floating point formats (%e, %f, %g, %a) are also not recognized. Use of any unsupported specifier or length qualifier results in a WARN and early return from vsnprintf. Raw pointer value SHOULD be printed with %p. The kernel supports the following extended format specifiers for pointer types: Symbols/Function Pointers: %pF versatile_init+0x0/0x110 %pf versatile_init %pS versatile_init+0x0/0x110 %pSR versatile_init+0x9/0x110 (with __builtin_extract_return_addr() translation) %ps versatile_init %pB prev_fn_of_versatile_init+0x88/0x88 For printing symbols and function pointers. The 'S' and 's' specifiers result in the symbol name with ('S') or without ('s') offsets. Where this is used on a kernel without KALLSYMS - the symbol address is printed instead. The 'B' specifier results in the symbol name with offsets and should be used when printing stack backtraces. The specifier takes into consideration the effect of compiler optimisations which may occur when tail-call's are used and marked with the noreturn GCC attribute. On ia64, ppc64 and parisc64 architectures function pointers are actually function descriptors which must first be resolved. The 'F' and 'f' specifiers perform this resolution and then provide the same functionality as the 'S' and 's' specifiers. Kernel Pointers: %pK 0x01234567 or 0x0123456789abcdef For printing kernel pointers which should be hidden from unprivileged users. The behaviour of %pK depends on the kptr_restrict sysctl - see Documentation/sysctl/kernel.txt for more details. Struct Resources: %pr [mem 0x60000000-0x6fffffff flags 0x2200] or [mem 0x0000000060000000-0x000000006fffffff flags 0x2200] %pR [mem 0x60000000-0x6fffffff pref] or [mem 0x0000000060000000-0x000000006fffffff pref] For printing struct resources. The 'R' and 'r' specifiers result in a printed resource with ('R') or without ('r') a decoded flags member. Passed by reference. Physical addresses types phys_addr_t: %pa[p] 0x01234567 or 0x0123456789abcdef For printing a phys_addr_t type (and its derivatives, such as resource_size_t) which can vary based on build options, regardless of the width of the CPU data path. Passed by reference. DMA addresses types dma_addr_t: %pad 0x01234567 or 0x0123456789abcdef For printing a dma_addr_t type which can vary based on build options, regardless of the width of the CPU data path. Passed by reference. Raw buffer as an escaped string: %*pE[achnops] For printing raw buffer as an escaped string. For the following buffer 1b 62 20 5c 43 07 22 90 0d 5d few examples show how the conversion would be done (the result string without surrounding quotes): %*pE "eb Ca"220 ]" %*pEhp "x1bb Cx07"x90x0d]" %*pEa "e142