On Fri, Dec 23, 2016 at 11:52:33AM +0000, Nicholas Mc Guire wrote: > On Fri, Dec 23, 2016 at 06:33:28AM -0500, Pasquier, Thomas wrote: > > Hello Wasim, > > > > On Fri, Dec 23, 2016 at 6:20 AM, Wasim Akram <wasim7702843288@xxxxxxxxx> > > wrote: > > > > > Hi , > > > > > > I have seen "bool" data type is used in linux kernel code . Can we > > > get documentation on data type used in linux kernel development ? > > > > > > > I think this should be a good start: > > http://lxr.free-electrons.com/source/include/linux/types.h > > > one of the problems though is that there are a number of > "historic" type systems "left over" in the kernel it seems so > there actually is a bit of a mess and its not simple to > figure out what things really are. For x86_64 I have a list > of type matches I use for code reading (still not complete) > which might help. > > x86 64bit: > ========== > > Type : equivalent types > bool : _Bool, > char : signed char, __signed__ char, __s8, s8, int8_t > unsigned char : unsigned char, u_char, __u8, u8, unchar, u_int8_t, uint8_t > __ticket_t, > insn_byte_t, > kprobe_opcode_t > short : signed short, __signed__ short, s16, int16_t > unsigned short : unsigned short, __u16, u16, u_short, ushort, u_int16_t, uint16_t, > __sum16, > umode_t, > __ticketpair_t, > apm_eventinfo_t, > apm_event_t, > Elf32_Sword, > Elf32_Half, > Elf64_Half, > Elf64_SHalf, > __kernel_sa_family_t, > __kernel_gid16_t, gid16_t, > __kernel_uid16_t, uid16_t, > __kernel_old_uid_t, old_uid_t, > __kernel_old_gid_t, old_gid_t, > arch cond: __le16/__be16 > int : signed int, __signed__ int, __s32, s32, int32_t, s_int32_t > Elf64_Sword, > Elf64_Sxword, > key_serial_t, > insn_value_t, > __kernel_daddr_t, daddr_t, > __kernel_ipc_pid_t, pid_t, > __kernel_pid_t, > __kernel_mqd_t, mqd_t, > __kernel_key_t, key_t, > __kernel_timer_t timer_t, > unsigned int : unsigned, unsigned int, __u32, u32, u_int32_t, uInt, u_int, uint, uint32_t, > __wsum, > nlink_t, > gfp_t, > fmode_t, > oom_flags_t, > isolate_mode_t, > Elf32_Addr, > Elf32_Off, > Elf32_Word, > Elf64_Word, > key_perm_t, > insn_attr_t, > sk_buff_data_t, > sctp_assoc_t. > __kernel_dev_t, dev_t, > __kernel_uid32_t, uid_t, projid_t, qid_t > __kernel_gid32_t, gid_t, > __kernel_uid_t, > __kernel_gid_t, > __kernel_mode_t, mode_t, > arch cond: __le32/__be32 > long : signed long, __kernel_long_t, > __kernel_suseconds_t, suseconds_t, > __kernel_ssize_t, ssize_t, > __kernel_ptrdiff_t, > __kernel_off_t, off_t, > __kernel_time_t, time_t, > __kernel_clock_t, clock_t, > unsigned long : __kernel_ulong_t, u_long, ulong > uintptr_t, > sector_t, > blkcnt_t, > irq_hw_number_t, > pteval_t, > pmdval_t, > pudval_t, > pgdval_t, > pgprotval_t, > vm_flags_t, > elf_greg_t, > cputime_t, > old_sigset_t, > aio_context_t, > flow_compare_t, > __kernel_ino_t, ino_t > __kernel_old_dev_t > __kernel_size_t. size_t, > arch cond: __le64/__be64 > long long : signed long long, __signed__ long long, __s64, s64, int64_t > time64_t, > qsize_t, > __kernel_loff_t, loff_t, > unsigned long long: u64, __u64, uint64_t, u_int64_t > dma_addr_t, > cycles_t, > phys_addr_t, resource_size_t > cycle_t, > Elf64_Addr, > Elf64_Off, > Elf64_Xword, > cputime64_t, > netdev_features_t That's crazy. Just use the data types that the LDD book says to use for in-kernel code: u8, u16, u32, u64, s8, s16, s32, s64, int, bool and if the data crosses the user/kernel boundry, use the correct ones for that (__ in front, no int). You can use others, but you better know what you are doing if you do :) Hope this helps, greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
