Data Structures

Here are the data structures with brief descriptions:

C[struct].irqs
C[struct].isa
C[struct].kargs
C[struct].request
C[struct].reserved
C[struct].routes
C[struct].unicode_extra
Caarch64_ctx	Where a thread goes on in the kernel when it runs again: the registers that a function call keeps (AAPCS64: x19 to x29, and the link register), and the stack pointer
Caarch64_regs	What an exception saves on the kernel stack (cpu/vectors.S): the context it interrupted
Caarch64_thread	A thread's aarch64 state (thread->arch)
Cacpi_gas	A register's address, ACPI's Generic Address Structure
Cacpi_hpet	The HPET table: where the HPET's registers are
Cacpi_madt	The MADT's header: the local APICs' address, and flags
Cacpi_madt_entry	The start of every MADT entry
Cacpi_madt_io_apic	An I/O APIC: its registers, and the first GSI its pins bring
Cacpi_madt_local_apic	A CPU's local APIC
Cacpi_madt_local_apic_nmi	Which local APIC input (LINT0 or LINT1) is the NMI
Cacpi_madt_override	An ISA IRQ that comes on another GSI, or with another polarity or trigger mode, than the default
Cacpi_rsdp	The Root System Description Pointer, which says where the RSDT is
Cacpi_rsdp2	ACPI 2.0's RSDP (revision 2 or more), which also says where the XSDT is, with 64-bit addresses
Cacpi_rsdt	The RSDT: the other tables' 32-bit addresses
Cacpi_sdt_header	The header that every table starts with
Cacpi_xsdt	The XSDT: the other tables' 64-bit addresses
Carch_cpu	A CPU's aarch64 state (struct cpu's arch)
Carp_entry
Carp_hdr	An ARP packet, for IPv4 over Ethernet
Carp_pending
Cata_channel	An IDE channel, with the master and slave drives on it
Cata_drive	A drive on a channel
Cbcache	A filesystem's block cache (fs/bcache.c): its blocks that were read, by their offset
Cbinfmt	A format of executable files: says whether a file is one, and loads it into a process (sys/binfmt/)
Cbitmap	A bitmap: its blocks, and its last bit's index
Cblk	A block of the cache
Cboot
Cbuddy	One order of a buddy allocator's zone (mm/buddy.c): a bitmap of its blocks, a set bit for a block that isn't free
Ccache_block	A cached block
Ccallout	A function to call later, with its argument
Ccallout_list	A list of callouts called from one context: the timer's interrupt (callout_set()), or a thread that runs its own list (the network's)
Ccmos_rtc	The real time clock's date and time, as it keeps them
Ccpio	What cpiofs keeps for each of its vnodes, a member of the archive
Ccpio_hdr	The header of a member of an old binary cpio archive, as it is in the archive: its name follows, then its data
Ccpu	A processor, and what runs on it
Cdev	A device driver: its operations, any of which may be NULL
Cdevid	Which device: its kind (S_IFCHR or S_IFBLK) and numbers
Ce1000	The controller: there is one
Cearlycon	An early console's operations
Celf32_dyn	An ELF32 dynamic section's entry
C[union].d_un
Celf32_hdr	An ELF32 file's header
Celf32_phdr	An ELF32 program header: a segment to load
Celf32_shdr	An ELF32 section header
Celf32_sym	An ELF32 symbol
Celf64_hdr	An ELF64 file's header
Celf64_phdr	An ELF64 program header: a segment to load
Celf64_shdr	An ELF64 section header
Celf64_sym	An ELF64 symbol
Cether_hdr	An Ethernet frame's header
Cext2	A mounted ext2 filesystem
Cext2_dentry	A directory entry, as it is on the disk
Cext2_group	A block group descriptor, as it is on the disk
Cext2_inode	An inode, as it is on the disk
Cext2_superblock	The superblock, as it is on the disk, 1024 bytes into it
Cfbdev	A framebuffer: its driver, its screen's information, its operations
Cfbdev_vesa	The boot loader's VBE framebuffer: what VBE said about the card and the mode (dev/fb/vesa/)
Cfd	A file descriptor: the open file it refers to (fs/file.c, shared with the descriptors that dup() and fork() copied), and its own flags
Cfd_set
Cfdt_header	The FDT's header (big-endian)
Cfile	An open file (POSIX's "open file description", fs/file.c)
C[union].__unnamed0__
Cfile_lock	An open file's lock
Cfops	An open file's operations
Cfs	A filesystem type
Cfs_list	The list of registered filesystem types
Chandler	An installed handler, on its interrupt's list
Chashmap	A hash table
Chashmap_node	A hash table's node: an entry, with its key's hash
Cicmp_hdr	An ICMP message's header
Cidt_entry
Cidt_ptr
Cinet_sock	A UDP or ping socket
Cioaddr	Where a device's registers are
Cioapic
Ciobuf	An iobuf
Ciobuf_seg	A piece of an iobuf's memory
Cipv4_hdr	An IPv4 packet's header
Ckeyboard	A keyboard: the bytes it sent, waiting to be read
Cksockaddr
Clist	A list: its first and last nodes, and how many there are
Clist_node	A link in a list, inside the structure that is listed
Cmalloc_type	A malloc type: what an allocation is for, which /proc/kvmem counts by
Cmbr	The master boot record
Cmbr_part	A partition table entry
C[struct].start_chs
C[struct].end_chs
Cminix	A mounted minix filesystem
Cminix3_superblock	The superblock of minix v3, as it is on the disk (not supported)
Cminix_dentry	A directory entry, as it is on the disk: 0 as the inode number is an unused entry
Cminix_inode	A minix v1 inode, as it is on the disk
Cminix_superblock	The superblock of minix v1 and v2, as it is on the disk
Cmmap_t
Cmode_info_block	A VBE mode's information block
Cmodule_t
Cmountpoint	A mount's description, as /proc/mounts shows it
Cmultiboot_aout_symbol_table
Cmultiboot_elf_section_header_table
Cmultiboot_header
Cmultiboot_info
C[union].u
Cmultiboot_mmap_entry
Cmultiboot_mod_list
Cnetbuf	A packet (net/netbuf.c)
Cnetif	A network interface (net/netif.c): a device that sends and receives Ethernet frames, and its IPv4 configuration
C[struct].stats
Cpci_address	What is written to CONFIG_ADDRESS: the register to reach
C[struct].structure
Cpci_bar	A base address register (BAR): where the device's registers are, how big they are, and whether they are ports or memory
Cpci_dev	A PCI function: its bus, device (slot) and function numbers
Cpci_host	The host bridge, which the platform describes (platform_init() sets it): how its configuration space is reached, which IRQs its devices' interrupt pins are routed to, and where their registers go if no firmware placed them
Cpf	What a page fault is about, passed to each of the steps below
Cpgroup	A process group: the processes of a job
Cpipe	A pipe, or a FIFO's pipe
Cpit_cmd_register	The PIT's command register: which channel, how it is loaded, and in which mode it counts
C[union].__unnamed0__
C[struct].__unnamed0__.__unnamed0__
Cplatform_device	A device of the platform's table
Cpm_info_block
Cpmap	An address space's page tables, on x86
Cpoll_reg	One wait queue that one polling thread waits for
Cprd	A physical region descriptor: one piece of memory to transfer
Cproc	A process
Cprocfs_entry	A file of the top directory: its name, and what makes its text
Cprocfs_proc_entry	A file of a process's directory: its name, and what makes its text
Cpseudofs_dirent	A directory entry, kept in memory
Cpty	A pseudo-terminal
Cqnode	A queue's node, holding one entry
Cqueue	A queue
Cramdev_priv	A RAM disk's memory
Cringbuf	A ring buffer
Crx_desc	A receive descriptor: a buffer, and what the controller put in it
Cseg	A received segment, with its header in host byte order
Csession	A session: its process groups, and its controlling terminal
Csigframe	A signal handler's frame, on the user stack
Cslab	A slab's header, at the start of its page
Csock_ops	A domain's socket operations
Csocket	A socket
Cstack_frame	A stack frame, as the compiler lays it out with frame pointers
Ctcp_hdr	A TCP segment's header
Ctcp_key	What identifies a connection: both ends' addresses and ports
Ctcp_pcb	A connection (its control block, or PCB)
Cthread	A thread
Ctimespec
Ctimeval
Ctimezone
Ctrampoline_data	What an AP needs to reach the kernel, at x86_trampoline_data (the fields are at trampoline.S's TR_ offsets)
Ctty	A terminal, and its line discipline's state
Ctx_desc	A transmit descriptor: a frame to send, and whether it was sent
Cuart	A serial port
Cuart_8250	One UART: the terminal layer's struct uart (first, so that a pointer to one is a pointer to the other), and its registers
Cudp_hdr	A UDP datagram's header
Cuio	Who does a filesystem operation: where its paths start, and its credentials and umask
Cun_conn	A connection between a client socket and the server that accepted it
Cun_socket	A listening socket, bound to a name in the file system
Cutimbuf
Cvbe_info_block	The VBE controller information block
C[union].vbe_signature
Cvcache	A filesystem's vnode cache (fs/vcache.c): its vnodes in memory, by their inode number, so that a file has one vnode however it's reached
Cvm_anon	An anon: a mapping's private pages, those the process wrote to
Cvm_aref	An anon's reference to a page (an aref)
Cvm_entry	A mapping (map entry): a range of an address space, its permissions, and where its pages come from
Cvm_object	A vm object: what a mapping's pages come from (a file), and its pages that have been read in
Cvm_page	A page of physical memory (pages[] has one for every page of RAM)
Cvm_pager	A vm object's pager: reads its pages in, and writes them out
Cvm_space	An address space: its mappings, and its page tables
Cvmem	An arena: a range, and its segments
Cvmem_seg	A segment of an arena: a range that is either free or allocated
Cvnode	A file in memory (a vnode): what its inode says, and the kernel's own state
Cvops	A filesystem's vnode operations, any of which may be NULL
Cvt	A virtual terminal: its screen, its emulator's state, and its tty
Cvt_cell	A character cell
Cvt_cursor	The cursor's state, saved by DECSC
Cvt_display	A display that virtual terminals are shown on
Cwaitq
Cx86_gdt_entry	A segment descriptor, an entry of the GDT
Cx86_irq_chip	An interrupt controller: the 8259s, or the APIC
Cx86_regs	The registers an interrupt or exception saved, on the kernel stack, as cpu.S's stubs push them: the general registers, the stub's vector and error code, then what the CPU pushed
Cx86_thread	A thread's x86 state: its kernel stack, and where it resumes
Cx86_tss