kernel/proc.h

1// Saved registers for kernel context switches.2struct context {3  uint64 ra;4  uint64 sp;56  // callee-saved7  uint64 s0;8  uint64 s1;9  uint64 s2;10  uint64 s3;11  uint64 s4;12  uint64 s5;13  uint64 s6;14  uint64 s7;15  uint64 s8;16  uint64 s9;17  uint64 s10;18  uint64 s11;19};2021// Per-CPU state.22struct cpu {23  struct proc *proc;          // The process running on this cpu, or null.24  struct context context;     // swtch() here to enter scheduler().25  int noff;                   // Depth of push_off() nesting.26  int intena;                 // Were interrupts enabled before push_off()?27};2829extern struct cpu cpus[NCPU];3031// per-process data for the trap handling code in trampoline.S.32// sits in a page by itself just under the trampoline page in the33// user page table. not specially mapped in the kernel page table.34// uservec in trampoline.S saves user registers in the trapframe,35// then initializes registers from the trapframe's36// kernel_sp, kernel_hartid, kernel_satp, and jumps to kernel_trap.37// usertrapret() and userret in trampoline.S set up38// the trapframe's kernel_*, restore user registers from the39// trapframe, switch to the user page table, and enter user space.40// the trapframe includes callee-saved user registers like s0-s11 because the41// return-to-user path via usertrapret() doesn't return through42// the entire kernel call stack.43struct trapframe {44  /*   0 */ uint64 kernel_satp;   // kernel page table45  /*   8 */ uint64 kernel_sp;     // top of process's kernel stack46  /*  16 */ uint64 kernel_trap;   // usertrap()47  /*  24 */ uint64 epc;           // saved user program counter48  /*  32 */ uint64 kernel_hartid; // saved kernel tp49  /*  40 */ uint64 ra;50  /*  48 */ uint64 sp;51  /*  56 */ uint64 gp;52  /*  64 */ uint64 tp;53  /*  72 */ uint64 t0;54  /*  80 */ uint64 t1;55  /*  88 */ uint64 t2;56  /*  96 */ uint64 s0;57  /* 104 */ uint64 s1;58  /* 112 */ uint64 a0;59  /* 120 */ uint64 a1;60  /* 128 */ uint64 a2;61  /* 136 */ uint64 a3;62  /* 144 */ uint64 a4;63  /* 152 */ uint64 a5;64  /* 160 */ uint64 a6;65  /* 168 */ uint64 a7;66  /* 176 */ uint64 s2;67  /* 184 */ uint64 s3;68  /* 192 */ uint64 s4;69  /* 200 */ uint64 s5;70  /* 208 */ uint64 s6;71  /* 216 */ uint64 s7;72  /* 224 */ uint64 s8;73  /* 232 */ uint64 s9;74  /* 240 */ uint64 s10;75  /* 248 */ uint64 s11;76  /* 256 */ uint64 t3;77  /* 264 */ uint64 t4;78  /* 272 */ uint64 t5;79  /* 280 */ uint64 t6;80};8182enum procstate { UNUSED, USED, SLEEPING, RUNNABLE, RUNNING, ZOMBIE };8384// Per-process state85struct proc {86  struct spinlock lock;8788  // p->lock must be held when using these:89  enum procstate state;        // Process state90  void *chan;                  // If non-zero, sleeping on chan91  int killed;                  // If non-zero, have been killed92  int xstate;                  // Exit status to be returned to parent's wait93  int pid;                     // Process ID9495  // wait_lock must be held when using this:96  struct proc *parent;         // Parent process9798  // these are private to the process, so p->lock need not be held.99  uint64 kstack;               // Virtual address of kernel stack100  uint64 sz;                   // Size of process memory (bytes)101  pagetable_t pagetable;       // User page table102  struct trapframe *trapframe; // data page for trampoline.S103  struct context context;      // swtch() here to run process104  struct file *ofile[NOFILE];  // Open files105  struct inode *cwd;           // Current directory106  char name[16];               // Process name (debugging)107};108