inc/env.h

   1 /* See COPYRIGHT for copyright information. */
   2
   3 #ifndef JOS_INC_ENV_H
   4 #define JOS_INC_ENV_H
   5
   6 #include <inc/types.h>
   7 #include <inc/queue.h>
   8 #include <inc/trap.h>
   9 #include <inc/memlayout.h>
  10
  11 typedef int32_t envid_t;
  12
  13 // An environment ID 'envid_t' has three parts:
  14 //
  15 // +1+---------------21-----------------+--------10--------+
  16 // |0|          Uniqueifier             |   Environment    |
  17 // | |                                  |      Index       |
  18 // +------------------------------------+------------------+
  19 //                                       \--- ENVX(eid) --/
  20 //
  21 // The environment index ENVX(eid) equals the environment's offset in the
  22 // 'envs[]' array.  The uniqueifier distinguishes environments that were
  23 // created at different times, but share the same environment index.
  24 //
  25 // All real environments are greater than 0 (so the sign bit is zero).
  26 // envid_ts less than 0 signify errors.  The envid_t == 0 is special, and
  27 // stands for the current environment.
  28
  29 #define LOG2NENV                10
  30 #define NENV                    (1 << LOG2NENV)
  31 #define ENVX(envid)             ((envid) & (NENV - 1))
  32
  33 // Values of env_status in struct Env
  34 #define ENV_FREE                0
  35 #define ENV_RUNNABLE            1
  36 #define ENV_NOT_RUNNABLE        2
  37
  38 struct Env {
  39         struct Trapframe env_tf;        // Saved registers
  40         LIST_ENTRY(Env) env_link;       // Free list link pointers
  41         envid_t env_id;                 // Unique environment identifier
  42         envid_t env_parent_id;          // env_id of this env's parent
  43         unsigned env_status;            // Status of the environment
  44         uint32_t env_runs;              // Number of times environment has run
  45
  46         // Address space
  47         pde_t *env_pgdir;               // Kernel virtual address of page dir
  48         physaddr_t env_cr3;             // Physical address of page dir
  49
  50         // Exception handling
  51         void *env_pgfault_upcall;       // page fault upcall entry point
  52
  53         // Lab 4 IPC
  54         bool env_ipc_recving;           // env is blocked receiving
  55         void *env_ipc_dstva;            // va at which to map received page
  56         uint32_t env_ipc_value;         // data value sent to us
  57         envid_t env_ipc_from;           // envid of the sender
  58         int env_ipc_perm;               // perm of page mapping received
  59 };
  60
  61 #endif // !JOS_INC_ENV_H