diff options
Diffstat (limited to 'kernel/proc.h')
| -rw-r--r-- | kernel/proc.h | 46 |
1 files changed, 27 insertions, 19 deletions
diff --git a/kernel/proc.h b/kernel/proc.h index 687fdd1..1524c74 100644 --- a/kernel/proc.h +++ b/kernel/proc.h @@ -18,33 +18,37 @@ struct context { uint64 s11; }; -// Per-CPU state +// Per-CPU state. struct cpu { - struct proc *proc; // The process running on this cpu or null - struct context scheduler; // swtch() here to enter scheduler - int noff; // Depth of push_off() nesting. - int intena; // Were interrupts enabled before push_off()? + struct proc *proc; // The process running on this cpu, or null. + struct context scheduler; // swtch() here to enter scheduler(). + int noff; // Depth of push_off() nesting. + int intena; // Were interrupts enabled before push_off()? }; extern struct cpu cpus[NCPU]; //PAGEBREAK: 17 -// per-process data for the early trap handling code in trampoline.S. +// per-process data for the trap handling code in trampoline.S. // sits in a page by itself just under the trampoline page in the // user page table. not specially mapped in the kernel page table. // the sscratch register points here. -// trampoline.S saves user registers, then restores kernel_sp and -// kernel_satp. -// includes callee-saved registers like s0-s11 because the +// trampin in trampoline.S saves user registers in the trapframe, +// then initializes registers from the trapframe's +// kernel_sp, kernel_hartid, kernel_satp, and jumps to kernel_trap. +// usertrapret() and trampout in trampoline.S set up +// the trapframe's kernel_*, restore user registers from the +// trapframe, switch to the user page table, and enter user space. +// the trapframe includes callee-saved user registers like s0-s11 because the // return-to-user path via usertrapret() doesn't return through // the entire kernel call stack. struct trapframe { - /* 0 */ uint64 kernel_satp; - /* 8 */ uint64 kernel_sp; - /* 16 */ uint64 kernel_trap; // usertrap() - /* 24 */ uint64 epc; // saved user program counter - /* 32 */ uint64 hartid; + /* 0 */ uint64 kernel_satp; // kernel page table + /* 8 */ uint64 kernel_sp; // top of process's kernel stack + /* 16 */ uint64 kernel_trap; // usertrap() + /* 24 */ uint64 epc; // saved user program counter + /* 32 */ uint64 kernel_hartid; // saved kernel tp /* 40 */ uint64 ra; /* 48 */ uint64 sp; /* 56 */ uint64 gp; @@ -83,16 +87,20 @@ enum procstate { UNUSED, SLEEPING, RUNNABLE, RUNNING, ZOMBIE }; // Per-process state struct proc { struct spinlock lock; + + // p->lock must be held when using these: + enum procstate state; // Process state + struct proc *parent; // Parent process + void *chan; // If non-zero, sleeping on chan + int killed; // If non-zero, have been killed + int pid; // Process ID + + // these are private to the process, so p->lock need not be held. char *kstack; // Bottom of kernel stack for this process uint64 sz; // Size of process memory (bytes) pagetable_t pagetable; // Page table - enum procstate state; // Process state - int pid; // Process ID - struct proc *parent; // Parent process struct trapframe *tf; // data page for trampoline.S struct context context; // swtch() here to run process - void *chan; // If non-zero, sleeping on chan - int killed; // If non-zero, have been killed struct file *ofile[NOFILE]; // Open files struct inode *cwd; // Current directory char name[16]; // Process name (debugging) |