1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
// Per-CPU state
struct cpu {
uint64 syscallno; // Temporary used by sysentry
uint64 usp; // Temporary used by sysentry
struct proc *proc; // The process running on this cpu or null
struct cpu *cpu; // XXX
uchar apicid; // Local APIC ID
struct context *scheduler; // swtch() here to enter scheduler
struct taskstate ts; // Used by x86 to find stack for interrupt
struct segdesc gdt[NSEGS]; // x86 global descriptor table
volatile uint started; // Has the CPU started?
int ncli; // Depth of pushcli nesting.
int intena; // Were interrupts enabled before pushcli?
};
extern struct cpu cpus[NCPU];
extern int ncpu;
//PAGEBREAK: 17
// Saved registers for kernel context switches.
// Don't need to save all the segment registers (%cs, etc),
// because they are constant across kernel contexts.
// Don't need to save %eax, %ecx, %edx, because the
// x86 convention is that the caller has saved them.
// Contexts are stored at the bottom of the stack they
// describe; the stack pointer is the address of the context.
// The layout of the context matches the layout of the stack in swtch.S
// at the "Switch stacks" comment. Switch doesn't save eip explicitly,
// but it is on the stack and allocproc() manipulates it.
struct context {
uint64 r15;
uint64 r14;
uint64 r13;
uint64 r12;
uint64 r11;
uint64 rbx;
uint64 rbp;
uint64 rip;
};
enum procstate { UNUSED, EMBRYO, SLEEPING, RUNNABLE, RUNNING, ZOMBIE };
// Per-process state
struct proc {
char *kstack; // Bottom of kernel stack for this process, must be first entry
uint64 sz; // Size of process memory (bytes)
pde_t* pgdir; // Page table
enum procstate state; // Process state
int pid; // Process ID
struct proc *parent; // Parent process
struct sysframe *sf; // Syscall frame for current syscall
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)
};
// Process memory is laid out contiguously, low addresses first:
// text
// original data and bss
// fixed-size stack
// expandable heap
|
