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annotate source/kalloc.c @ 0:c450faca55f4

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author Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
date Sun, 22 Oct 2017 18:25:39 +0900
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Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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1 #include "types.h"
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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2 #include "defs.h"
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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3 #include "param.h"
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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4 #include "memlayout.h"
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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5 #include "mmu.h"
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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6 #include "spinlock.h"
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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7
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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8 void freerange(void *vstart, void *vend);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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9 extern char end[]; // first address after kernel loaded from ELF file
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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10
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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11 struct run {
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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12 struct run *next;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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13 };
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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14
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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15 struct {
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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16 struct spinlock lock;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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17 int use_lock;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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18 struct run *freelist;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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19 } kmem;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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20
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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21 // Initialization happens in two phases.
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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22 // 1. main() calls kinit1() while still using entrypgdir to place just
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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23 // the pages mapped by entrypgdir on free list.
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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24 // 2. main() calls kinit2() with the rest of the physical pages
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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25 // after installing a full page table that maps them on all cores.
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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26 void
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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27 kinit1(void *vstart, void *vend)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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28 {
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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29 initlock(&kmem.lock, "kmem");
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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30 kmem.use_lock = 0;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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31 kmem.freelist = 0;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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32 freerange(vstart, vend);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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33 }
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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34
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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35 void
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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36 kinit2(void *vstart, void *vend)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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37 {
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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38 freerange(vstart, vend);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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39 kmem.use_lock = 1;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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40 }
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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41
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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42 void
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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43 freerange(void *vstart, void *vend)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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44 {
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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45 char *p;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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46 p = (char*)PGROUNDUP((uint)vstart);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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47 for(; p + PGSIZE <= (char*)vend; p += PGSIZE)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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48 kfree(p);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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49 }
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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50
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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51 //PAGEBREAK: 21
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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52 // Free the page of physical memory pointed at by v,
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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53 // which normally should have been returned by a
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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54 // call to kalloc(). (The exception is when
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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55 // initializing the allocator; see kinit above.)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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56 void
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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57 kfree(char *v)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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58 {
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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59 struct run *r;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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60
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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61 if((uint)v % PGSIZE || v < end || v2p(v) >= PHYSTOP)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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62 panic("kfree");
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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63
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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64 // Fill with junk to catch dangling refs.
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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65 memset(v, 1, PGSIZE);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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66
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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67 if(kmem.use_lock)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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68 acquire(&kmem.lock);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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69 r = (struct run*)v;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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70 r->next = kmem.freelist;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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71 kmem.freelist = r;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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72 if(kmem.use_lock)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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73 release(&kmem.lock);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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74 }
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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75
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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76 // Allocate one 4096-byte page of physical memory.
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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77 // Returns a pointer that the kernel can use.
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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78 // Returns 0 if the memory cannot be allocated.
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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79 char*
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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80 kalloc(void)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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81 {
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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82 struct run *r;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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83
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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84 if(kmem.use_lock)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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85 acquire(&kmem.lock);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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86 r = kmem.freelist;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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87 if(r)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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88 kmem.freelist = r->next;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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89 if(kmem.use_lock)
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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90 release(&kmem.lock);
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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91 return (char*)r;
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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92 }
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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93
Tatsuki IHA <innparusu@cr.ie.u-ryukyu.ac.jp>
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94