Imbus/xv6-riscv-kernel
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fork/wait/exit work

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This commit is contained in:
Robert Morris 2019-05-31 09:45:59 -04:00
parent 0f90388c89
commit 2ec1959fd1
30 changed files with 1098 additions and 1863 deletions
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58
kalloc.c
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@ -3,13 +3,14 @@
// and pipe buffers. Allocates 4096-byte pages.
#include "types.h"
#include "defs.h"
#include "param.h"
#include "memlayout.h"
#include "mmu.h"
#include "spinlock.h"
#include "riscv.h"
#include "defs.h"
void freerange(void *pa_start, void *pa_end);
void freerange(void *vstart, void *vend);
extern char end[]; // first address after kernel loaded from ELF file
// defined by the kernel linker script in kernel.ld
@ -19,36 +20,22 @@ struct run {
struct {
struct spinlock lock;
int use_lock;
struct run *freelist;
} kmem;
// Initialization happens in two phases.
// 1. main() calls kinit1() while still using entrypgdir to place just
// the pages mapped by entrypgdir on free list.
// 2. main() calls kinit2() with the rest of the physical pages
// after installing a full page table that maps them on all cores.
void
kinit1(void *vstart, void *vend)
kinit()
{
initlock(&kmem.lock, "kmem");
kmem.use_lock = 0;
freerange(vstart, vend);
freerange(end, (void*)PHYSTOP);
}
void
kinit2(void *vstart, void *vend)
{
freerange(vstart, vend);
kmem.use_lock = 1;
}
void
freerange(void *vstart, void *vend)
freerange(void *pa_start, void *pa_end)
{
char *p;
p = (char*)PGROUNDUP((uint64)vstart);
for(; p + PGSIZE <= (char*)vend; p += PGSIZE)
p = (char*)PGROUNDUP((uint64)pa_start);
for(; p + PGSIZE <= (char*)pa_end; p += PGSIZE)
kfree(p);
}
//PAGEBREAK: 21
@ -57,42 +44,37 @@ freerange(void *vstart, void *vend)
// call to kalloc(). (The exception is when
// initializing the allocator; see kinit above.)
void
kfree(char *v)
kfree(void *pa)
{
struct run *r;
if((uint64)v % PGSIZE || v < end || V2P(v) >= PHYSTOP)
if(((uint64)pa % PGSIZE) != 0 || (char*)pa < end || (uint64)pa >= PHYSTOP)
panic("kfree");
// Fill with junk to catch dangling refs.
memset(v, 1, PGSIZE);
memset(pa, 1, PGSIZE);
if(kmem.use_lock)
acquire(&kmem.lock);
r = (struct run*)v;
acquire(&kmem.lock);
r = (struct run*)pa;
r->next = kmem.freelist;
kmem.freelist = r;
if(kmem.use_lock)
release(&kmem.lock);
release(&kmem.lock);
}
// Allocate one 4096-byte page of physical memory.
// Returns a pointer that the kernel can use.
// Returns 0 if the memory cannot be allocated.
char*
void *
kalloc(void)
{
struct run *r;
if(kmem.use_lock)
acquire(&kmem.lock);
acquire(&kmem.lock);
r = kmem.freelist;
if(r)
kmem.freelist = r->next;
if(kmem.use_lock)
release(&kmem.lock);
if(r != 0 && (uint64) r < KERNBASE)
panic("kalloc");
return (char*)r;
release(&kmem.lock);
memset((char*)r, 5, PGSIZE); // fill with junk
return (void*)r;
}