Separate paging code from vmap code so it's easier to explore vm.c.

e096f2f8 · Silas Boyd-Wickizer · 561b41ed · e096f2f8 · e096f2f8 · e096f2f8
--- a/Makefile
+++ b/Makefile
@@ -32,6 +32,7 @@ OBJS = \
 	fs.o \
 	ioapic.o \
 	lapic.o \
+	hwvm.o \
 	hz.o \
 	kalloc.o \
 	kbd.o \

--- a/hwvm.c
+++ b/hwvm.c
+#include "param.h"
+#include "types.h"
+#include "amd64.h"
+#include "mmu.h"
+#include "cpu.h"
+#include "kernel.h"
+#include "bits.h"
+#include "spinlock.h"
+#include "kalloc.h"
+#include "queue.h"
+#include "condvar.h"
+#include "proc.h"
+#include <stddef.h>
+extern pml4e_t kpml4[];
+static pme_t*
+descend(pme_t *dir, const void *va, u64 flags, int create, int level)
+{
+  pme_t entry;
+  pme_t *next;
+retry:
+  dir = &dir[PX(level, va)];
+  entry = *dir;
+  if (entry & PTE_P) {
+    next = p2v(PTE_ADDR(entry));
+  } else {
+    if (!create)
+      return NULL;
+    next = (pme_t*) kalloc();
+    if (!next)
+      return NULL;
+    memset(next, 0, PGSIZE);
+    if (!cmpswap(dir, entry, v2p(next) | PTE_P | PTE_W | flags)) {
+      kfree((void*) next);
+      goto retry;
+    }
+  }
+  return next;
+}
+// Return the address of the PTE in page table pgdir
+// that corresponds to linear address va.  If create!=0,
+// create any required page table pages.
+pme_t *
+walkpgdir(pml4e_t *pml4, const void *va, int create)
+{
+  pme_t *pdp;
+  pme_t *pd;
+  pme_t *pt;
+  pdp = descend(pml4, va, PTE_U, create, 3);
+  if (pdp == NULL)
+    return NULL;
+  pd = descend(pdp, va, PTE_U, create, 2);
+  if (pd == NULL)
+    return NULL;
+  pt = descend(pd, va, PTE_U, create, 1);
+  if (pt == NULL)
+    return NULL;
+  return &pt[PX(0,va)];
+}
+void
+updatepages(pme_t *pml4, void *begin, void *end, int perm)
+{
+  char *a, *last;
+  pme_t *pte;
+  a = PGROUNDDOWN(begin);
+  last = PGROUNDDOWN(end);
+  for (;;) {
+    pte = walkpgdir(pml4, a, 1);
+    if(pte != 0) {
+      if (perm == 0) *pte = 0;
+      else *pte = PTE_ADDR(*pte) | perm | PTE_P;
+    }
+    if (a == last)
+      break;
+    a += PGSIZE;
+  }
+}
+static void
+pgmap(void *va, void *last, paddr pa)
+{
+  pme_t *pdp;
+  pme_t *pd;
+  pme_t *pt;
+  for (;;) {
+    pdp = descend(kpml4, va, 0, 1, 3);
+    pd = descend(pdp, va, 0, 1, 2);
+    pt = descend(pd, va, 0, 1, 1);
+    pt = &pt[PX(0,va)];
+    *pt = pa | PTE_W | PTE_P;
+    if(va == last)
+      break;
+    va += PGSIZE;
+    pa += PGSIZE;
+  }
+}
+// set up a page table to get off the ground
+void
+initpg(char* (*alloc)(void))
+{
+  // Map first 4GB to PBASE
+  pgmap((void *) PBASE, (void *) (PBASE+(1UL<<32)), 0);
+  // boot.S maps first 1GB to KBASE and gets us running with kpml4
+}
+// Set up kernel part of a page table.
+pml4e_t*
+setupkvm(void)
+{
+  pml4e_t *pml4;
+  int k;
+  if((pml4 = (pml4e_t*)kalloc()) == 0)
+    return 0;
+  k = PX(3, PBASE);
+  memset(&pml4[0], 0, 8*k);
+  memmove(&pml4[k], &kpml4[k], 8*(512-k));
+  return pml4;
+}
+// Switch h/w page table register to the kernel-only page table,
+// for when no process is running.
+void
+switchkvm(void)
+{
+  lcr3(v2p(kpml4));   // switch to the kernel page table
+}
+// Switch TSS and h/w page table to correspond to process p.
+void
+switchuvm(struct proc *p)
+{
+  u64 base = (u64) &mycpu()->ts;
+  pushcli();
+  mycpu()->gdt[TSSSEG>>3] = (struct segdesc)
+    SEGDESC(base, (sizeof(mycpu()->ts)-1), SEG_P|SEG_TSS64A);
+  mycpu()->gdt[(TSSSEG>>3)+1] = (struct segdesc) SEGDESCHI(base);
+  mycpu()->ts.rsp[0] = (u64) myproc()->kstack + KSTACKSIZE;
+  mycpu()->ts.iomba = (u16)offsetof(struct taskstate, iopb);
+  ltr(TSSSEG);
+  if(p->vmap == 0 || p->vmap->pml4 == 0)
+    panic("switchuvm: no vmap/pml4");
+  lcr3(v2p(p->vmap->pml4));  // switch to new address space
+  popcli();
+}
+static void
+freepm(pme_t *pm, int level)
+{
+  int i;
+  if (level != 0) {
+    for (i = 0; i < 512; i++) {
+      if (pm[i] & PTE_P)
+        freepm(p2v(PTE_ADDR(pm[i])), level - 1);
+    }
+  }
+  kfree(pm);
+}
+// Free a page table and all the physical memory pages
+// in the user part.
+void
+freevm(pml4e_t *pml4)
+{
+  int k;
+  int i;
+  if(pml4 == 0)
+    panic("freevm: no pgdir");
+  // Don't free kernel portion of the pml4
+  k = PX(3, PBASE);
+  for (i = 0; i < k; i++) {
+    if (pml4[i] & PTE_P) {
+      freepm(p2v(PTE_ADDR(pml4[i])), 2);
+    }
+  }
+  kfree(pml4);
+}
--- a/kernel.h
+++ b/kernel.h
@@ -81,6 +81,11 @@ int             dirlink(struct inode*, char*, u32);
 void            dir_init(struct inode *dp);
 void	        dir_flush(struct inode *dp);
+// hwvm.c
+void            freevm(pml4e_t*);
+pml4e_t*        setupkvm(void);
+pme_t *         walkpgdir(pml4e_t*, const void*, int);
 // hz.c
 void            microdelay(u64);

--- a/vm.c
+++ b/vm.c
@@ -12,68 +12,6 @@
 #include "proc.h"
 #include <stddef.h>
-extern char data[];  // defined in data.S
-extern pml4e_t kpml4[];
-extern char* pgalloc(void);
-static pme_t*
-descend(pme_t *dir, const void *va, u64 flags, int create, int level)
-{
-  pme_t entry;
-  pme_t *next;
-retry:
-  dir = &dir[PX(level, va)];
-  entry = *dir;
-  if (entry & PTE_P) {
-    next = p2v(PTE_ADDR(entry));
-  } else {
-    if (!create)
-      return NULL;
-    next = (pme_t*) pgalloc();
-    if (!next)
-      return NULL;
-    memset(next, 0, PGSIZE);
-    if (!cmpswap(dir, entry, v2p(next) | PTE_P | PTE_W | flags)) {
-      kfree((void*) next);
-      goto retry;
-    }
-  }
-  return next;
-}
-static void
-pgmap(void *va, void *last, paddr pa)
-{
-  pme_t *pdp;
-  pme_t *pd;
-  pme_t *pt;
-  for (;;) {
-    pdp = descend(kpml4, va, 0, 1, 3);
-    pd = descend(pdp, va, 0, 1, 2);
-    pt = descend(pd, va, 0, 1, 1);
-    pt = &pt[PX(0,va)];
-    *pt = pa | PTE_W | PTE_P;
-    if(va == last)
-      break;
-    va += PGSIZE;
-    pa += PGSIZE;
-  }
-}
-// set up a page table to get off the ground
-void
-initpg(char* (*alloc)(void))
-{
-  // Map first 4GB to PBASE
-  pgmap((void *) PBASE, (void *) (PBASE+(1UL<<32)), 0);
-  // boot.S maps first 1GB to KBASE and gets us running with kpml4
-}
 // Set up CPU's kernel segment descriptors.
 // Run once at boot time on each CPU.
 void
@@ -90,47 +28,6 @@ inittls(void)
  c->kmem = &kmems[cpunum()];
 }
-// Set up kernel part of a page table.
-static pml4e_t*
-setupkvm(void)
-{
-  pml4e_t *pml4;
-  int k;
-  if((pml4 = (pml4e_t*)kalloc()) == 0)
-    return 0;
-  k = PX(3, PBASE);
-  memset(&pml4[0], 0, 8*k);
-  memmove(&pml4[k], &kpml4[k], 8*(512-k));
-  return pml4;
-}
-// Switch h/w page table register to the kernel-only page table,
-// for when no process is running.
-void
-switchkvm(void)
-{
-  lcr3(v2p(kpml4));   // switch to the kernel page table
-}
-// Switch TSS and h/w page table to correspond to process p.
-void
-switchuvm(struct proc *p)
-{
-  u64 base = (u64) &mycpu()->ts;
-  pushcli();
-  mycpu()->gdt[TSSSEG>>3] = (struct segdesc)
-    SEGDESC(base, (sizeof(mycpu()->ts)-1), SEG_P|SEG_TSS64A);
-  mycpu()->gdt[(TSSSEG>>3)+1] = (struct segdesc) SEGDESCHI(base);
-  mycpu()->ts.rsp[0] = (u64) myproc()->kstack + KSTACKSIZE;
-  mycpu()->ts.iomba = (u16)offsetof(struct taskstate, iopb);
-  ltr(TSSSEG);
-  if(p->vmap == 0 || p->vmap->pml4 == 0)
-    panic("switchuvm: no vmap/pml4");
-  lcr3(v2p(p->vmap->pml4));  // switch to new address space
-  popcli();
-}
 static struct vma *
 vma_alloc(void)
 {
@@ -160,43 +57,6 @@ vma_free(void *p)
  kmfree(e);
 }
-static void
-freepm(pme_t *pm, int level)
-{
-  int i;
-  if (level != 0) {
-    for (i = 0; i < 512; i++) {
-      if (pm[i] & PTE_P)
-        freepm(p2v(PTE_ADDR(pm[i])), level - 1);
-    }
-  }
-  kfree(pm);
-}
-// Free a page table and all the physical memory pages
-// in the user part.
-static void
-freevm(pml4e_t *pml4)
-{
-  int k;
-  int i;
-  if(pml4 == 0)
-    panic("freevm: no pgdir");
-  // Don't free kernel portion of the pml4
-  k = PX(3, PBASE);
-  for (i = 0; i < k; i++) {
-    if (pml4[i] & PTE_P) {
-      freepm(p2v(PTE_ADDR(pml4[i])), 2);
-    }
-  }
-  kfree(pml4);
-}
 #ifdef TREE
 struct state {
  int share;
@@ -441,48 +301,6 @@ copyout(struct vmap *vmap, uptr va, void *p, u64 len)
  return 0;
 }
-// Return the address of the PTE in page table pgdir
-// that corresponds to linear address va.  If create!=0,
-// create any required page table pages.
-static pme_t *
-walkpgdir(pml4e_t *pml4, const void *va, int create)
-{
-  pme_t *pdp;
-  pme_t *pd;
-  pme_t *pt;
-  pdp = descend(pml4, va, PTE_U, create, 3);
-  if (pdp == NULL)
-    return NULL;
-  pd = descend(pdp, va, PTE_U, create, 2);
-  if (pd == NULL)
-    return NULL;
-  pt = descend(pd, va, PTE_U, create, 1);
-  if (pt == NULL)
-    return NULL;
-  return &pt[PX(0,va)];
-}
-void
-updatepages(pme_t *pml4, void *begin, void *end, int perm)
-{
-  char *a, *last;
-  pme_t *pte;
-  a = PGROUNDDOWN(begin);
-  last = PGROUNDDOWN(end);
-  for (;;) {
-    pte = walkpgdir(pml4, a, 1);
-    if(pte != 0) {
-      if (perm == 0) *pte = 0;
-      else *pte = PTE_ADDR(*pte) | perm | PTE_P;
-    }
-    if (a == last)
-      break;
-    a += PGSIZE;
-  }
-}
 struct vmnode *
 vmn_copy(struct vmnode *n)
 {