pc64: simplify mmuwalk by factoring out mmu page table creation into separate function

diff --git a/sys/src/9/pc64/mmu.c b/sys/src/9/pc64/mmu.c
index 74857b90f382e6ada20ec2a3c719b7de068515a5..2d7633aa69aeba5be4b470be94628f3ab7fe6141 100644 (file)
--- a/sys/src/9/pc64/mmu.c
+++ b/sys/src/9/pc64/mmu.c
@@ -205,12 +205,58 @@ mmualloc(void)
        return p;
 }
 
+static uintptr*
+mmucreate(uintptr *table, uintptr va, int level, int index)
+{
+       uintptr *page, flags;
+       MMU *p;
+       
+       flags = PTEWRITE|PTEVALID;
+       if(va < VMAP){
+               assert(up != nil);
+               assert((va < TSTKTOP) || (va >= KMAP && va < KMAP+KMAPSIZE));
+
+               p = mmualloc();
+               p->index = level;
+               p->level = index;
+               if(va < TSTKTOP){
+                       flags |= PTEUSER;
+                       if(level == PML4E){
+                               if((p->next = up->mmuhead) == nil)
+                                       up->mmutail = p;
+                               up->mmuhead = p;
+                               m->mmumap[index/MAPBITS] |= 1ull<<(index%MAPBITS);
+                       } else {
+                               up->mmutail->next = p;
+                               up->mmutail = p;
+                       }
+                       up->mmucount++;
+               } else {
+                       if(level == PML4E){
+                               up->kmaptail = p;
+                               up->kmaphead = p;
+                       } else {
+                               up->kmaptail->next = p;
+                               up->kmaptail = p;
+                       }
+                       up->kmapcount++;
+               }
+               page = p->page;
+       } else if(didmmuinit) {
+               page = mallocalign(PTSZ, BY2PG, 0, 0);
+       } else {
+               page = rampage();
+       }
+       memset(page, 0, PTSZ);
+       table[index] = PADDR(page) | flags;
+       return page;
+}
+
 uintptr*
 mmuwalk(uintptr* table, uintptr va, int level, int create)
 {
-       uintptr pte, *page;
+       uintptr pte;
        int i, x;
-       MMU *p;
 
        x = PTLX(va, 3);
        for(i = 2; i >= level; i--){
@@ -219,49 +265,10 @@ mmuwalk(uintptr* table, uintptr va, int level, int create)
                        if(pte & PTESIZE)
                                return 0;
                        table = KADDR(PPN(pte));
-               } else {                        
+               } else {
                        if(!create)
                                return 0;
-                       pte = PTEWRITE|PTEVALID;
-                       if(va < VMAP){
-                               if(va < TSTKTOP){
-                                       pte |= PTEUSER;
-
-                                       p = mmualloc();
-                                       p->index = x;
-                                       p->level = i;
-                                       if(i == PML4E){
-                                               if((p->next = up->mmuhead) == nil)
-                                                       up->mmutail = p;
-                                               up->mmuhead = p;
-                                               m->mmumap[p->index/MAPBITS] |= 1ull<<(p->index%MAPBITS);
-                                       } else {
-                                               up->mmutail->next = p;
-                                               up->mmutail = p;
-                                       }
-                                       up->mmucount++;
-                               } else if(va >= KMAP && va < (KMAP+KMAPSIZE)) {
-                                       p = mmualloc();
-                                       p->index = x;
-                                       p->level = i;
-                                       if(i == PML4E){
-                                               up->kmaptail = p;
-                                               up->kmaphead = p;
-                                       } else {
-                                               up->kmaptail->next = p;
-                                               up->kmaptail = p;
-                                       }
-                                       up->kmapcount++;
-                               } else
-                                       return 0;
-                               page = p->page;
-                       } else if(didmmuinit) {
-                               page = mallocalign(PTSZ, BY2PG, 0, 0);
-                       } else
-                               page = rampage();
-                       memset(page, 0, PTSZ);
-                       table[x] = PADDR(page) | pte;
-                       table = page;
+                       table = mmucreate(table, va, i, x);
                }
                x = PTLX(va, i);
        }