pc64: allocate palloc.pages from upages

the palloc.pages array takes arround 5% of the upages which
gives us:

16GB = ~0.8GB
32GB = ~1.6GB
64GB = ~3.2GB

we only have 2GB of address space above KZERO so this will not
work for long.

instead, pageinit() was altered to accept a preallocated memory
in palloc.pages. and preallocpages() in pc64/main.c allocates the
in upages memory, mapping it in the VMAP area (which has 512GB).

the drawback is that we cannot poke at Page structures now from
/proc/n/mem as the VMAP area is not accessible from it.

1 files changed, 2 insertions, 37 deletions

diff --git a/sys/src/9/pc64/memory.c b/sys/src/9/pc64/memory.c
index 37c611e00..1c7759dad 100644
--- a/sys/src/9/pc64/memory.c
+++ b/sys/src/9/pc64/memory.c
@@ -371,25 +371,6 @@ sigsearch(char* signature)
 	return sigscan(KADDR(0xe0000), 0x20000, signature);
 }
 
-static void
-lowraminit(void)
-{
-	uintptr pa, x;
-
-	/*
-	 * Initialise the memory bank information for conventional memory
-	 * (i.e. less than 640KB). The base is the first location after the
-	 * bootstrap processor MMU information and the limit is obtained from
-	 * the BIOS data area.
-	 */
-	x = PADDR(PGROUND((uintptr)end));
-	pa = MemMin;
-	if(x > pa)
-		panic("kernel too big");
-	mapfree(&rmapram, x, pa-x);
-	memset(KADDR(x), 0, pa-x);		/* keep us honest */
-}
-
 typedef struct Emap Emap;
 struct Emap
 {
@@ -421,7 +402,7 @@ emapcmp(const void *va, const void *vb)
 static void
 map(uintptr base, uintptr len, int type)
 {
-	uintptr e, n, *pte, flags, maxkpa;
+	uintptr n, flags, maxkpa;
 
 	/*
 	 * Split any call crossing MemMin to make below simpler.
@@ -433,7 +414,7 @@ map(uintptr base, uintptr len, int type)
 	}
 	
 	/*
-	 * Let lowraminit and umbscan hash out the low MemMin.
+	 * Let umbscan hash out the low MemMin.
 	 */
 	if(base < MemMin)
 		return;
@@ -497,21 +478,6 @@ map(uintptr base, uintptr len, int type)
 		break;
 	}
 	
-	/*
-	 * bottom MemMin is already mapped - just twiddle flags.
-	 * (not currently used - see above)
-	 */
-	if(base < MemMin){
-		e = base+len;
-		base &= ~((uintptr)PGLSZ(1)-1);
-		for(; base<e; base+=PGLSZ(1)){
-			pte = mmuwalk(m->pml4, base+KZERO, 1, 0);
-			if(pte != 0 && *pte & PTEVALID)
-				*pte |= flags;
-		}
-		return;
-	}
-	
 	if(flags){
 		maxkpa = -KZERO;
 		if(base >= maxkpa)
@@ -595,7 +561,6 @@ meminit(void)
 	uintptr lost;
 
 	umbscan();
-	// lowraminit();
 	e820scan();
 
 	/*