From: Philip Homburg <philip@cs.vu.nl>
Date: Fri, 30 Sep 2005 12:56:00 +0000 (+0000)
Subject: Hack to provide kernel with space for page table.
X-Git-Tag: v3.1.2a~684
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/zpipe.c?a=commitdiff_plain;h=42e1dad99c6e5c6a645540d3ef027464f51e9bdb;p=minix.git

Hack to provide kernel with space for page table.
---

diff --git a/servers/pm/alloc.c b/servers/pm/alloc.c
index 391e1f823..edb8e8fcf 100644
--- a/servers/pm/alloc.c
+++ b/servers/pm/alloc.c
@@ -227,6 +227,8 @@ phys_clicks *free;		/* memory size summaries */
   *free = 0;
   for (i=NR_MEMS-1; i>=0; i--) {
   	if (chunks[i].size > 0) {
+  		printf("mem_init: adding (clicks) 0x%x @ 0x%x\n",
+  			chunks[i].size, chunks[i].base);
 		free_mem(chunks[i].base, chunks[i].size);
 		*free += chunks[i].size;
 #if ENABLE_SWAP
diff --git a/servers/pm/main.c b/servers/pm/main.c
index 0225c1211..04e98843b 100644
--- a/servers/pm/main.c
+++ b/servers/pm/main.c
@@ -32,6 +32,7 @@ FORWARD _PROTOTYPE( int get_nice_value, (int queue)			);
 FORWARD _PROTOTYPE( void get_mem_chunks, (struct memory *mem_chunks) 	);
 FORWARD _PROTOTYPE( void patch_mem_chunks, (struct memory *mem_chunks, 
 	struct mem_map *map_ptr) 	);
+FORWARD _PROTOTYPE( void do_x86_vm, (struct memory mem_chunks[NR_MEMS])	);
 
 #define click_to_round_k(n) \
 	((unsigned) ((((unsigned long) (n) << CLICK_SHIFT) + 512) / 1024))
@@ -259,6 +260,9 @@ PRIVATE void pm_init()
   }
 #endif /* ENABLE_BOOTDEV */
 
+  /* Withhold some memory from x86 VM */
+  do_x86_vm(mem_chunks);
+
   /* Initialize tables to all physical memory and print memory information. */
   printf("Physical memory:");
   mem_init(mem_chunks, &free_clicks);
@@ -380,3 +384,58 @@ struct mem_map *map_ptr;			/* memory to remove */
   }
 }
 
+#define PAGE_SIZE	4096
+#define PAGE_TABLE_COVER (1024*PAGE_SIZE)
+/*=========================================================================*
+ *				do_x86_vm				   *
+ *=========================================================================*/
+PRIVATE void do_x86_vm(mem_chunks)
+struct memory mem_chunks[NR_MEMS];
+{
+	phys_bytes high, bytes;
+	phys_clicks clicks, base_click;
+	unsigned pages;
+	int i, r;
+
+	/* Compute the highest memory location */
+	high= 0;
+	for (i= 0; i<NR_MEMS; i++)
+	{
+		if (mem_chunks[i].size == 0)
+			continue;
+		if (mem_chunks[i].base + mem_chunks[i].size > high)
+			high= mem_chunks[i].base + mem_chunks[i].size;
+	}
+
+	high <<= CLICK_SHIFT;
+	printf("do_x86_vm: found high 0x%x\n", high);
+
+	/* The number of pages we need is one for the page directory, enough
+	 * page tables to cover the memory, and one page for alignement.
+	 */
+	pages= 1 + (high + PAGE_TABLE_COVER-1)/PAGE_TABLE_COVER + 1;
+	bytes= pages*PAGE_SIZE;
+	clicks= (bytes + CLICK_SIZE-1) >> CLICK_SHIFT;
+
+	printf("do_x86_vm: need %d pages\n", pages);
+	printf("do_x86_vm: need %d bytes\n", bytes);
+	printf("do_x86_vm: need %d clicks\n", clicks);
+
+	for (i= 0; i<NR_MEMS; i++)
+	{
+		if (mem_chunks[i].size <= clicks)
+			continue;
+		break;
+	}
+	if (i >= NR_MEMS)
+		panic("PM", "not enough memory for VM page tables?", NO_NUM);
+	base_click= mem_chunks[i].base;
+	mem_chunks[i].base += clicks;
+	mem_chunks[i].size -= clicks;
+
+	printf("do_x86_vm: using 0x%x clicks @ 0x%x\n", clicks, base_click);
+	r= sys_vm_setbuf(base_click << CLICK_SHIFT, clicks << CLICK_SHIFT,
+		high);
+	if (r != 0)
+		printf("do_x86_vm: sys_vm_setbuf failed: %d\n", r);
+}