Import of Linus's Linux 1.1.68

1 files changed, 202 insertions, 0 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
new file mode 100644
index 000000000..0dbd16d54
--- /dev/null
+++ b/mm/vmalloc.c
@@ -0,0 +1,202 @@
+/*
+ *  linux/mm/vmalloc.c
+ *
+ *  Copyright (C) 1993  Linus Torvalds
+ */
+
+#include <asm/system.h>
+#include <linux/config.h>
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/head.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/malloc.h>
+#include <asm/segment.h>
+
+struct vm_struct {
+	unsigned long flags;
+	void * addr;
+	unsigned long size;
+	struct vm_struct * next;
+};
+
+static struct vm_struct * vmlist = NULL;
+
+/* Just any arbitrary offset to the start of the vmalloc VM area: the
+ * current 8MB value just means that there will be a 8MB "hole" after the
+ * physical memory until the kernel virtual memory starts.  That means that
+ * any out-of-bounds memory accesses will hopefully be caught.
+ * The vmalloc() routines leaves a hole of 4kB between each vmalloced
+ * area for the same reason. ;)
+ */
+#define VMALLOC_OFFSET	(8*1024*1024)
+
+static inline void set_pgdir(unsigned long dindex, unsigned long value)
+{
+	struct task_struct * p;
+
+	p = &init_task;
+	do {
+		((unsigned long *) p->tss.cr3)[dindex] = value;
+		p = p->next_task;
+	} while (p != &init_task);
+}
+
+static int free_area_pages(unsigned long dindex, unsigned long index, unsigned long nr)
+{
+	unsigned long page, *pte;
+
+	if (!(PAGE_PRESENT & (page = swapper_pg_dir[dindex])))
+		return 0;
+	page &= PAGE_MASK;
+	pte = index + (unsigned long *) page;
+	do {
+		unsigned long pg = *pte;
+		*pte = 0;
+		if (pg & PAGE_PRESENT)
+			free_page(pg);
+		pte++;
+	} while (--nr);
+	pte = (unsigned long *) page;
+	for (nr = 0 ; nr < 1024 ; nr++, pte++)
+		if (*pte)
+			return 0;
+	set_pgdir(dindex,0);
+	mem_map[MAP_NR(page)] = 1;
+	free_page(page);
+	invalidate();
+	return 0;
+}
+
+static int alloc_area_pages(unsigned long dindex, unsigned long index, unsigned long nr)
+{
+	unsigned long page, *pte;
+
+	page = swapper_pg_dir[dindex];
+	if (!page) {
+		page = get_free_page(GFP_KERNEL);
+		if (!page)
+			return -ENOMEM;
+		if (swapper_pg_dir[dindex]) {
+			free_page(page);
+			page = swapper_pg_dir[dindex];
+		} else {
+			mem_map[MAP_NR(page)] = MAP_PAGE_RESERVED;
+			set_pgdir(dindex, page | PAGE_SHARED);
+		}
+	}
+	page &= PAGE_MASK;
+	pte = index + (unsigned long *) page;
+	*pte = PAGE_SHARED;		/* remove a race with vfree() */
+	do {
+		unsigned long pg = get_free_page(GFP_KERNEL);
+
+		if (!pg)
+			return -ENOMEM;
+		*pte = pg | PAGE_SHARED;
+		pte++;
+	} while (--nr);
+	invalidate();
+	return 0;
+}
+
+static int do_area(void * addr, unsigned long size,
+	int (*area_fn)(unsigned long,unsigned long,unsigned long))
+{
+	unsigned long nr, dindex, index;
+
+	nr = size >> PAGE_SHIFT;
+	dindex = (TASK_SIZE + (unsigned long) addr) >> 22;
+	index = (((unsigned long) addr) >> PAGE_SHIFT) & (PTRS_PER_PAGE-1);
+	while (nr > 0) {
+		unsigned long i = PTRS_PER_PAGE - index;
+
+		if (i > nr)
+			i = nr;
+		nr -= i;
+		if (area_fn(dindex, index, i))
+			return -1;
+		index = 0;
+		dindex++;
+	}
+	return 0;
+}
+
+void vfree(void * addr)
+{
+	struct vm_struct **p, *tmp;
+
+	if (!addr)
+		return;
+	if ((PAGE_SIZE-1) & (unsigned long) addr) {
+		printk("Trying to vfree() bad address (%p)\n", addr);
+		return;
+	}
+	for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
+		if (tmp->addr == addr) {
+			*p = tmp->next;
+			do_area(tmp->addr, tmp->size, free_area_pages);
+			kfree(tmp);
+			return;
+		}
+	}
+	printk("Trying to vfree() nonexistent vm area (%p)\n", addr);
+}
+
+void * vmalloc(unsigned long size)
+{
+	void * addr;
+	struct vm_struct **p, *tmp, *area;
+
+	size = PAGE_ALIGN(size);
+	if (!size || size > high_memory)
+		return NULL;
+	area = (struct vm_struct *) kmalloc(sizeof(*area), GFP_KERNEL);
+	if (!area)
+		return NULL;
+	addr = (void *) ((high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1));
+	area->size = size + PAGE_SIZE;
+	area->next = NULL;
+	for (p = &vmlist; (tmp = *p) ; p = &tmp->next) {
+		if (size + (unsigned long) addr < (unsigned long) tmp->addr)
+			break;
+		addr = (void *) (tmp->size + (unsigned long) tmp->addr);
+	}
+	area->addr = addr;
+	area->next = *p;
+	*p = area;
+	if (do_area(addr, size, alloc_area_pages)) {
+		vfree(addr);
+		return NULL;
+	}
+	return addr;
+}
+
+int vread(char *buf, char *addr, int count)
+{
+	struct vm_struct **p, *tmp;
+	char *vaddr, *buf_start = buf;
+	int n;
+
+	for (p = &vmlist; (tmp = *p) ; p = &tmp->next) {
+		vaddr = (char *) tmp->addr;
+		while (addr < vaddr) {
+			if (count == 0)
+				goto finished;
+			put_fs_byte('\0', buf++), addr++, count--;
+		}
+		n = tmp->size - PAGE_SIZE;
+		if (addr > vaddr)
+			n -= addr - vaddr;
+		while (--n >= 0) {
+			if (count == 0)
+				goto finished;
+			put_fs_byte(*addr++, buf++), count--;
+		}
+	}
+finished:
+	return buf - buf_start;
+}