Lab6

tools/labs/skels/Kbuild

@@ -0,0 +1,4 @@
+# autogenerated, do not edit 
+ccflags-y += -Wno-unused-function -Wno-unused-label -Wno-unused-variable 
+obj-m += ./memory_mapping/vmmap/
+obj-m += ./memory_mapping/kmmap/

tools/labs/skels/memory_mapping/kmmap/Kbuild

@@ -0,0 +1,3 @@
+ccflags-y = -Wno-unused-function -Wno-unused-label -Wno-unused-variable
+
+obj-m	:= kmmap.o

tools/labs/skels/memory_mapping/kmmap/kmmap.c

@@ -0,0 +1,226 @@
+/*
+ * PSO - Memory Mapping Lab(#11)
+ *
+ * Exercise #1: memory mapping using kmalloc'd kernel areas
+ */
+
+#include <linux/version.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <asm/pgtable.h>
+#include <linux/sched/mm.h>
+#include <linux/sched.h>
+#include <asm/io.h>
+#include <asm/highmem.h>
+#include <linux/rmap.h>
+#include <asm/uaccess.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#include "../test/mmap-test.h"
+
+MODULE_DESCRIPTION("simple mmap driver");
+MODULE_AUTHOR("PSO");
+MODULE_LICENSE("Dual BSD/GPL");
+
+#define MY_MAJOR	42
+/* how many pages do we actually kmalloc */
+#define NPAGES		16
+
+/* character device basic structure */
+static struct cdev mmap_cdev;
+
+/* pointer to kmalloc'd area */
+static void *kmalloc_ptr;
+
+/* pointer to the kmalloc'd area, rounded up to a page boundary */
+static char *kmalloc_area;
+
+static int my_open(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+static int my_release(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+static int my_read(struct file *file, char __user *user_buffer,
+		size_t size, loff_t *offset)
+{
+	/* TODO 2: check size doesn't exceed our mapped area size */
+	if (size > NPAGES * PAGE_SIZE)
+		size = NPAGES * PAGE_SIZE;
+
+	/* TODO 2: copy from mapped area to user buffer */
+	if (copy_to_user(user_buffer, kmalloc_area, size))
+		return -EFAULT;
+
+	return size;
+}
+
+static int my_write(struct file *file, const char __user *user_buffer,
+		size_t size, loff_t *offset)
+{
+	/* TODO 2: check size doesn't exceed our mapped area size */
+	if (size > NPAGES * PAGE_SIZE)
+		size = NPAGES * PAGE_SIZE;
+
+	/* TODO 2: copy from user buffer to mapped area */
+	if (copy_from_user(kmalloc_area, user_buffer, size))
+		return -EFAULT;
+
+	return size;
+}
+
+static int my_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	int ret;
+	long length = vma->vm_end - vma->vm_start;
+
+	/* do not map more than we can */
+	if (length > NPAGES * PAGE_SIZE)
+		return -EIO;
+
+	/* TODO 1: map the whole physically contiguous area in one piece */
+	ret = remap_pfn_range(vma, vma->vm_start,
+			virt_to_phys((void *)kmalloc_area) >> PAGE_SHIFT,
+			length, vma->vm_page_prot);
+	if (ret < 0) {
+		pr_err("could not map address area\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct file_operations mmap_fops = {
+	.owner = THIS_MODULE,
+	.open = my_open,
+	.release = my_release,
+	.mmap = my_mmap,
+	.read = my_read,
+	.write = my_write
+};
+
+static int my_seq_show(struct seq_file *seq, void *v)
+{
+	struct mm_struct *mm;
+	struct vm_area_struct *vma_iterator;
+	unsigned long total = 0;
+
+	/* TODO 3: Get current process' mm_struct */
+	mm = get_task_mm(current);
+
+	/* TODO 3: Iterate through all memory mappings */
+	while (vma_iterator != NULL) {
+		pr_info("%lx %lx\n", vma_iterator->vm_start, vma_iterator->vm_end);
+		total += vma_iterator->vm_end - vma_iterator->vm_start;
+		vma_iterator = vma_iterator->vm_next;
+	}
+
+	/* TODO 3: Release mm_struct */
+	mmput(mm);
+
+	/* TODO 3: write the total count to file  */
+	seq_printf(seq, "%lu %s\n", total, current->comm);
+	return 0;
+}
+
+static int my_seq_open(struct inode *inode, struct file *file)
+{
+	/* TODO 3: Register the display function */
+	return single_open(file, my_seq_show, NULL);
+}
+
+static const struct proc_ops my_proc_ops = {
+	.proc_open    = my_seq_open,
+	.proc_read    = seq_read,
+	.proc_lseek   = seq_lseek,
+	.proc_release = single_release,
+};
+
+static int __init my_init(void)
+{
+	int ret = 0;
+	int i;
+	/* TODO 3: create a new entry in procfs */
+	struct proc_dir_entry *entry;
+	entry = proc_create(PROC_ENTRY_NAME, 0, NULL, &my_proc_ops);
+	if (!entry) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = register_chrdev_region(MKDEV(MY_MAJOR, 0), 1, "mymap");
+	if (ret < 0) {
+		pr_err("could not register region\n");
+		goto out_no_chrdev;
+	}
+
+	/* TODO 1: allocate NPAGES+2 pages using kmalloc */
+	kmalloc_ptr = kmalloc((NPAGES + 2) * PAGE_SIZE, GFP_KERNEL);
+	if (kmalloc_ptr == NULL) {
+		ret = -ENOMEM;
+		pr_err("could not allocate memory\n");
+		goto out_unreg;
+	}
+
+	/* TODO 1: round kmalloc_ptr to nearest page start address */
+	kmalloc_area = (char *) PAGE_ALIGN(((unsigned long)kmalloc_ptr));
+
+	/* TODO 1: mark pages as reserved */
+	for (i = 0; i < NPAGES * PAGE_SIZE; i += PAGE_SIZE)
+		SetPageReserved(virt_to_page(((unsigned long)kmalloc_area)+i));
+
+	/* TODO 1: write data in each page */
+	for (i = 0; i < NPAGES * PAGE_SIZE; i += PAGE_SIZE) {
+		kmalloc_area[i] = 0xaa;
+		kmalloc_area[i + 1] = 0xbb;
+		kmalloc_area[i + 2] = 0xcc;
+		kmalloc_area[i + 3] = 0xdd;
+	}
+
+	/* Init device. */
+	cdev_init(&mmap_cdev, &mmap_fops);
+	ret = cdev_add(&mmap_cdev, MKDEV(MY_MAJOR, 0), 1);
+	if (ret < 0) {
+		pr_err("could not add device\n");
+		goto out_kfree;
+	}
+
+	return 0;
+
+out_kfree:
+	kfree(kmalloc_ptr);
+out_unreg:
+	unregister_chrdev_region(MKDEV(MY_MAJOR, 0), 1);
+out_no_chrdev:
+	remove_proc_entry(PROC_ENTRY_NAME, NULL);
+out:
+	return ret;
+}
+
+static void __exit my_exit(void)
+{
+	int i;
+
+	cdev_del(&mmap_cdev);
+
+	/* TODO 1: clear reservation on pages and free mem. */
+	for (i = 0; i < NPAGES * PAGE_SIZE; i += PAGE_SIZE)
+		ClearPageReserved(virt_to_page(((unsigned long)kmalloc_area)+i));
+	kfree(kmalloc_ptr);
+
+	unregister_chrdev_region(MKDEV(MY_MAJOR, 0), 1);
+	/* TODO 3: remove proc entry */
+	remove_proc_entry(PROC_ENTRY_NAME, NULL);
+}
+
+module_init(my_init);
+module_exit(my_exit);

tools/labs/skels/memory_mapping/test/.gitignore

@@ -0,0 +1 @@
+/mmap-test

tools/labs/skels/memory_mapping/test/Makefile

@@ -0,0 +1,9 @@
+CFLAGS=-Wall -m32
+LDFLAGS=-static -m32
+
+mmap-test: mmap-test.o
+
+.PHONY: clean
+
+clean:
+	-rm -f *~ *.o mmap-test