1 files changed, 222 insertions, 0 deletions
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
new file mode 100644
index 000000000..91485119a
--- /dev/null
+++ b/arch/um/kernel/physmem.c
@@ -0,0 +1,222 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#include <linux/module.h>
+#include <linux/memblock.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <asm/page.h>
+#include <asm/sections.h>
+#include <as-layout.h>
+#include <init.h>
+#include <kern.h>
+#include <mem_user.h>
+#include <os.h>
+
+static int physmem_fd = -1;
+
+/* Changed during early boot */
+unsigned long high_physmem;
+EXPORT_SYMBOL(high_physmem);
+
+extern unsigned long long physmem_size;
+
+void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
+		     unsigned long highmem)
+{
+	unsigned long phys_pages, highmem_pages;
+	unsigned long iomem_pages, total_pages;
+
+	phys_pages    = physmem >> PAGE_SHIFT;
+	iomem_pages   = iomem   >> PAGE_SHIFT;
+	highmem_pages = highmem >> PAGE_SHIFT;
+
+	total_pages   = phys_pages + iomem_pages + highmem_pages;
+
+	max_mapnr = total_pages;
+}
+
+void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
+		int r, int w, int x)
+{
+	__u64 offset;
+	int fd, err;
+
+	fd = phys_mapping(phys, &offset);
+	err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
+	if (err) {
+		if (err == -ENOMEM)
+			printk(KERN_ERR "try increasing the host's "
+			       "/proc/sys/vm/max_map_count to <physical "
+			       "memory size>/4096\n");
+		panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
+		      "err = %d\n", virt, fd, offset, len, r, w, x, err);
+	}
+}
+
+/**
+ * setup_physmem() - Setup physical memory for UML
+ * @start:	Start address of the physical kernel memory,
+ *		i.e start address of the executable image.
+ * @reserve_end:	end address of the physical kernel memory.
+ * @len:	Length of total physical memory that should be mapped/made
+ *		available, in bytes.
+ * @highmem:	Number of highmem bytes that should be mapped/made available.
+ *
+ * Creates an unlinked temporary file of size (len + highmem) and memory maps
+ * it on the last executable image address (uml_reserved).
+ *
+ * The offset is needed as the length of the total physical memory
+ * (len + highmem) includes the size of the memory used be the executable image,
+ * but the mapped-to address is the last address of the executable image
+ * (uml_reserved == end address of executable image).
+ *
+ * The memory mapped memory of the temporary file is used as backing memory
+ * of all user space processes/kernel tasks.
+ */
+void __init setup_physmem(unsigned long start, unsigned long reserve_end,
+			  unsigned long len, unsigned long long highmem)
+{
+	unsigned long reserve = reserve_end - start;
+	long map_size = len - reserve;
+	int err;
+
+	if(map_size <= 0) {
+		os_warn("Too few physical memory! Needed=%lu, given=%lu\n",
+			reserve, len);
+		exit(1);
+	}
+
+	physmem_fd = create_mem_file(len + highmem);
+
+	err = os_map_memory((void *) reserve_end, physmem_fd, reserve,
+			    map_size, 1, 1, 1);
+	if (err < 0) {
+		os_warn("setup_physmem - mapping %ld bytes of memory at 0x%p "
+			"failed - errno = %d\n", map_size,
+			(void *) reserve_end, err);
+		exit(1);
+	}
+
+	/*
+	 * Special kludge - This page will be mapped in to userspace processes
+	 * from physmem_fd, so it needs to be written out there.
+	 */
+	os_seek_file(physmem_fd, __pa(__syscall_stub_start));
+	os_write_file(physmem_fd, __syscall_stub_start, PAGE_SIZE);
+	os_fsync_file(physmem_fd);
+
+	memblock_add(__pa(start), len + highmem);
+	memblock_reserve(__pa(start), reserve);
+
+	min_low_pfn = PFN_UP(__pa(reserve_end));
+	max_low_pfn = min_low_pfn + (map_size >> PAGE_SHIFT);
+}
+
+int phys_mapping(unsigned long phys, unsigned long long *offset_out)
+{
+	int fd = -1;
+
+	if (phys < physmem_size) {
+		fd = physmem_fd;
+		*offset_out = phys;
+	}
+	else if (phys < __pa(end_iomem)) {
+		struct iomem_region *region = iomem_regions;
+
+		while (region != NULL) {
+			if ((phys >= region->phys) &&
+			    (phys < region->phys + region->size)) {
+				fd = region->fd;
+				*offset_out = phys - region->phys;
+				break;
+			}
+			region = region->next;
+		}
+	}
+	else if (phys < __pa(end_iomem) + highmem) {
+		fd = physmem_fd;
+		*offset_out = phys - iomem_size;
+	}
+
+	return fd;
+}
+EXPORT_SYMBOL(phys_mapping);
+
+static int __init uml_mem_setup(char *line, int *add)
+{
+	char *retptr;
+	physmem_size = memparse(line,&retptr);
+	return 0;
+}
+__uml_setup("mem=", uml_mem_setup,
+"mem=<Amount of desired ram>\n"
+"    This controls how much \"physical\" memory the kernel allocates\n"
+"    for the system. The size is specified as a number followed by\n"
+"    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
+"    This is not related to the amount of memory in the host.  It can\n"
+"    be more, and the excess, if it's ever used, will just be swapped out.\n"
+"	Example: mem=64M\n\n"
+);
+
+extern int __init parse_iomem(char *str, int *add);
+
+__uml_setup("iomem=", parse_iomem,
+"iomem=<name>,<file>\n"
+"    Configure <file> as an IO memory region named <name>.\n\n"
+);
+
+/*
+ * This list is constructed in parse_iomem and addresses filled in
+ * setup_iomem, both of which run during early boot.  Afterwards, it's
+ * unchanged.
+ */
+struct iomem_region *iomem_regions;
+
+/* Initialized in parse_iomem and unchanged thereafter */
+int iomem_size;
+
+unsigned long find_iomem(char *driver, unsigned long *len_out)
+{
+	struct iomem_region *region = iomem_regions;
+
+	while (region != NULL) {
+		if (!strcmp(region->driver, driver)) {
+			*len_out = region->size;
+			return region->virt;
+		}
+
+		region = region->next;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(find_iomem);
+
+static int setup_iomem(void)
+{
+	struct iomem_region *region = iomem_regions;
+	unsigned long iomem_start = high_physmem + PAGE_SIZE;
+	int err;
+
+	while (region != NULL) {
+		err = os_map_memory((void *) iomem_start, region->fd, 0,
+				    region->size, 1, 1, 0);
+		if (err)
+			printk(KERN_ERR "Mapping iomem region for driver '%s' "
+			       "failed, errno = %d\n", region->driver, -err);
+		else {
+			region->virt = iomem_start;
+			region->phys = __pa(region->virt);
+		}
+
+		iomem_start += region->size + PAGE_SIZE;
+		region = region->next;
+	}
+
+	return 0;
+}
+
+__initcall(setup_iomem);