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// 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 <kern_util.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);
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.
*
* Creates an unlinked temporary file of size (len) 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) 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 reserve = reserve_end - start;
unsigned long map_size = len - reserve;
int err;
if (len <= reserve) {
os_warn("Too few physical memory! Needed=%lu, given=%lu\n",
reserve, len);
exit(1);
}
physmem_fd = create_mem_file(len);
err = os_map_memory((void *) reserve_end, physmem_fd, reserve,
map_size, 1, 1, 1);
if (err < 0) {
os_warn("setup_physmem - mapping %lu 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);
memblock_add(__pa(start), len);
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;
}
return fd;
}
EXPORT_SYMBOL(phys_mapping);
static int __init uml_mem_setup(char *line, int *add)
{
char *retptr;
*add = 0;
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"
);
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