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minix/servers/vm/mmap.c
Ben Gras d343041caa VM: make mapping types explicit 
Introduce explicit abstractions for different mapping types,
handling the instantiation, forking, pagefaults and freeing of
anonymous memory, direct physical mappings, shared memory and
physically contiguous anonymous memory as separate types, making
region.c more generic.

Also some other genericification like merging the 3 munmap cases
into one.

COW and SMAP safemap code is still implicit in region.c.
2012-10-12 14:52:01 +02:00

388 lines
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#define _SYSTEM 1
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/ds.h>
#include <minix/endpoint.h>
#include <minix/keymap.h>
#include <minix/minlib.h>
#include <minix/type.h>
#include <minix/ipc.h>
#include <minix/sysutil.h>
#include <minix/syslib.h>
#include <minix/safecopies.h>
#include <minix/bitmap.h>
#include <minix/debug.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <errno.h>
#include <assert.h>
#include <string.h>
#include <env.h>
#include <stdio.h>
#include <fcntl.h>
#include <memory.h>
#include "glo.h"
#include "proto.h"
#include "util.h"
#include "region.h"
/*===========================================================================*
* do_mmap *
*===========================================================================*/
int do_mmap(message *m)
{
int r, n;
struct vmproc *vmp;
int mfflags = 0;
vir_bytes addr;
struct vir_region *vr = NULL;
int execpriv = 0;
/* RS and VFS can do slightly more special mmap() things */
if(m->m_source == VFS_PROC_NR || m->m_source == RS_PROC_NR)
execpriv = 1;
if(m->VMM_FLAGS & MAP_THIRDPARTY) {
if(!execpriv) return EPERM;
if((r=vm_isokendpt(m->VMM_FORWHOM, &n)) != OK)
return ESRCH;
} else {
/* regular mmap, i.e. for caller */
if((r=vm_isokendpt(m->m_source, &n)) != OK) {
panic("do_mmap: message from strange source: %d",
m->m_source);
}
}
vmp = &vmproc[n];
if(m->VMM_FD == -1 || (m->VMM_FLAGS & MAP_ANON)) {
mem_type_t *mt;
u32_t vrflags = VR_ANON | VR_WRITABLE;
size_t len = (vir_bytes) m->VMM_LEN;
if(m->VMM_FD != -1 || len <= 0) {
return EINVAL;
}
/* Contiguous phys memory has to be preallocated. */
if((m->VMM_FLAGS & (MAP_CONTIG|MAP_PREALLOC)) == MAP_CONTIG) {
return EINVAL;
}
if(m->VMM_FLAGS & MAP_PREALLOC) mfflags |= MF_PREALLOC;
if(m->VMM_FLAGS & MAP_LOWER16M) vrflags |= VR_LOWER16MB;
if(m->VMM_FLAGS & MAP_LOWER1M) vrflags |= VR_LOWER1MB;
if(m->VMM_FLAGS & MAP_ALIGN64K) vrflags |= VR_PHYS64K;
if(m->VMM_FLAGS & MAP_UNINITIALIZED) {
if(!execpriv) return EPERM;
vrflags |= VR_UNINITIALIZED;
}
if(m->VMM_FLAGS & MAP_CONTIG) {
vrflags |= VR_CONTIG;
mt = &mem_type_anon_contig;
} else mt = &mem_type_anon;
if(len % VM_PAGE_SIZE)
len += VM_PAGE_SIZE - (len % VM_PAGE_SIZE);
vr = NULL;
if (m->VMM_ADDR || (m->VMM_FLAGS & MAP_FIXED)) {
/* An address is given, first try at that address. */
addr = m->VMM_ADDR;
vr = map_page_region(vmp, addr, 0, len,
vrflags, mfflags, mt);
if(!vr && (m->VMM_FLAGS & MAP_FIXED))
return ENOMEM;
}
if (!vr) {
/* No address given or address already in use. */
vr = map_page_region(vmp, 0, VM_DATATOP, len,
vrflags, mfflags, mt);
}
if (!vr) {
return ENOMEM;
}
} else {
return ENOSYS;
}
/* Return mapping, as seen from process. */
assert(vr);
m->VMM_RETADDR = vr->vaddr;
return OK;
}
/*===========================================================================*
* map_perm_check *
*===========================================================================*/
int map_perm_check(endpoint_t caller, endpoint_t target,
phys_bytes physaddr, phys_bytes len)
{
int r;
/* TTY and memory are allowed to do anything.
* They have to be special cases as they have to be able to do
* anything; TTY even on behalf of anyone for the TIOCMAPMEM
* ioctl. MEM just for itself.
*/
if(caller == TTY_PROC_NR)
return OK;
if(caller != target)
return EPERM;
if(caller == MEM_PROC_NR)
return OK;
/* Anyone else needs explicit permission from the kernel (ultimately
* set by PCI).
*/
r = sys_privquery_mem(caller, physaddr, len);
return r;
}
/*===========================================================================*
* do_map_phys *
*===========================================================================*/
int do_map_phys(message *m)
{
int r, n;
struct vmproc *vmp;
endpoint_t target;
struct vir_region *vr;
vir_bytes len;
phys_bytes startaddr;
size_t offset;
target = m->VMMP_EP;
len = m->VMMP_LEN;
if (len <= 0) return EINVAL;
if(target == SELF)
target = m->m_source;
if((r=vm_isokendpt(target, &n)) != OK)
return EINVAL;
startaddr = (vir_bytes)m->VMMP_PHADDR;
/* First check permission, then round range down/up. Caller can't
* help it if we can't map in lower than page granularity.
*/
if(map_perm_check(m->m_source, target, startaddr, len) != OK) {
printf("VM: unauthorized mapping of 0x%lx by %d\n",
startaddr, m->m_source);
return EPERM;
}
vmp = &vmproc[n];
offset = startaddr % VM_PAGE_SIZE;
len += offset;
startaddr -= offset;
if(len % VM_PAGE_SIZE)
len += VM_PAGE_SIZE - (len % VM_PAGE_SIZE);
if(!(vr = map_page_region(vmp, 0, VM_DATATOP, len,
VR_DIRECT | VR_WRITABLE, 0, &mem_type_directphys))) {
return ENOMEM;
}
phys_setphys(vr, startaddr);
m->VMMP_VADDR_REPLY = (void *) (vr->vaddr + offset);
return OK;
}
/*===========================================================================*
* do_remap *
*===========================================================================*/
int do_remap(message *m)
{
int dn, sn;
vir_bytes da, sa;
size_t size;
u32_t flags;
struct vir_region *src_region, *vr;
struct vmproc *dvmp, *svmp;
int r;
int readonly;
if(m->m_type == VM_REMAP)
readonly = 0;
else if(m->m_type == VM_REMAP_RO)
readonly = 1;
else panic("do_remap: can't be");
da = (vir_bytes) m->VMRE_DA;
sa = (vir_bytes) m->VMRE_SA;
size = m->VMRE_SIZE;
if (size <= 0) return EINVAL;
if ((r = vm_isokendpt((endpoint_t) m->VMRE_D, &dn)) != OK)
return EINVAL;
if ((r = vm_isokendpt((endpoint_t) m->VMRE_S, &sn)) != OK)
return EINVAL;
dvmp = &vmproc[dn];
svmp = &vmproc[sn];
if (!(src_region = map_lookup(svmp, sa, NULL)))
return EINVAL;
if(src_region->vaddr != sa) {
printf("VM: do_remap: not start of region.\n");
return EFAULT;
}
if (size % VM_PAGE_SIZE)
size += VM_PAGE_SIZE - size % VM_PAGE_SIZE;
if(size != src_region->length) {
printf("VM: do_remap: not size of region.\n");
return EFAULT;
}
flags = VR_SHARED;
if(!readonly)
flags |= VR_WRITABLE;
if(da)
vr = map_page_region(dvmp, da, 0, size, flags, 0,
&mem_type_shared);
else
vr = map_page_region(dvmp, 0, VM_DATATOP, size, flags, 0,
&mem_type_shared);
if(!vr) {
printf("VM: re-map of shared area failed\n");
return ENOMEM;
}
shared_setsource(vr, svmp->vm_endpoint, src_region);
m->VMRE_RETA = (char *) vr->vaddr;
return OK;
}
/*===========================================================================*
* do_get_phys *
*===========================================================================*/
int do_get_phys(message *m)
{
int r, n;
struct vmproc *vmp;
endpoint_t target;
phys_bytes ret;
vir_bytes addr;
target = m->VMPHYS_ENDPT;
addr = m->VMPHYS_ADDR;
if ((r = vm_isokendpt(target, &n)) != OK)
return EINVAL;
vmp = &vmproc[n];
r = map_get_phys(vmp, addr, &ret);
m->VMPHYS_RETA = ret;
return r;
}
/*===========================================================================*
* do_get_refcount *
*===========================================================================*/
int do_get_refcount(message *m)
{
int r, n;
struct vmproc *vmp;
endpoint_t target;
u8_t cnt;
vir_bytes addr;
target = m->VMREFCNT_ENDPT;
addr = m->VMREFCNT_ADDR;
if ((r = vm_isokendpt(target, &n)) != OK)
return EINVAL;
vmp = &vmproc[n];
r = map_get_ref(vmp, addr, &cnt);
m->VMREFCNT_RETC = cnt;
return r;
}
/*===========================================================================*
* do_munmap *
*===========================================================================*/
int do_munmap(message *m)
{
int r, n;
struct vmproc *vmp;
vir_bytes addr, len, offset;
struct vir_region *vr;
endpoint_t target = SELF;
if(m->m_type == VM_UNMAP_PHYS) {
target = m->VMUP_EP;
} else if(m->m_type == VM_SHM_UNMAP) {
target = m->VMUN_ENDPT;
}
if(target == SELF)
target = m->m_source;
if((r=vm_isokendpt(target, &n)) != OK) {
panic("do_mmap: message from strange source: %d", m->m_source);
}
vmp = &vmproc[n];
if(m->m_type == VM_SHM_UNMAP) {
addr = (vir_bytes) m->VMUN_ADDR;
} else addr = (vir_bytes) m->VMUM_ADDR;
if(!(vr = map_lookup(vmp, addr, NULL))) {
printf("VM: unmap: virtual address %p not found in %d\n",
m->VMUM_ADDR, vmp->vm_endpoint);
return EFAULT;
}
if(addr % VM_PAGE_SIZE)
return EFAULT;
if(m->m_type == VM_SHM_UNMAP) {
len = vr->length;
} else len = roundup(m->VMUM_LEN, VM_PAGE_SIZE);
offset = addr - vr->vaddr;
if(offset + len > vr->length) {
printf("munmap: addr 0x%lx len 0x%lx spills out of region\n",
addr, len);
return EFAULT;
}
if(map_unmap_region(vmp, vr, offset, len) != OK)
panic("do_munmap: map_unmap_region failed");
return OK;
}
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