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minix/servers/vm/arch/i386/pagetable.c
Kees Jongenburger b82f01ea69 arm:clarify pagetable code. 
Make it clear that non RW mapped memory is mapped RO.
2013-09-26 11:45:44 +02:00

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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/cpufeature.h>
#include <minix/bitmap.h>
#include <minix/debug.h>
#include <errno.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <env.h>
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include "proto.h"
#include "glo.h"
#include "util.h"
#include "vm.h"
#include "sanitycheck.h"
static int vm_self_pages;
/* PDE used to map in kernel, kernel physical address. */
#define MAX_PAGEDIR_PDES 5
static struct pdm {
int pdeno;
u32_t val;
phys_bytes phys;
u32_t *page_directories;
} pagedir_mappings[MAX_PAGEDIR_PDES];
static multiboot_module_t *kern_mb_mod = NULL;
static size_t kern_size = 0;
static int kern_start_pde = -1;
/* big page size available in hardware? */
static int bigpage_ok = 1;
/* Our process table entry. */
struct vmproc *vmprocess = &vmproc[VM_PROC_NR];
/* Spare memory, ready to go after initialization, to avoid a
* circular dependency on allocating memory and writing it into VM's
* page table.
*/
#if SANITYCHECKS
#define SPAREPAGES 200
#define STATIC_SPAREPAGES 190
#else
#ifdef __arm__
# define SPAREPAGES 150
# define STATIC_SPAREPAGES 140
#else
static u32_t global_bit = 0;
# define SPAREPAGES 20
# define STATIC_SPAREPAGES 15
#endif /* __arm__ */
#endif
#define SPAREPAGEDIRS 1
#define STATIC_SPAREPAGEDIRS 1
int missing_sparedirs = SPAREPAGEDIRS;
static struct {
void *pagedir;
phys_bytes phys;
} sparepagedirs[SPAREPAGEDIRS];
extern char _end;
#define is_staticaddr(v) ((vir_bytes) (v) < (vir_bytes) &_end)
#define MAX_KERNMAPPINGS 10
static struct {
phys_bytes phys_addr; /* Physical addr. */
phys_bytes len; /* Length in bytes. */
vir_bytes vir_addr; /* Offset in page table. */
int flags;
} kern_mappings[MAX_KERNMAPPINGS];
int kernmappings = 0;
/* Clicks must be pages, as
* - they must be page aligned to map them
* - they must be a multiple of the page size
* - it's inconvenient to have them bigger than pages, because we often want
* just one page
* May as well require them to be equal then.
*/
#if CLICK_SIZE != VM_PAGE_SIZE
#error CLICK_SIZE must be page size.
#endif
static void *spare_pagequeue;
static char static_sparepages[VM_PAGE_SIZE*STATIC_SPAREPAGES]
__aligned(VM_PAGE_SIZE);
#if defined(__arm__)
static char static_sparepagedirs[ARCH_PAGEDIR_SIZE*STATIC_SPAREPAGEDIRS + ARCH_PAGEDIR_SIZE] __aligned(ARCH_PAGEDIR_SIZE);
#endif
#if SANITYCHECKS
/*===========================================================================*
* pt_sanitycheck *
*===========================================================================*/
void pt_sanitycheck(pt_t *pt, char *file, int line)
{
/* Basic pt sanity check. */
int slot;
MYASSERT(pt);
MYASSERT(pt->pt_dir);
MYASSERT(pt->pt_dir_phys);
for(slot = 0; slot < ELEMENTS(vmproc); slot++) {
if(pt == &vmproc[slot].vm_pt)
break;
}
if(slot >= ELEMENTS(vmproc)) {
panic("pt_sanitycheck: passed pt not in any proc");
}
MYASSERT(usedpages_add(pt->pt_dir_phys, VM_PAGE_SIZE) == OK);
}
#endif
/*===========================================================================*
* findhole *
*===========================================================================*/
static u32_t findhole(int pages)
{
/* Find a space in the virtual address space of VM. */
u32_t curv;
int pde = 0, try_restart;
static u32_t lastv = 0;
pt_t *pt = &vmprocess->vm_pt;
vir_bytes vmin, vmax;
u32_t holev = NO_MEM;
int holesize = -1;
vmin = (vir_bytes) (&_end); /* marks end of VM BSS */
vmin += 1024*1024*1024; /* reserve 1GB virtual address space for VM heap */
vmin &= ARCH_VM_ADDR_MASK;
vmax = vmin + 100 * 1024 * 1024; /* allow 100MB of address space for VM */
/* Input sanity check. */
assert(vmin + VM_PAGE_SIZE >= vmin);
assert(vmax >= vmin + VM_PAGE_SIZE);
assert((vmin % VM_PAGE_SIZE) == 0);
assert((vmax % VM_PAGE_SIZE) == 0);
assert(pages > 0);
curv = lastv;
if(curv < vmin || curv >= vmax)
curv = vmin;
try_restart = 1;
/* Start looking for a free page starting at vmin. */
while(curv < vmax) {
int pte;
assert(curv >= vmin);
assert(curv < vmax);
pde = ARCH_VM_PDE(curv);
pte = ARCH_VM_PTE(curv);
if((pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT) &&
(pt->pt_pt[pde][pte] & ARCH_VM_PTE_PRESENT)) {
/* there is a page here - so keep looking for holes */
holev = NO_MEM;
holesize = 0;
} else {
/* there is no page here - so we have a hole, a bigger
* one if we already had one
*/
if(holev == NO_MEM) {
holev = curv;
holesize = 1;
} else holesize++;
assert(holesize > 0);
assert(holesize <= pages);
/* if it's big enough, return it */
if(holesize == pages) {
lastv = curv + VM_PAGE_SIZE;
return holev;
}
}
curv+=VM_PAGE_SIZE;
/* if we reached the limit, start scanning from the beginning if
* we haven't looked there yet
*/
if(curv >= vmax && try_restart) {
try_restart = 0;
curv = vmin;
}
}
printf("VM: out of virtual address space in vm\n");
return NO_MEM;
}
/*===========================================================================*
* vm_freepages *
*===========================================================================*/
void vm_freepages(vir_bytes vir, int pages)
{
assert(!(vir % VM_PAGE_SIZE));
if(is_staticaddr(vir)) {
printf("VM: not freeing static page\n");
return;
}
if(pt_writemap(vmprocess, &vmprocess->vm_pt, vir,
MAP_NONE, pages*VM_PAGE_SIZE, 0,
WMF_OVERWRITE | WMF_FREE) != OK)
panic("vm_freepages: pt_writemap failed");
vm_self_pages--;
#if SANITYCHECKS
/* If SANITYCHECKS are on, flush tlb so accessing freed pages is
* always trapped, also if not in tlb.
*/
if((sys_vmctl(SELF, VMCTL_FLUSHTLB, 0)) != OK) {
panic("VMCTL_FLUSHTLB failed");
}
#endif
}
/*===========================================================================*
* vm_getsparepage *
*===========================================================================*/
static void *vm_getsparepage(phys_bytes *phys)
{
void *ptr;
if(reservedqueue_alloc(spare_pagequeue, phys, &ptr) != OK) {
printf("vm_getsparepage: no spare found\n");
return NULL;
}
assert(ptr);
return ptr;
}
/*===========================================================================*
* vm_getsparepagedir *
*===========================================================================*/
static void *vm_getsparepagedir(phys_bytes *phys)
{
int s;
assert(missing_sparedirs >= 0 && missing_sparedirs <= SPAREPAGEDIRS);
for(s = 0; s < SPAREPAGEDIRS; s++) {
if(sparepagedirs[s].pagedir) {
void *sp;
sp = sparepagedirs[s].pagedir;
*phys = sparepagedirs[s].phys;
sparepagedirs[s].pagedir = NULL;
missing_sparedirs++;
assert(missing_sparedirs >= 0 && missing_sparedirs <= SPAREPAGEDIRS);
return sp;
}
}
return NULL;
}
void *vm_mappages(phys_bytes p, int pages)
{
vir_bytes loc;
int r;
pt_t *pt = &vmprocess->vm_pt;
/* Where in our virtual address space can we put it? */
loc = findhole(pages);
if(loc == NO_MEM) {
printf("vm_mappages: findhole failed\n");
return NULL;
}
/* Map this page into our address space. */
if((r=pt_writemap(vmprocess, pt, loc, p, VM_PAGE_SIZE*pages,
ARCH_VM_PTE_PRESENT | ARCH_VM_PTE_USER | ARCH_VM_PTE_RW
#if defined(__arm__)
| ARM_VM_PTE_WT
#endif
, 0)) != OK) {
printf("vm_mappages writemap failed\n");
return NULL;
}
if((r=sys_vmctl(SELF, VMCTL_FLUSHTLB, 0)) != OK) {
panic("VMCTL_FLUSHTLB failed: %d", r);
}
assert(loc);
return (void *) loc;
}
static int pt_init_done;
/*===========================================================================*
* vm_allocpage *
*===========================================================================*/
void *vm_allocpages(phys_bytes *phys, int reason, int pages)
{
/* Allocate a page for use by VM itself. */
phys_bytes newpage;
static int level = 0;
void *ret;
u32_t mem_flags = 0;
assert(reason >= 0 && reason < VMP_CATEGORIES);
assert(pages > 0);
level++;
assert(level >= 1);
assert(level <= 2);
if((level > 1) || !pt_init_done) {
void *s;
if(pages == 1) s=vm_getsparepage(phys);
else if(pages == 4) s=vm_getsparepagedir(phys);
else panic("%d pages", pages);
level--;
if(!s) {
util_stacktrace();
printf("VM: warning: out of spare pages\n");
}
if(!is_staticaddr(s)) vm_self_pages++;
return s;
}
#if defined(__arm__)
if (reason == VMP_PAGEDIR) {
mem_flags |= PAF_ALIGN16K;
}
#endif
/* Allocate page of memory for use by VM. As VM
* is trusted, we don't have to pre-clear it.
*/
if((newpage = alloc_mem(pages, mem_flags)) == NO_MEM) {
level--;
printf("VM: vm_allocpage: alloc_mem failed\n");
return NULL;
}
*phys = CLICK2ABS(newpage);
if(!(ret = vm_mappages(*phys, pages))) {
level--;
printf("VM: vm_allocpage: vm_mappages failed\n");
return NULL;
}
level--;
vm_self_pages++;
return ret;
}
void *vm_allocpage(phys_bytes *phys, int reason)
{
return vm_allocpages(phys, reason, 1);
}
/*===========================================================================*
* vm_pagelock *
*===========================================================================*/
void vm_pagelock(void *vir, int lockflag)
{
/* Mark a page allocated by vm_allocpage() unwritable, i.e. only for VM. */
vir_bytes m = (vir_bytes) vir;
int r;
u32_t flags = ARCH_VM_PTE_PRESENT | ARCH_VM_PTE_USER;
pt_t *pt;
pt = &vmprocess->vm_pt;
assert(!(m % VM_PAGE_SIZE));
if(!lockflag)
flags |= ARCH_VM_PTE_RW;
#if defined(__arm__)
else
flags |= ARCH_VM_PTE_RO;
flags |= ARM_VM_PTE_WT ;
#endif
/* Update flags. */
if((r=pt_writemap(vmprocess, pt, m, 0, VM_PAGE_SIZE,
flags, WMF_OVERWRITE | WMF_WRITEFLAGSONLY)) != OK) {
panic("vm_lockpage: pt_writemap failed");
}
if((r=sys_vmctl(SELF, VMCTL_FLUSHTLB, 0)) != OK) {
panic("VMCTL_FLUSHTLB failed: %d", r);
}
return;
}
/*===========================================================================*
* vm_addrok *
*===========================================================================*/
int vm_addrok(void *vir, int writeflag)
{
pt_t *pt = &vmprocess->vm_pt;
int pde, pte;
vir_bytes v = (vir_bytes) vir;
pde = ARCH_VM_PDE(v);
pte = ARCH_VM_PTE(v);
if(!(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT)) {
printf("addr not ok: missing pde %d\n", pde);
return 0;
}
#if defined(__i386__)
if(writeflag &&
!(pt->pt_dir[pde] & ARCH_VM_PTE_RW)) {
printf("addr not ok: pde %d present but pde unwritable\n", pde);
return 0;
}
#elif defined(__arm__)
if(writeflag &&
(pt->pt_dir[pde] & ARCH_VM_PTE_RO)) {
printf("addr not ok: pde %d present but pde unwritable\n", pde);
return 0;
}
#endif
if(!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_PRESENT)) {
printf("addr not ok: missing pde %d / pte %d\n",
pde, pte);
return 0;
}
#if defined(__i386__)
if(writeflag &&
!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_RW)) {
printf("addr not ok: pde %d / pte %d present but unwritable\n",
pde, pte);
#elif defined(__arm__)
if(writeflag &&
(pt->pt_pt[pde][pte] & ARCH_VM_PTE_RO)) {
printf("addr not ok: pde %d / pte %d present but unwritable\n",
pde, pte);
#endif
return 0;
}
return 1;
}
/*===========================================================================*
* pt_ptalloc *
*===========================================================================*/
static int pt_ptalloc(pt_t *pt, int pde, u32_t flags)
{
/* Allocate a page table and write its address into the page directory. */
int i;
phys_bytes pt_phys;
/* Argument must make sense. */
assert(pde >= 0 && pde < ARCH_VM_DIR_ENTRIES);
assert(!(flags & ~(PTF_ALLFLAGS)));
/* We don't expect to overwrite page directory entry, nor
* storage for the page table.
*/
assert(!(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT));
assert(!pt->pt_pt[pde]);
/* Get storage for the page table. */
if(!(pt->pt_pt[pde] = vm_allocpage(&pt_phys, VMP_PAGETABLE)))
return ENOMEM;
for(i = 0; i < ARCH_VM_PT_ENTRIES; i++)
pt->pt_pt[pde][i] = 0; /* Empty entry. */
/* Make page directory entry.
* The PDE is always 'present,' 'writable,' and 'user accessible,'
* relying on the PTE for protection.
*/
#if defined(__i386__)
pt->pt_dir[pde] = (pt_phys & ARCH_VM_ADDR_MASK) | flags
| ARCH_VM_PDE_PRESENT | ARCH_VM_PTE_USER | ARCH_VM_PTE_RW;
#elif defined(__arm__)
pt->pt_dir[pde] = (pt_phys & ARCH_VM_PDE_MASK)
| ARCH_VM_PDE_PRESENT | ARM_VM_PDE_DOMAIN; //LSC FIXME
#endif
return OK;
}
/*===========================================================================*
* pt_ptalloc_in_range *
*===========================================================================*/
int pt_ptalloc_in_range(pt_t *pt, vir_bytes start, vir_bytes end,
u32_t flags, int verify)
{
/* Allocate all the page tables in the range specified. */
int pde, first_pde, last_pde;
first_pde = ARCH_VM_PDE(start);
last_pde = ARCH_VM_PDE(end-1);
assert(first_pde >= 0);
assert(last_pde < ARCH_VM_DIR_ENTRIES);
/* Scan all page-directory entries in the range. */
for(pde = first_pde; pde <= last_pde; pde++) {
assert(!(pt->pt_dir[pde] & ARCH_VM_BIGPAGE));
if(!(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT)) {
int r;
if(verify) {
printf("pt_ptalloc_in_range: no pde %d\n", pde);
return EFAULT;
}
assert(!pt->pt_dir[pde]);
if((r=pt_ptalloc(pt, pde, flags)) != OK) {
/* Couldn't do (complete) mapping.
* Don't bother freeing any previously
* allocated page tables, they're
* still writable, don't point to nonsense,
* and pt_ptalloc leaves the directory
* and other data in a consistent state.
*/
return r;
}
assert(pt->pt_pt[pde]);
}
assert(pt->pt_pt[pde]);
assert(pt->pt_dir[pde]);
assert(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT);
}
return OK;
}
static const char *ptestr(u32_t pte)
{
#define FLAG(constant, name) { \
if(pte & (constant)) { strcat(str, name); strcat(str, " "); } \
}
static char str[30];
if(!(pte & ARCH_VM_PTE_PRESENT)) {
return "not present";
}
str[0] = '\0';
#if defined(__i386__)
FLAG(ARCH_VM_PTE_RW, "W");
#elif defined(__arm__)
if(pte & ARCH_VM_PTE_RO) {
strcat(str, "R ");
} else {
strcat(str, "W ");
}
#endif
FLAG(ARCH_VM_PTE_USER, "U");
#if defined(__i386__)
FLAG(I386_VM_PWT, "PWT");
FLAG(I386_VM_PCD, "PCD");
FLAG(I386_VM_ACC, "ACC");
FLAG(I386_VM_DIRTY, "DIRTY");
FLAG(I386_VM_PS, "PS");
FLAG(I386_VM_GLOBAL, "G");
FLAG(I386_VM_PTAVAIL1, "AV1");
FLAG(I386_VM_PTAVAIL2, "AV2");
FLAG(I386_VM_PTAVAIL3, "AV3");
#elif defined(__arm__)
FLAG(ARM_VM_PTE_SUPER, "S");
FLAG(ARM_VM_PTE_S, "SH");
FLAG(ARM_VM_PTE_WB, "WB");
FLAG(ARM_VM_PTE_WT, "WT");
#endif
return str;
}
/*===========================================================================*
* pt_map_in_range *
*===========================================================================*/
int pt_map_in_range(struct vmproc *src_vmp, struct vmproc *dst_vmp,
vir_bytes start, vir_bytes end)
{
/* Transfer all the mappings from the pt of the source process to the pt of
* the destination process in the range specified.
*/
int pde, pte;
vir_bytes viraddr;
pt_t *pt, *dst_pt;
pt = &src_vmp->vm_pt;
dst_pt = &dst_vmp->vm_pt;
end = end ? end : VM_DATATOP;
assert(start % VM_PAGE_SIZE == 0);
assert(end % VM_PAGE_SIZE == 0);
assert( /* ARCH_VM_PDE(start) >= 0 && */ start <= end);
assert(ARCH_VM_PDE(end) < ARCH_VM_DIR_ENTRIES);
#if LU_DEBUG
printf("VM: pt_map_in_range: src = %d, dst = %d\n",
src_vmp->vm_endpoint, dst_vmp->vm_endpoint);
printf("VM: pt_map_in_range: transferring from 0x%08x (pde %d pte %d) to 0x%08x (pde %d pte %d)\n",
start, ARCH_VM_PDE(start), ARCH_VM_PTE(start),
end, ARCH_VM_PDE(end), ARCH_VM_PTE(end));
#endif
/* Scan all page-table entries in the range. */
for(viraddr = start; viraddr <= end; viraddr += VM_PAGE_SIZE) {
pde = ARCH_VM_PDE(viraddr);
if(!(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT)) {
if(viraddr == VM_DATATOP) break;
continue;
}
pte = ARCH_VM_PTE(viraddr);
if(!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_PRESENT)) {
if(viraddr == VM_DATATOP) break;
continue;
}
/* Transfer the mapping. */
dst_pt->pt_pt[pde][pte] = pt->pt_pt[pde][pte];
if(viraddr == VM_DATATOP) break;
}
return OK;
}
/*===========================================================================*
* pt_ptmap *
*===========================================================================*/
int pt_ptmap(struct vmproc *src_vmp, struct vmproc *dst_vmp)
{
/* Transfer mappings to page dir and page tables from source process and
* destination process. Make sure all the mappings are above the stack, not
* to corrupt valid mappings in the data segment of the destination process.
*/
int pde, r;
phys_bytes physaddr;
vir_bytes viraddr;
pt_t *pt;
pt = &src_vmp->vm_pt;
#if LU_DEBUG
printf("VM: pt_ptmap: src = %d, dst = %d\n",
src_vmp->vm_endpoint, dst_vmp->vm_endpoint);
#endif
/* Transfer mapping to the page directory. */
viraddr = (vir_bytes) pt->pt_dir;
physaddr = pt->pt_dir_phys & ARCH_VM_ADDR_MASK;
#if defined(__i386__)
if((r=pt_writemap(dst_vmp, &dst_vmp->vm_pt, viraddr, physaddr, VM_PAGE_SIZE,
ARCH_VM_PTE_PRESENT | ARCH_VM_PTE_USER | ARCH_VM_PTE_RW,
#elif defined(__arm__)
if((r=pt_writemap(dst_vmp, &dst_vmp->vm_pt, viraddr, physaddr, ARCH_PAGEDIR_SIZE,
ARCH_VM_PTE_PRESENT | ARCH_VM_PTE_USER |
ARM_VM_PTE_WT ,
#endif
WMF_OVERWRITE)) != OK) {
return r;
}
#if LU_DEBUG
printf("VM: pt_ptmap: transferred mapping to page dir: 0x%08x (0x%08x)\n",
viraddr, physaddr);
#endif
/* Scan all non-reserved page-directory entries. */
for(pde=0; pde < ARCH_VM_DIR_ENTRIES; pde++) {
if(!(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT)) {
continue;
}
/* Transfer mapping to the page table. */
viraddr = (vir_bytes) pt->pt_pt[pde];
#if defined(__i386__)
physaddr = pt->pt_dir[pde] & ARCH_VM_ADDR_MASK;
#elif defined(__arm__)
physaddr = pt->pt_dir[pde] & ARCH_VM_PDE_MASK;
#endif
if((r=pt_writemap(dst_vmp, &dst_vmp->vm_pt, viraddr, physaddr, VM_PAGE_SIZE,
ARCH_VM_PTE_PRESENT | ARCH_VM_PTE_USER | ARCH_VM_PTE_RW
#ifdef __arm__
| ARM_VM_PTE_WT
#endif
,
WMF_OVERWRITE)) != OK) {
return r;
}
}
return OK;
}
void pt_clearmapcache(void)
{
/* Make sure kernel will invalidate tlb when using current
* pagetable (i.e. vm's) to make new mappings before new cr3
* is loaded.
*/
if(sys_vmctl(SELF, VMCTL_CLEARMAPCACHE, 0) != OK)
panic("VMCTL_CLEARMAPCACHE failed");
}
int pt_writable(struct vmproc *vmp, vir_bytes v)
{
u32_t entry;
pt_t *pt = &vmp->vm_pt;
assert(!(v % VM_PAGE_SIZE));
int pde = ARCH_VM_PDE(v);
int pte = ARCH_VM_PTE(v);
assert(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT);
assert(pt->pt_pt[pde]);
entry = pt->pt_pt[pde][pte];
#if defined(__i386__)
return((entry & PTF_WRITE) ? 1 : 0);
#elif defined(__arm__)
return((entry & ARCH_VM_PTE_RO) ? 0 : 1);
#endif
}
/*===========================================================================*
* pt_writemap *
*===========================================================================*/
int pt_writemap(struct vmproc * vmp,
pt_t *pt,
vir_bytes v,
phys_bytes physaddr,
size_t bytes,
u32_t flags,
u32_t writemapflags)
{
/* Write mapping into page table. Allocate a new page table if necessary. */
/* Page directory and table entries for this virtual address. */
int p, pages;
int verify = 0;
int ret = OK;
#ifdef CONFIG_SMP
int vminhibit_clear = 0;
/* FIXME
* don't do it everytime, stop the process only on the first change and
* resume the execution on the last change. Do in a wrapper of this
* function
*/
if (vmp && vmp->vm_endpoint != NONE && vmp->vm_endpoint != VM_PROC_NR &&
!(vmp->vm_flags & VMF_EXITING)) {
sys_vmctl(vmp->vm_endpoint, VMCTL_VMINHIBIT_SET, 0);
vminhibit_clear = 1;
}
#endif
if(writemapflags & WMF_VERIFY)
verify = 1;
assert(!(bytes % VM_PAGE_SIZE));
assert(!(flags & ~(PTF_ALLFLAGS)));
pages = bytes / VM_PAGE_SIZE;
/* MAP_NONE means to clear the mapping. It doesn't matter
* what's actually written into the PTE if PRESENT
* isn't on, so we can just write MAP_NONE into it.
*/
assert(physaddr == MAP_NONE || (flags & ARCH_VM_PTE_PRESENT));
assert(physaddr != MAP_NONE || !flags);
/* First make sure all the necessary page tables are allocated,
* before we start writing in any of them, because it's a pain
* to undo our work properly.
*/
ret = pt_ptalloc_in_range(pt, v, v + VM_PAGE_SIZE*pages, flags, verify);
if(ret != OK) {
printf("VM: writemap: pt_ptalloc_in_range failed\n");
goto resume_exit;
}
/* Now write in them. */
for(p = 0; p < pages; p++) {
u32_t entry;
int pde = ARCH_VM_PDE(v);
int pte = ARCH_VM_PTE(v);
assert(!(v % VM_PAGE_SIZE));
assert(pte >= 0 && pte < ARCH_VM_PT_ENTRIES);
assert(pde >= 0 && pde < ARCH_VM_DIR_ENTRIES);
/* Page table has to be there. */
assert(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT);
/* We do not expect it to be a bigpage. */
assert(!(pt->pt_dir[pde] & ARCH_VM_BIGPAGE));
/* Make sure page directory entry for this page table
* is marked present and page table entry is available.
*/
assert(pt->pt_pt[pde]);
#if SANITYCHECKS
/* We don't expect to overwrite a page. */
if(!(writemapflags & (WMF_OVERWRITE|WMF_VERIFY)))
assert(!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_PRESENT));
#endif
if(writemapflags & (WMF_WRITEFLAGSONLY|WMF_FREE)) {
#if defined(__i386__)
physaddr = pt->pt_pt[pde][pte] & ARCH_VM_ADDR_MASK;
#elif defined(__arm__)
physaddr = pt->pt_pt[pde][pte] & ARM_VM_PTE_MASK;
#endif
}
if(writemapflags & WMF_FREE) {
free_mem(ABS2CLICK(physaddr), 1);
}
/* Entry we will write. */
#if defined(__i386__)
entry = (physaddr & ARCH_VM_ADDR_MASK) | flags;
#elif defined(__arm__)
entry = (physaddr & ARM_VM_PTE_MASK) | flags;
#endif
if(verify) {
u32_t maskedentry;
maskedentry = pt->pt_pt[pde][pte];
#if defined(__i386__)
maskedentry &= ~(I386_VM_ACC|I386_VM_DIRTY);
#endif
/* Verify pagetable entry. */
#if defined(__i386__)
if(entry & ARCH_VM_PTE_RW) {
/* If we expect a writable page, allow a readonly page. */
maskedentry |= ARCH_VM_PTE_RW;
}
#elif defined(__arm__)
if(!(entry & ARCH_VM_PTE_RO)) {
/* If we expect a writable page, allow a readonly page. */
maskedentry &= ~ARCH_VM_PTE_RO;
}
maskedentry &= ~(ARM_VM_PTE_WB|ARM_VM_PTE_WT);
#endif
if(maskedentry != entry) {
printf("pt_writemap: mismatch: ");
#if defined(__i386__)
if((entry & ARCH_VM_ADDR_MASK) !=
(maskedentry & ARCH_VM_ADDR_MASK)) {
#elif defined(__arm__)
if((entry & ARM_VM_PTE_MASK) !=
(maskedentry & ARM_VM_PTE_MASK)) {
#endif
printf("pt_writemap: physaddr mismatch (0x%lx, 0x%lx); ",
(long)entry, (long)maskedentry);
} else printf("phys ok; ");
printf(" flags: found %s; ",
ptestr(pt->pt_pt[pde][pte]));
printf(" masked %s; ",
ptestr(maskedentry));
printf(" expected %s\n", ptestr(entry));
printf("found 0x%x, wanted 0x%x\n",
pt->pt_pt[pde][pte], entry);
ret = EFAULT;
goto resume_exit;
}
} else {
/* Write pagetable entry. */
pt->pt_pt[pde][pte] = entry;
}
physaddr += VM_PAGE_SIZE;
v += VM_PAGE_SIZE;
}
resume_exit:
#ifdef CONFIG_SMP
if (vminhibit_clear) {
assert(vmp && vmp->vm_endpoint != NONE && vmp->vm_endpoint != VM_PROC_NR &&
!(vmp->vm_flags & VMF_EXITING));
sys_vmctl(vmp->vm_endpoint, VMCTL_VMINHIBIT_CLEAR, 0);
}
#endif
return ret;
}
/*===========================================================================*
* pt_checkrange *
*===========================================================================*/
int pt_checkrange(pt_t *pt, vir_bytes v, size_t bytes,
int write)
{
int p, pages;
assert(!(bytes % VM_PAGE_SIZE));
pages = bytes / VM_PAGE_SIZE;
for(p = 0; p < pages; p++) {
int pde = ARCH_VM_PDE(v);
int pte = ARCH_VM_PTE(v);
assert(!(v % VM_PAGE_SIZE));
assert(pte >= 0 && pte < ARCH_VM_PT_ENTRIES);
assert(pde >= 0 && pde < ARCH_VM_DIR_ENTRIES);
/* Page table has to be there. */
if(!(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT))
return EFAULT;
/* Make sure page directory entry for this page table
* is marked present and page table entry is available.
*/
assert((pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT) && pt->pt_pt[pde]);
if(!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_PRESENT)) {
return EFAULT;
}
#if defined(__i386__)
if(write && !(pt->pt_pt[pde][pte] & ARCH_VM_PTE_RW)) {
#elif defined(__arm__)
if(write && (pt->pt_pt[pde][pte] & ARCH_VM_PTE_RO)) {
#endif
return EFAULT;
}
v += VM_PAGE_SIZE;
}
return OK;
}
/*===========================================================================*
* pt_new *
*===========================================================================*/
int pt_new(pt_t *pt)
{
/* Allocate a pagetable root. Allocate a page-aligned page directory
* and set them to 0 (indicating no page tables are allocated). Lookup
* its physical address as we'll need that in the future. Verify it's
* page-aligned.
*/
int i, r;
/* Don't ever re-allocate/re-move a certain process slot's
* page directory once it's been created. This is a fraction
* faster, but also avoids having to invalidate the page
* mappings from in-kernel page tables pointing to
* the page directories (the page_directories data).
*/
if(!pt->pt_dir &&
!(pt->pt_dir = vm_allocpages((phys_bytes *)&pt->pt_dir_phys,
VMP_PAGEDIR, ARCH_PAGEDIR_SIZE/VM_PAGE_SIZE))) {
return ENOMEM;
}
assert(!((u32_t)pt->pt_dir_phys % ARCH_PAGEDIR_SIZE));
for(i = 0; i < ARCH_VM_DIR_ENTRIES; i++) {
pt->pt_dir[i] = 0; /* invalid entry (PRESENT bit = 0) */
pt->pt_pt[i] = NULL;
}
/* Where to start looking for free virtual address space? */
pt->pt_virtop = 0;
/* Map in kernel. */
if((r=pt_mapkernel(pt)) != OK)
return r;
return OK;
}
static int freepde(void)
{
int p = kernel_boot_info.freepde_start++;
assert(kernel_boot_info.freepde_start < ARCH_VM_DIR_ENTRIES);
return p;
}
/*===========================================================================*
* pt_init *
*===========================================================================*/
void pt_init(void)
{
pt_t *newpt;
int s, r, p;
vir_bytes sparepages_mem;
#if defined(__arm__)
vir_bytes sparepagedirs_mem;
#endif
static u32_t currentpagedir[ARCH_VM_DIR_ENTRIES];
int m = kernel_boot_info.kern_mod;
#if defined(__i386__)
int global_bit_ok = 0;
u32_t mypdbr; /* Page Directory Base Register (cr3) value */
#elif defined(__arm__)
u32_t myttbr;
#endif
/* Find what the physical location of the kernel is. */
assert(m >= 0);
assert(m < kernel_boot_info.mods_with_kernel);
assert(kernel_boot_info.mods_with_kernel < MULTIBOOT_MAX_MODS);
kern_mb_mod = &kernel_boot_info.module_list[m];
kern_size = kern_mb_mod->mod_end - kern_mb_mod->mod_start;
assert(!(kern_mb_mod->mod_start % ARCH_BIG_PAGE_SIZE));
assert(!(kernel_boot_info.vir_kern_start % ARCH_BIG_PAGE_SIZE));
kern_start_pde = kernel_boot_info.vir_kern_start / ARCH_BIG_PAGE_SIZE;
/* Get ourselves spare pages. */
sparepages_mem = (vir_bytes) static_sparepages;
assert(!(sparepages_mem % VM_PAGE_SIZE));
#if defined(__arm__)
/* Get ourselves spare pagedirs. */
sparepagedirs_mem = (vir_bytes) static_sparepagedirs;
assert(!(sparepagedirs_mem % ARCH_PAGEDIR_SIZE));
#endif
/* Spare pages are used to allocate memory before VM has its own page
* table that things (i.e. arbitrary physical memory) can be mapped into.
* We get it by pre-allocating it in our bss (allocated and mapped in by
* the kernel) in static_sparepages. We also need the physical addresses
* though; we look them up now so they are ready for use.
*/
#if defined(__arm__)
missing_sparedirs = 0;
assert(STATIC_SPAREPAGEDIRS <= SPAREPAGEDIRS);
for(s = 0; s < SPAREPAGEDIRS; s++) {
vir_bytes v = (sparepagedirs_mem + s*ARCH_PAGEDIR_SIZE);;
phys_bytes ph;
if((r=sys_umap(SELF, VM_D, (vir_bytes) v,
ARCH_PAGEDIR_SIZE, &ph)) != OK)
panic("pt_init: sys_umap failed: %d", r);
if(s >= STATIC_SPAREPAGEDIRS) {
sparepagedirs[s].pagedir = NULL;
missing_sparedirs++;
continue;
}
sparepagedirs[s].pagedir = (void *) v;
sparepagedirs[s].phys = ph;
}
#endif
if(!(spare_pagequeue = reservedqueue_new(SPAREPAGES, 1, 1, 0)))
panic("reservedqueue_new for single pages failed");
assert(STATIC_SPAREPAGES < SPAREPAGES);
for(s = 0; s < STATIC_SPAREPAGES; s++) {
void *v = (void *) (sparepages_mem + s*VM_PAGE_SIZE);
phys_bytes ph;
if((r=sys_umap(SELF, VM_D, (vir_bytes) v,
VM_PAGE_SIZE*SPAREPAGES, &ph)) != OK)
panic("pt_init: sys_umap failed: %d", r);
reservedqueue_add(spare_pagequeue, v, ph);
}
#if defined(__i386__)
/* global bit and 4MB pages available? */
global_bit_ok = _cpufeature(_CPUF_I386_PGE);
bigpage_ok = _cpufeature(_CPUF_I386_PSE);
/* Set bit for PTE's and PDE's if available. */
if(global_bit_ok)
global_bit = I386_VM_GLOBAL;
#endif
/* Now reserve another pde for kernel's own mappings. */
{
int kernmap_pde;
phys_bytes addr, len;
int flags, pindex = 0;
u32_t offset = 0;
kernmap_pde = freepde();
offset = kernmap_pde * ARCH_BIG_PAGE_SIZE;
while(sys_vmctl_get_mapping(pindex, &addr, &len,
&flags) == OK) {
int usedpde;
vir_bytes vir;
if(pindex >= MAX_KERNMAPPINGS)
panic("VM: too many kernel mappings: %d", pindex);
kern_mappings[pindex].phys_addr = addr;
kern_mappings[pindex].len = len;
kern_mappings[pindex].flags = flags;
kern_mappings[pindex].vir_addr = offset;
kern_mappings[pindex].flags =
ARCH_VM_PTE_PRESENT;
if(flags & VMMF_UNCACHED)
#if defined(__i386__)
kern_mappings[pindex].flags |= PTF_NOCACHE;
#elif defined(__arm__)
kern_mappings[pindex].flags |= ARM_VM_PTE_DEVICE;
#endif
if(flags & VMMF_USER)
kern_mappings[pindex].flags |= ARCH_VM_PTE_USER;
#if defined(__arm__)
else
kern_mappings[pindex].flags |= ARM_VM_PTE_SUPER;
#endif
if(flags & VMMF_WRITE)
kern_mappings[pindex].flags |= ARCH_VM_PTE_RW;
#if defined(__arm__)
else
kern_mappings[pindex].flags |= ARCH_VM_PTE_RO;
#endif
#if defined(__i386__)
if(flags & VMMF_GLO)
kern_mappings[pindex].flags |= I386_VM_GLOBAL;
#endif
if(addr % VM_PAGE_SIZE)
panic("VM: addr unaligned: %lu", addr);
if(len % VM_PAGE_SIZE)
panic("VM: len unaligned: %lu", len);
vir = offset;
if(sys_vmctl_reply_mapping(pindex, vir) != OK)
panic("VM: reply failed");
offset += len;
pindex++;
kernmappings++;
usedpde = ARCH_VM_PDE(offset);
while(usedpde > kernmap_pde) {
int newpde = freepde();
assert(newpde == kernmap_pde+1);
kernmap_pde = newpde;
}
}
}
/* Reserve PDEs available for mapping in the page directories. */
{
int pd;
for(pd = 0; pd < MAX_PAGEDIR_PDES; pd++) {
struct pdm *pdm = &pagedir_mappings[pd];
pdm->pdeno = freepde();
phys_bytes ph;
/* Allocate us a page table in which to
* remember page directory pointers.
*/
if(!(pdm->page_directories =
vm_allocpage(&ph, VMP_PAGETABLE))) {
panic("no virt addr for vm mappings");
}
memset(pdm->page_directories, 0, VM_PAGE_SIZE);
pdm->phys = ph;
#if defined(__i386__)
pdm->val = (ph & ARCH_VM_ADDR_MASK) |
ARCH_VM_PDE_PRESENT | ARCH_VM_PTE_RW;
#elif defined(__arm__)
pdm->val = (ph & ARCH_VM_PDE_MASK)
| ARCH_VM_PDE_PRESENT
| ARM_VM_PDE_DOMAIN; //LSC FIXME
#endif
}
}
/* Allright. Now. We have to make our own page directory and page tables,
* that the kernel has already set up, accessible to us. It's easier to
* understand if we just copy all the required pages (i.e. page directory
* and page tables), and set up the pointers as if VM had done it itself.
*
* This allocation will happen without using any page table, and just
* uses spare pages.
*/
newpt = &vmprocess->vm_pt;
if(pt_new(newpt) != OK)
panic("vm pt_new failed");
/* Get our current pagedir so we can see it. */
#if defined(__i386__)
if(sys_vmctl_get_pdbr(SELF, &mypdbr) != OK)
#elif defined(__arm__)
if(sys_vmctl_get_pdbr(SELF, &myttbr) != OK)
#endif
panic("VM: sys_vmctl_get_pdbr failed");
#if defined(__i386__)
if(sys_vircopy(NONE, mypdbr, SELF,
(vir_bytes) currentpagedir, VM_PAGE_SIZE) != OK)
#elif defined(__arm__)
if(sys_vircopy(NONE, myttbr, SELF,
(vir_bytes) currentpagedir, ARCH_PAGEDIR_SIZE) != OK)
#endif
panic("VM: sys_vircopy failed");
/* We have mapped in kernel ourselves; now copy mappings for VM
* that kernel made, including allocations for BSS. Skip identity
* mapping bits; just map in VM.
*/
for(p = 0; p < ARCH_VM_DIR_ENTRIES; p++) {
u32_t entry = currentpagedir[p];
phys_bytes ptaddr_kern, ptaddr_us;
/* BIGPAGEs are kernel mapping (do ourselves) or boot
* identity mapping (don't want).
*/
if(!(entry & ARCH_VM_PDE_PRESENT)) continue;
if((entry & ARCH_VM_BIGPAGE)) continue;
if(pt_ptalloc(newpt, p, 0) != OK)
panic("pt_ptalloc failed");
assert(newpt->pt_dir[p] & ARCH_VM_PDE_PRESENT);
#if defined(__i386__)
ptaddr_kern = entry & ARCH_VM_ADDR_MASK;
ptaddr_us = newpt->pt_dir[p] & ARCH_VM_ADDR_MASK;
#elif defined(__arm__)
ptaddr_kern = entry & ARCH_VM_PDE_MASK;
ptaddr_us = newpt->pt_dir[p] & ARCH_VM_PDE_MASK;
#endif
/* Copy kernel-initialized pagetable contents into our
* normally accessible pagetable.
*/
if(sys_abscopy(ptaddr_kern, ptaddr_us, VM_PAGE_SIZE) != OK)
panic("pt_init: abscopy failed");
}
/* Inform kernel vm has a newly built page table. */
assert(vmproc[VM_PROC_NR].vm_endpoint == VM_PROC_NR);
pt_bind(newpt, &vmproc[VM_PROC_NR]);
pt_init_done = 1;
/* All OK. */
return;
}
/*===========================================================================*
* pt_bind *
*===========================================================================*/
int pt_bind(pt_t *pt, struct vmproc *who)
{
int procslot, pdeslot;
u32_t phys;
void *pdes;
int pagedir_pde;
int slots_per_pde;
int pages_per_pagedir = ARCH_PAGEDIR_SIZE/VM_PAGE_SIZE;
struct pdm *pdm;
slots_per_pde = ARCH_VM_PT_ENTRIES / pages_per_pagedir;
/* Basic sanity checks. */
assert(who);
assert(who->vm_flags & VMF_INUSE);
assert(pt);
procslot = who->vm_slot;
pdm = &pagedir_mappings[procslot/slots_per_pde];
pdeslot = procslot%slots_per_pde;
pagedir_pde = pdm->pdeno;
assert(pdeslot >= 0);
assert(procslot < ELEMENTS(vmproc));
assert(pdeslot < ARCH_VM_PT_ENTRIES / pages_per_pagedir);
assert(pagedir_pde >= 0);
#if defined(__i386__)
phys = pt->pt_dir_phys & ARCH_VM_ADDR_MASK;
#elif defined(__arm__)
phys = pt->pt_dir_phys & ARM_VM_PTE_MASK;
#endif
assert(pt->pt_dir_phys == phys);
assert(!(pt->pt_dir_phys % ARCH_PAGEDIR_SIZE));
/* Update "page directory pagetable." */
#if defined(__i386__)
pdm->page_directories[pdeslot] =
phys | ARCH_VM_PDE_PRESENT|ARCH_VM_PTE_RW;
#elif defined(__arm__)
{
int i;
for (i = 0; i < pages_per_pagedir; i++) {
pdm->page_directories[pdeslot*pages_per_pagedir+i] =
(phys+i*VM_PAGE_SIZE)
| ARCH_VM_PTE_PRESENT
| ARCH_VM_PTE_RW
| ARCH_VM_PTE_USER; //LSC FIXME
}
}
#endif
/* This is where the PDE's will be visible to the kernel
* in its address space.
*/
pdes = (void *) (pagedir_pde*ARCH_BIG_PAGE_SIZE +
#if defined(__i386__)
pdeslot * VM_PAGE_SIZE);
#elif defined(__arm__)
pdeslot * ARCH_PAGEDIR_SIZE);
#endif
/* Tell kernel about new page table root. */
return sys_vmctl_set_addrspace(who->vm_endpoint, pt->pt_dir_phys, pdes);
}
/*===========================================================================*
* pt_free *
*===========================================================================*/
void pt_free(pt_t *pt)
{
/* Free memory associated with this pagetable. */
int i;
for(i = 0; i < ARCH_VM_DIR_ENTRIES; i++)
if(pt->pt_pt[i])
vm_freepages((vir_bytes) pt->pt_pt[i], 1);
return;
}
/*===========================================================================*
* pt_mapkernel *
*===========================================================================*/
int pt_mapkernel(pt_t *pt)
{
int i;
int kern_pde = kern_start_pde;
phys_bytes addr, mapped = 0;
/* Any page table needs to map in the kernel address space. */
assert(bigpage_ok);
assert(kern_pde >= 0);
/* pt_init() has made sure this is ok. */
addr = kern_mb_mod->mod_start;
/* Actually mapping in kernel */
while(mapped < kern_size) {
#if defined(__i386__)
pt->pt_dir[kern_pde] = addr | ARCH_VM_PDE_PRESENT |
ARCH_VM_BIGPAGE | ARCH_VM_PTE_RW | global_bit;
#elif defined(__arm__)
pt->pt_dir[kern_pde] = (addr & ARM_VM_SECTION_MASK)
| ARM_VM_SECTION
| ARM_VM_SECTION_DOMAIN
| ARM_VM_SECTION_WT
| ARM_VM_SECTION_SUPER;
#endif
kern_pde++;
mapped += ARCH_BIG_PAGE_SIZE;
addr += ARCH_BIG_PAGE_SIZE;
}
/* Kernel also wants to know about all page directories. */
{
int pd;
for(pd = 0; pd < MAX_PAGEDIR_PDES; pd++) {
struct pdm *pdm = &pagedir_mappings[pd];
assert(pdm->pdeno > 0);
assert(pdm->pdeno > kern_pde);
pt->pt_dir[pdm->pdeno] = pdm->val;
}
}
/* Kernel also wants various mappings of its own. */
for(i = 0; i < kernmappings; i++) {
int r;
if((r=pt_writemap(NULL, pt,
kern_mappings[i].vir_addr,
kern_mappings[i].phys_addr,
kern_mappings[i].len,
kern_mappings[i].flags, 0)) != OK) {
return r;
}
}
return OK;
}
int get_vm_self_pages(void) { return vm_self_pages; }
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