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minix/servers/vm/i386/pagetable.c
Ben Gras ef8a741301 set global flag for kernel pages, so tlb entries for kernel aren't thrown 
away on cr3 reload. minor optimization.
2009-04-23 15:11:16 +00:00

948 lines
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#define _SYSTEM 1
#define VERBOSE 0
#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 <errno.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"
#include "memory.h"
/* Location in our virtual address space where we can map in
* any physical page we want.
*/
static unsigned char *varmap = NULL; /* Our address space. */
static u32_t varmap_loc; /* Our page table. */
/* Our process table entry. */
struct vmproc *vmp = &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.
*/
#define SPAREPAGES 3
static struct {
void *page;
u32_t phys;
} sparepages[SPAREPAGES];
/* 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 != I386_PAGE_SIZE
#error CLICK_SIZE must be page size.
#endif
/* Bytes of virtual address space one pde controls. */
#define BYTESPERPDE (I386_VM_PT_ENTRIES * I386_PAGE_SIZE)
/* Nevertheless, introduce these macros to make the code readable. */
#define CLICK2PAGE(c) ((c) / CLICKSPERPAGE)
#if SANITYCHECKS
#define PT_SANE(p) { pt_sanitycheck((p), __FILE__, __LINE__); SANITYCHECK(SCL_DETAIL); }
/*===========================================================================*
* pt_sanitycheck *
*===========================================================================*/
PUBLIC void pt_sanitycheck(pt_t *pt, char *file, int line)
{
/* Basic pt sanity check. */
int i;
MYASSERT(pt);
MYASSERT(pt->pt_dir);
MYASSERT(pt->pt_dir_phys);
for(i = 0; i < I386_VM_DIR_ENTRIES; i++) {
if(pt->pt_pt[i]) {
MYASSERT(pt->pt_dir[i] & I386_VM_PRESENT);
} else {
MYASSERT(!(pt->pt_dir[i] & I386_VM_PRESENT));
}
}
}
#else
#define PT_SANE(p)
#endif
/*===========================================================================*
* aalloc *
*===========================================================================*/
PRIVATE void *aalloc(size_t bytes)
{
/* Page-aligned malloc(). only used if vm_allocpages can't be used. */
u32_t b;
b = (u32_t) malloc(I386_PAGE_SIZE + bytes);
if(!b) vm_panic("aalloc: out of memory", bytes);
b += I386_PAGE_SIZE - (b % I386_PAGE_SIZE);
return (void *) b;
}
/*===========================================================================*
* findhole *
*===========================================================================*/
PRIVATE u32_t findhole(pt_t *pt, u32_t virbytes, u32_t vmin, u32_t vmax)
{
/* Find a space in the virtual address space of pageteble 'pt',
* between page-aligned BYTE offsets vmin and vmax, to fit
* 'virbytes' in. Return byte offset.
*
* As a simple way to speed up the search a bit, we start searching
* after the location we found the previous hole, if that's in range.
* If that's not in range (or if that doesn't work), search the entire
* range (as well). try_restart controls whether we have to restart
* the search if it fails. (Just once of course.)
*/
u32_t freeneeded, freefound = 0, freestart = 0, curv;
int pde = 0, try_restart;
/* Input sanity check. */
vm_assert(vmin + virbytes >= vmin);
vm_assert(vmax >= vmin + virbytes);
vm_assert((virbytes % I386_PAGE_SIZE) == 0);
vm_assert((vmin % I386_PAGE_SIZE) == 0);
vm_assert((vmax % I386_PAGE_SIZE) == 0);
/* How many pages do we need? */
freeneeded = virbytes / I386_PAGE_SIZE;
if(pt->pt_virtop >= vmin && pt->pt_virtop <= vmax - virbytes) {
curv = pt->pt_virtop;
try_restart = 1;
} else {
curv = vmin;
try_restart = 0;
}
/* Start looking for a consecutive block of free pages
* starting at vmin.
*/
for(freestart = curv; curv < vmax; ) {
int pte;
pde = I386_VM_PDE(curv);
pte = I386_VM_PTE(curv);
if(!(pt->pt_dir[pde] & I386_VM_PRESENT)) {
int rempte;
rempte = I386_VM_PT_ENTRIES - pte;
freefound += rempte;
curv += rempte * I386_PAGE_SIZE;
} else {
if(pt->pt_pt[pde][pte] & I386_VM_PRESENT) {
freefound = 0;
freestart = curv + I386_PAGE_SIZE;
} else {
freefound++;
}
curv+=I386_PAGE_SIZE;
}
if(freefound >= freeneeded) {
u32_t v;
v = freestart;
vm_assert(v != NO_MEM);
vm_assert(v >= vmin);
vm_assert(v < vmax);
/* Next time, start looking here. */
pt->pt_virtop = v + virbytes;
return v;
}
if(curv >= vmax && try_restart) {
curv = vmin;
try_restart = 0;
}
}
printf("VM: out of virtual address space in a process\n");
return NO_MEM;
}
/*===========================================================================*
* vm_freepages *
*===========================================================================*/
PRIVATE void vm_freepages(vir_bytes vir, vir_bytes phys, int pages, int reason)
{
vm_assert(reason >= 0 && reason < VMP_CATEGORIES);
if(vir >= vmp->vm_stacktop) {
vm_assert(!(vir % I386_PAGE_SIZE));
vm_assert(!(phys % I386_PAGE_SIZE));
FREE_MEM(ABS2CLICK(phys), pages);
if(pt_writemap(&vmp->vm_pt,
vir + CLICK2ABS(vmp->vm_arch.vm_seg[D].mem_phys),
MAP_NONE, pages*I386_PAGE_SIZE, 0, WMF_OVERWRITE) != OK)
vm_panic("vm_freepages: pt_writemap failed",
NO_NUM);
} else {
printf("VM: vm_freepages not freeing VM heap pages (%d)\n",
pages);
}
}
/*===========================================================================*
* vm_getsparepage *
*===========================================================================*/
PRIVATE void *vm_getsparepage(u32_t *phys)
{
int s;
for(s = 0; s < SPAREPAGES; s++) {
if(sparepages[s].page) {
void *sp;
sp = sparepages[s].page;
*phys = sparepages[s].phys;
sparepages[s].page = NULL;
return sp;
}
}
vm_panic("VM: out of spare pages", NO_NUM);
return NULL;
}
/*===========================================================================*
* vm_checkspares *
*===========================================================================*/
PRIVATE void *vm_checkspares(void)
{
int s, n = 0;
static int total = 0, worst = 0;
for(s = 0; s < SPAREPAGES; s++)
if(!sparepages[s].page) {
n++;
sparepages[s].page = vm_allocpages(&sparepages[s].phys, 1,
VMP_SPARE);
}
if(worst < n) worst = n;
total += n;
#if 0
if(n > 0)
printf("VM: made %d spares, total %d, worst %d\n", n, total, worst);
#endif
return NULL;
}
/*===========================================================================*
* vm_allocpages *
*===========================================================================*/
PUBLIC void *vm_allocpages(phys_bytes *phys, int pages, int reason)
{
/* Allocate a number of pages for use by VM itself. */
phys_bytes newpage;
vir_bytes loc;
pt_t *pt;
int r;
vir_bytes bytes = pages * I386_PAGE_SIZE;
static int level = 0;
#define MAXDEPTH 10
static int reasons[MAXDEPTH];
pt = &vmp->vm_pt;
vm_assert(reason >= 0 && reason < VMP_CATEGORIES);
vm_assert(pages > 0);
reasons[level++] = reason;
vm_assert(level >= 1);
vm_assert(level <= 2);
if(level > 1 || !(vmp->vm_flags & VMF_HASPT)) {
int r;
void *s;
vm_assert(pages == 1);
s=vm_getsparepage(phys);
level--;
return s;
}
/* VM does have a pagetable, so get a page and map it in there.
* Where in our virtual address space can we put it?
*/
loc = findhole(pt, I386_PAGE_SIZE * pages,
CLICK2ABS(vmp->vm_arch.vm_seg[D].mem_phys) + vmp->vm_stacktop,
vmp->vm_arch.vm_data_top);
if(loc == NO_MEM) {
level--;
return NULL;
}
/* Allocate 'pages' pages of memory for use by VM. As VM
* is trusted, we don't have to pre-clear it.
*/
if((newpage = ALLOC_MEM(CLICKSPERPAGE * pages, 0)) == NO_MEM) {
level--;
return NULL;
}
*phys = CLICK2ABS(newpage);
/* Map this page into our address space. */
if((r=pt_writemap(pt, loc, *phys, bytes,
I386_VM_PRESENT | I386_VM_USER | I386_VM_WRITE, 0)) != OK) {
FREE_MEM(newpage, CLICKSPERPAGE * pages / I386_PAGE_SIZE);
return NULL;
}
level--;
/* Return user-space-ready pointer to it. */
return (void *) (loc - CLICK2ABS(vmp->vm_arch.vm_seg[D].mem_phys));
}
/*===========================================================================*
* pt_ptalloc *
*===========================================================================*/
PRIVATE 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;
u32_t pt_phys;
/* Argument must make sense. */
vm_assert(pde >= 0 && pde < I386_VM_DIR_ENTRIES);
vm_assert(!(flags & ~(PTF_ALLFLAGS | PTF_MAPALLOC)));
/* We don't expect to overwrite page directory entry, nor
* storage for the page table.
*/
vm_assert(!(pt->pt_dir[pde] & I386_VM_PRESENT));
vm_assert(!pt->pt_pt[pde]);
PT_SANE(pt);
/* Get storage for the page table. */
if(!(pt->pt_pt[pde] = vm_allocpages(&pt_phys, 1, VMP_PAGETABLE)))
return ENOMEM;
for(i = 0; i < I386_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.
*/
pt->pt_dir[pde] = (pt_phys & I386_VM_ADDR_MASK) | flags
| I386_VM_PRESENT | I386_VM_USER | I386_VM_WRITE;
vm_assert(flags & I386_VM_PRESENT);
PT_SANE(pt);
return OK;
}
/*===========================================================================*
* pt_writemap *
*===========================================================================*/
PUBLIC int pt_writemap(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, pde;
SANITYCHECK(SCL_FUNCTIONS);
vm_assert(!(bytes % I386_PAGE_SIZE));
vm_assert(!(flags & ~(PTF_ALLFLAGS | PTF_MAPALLOC)));
pages = bytes / I386_PAGE_SIZE;
/* MAP_NONE means to clear the mapping. It doesn't matter
* what's actually written into the PTE if I386_VM_PRESENT
* isn't on, so we can just write MAP_NONE into it.
*/
#if SANITYCHECKS
if(physaddr != MAP_NONE && !(flags & I386_VM_PRESENT)) {
vm_panic("pt_writemap: writing dir with !P\n", NO_NUM);
}
if(physaddr == MAP_NONE && flags) {
vm_panic("pt_writemap: writing 0 with flags\n", NO_NUM);
}
#endif
PT_SANE(pt);
/* 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. Walk the range in page-directory-entry
* sized leaps.
*/
for(pde = I386_VM_PDE(v); pde <= I386_VM_PDE(v + I386_PAGE_SIZE * pages); pde++) {
vm_assert(pde >= 0 && pde < I386_VM_DIR_ENTRIES);
if(!(pt->pt_dir[pde] & I386_VM_PRESENT)) {
int r;
vm_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;
}
}
vm_assert(pt->pt_dir[pde] & I386_VM_PRESENT);
}
PT_SANE(pt);
/* Now write in them. */
for(p = 0; p < pages; p++) {
int pde = I386_VM_PDE(v);
int pte = I386_VM_PTE(v);
PT_SANE(pt);
vm_assert(!(v % I386_PAGE_SIZE));
vm_assert(pte >= 0 && pte < I386_VM_PT_ENTRIES);
vm_assert(pde >= 0 && pde < I386_VM_DIR_ENTRIES);
/* Page table has to be there. */
vm_assert(pt->pt_dir[pde] & I386_VM_PRESENT);
/* Make sure page directory entry for this page table
* is marked present and page table entry is available.
*/
vm_assert((pt->pt_dir[pde] & I386_VM_PRESENT) && pt->pt_pt[pde]);
PT_SANE(pt);
#if SANITYCHECKS
/* We don't expect to overwrite a page. */
if(!(writemapflags & WMF_OVERWRITE))
vm_assert(!(pt->pt_pt[pde][pte] & I386_VM_PRESENT));
#endif
/* Write pagetable entry. */
pt->pt_pt[pde][pte] = (physaddr & I386_VM_ADDR_MASK) | flags;
physaddr += I386_PAGE_SIZE;
v += I386_PAGE_SIZE;
PT_SANE(pt);
}
SANITYCHECK(SCL_FUNCTIONS);
PT_SANE(pt);
return OK;
}
/*===========================================================================*
* pt_new *
*===========================================================================*/
PUBLIC int pt_new(pt_t *pt)
{
/* Allocate a pagetable root. On i386, 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;
if(!(pt->pt_dir = vm_allocpages(&pt->pt_dir_phys, 1, VMP_PAGEDIR))) {
return ENOMEM;
}
for(i = 0; i < I386_VM_DIR_ENTRIES; i++) {
pt->pt_dir[i] = 0; /* invalid entry (I386_VM_PRESENT bit = 0) */
pt->pt_pt[i] = NULL;
}
/* Where to start looking for free virtual address space? */
pt->pt_virtop = VM_STACKTOP +
CLICK2ABS(vmproc[VMP_SYSTEM].vm_arch.vm_seg[D].mem_phys);
return OK;
}
/*===========================================================================*
* pt_allocmap *
*===========================================================================*/
PUBLIC int pt_allocmap(pt_t *pt, vir_bytes v_min, vir_bytes v_max,
size_t bytes, u32_t pageflags, u32_t memflags, vir_bytes *v_final)
{
/* Allocate new memory, and map it into the page table. */
u32_t newpage;
u32_t v;
int r;
/* Input sanity check. */
PT_SANE(pt);
vm_assert(!(pageflags & ~PTF_ALLFLAGS));
/* Valid no-op. */
if(bytes == 0) return OK;
/* Round no. of bytes up to a page. */
if(bytes % I386_PAGE_SIZE) {
bytes += I386_PAGE_SIZE - (bytes % I386_PAGE_SIZE);
}
/* Special case; if v_max is 0, the request is to map the memory
* into v_min at exactly that location. We raise v_max as necessary,
* so the check to see if the virtual space is free does happen.
*/
if(v_max == 0) {
v_max = v_min + bytes;
/* Sanity check. */
if(v_max < v_min) {
printf("pt_allocmap: v_min 0x%lx and bytes 0x%lx\n",
v_min, bytes);
return ENOMEM;
}
}
/* Basic sanity check. */
if(v_max < v_min) {
printf("pt_allocmap: v_min 0x%lx, v_max 0x%lx\n", v_min, v_max);
return ENOMEM;
}
/* v_max itself may not be used. Bytes may be 0. */
if(v_max < v_min + bytes) {
printf("pt_allocmap: v_min 0x%lx, bytes 0x%lx, v_max 0x%lx\n",
v_min, bytes, v_max);
return ENOMEM;
}
/* Find where to fit this into the virtual address space. */
v = findhole(pt, bytes, v_min, v_max);
if(v == NO_MEM) {
printf("pt_allocmap: no hole found to map 0x%lx bytes into\n",
bytes);
return ENOSPC;
}
vm_assert(!(v % I386_PAGE_SIZE));
if(v_final) *v_final = v;
/* Memory is currently always allocated contiguously physically,
* but if that were to change, note the setting of
* PAF_CONTIG in memflags.
*/
newpage = ALLOC_MEM(CLICKSPERPAGE * bytes / I386_PAGE_SIZE, memflags);
if(newpage == NO_MEM) {
printf("pt_allocmap: out of memory\n");
return ENOMEM;
}
/* Write into the page table. */
if((r=pt_writemap(pt, v, CLICK2ABS(newpage), bytes,
pageflags | PTF_MAPALLOC, 0)) != OK) {
FREE_MEM(newpage, CLICKSPERPAGE * bytes / I386_PAGE_SIZE);
return r;
}
/* Sanity check result. */
PT_SANE(pt);
return OK;
}
/*===========================================================================*
* raw_readmap *
*===========================================================================*/
PRIVATE int raw_readmap(phys_bytes root, u32_t v, u32_t *phys, u32_t *flags)
{
u32_t dir[I386_VM_DIR_ENTRIES];
u32_t tab[I386_VM_PT_ENTRIES];
int pde, pte, r;
/* Sanity check. */
vm_assert((root % I386_PAGE_SIZE) == 0);
vm_assert((v % I386_PAGE_SIZE) == 0);
/* Get entry in page directory. */
pde = I386_VM_PDE(v);
if((r=sys_physcopy(SYSTEM, PHYS_SEG, root,
SELF, VM_D, (phys_bytes) dir, sizeof(dir))) != OK) {
printf("VM: raw_readmap: sys_physcopy failed (dir) (%d)\n", r);
return EFAULT;
}
if(!(dir[pde] & I386_VM_PRESENT)) {
printf("raw_readmap: 0x%lx: pde %d not present: 0x%lx\n",
v, pde, dir[pde]);
return EFAULT;
}
/* Get entry in page table. */
if((r=sys_physcopy(SYSTEM, PHYS_SEG, I386_VM_PFA(dir[pde]),
SELF, VM_D, (vir_bytes) tab, sizeof(tab))) != OK) {
printf("VM: raw_readmap: sys_physcopy failed (tab) (r)\n");
return EFAULT;
}
pte = I386_VM_PTE(v);
if(!(tab[pte] & I386_VM_PRESENT)) {
printf("raw_readmap: 0x%lx: pde %d not present: 0x%lx\n",
v, pte, tab[pte]);
return EFAULT;
}
/* Get address and flags. */
*phys = I386_VM_PFA(tab[pte]);
*flags = tab[pte] & PTF_ALLFLAGS;
return OK;
}
/*===========================================================================*
* pt_init *
*===========================================================================*/
PUBLIC void pt_init(void)
{
/* By default, the kernel gives us a data segment with pre-allocated
* memory that then can't grow. We want to be able to allocate memory
* dynamically, however. So here we copy the part of the page table
* that's ours, so we get a private page table. Then we increase the
* hardware segment size so we can allocate memory above our stack.
*/
u32_t my_cr3;
pt_t *newpt;
int s, r;
vir_bytes v;
phys_bytes lo, hi;
vir_bytes extra_clicks;
/* Retrieve current CR3 - shared page table. */
if((r=sys_vmctl_get_cr3_i386(SELF, &my_cr3)) != OK)
vm_panic("pt_init: sys_vmctl_get_cr3_i386 failed", r);
/* Shorthand. */
newpt = &vmp->vm_pt;
/* Get ourselves a spare page. */
for(s = 0; s < SPAREPAGES; s++) {
if(!(sparepages[s].page = aalloc(I386_PAGE_SIZE)))
vm_panic("pt_init: aalloc for spare failed", NO_NUM);
if((r=sys_umap(SELF, VM_D, (vir_bytes) sparepages[s].page,
I386_PAGE_SIZE, &sparepages[s].phys)) != OK)
vm_panic("pt_init: sys_umap failed", r);
}
/* Make new page table for ourselves, partly copied
* from the current one.
*/
if(pt_new(newpt) != OK)
vm_panic("pt_init: pt_new failed", NO_NUM);
/* Initial (current) range of our virtual address space. */
lo = CLICK2ABS(vmp->vm_arch.vm_seg[T].mem_phys);
hi = CLICK2ABS(vmp->vm_arch.vm_seg[S].mem_phys +
vmp->vm_arch.vm_seg[S].mem_len);
/* Copy the mappings from the shared page table to our private one. */
for(v = lo; v < hi; v += I386_PAGE_SIZE) {
phys_bytes addr;
u32_t flags;
if(raw_readmap(my_cr3, v, &addr, &flags) != OK)
vm_panic("pt_init: raw_readmap failed", NO_NUM);
if(pt_writemap(newpt, v, addr, I386_PAGE_SIZE, flags, 0) != OK)
vm_panic("pt_init: pt_writemap failed", NO_NUM);
}
/* Map in kernel. */
if(pt_mapkernel(newpt) != OK)
vm_panic("pt_init: pt_mapkernel failed", NO_NUM);
/* Give our process the new, copied, private page table. */
pt_bind(newpt, vmp);
/* Increase our hardware data segment to create virtual address
* space above our stack. We want to increase it to VM_DATATOP,
* like regular processes have.
*/
extra_clicks = ABS2CLICK(VM_DATATOP - hi);
vmp->vm_arch.vm_seg[S].mem_len += extra_clicks;
/* We pretend to the kernel we have a huge stack segment to
* increase our data segment.
*/
vmp->vm_arch.vm_data_top =
(vmp->vm_arch.vm_seg[S].mem_vir +
vmp->vm_arch.vm_seg[S].mem_len) << CLICK_SHIFT;
if((s=sys_newmap(VM_PROC_NR, vmp->vm_arch.vm_seg)) != OK)
vm_panic("VM: pt_init: sys_newmap failed", s);
/* Back to reality - this is where the stack actually is. */
vmp->vm_arch.vm_seg[S].mem_len -= extra_clicks;
/* Where our free virtual address space starts.
* This is only a hint to the VM system.
*/
newpt->pt_virtop = (vmp->vm_arch.vm_seg[S].mem_vir +
vmp->vm_arch.vm_seg[S].mem_len) << CLICK_SHIFT;
/* Let other functions know VM now has a private page table. */
vmp->vm_flags |= VMF_HASPT;
/* Reserve a page in our virtual address space that we
* can use to map in arbitrary physical pages.
*/
varmap_loc = findhole(newpt, I386_PAGE_SIZE,
CLICK2ABS(vmp->vm_arch.vm_seg[D].mem_phys) + vmp->vm_stacktop,
vmp->vm_arch.vm_data_top);
if(varmap_loc == NO_MEM) {
vm_panic("no virt addr for vm mappings", NO_NUM);
}
varmap = (unsigned char *) (varmap_loc -
CLICK2ABS(vmp->vm_arch.vm_seg[D].mem_phys));
/* All OK. */
return;
}
/*===========================================================================*
* pt_bind *
*===========================================================================*/
PUBLIC int pt_bind(pt_t *pt, struct vmproc *who)
{
/* Basic sanity checks. */
vm_assert(who);
vm_assert(who->vm_flags & VMF_INUSE);
if(pt) PT_SANE(pt);
/* Tell kernel about new page table root. */
return sys_vmctl(who->vm_endpoint, VMCTL_I386_SETCR3,
pt ? pt->pt_dir_phys : 0);
}
/*===========================================================================*
* pt_free *
*===========================================================================*/
PUBLIC void pt_free(pt_t *pt)
{
/* Free memory associated with this pagetable. */
int i;
PT_SANE(pt);
for(i = 0; i < I386_VM_DIR_ENTRIES; i++) {
int p;
if(pt->pt_pt[i]) {
for(p = 0; p < I386_VM_PT_ENTRIES; p++) {
if((pt->pt_pt[i][p] & (PTF_MAPALLOC | I386_VM_PRESENT))
== (PTF_MAPALLOC | I386_VM_PRESENT)) {
u32_t pa = I386_VM_PFA(pt->pt_pt[i][p]);
FREE_MEM(ABS2CLICK(pa), CLICKSPERPAGE);
}
}
vm_freepages((vir_bytes) pt->pt_pt[i],
I386_VM_PFA(pt->pt_dir[i]), 1, VMP_PAGETABLE);
}
}
vm_freepages((vir_bytes) pt->pt_dir, pt->pt_dir_phys, 1, VMP_PAGEDIR);
return;
}
/*===========================================================================*
* pt_mapkernel *
*===========================================================================*/
PUBLIC int pt_mapkernel(pt_t *pt)
{
int r;
/* Any i386 page table needs to map in the kernel address space. */
vm_assert(vmproc[VMP_SYSTEM].vm_flags & VMF_INUSE);
/* Map in text. flags: don't write, supervisor only */
if((r=pt_writemap(pt, KERNEL_TEXT, KERNEL_TEXT, KERNEL_TEXT_LEN,
I386_VM_PRESENT|I386_VM_GLOBAL, 0)) != OK)
return r;
/* Map in data. flags: read-write, supervisor only */
if((r=pt_writemap(pt, KERNEL_DATA, KERNEL_DATA, KERNEL_DATA_LEN,
I386_VM_PRESENT|I386_VM_WRITE|I386_VM_GLOBAL, 0)) != OK)
return r;
return OK;
}
/*===========================================================================*
* pt_freerange *
*===========================================================================*/
PUBLIC void pt_freerange(pt_t *pt, vir_bytes low, vir_bytes high)
{
/* Free memory allocated by pagetable functions in this range. */
int pde;
u32_t v;
PT_SANE(pt);
for(v = low; v < high; v += I386_PAGE_SIZE) {
int pte;
pde = I386_VM_PDE(v);
pte = I386_VM_PTE(v);
if(!(pt->pt_dir[pde] & I386_VM_PRESENT))
continue;
if((pt->pt_pt[pde][pte] & (PTF_MAPALLOC | I386_VM_PRESENT))
== (PTF_MAPALLOC | I386_VM_PRESENT)) {
u32_t pa = I386_VM_PFA(pt->pt_pt[pde][pte]);
FREE_MEM(ABS2CLICK(pa), CLICKSPERPAGE);
pt->pt_pt[pde][pte] = 0;
}
}
PT_SANE(pt);
return;
}
/*===========================================================================*
* pt_cycle *
*===========================================================================*/
PUBLIC void pt_cycle(void)
{
vm_checkspares();
}
/*===========================================================================*
* pt_copy *
*===========================================================================*/
PUBLIC int pt_copy(pt_t *src, pt_t *dst)
{
int i, r;
SANITYCHECK(SCL_FUNCTIONS);
PT_SANE(src);
if((r=pt_new(dst)) != OK)
return r;
for(i = 0; i < I386_VM_DIR_ENTRIES; i++) {
int p;
if(!(src->pt_dir[i] & I386_VM_PRESENT))
continue;
for(p = 0; p < I386_VM_PT_ENTRIES; p++) {
u32_t v = i * I386_VM_PT_ENTRIES * I386_PAGE_SIZE +
p * I386_PAGE_SIZE;
u32_t pa1, pa2, flags;
if(!(src->pt_pt[i][p] & I386_VM_PRESENT))
continue;
#if 0
if((dst->pt_pt[i] &&
(dst->pt_pt[i][p] & I386_VM_PRESENT)))
continue;
#endif
flags = src->pt_pt[i][p] & (PTF_WRITE | PTF_USER);
flags |= I386_VM_PRESENT;
pa1 = I386_VM_PFA(src->pt_pt[i][p]);
if(PTF_MAPALLOC & src->pt_pt[i][p]) {
PT_SANE(dst);
if(pt_allocmap(dst, v, 0,
I386_PAGE_SIZE, flags, 0, NULL) != OK) {
pt_free(dst);
return ENOMEM;
}
pa2 = I386_VM_PFA(dst->pt_pt[i][p]);
sys_abscopy(pa1, pa2, I386_PAGE_SIZE);
} else {
PT_SANE(dst);
if(pt_writemap(dst, v, pa1, I386_PAGE_SIZE, flags, 0) != OK) {
pt_free(dst);
return ENOMEM;
}
}
}
}
PT_SANE(src);
PT_SANE(dst);
SANITYCHECK(SCL_FUNCTIONS);
return OK;
}
#define PHYS_MAP(a, o) \
{ int r; \
vm_assert(varmap); \
(o) = (a) % I386_PAGE_SIZE; \
r = pt_writemap(&vmp->vm_pt, varmap_loc, (a) - (o), I386_PAGE_SIZE, \
I386_VM_PRESENT | I386_VM_USER | I386_VM_WRITE, 0); \
if(r != OK) \
vm_panic("PHYS_MAP: pt_writemap failed", NO_NUM); \
/* pt_bind() flushes TLB. */ \
pt_bind(&vmp->vm_pt, vmp); \
}
#define PHYSMAGIC 0x7b9a0590
#define PHYS_UNMAP if(OK != pt_writemap(&vmp->vm_pt, varmap_loc, MAP_NONE,\
I386_PAGE_SIZE, 0, WMF_OVERWRITE)) { \
vm_panic("PHYS_UNMAP: pt_writemap failed", NO_NUM); }
#define PHYS_VAL(o) (* (phys_bytes *) (varmap + (o)))
/*===========================================================================*
* phys_writeaddr *
*===========================================================================*/
PUBLIC void phys_writeaddr(phys_bytes addr, phys_bytes v1, phys_bytes v2)
{
phys_bytes offset;
SANITYCHECK(SCL_DETAIL);
PHYS_MAP(addr, offset);
PHYS_VAL(offset) = v1;
PHYS_VAL(offset + sizeof(phys_bytes)) = v2;
#if SANITYCHECKS
PHYS_VAL(offset + 2*sizeof(phys_bytes)) = PHYSMAGIC;
#endif
PHYS_UNMAP;
SANITYCHECK(SCL_DETAIL);
}
/*===========================================================================*
* phys_readaddr *
*===========================================================================*/
PUBLIC void phys_readaddr(phys_bytes addr, phys_bytes *v1, phys_bytes *v2)
{
phys_bytes offset;
SANITYCHECK(SCL_DETAIL);
PHYS_MAP(addr, offset);
*v1 = PHYS_VAL(offset);
*v2 = PHYS_VAL(offset + sizeof(phys_bytes));
#if SANITYCHECKS
vm_assert(PHYS_VAL(offset + 2*sizeof(phys_bytes)) == PHYSMAGIC);
#endif
PHYS_UNMAP;
SANITYCHECK(SCL_DETAIL);
}
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