ref: a15863b8ae23a26a2f825daf6107ab92e53c2669
dir: /sys/src/9/bcm/mmu.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "arm.h"
#define FEXT(d, o, w) (((d)>>(o)) & ((1<<(w))-1))
#define L1X(va) FEXT((va), 20, 12)
#define L2X(va) FEXT((va), 12, 8)
#define L1ptedramattrs soc.l1ptedramattrs
#define L2ptedramattrs soc.l2ptedramattrs
#define PTEDRAM (PHYSDRAM|Dom0|L1AP(Krw)|Section|L1ptedramattrs)
enum {
L1lo = UZERO/MiB, /* L1X(UZERO)? */
L1hi = (USTKTOP+MiB-1)/MiB, /* L1X(USTKTOP+MiB-1)? */
L2size = 256*sizeof(PTE),
};
/*
* Set up initial PTEs for cpu0 (called with mmu off)
*/
void
mmuinit(void *a)
{
PTE *l1, *l2;
uintptr pa, va;
l1 = (PTE*)a;
l2 = (PTE*)PADDR(L2);
/*
* map all of ram at KZERO
*/
va = KZERO;
for(pa = PHYSDRAM; pa < PHYSDRAM+soc.dramsize; pa += MiB){
l1[L1X(va)] = pa|Dom0|L1AP(Krw)|Section|L1ptedramattrs;
va += MiB;
}
/*
* identity map first MB of ram so mmu can be enabled
*/
l1[L1X(PHYSDRAM)] = PTEDRAM;
/*
* map i/o registers
*/
va = soc.virtio;
for(pa = soc.physio; pa < soc.physio+soc.iosize; pa += MiB){
l1[L1X(va)] = pa|Dom0|L1AP(Krw)|Section|L1noexec;
va += MiB;
}
pa = soc.armlocal;
if(pa)
l1[L1X(va)] = pa|Dom0|L1AP(Krw)|Section|L1noexec;
/*
* double map exception vectors near top of virtual memory
*/
va = HVECTORS;
l1[L1X(va)] = (uintptr)l2|Dom0|Coarse;
l2[L2X(va)] = PHYSDRAM|L2AP(Krw)|Small|L2ptedramattrs;
}
/*
* enable/disable identity map of first MB of ram
*/
void
mmuinit1(int on)
{
PTE *l1;
l1 = m->mmul1;
l1[L1X(PHYSDRAM)] = on? PTEDRAM: Fault;
cachedwbtlb(&l1[L1X(PHYSDRAM)], sizeof(PTE));
mmuinvalidateaddr(PHYSDRAM);
mmuinvalidate();
}
static void
mmul2empty(Proc* proc, int clear)
{
PTE *l1;
Page **l2, *page;
l1 = m->mmul1;
l2 = &proc->mmul2;
for(page = *l2; page != nil; page = page->next){
if(clear)
memset((void*)page->va, 0, L2size);
l1[page->daddr] = Fault;
l2 = &page->next;
}
coherence();
*l2 = proc->mmul2cache;
proc->mmul2cache = proc->mmul2;
proc->mmul2 = nil;
}
static void
mmul1empty(void)
{
PTE *l1;
/* clean out any user mappings still in l1 */
if(m->mmul1lo > 0){
if(m->mmul1lo == 1)
m->mmul1[L1lo] = Fault;
else
memset(&m->mmul1[L1lo], 0, m->mmul1lo*sizeof(PTE));
m->mmul1lo = 0;
}
if(m->mmul1hi > 0){
l1 = &m->mmul1[L1hi - m->mmul1hi];
if(m->mmul1hi == 1)
*l1 = Fault;
else
memset(l1, 0, m->mmul1hi*sizeof(PTE));
m->mmul1hi = 0;
}
}
void
mmuswitch(Proc* proc)
{
int x;
PTE *l1;
Page *page;
if(proc != nil && proc->newtlb){
mmul2empty(proc, 1);
proc->newtlb = 0;
}
mmul1empty();
/* move in new map */
l1 = m->mmul1;
if(proc != nil)
for(page = proc->mmul2; page != nil; page = page->next){
x = page->daddr;
l1[x] = PPN(page->pa)|Dom0|Coarse;
if(x >= L1lo + m->mmul1lo && x < L1hi - m->mmul1hi){
if(x+1 - L1lo < L1hi - x)
m->mmul1lo = x+1 - L1lo;
else
m->mmul1hi = L1hi - x;
}
}
/* make sure map is in memory */
/* could be smarter about how much? */
cachedwbtlb(&l1[L1X(UZERO)], (L1hi - L1lo)*sizeof(PTE));
/* lose any possible stale tlb entries */
mmuinvalidate();
}
void
flushmmu(void)
{
int s;
s = splhi();
up->newtlb = 1;
mmuswitch(up);
splx(s);
}
void
mmurelease(Proc* proc)
{
mmul2empty(proc, 0);
freepages(proc->mmul2cache, nil, 0);
proc->mmul2cache = nil;
mmul1empty();
/* make sure map is in memory */
/* could be smarter about how much? */
cachedwbtlb(&m->mmul1[L1X(UZERO)], (L1hi - L1lo)*sizeof(PTE));
/* lose any possible stale tlb entries */
mmuinvalidate();
}
void
putmmu(uintptr va, uintptr pa, Page* page)
{
int x, s;
Page *pg;
PTE *l1, *pte;
/*
* disable interrupts to prevent flushmmu (called from hzclock)
* from clearing page tables while we are setting them
*/
s = splhi();
x = L1X(va);
l1 = &m->mmul1[x];
if(*l1 == Fault){
/* l2 pages only have 256 entries - wastes 3K per 1M of address space */
if(up->mmul2cache == nil){
spllo();
pg = newpage(1, 0, 0);
splhi();
/* if newpage slept, we might be on a different cpu */
l1 = &m->mmul1[x];
pg->va = VA(kmap(pg));
}else{
pg = up->mmul2cache;
up->mmul2cache = pg->next;
}
pg->daddr = x;
pg->next = up->mmul2;
up->mmul2 = pg;
/* force l2 page to memory (armv6) */
cachedwbtlb((void *)pg->va, L2size);
*l1 = PPN(pg->pa)|Dom0|Coarse;
cachedwbtlb(l1, sizeof *l1);
if(x >= L1lo + m->mmul1lo && x < L1hi - m->mmul1hi){
if(x+1 - L1lo < L1hi - x)
m->mmul1lo = x+1 - L1lo;
else
m->mmul1hi = L1hi - x;
}
}
pte = KADDR(PPN(*l1));
/* protection bits are
* PTERONLY|PTEVALID;
* PTEWRITE|PTEVALID;
* PTEWRITE|PTEUNCACHED|PTEVALID;
*/
x = Small;
if(!(pa & PTEUNCACHED))
x |= L2ptedramattrs;
if(pa & PTEWRITE)
x |= L2AP(Urw);
else
x |= L2AP(Uro);
if(pa & PTENOEXEC)
x |= L2noexec;
pte[L2X(va)] = PPN(pa)|x;
cachedwbtlb(&pte[L2X(va)], sizeof(PTE));
/* clear out the current entry */
mmuinvalidateaddr(PPN(va));
if(needtxtflush(page)){
cachedwbse((void*)(page->pa|KZERO), BY2PG);
cacheiinvse((void*)page->va, BY2PG);
donetxtflush(page);
}
//checkmmu(va, PPN(pa));
splx(s);
}
void*
mmuuncache(void* v, usize size)
{
int x;
PTE *pte;
uintptr va;
/*
* Simple helper for ucalloc().
* Uncache a Section, must already be
* valid in the MMU.
*/
va = (uintptr)v;
assert(!(va & (1*MiB-1)) && size == 1*MiB);
x = L1X(va);
pte = &m->mmul1[x];
if((*pte & (Fine|Section|Coarse)) != Section)
return nil;
*pte &= ~L1ptedramattrs;
mmuinvalidateaddr(va);
cachedwbinvse(pte, 4);
return v;
}
/*
* Return the number of bytes that can be accessed via KADDR(pa).
* If pa is not a valid argument to KADDR, return 0.
*/
uintptr
cankaddr(uintptr pa)
{
if(pa < PHYSDRAM+soc.dramsize)
return ((uintptr)PHYSDRAM+soc.dramsize) - pa;
return 0;
}
uintptr
mmukmap(uintptr va, uintptr pa, usize size)
{
int o;
usize n;
PTE *pte, *pte0;
assert((va & (MiB-1)) == 0);
o = pa & (MiB-1);
pa -= o;
size += o;
pte = pte0 = &m->mmul1[L1X(va)];
for(n = 0; n < size; n += MiB)
if(*pte++ != Fault)
return 0;
pte = pte0;
for(n = 0; n < size; n += MiB){
*pte++ = (pa+n)|Dom0|L1AP(Krw)|Section|L1noexec;
mmuinvalidateaddr(va+n);
}
cachedwbtlb(pte0, (uintptr)pte - (uintptr)pte0);
return va + o;
}
void
checkmmu(uintptr va, uintptr pa)
{
int x;
PTE *l1, *pte;
x = L1X(va);
l1 = &m->mmul1[x];
if(*l1 == Fault){
iprint("checkmmu cpu%d va=%lux l1 %p=%ux\n", m->machno, va, l1, *l1);
return;
}
pte = KADDR(PPN(*l1));
pte += L2X(va);
if(pa == ~0 || (pa != 0 && PPN(*pte) != pa))
iprint("checkmmu va=%lux pa=%lux l1 %p=%ux pte %p=%ux\n", va, pa, l1, *l1, pte, *pte);
}
void
kunmap(KMap *k)
{
USED(k);
coherence();
}