ref: f4122cfbc9ee6b99f69f1194ea38565fdfad36bb
dir: /sys/src/9/kw/mmu.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "arm.h"
#define L1X(va) FEXT((va), 20, 12)
#define L2X(va) FEXT((va), 12, 8)
enum {
L1lo = UZERO/MiB, /* L1X(UZERO)? */
L1hi = (USTKTOP+MiB-1)/MiB, /* L1X(USTKTOP+MiB-1)? */
};
#define ISHOLE(pte) ((pte) == 0)
/* dump level 1 page table at virtual addr l1 */
void
mmudump(PTE *l1)
{
int i, type, rngtype;
uintptr pa, startva, startpa;
uvlong va, endva;
PTE pte;
iprint("\n");
endva = startva = startpa = 0;
rngtype = 0;
/* dump first level of ptes */
for (va = i = 0; i < 4096; i++) {
pte = l1[i];
pa = pte & ~(MB - 1);
type = pte & (Fine|Section|Coarse);
if (ISHOLE(pte)) {
if (endva != 0) { /* open range? close it */
iprint("l1 maps va (%#lux-%#llux) -> pa %#lux type %#ux\n",
startva, endva-1, startpa, rngtype);
endva = 0;
}
} else {
if (endva == 0) { /* no open range? start one */
startva = va;
startpa = pa;
rngtype = type;
}
endva = va + MB; /* continue the open range */
}
va += MB;
}
if (endva != 0) /* close an open range */
iprint("l1 maps va (%#lux-%#llux) -> pa %#lux type %#ux\n",
startva, endva-1, startpa, rngtype);
}
#ifdef CRYPTOSANDBOX
extern uchar sandbox[64*1024+BY2PG];
#endif
/* identity map `mbs' megabytes from phys */
void
mmuidmap(uintptr phys, int mbs)
{
PTE *l1;
uintptr pa, fpa;
pa = ttbget();
l1 = KADDR(pa);
for (fpa = phys; mbs-- > 0; fpa += MiB)
l1[L1X(fpa)] = fpa|Dom0|L1AP(Krw)|Section;
coherence();
mmuinvalidate();
cacheuwbinv();
l2cacheuwbinv();
}
void
mmuinit(void)
{
PTE *l1, *l2;
uintptr pa, i;
pa = ttbget();
l1 = KADDR(pa);
/*
* map high vectors to start of dram, but only 4K, not 1MB.
*/
pa -= MACHSIZE+2*1024;
l2 = KADDR(pa);
memset(l2, 0, 1024);
/* vectors step on u-boot, but so do page tables */
l2[L2X(HVECTORS)] = PHYSDRAM|L2AP(Krw)|Small;
l1[L1X(HVECTORS)] = pa|Dom0|Coarse; /* vectors -> ttb-machsize-2k */
/* double map vectors at virtual 0 so reset will see them */
pa -= 1024;
l2 = KADDR(pa);
memset(l2, 0, 1024);
l2[L2X(0)] = PHYSDRAM|L2AP(Krw)|Small;
l1[L1X(0)] = pa|Dom0|Coarse;
/*
* set up L2 ptes for PHYSIO (i/o registers), with smaller pages to
* enable user-mode access to a few devices.
*/
pa -= 1024;
l2 = KADDR(pa);
/* identity map by default */
for (i = 0; i < 1024/4; i++)
l2[L2X(VIRTIO + i*BY2PG)] = (PHYSIO + i*BY2PG)|L2AP(Krw)|Small;
#ifdef CRYPTOSANDBOX
/*
* rest is to let rae experiment with the crypto hardware
*/
/* access to cycle counter */
l2[L2X(soc.clock)] = soc.clock | L2AP(Urw)|Small;
/* cesa registers; also visible in user space */
for (i = 0; i < 16; i++)
l2[L2X(soc.cesa + i*BY2PG)] = (soc.cesa + i*BY2PG) |
L2AP(Urw)|Small;
/* crypto sram; remapped to unused space and visible in user space */
l2[L2X(PHYSIO + 0xa0000)] = PHYSCESASRAM | L2AP(Urw)|Small;
/* 64k of scratch dram */
for (i = 0; i < 16; i++)
l2[L2X(PHYSIO + 0xb0000 + i*BY2PG)] =
(PADDR((uintptr)sandbox & ~(BY2PG-1)) + i*BY2PG) |
L2AP(Urw) | Small;
#endif
l1[L1X(VIRTIO)] = pa|Dom0|Coarse;
coherence();
mmuinvalidate();
cacheuwbinv();
l2cacheuwbinv();
m->mmul1 = l1;
// mmudump(l1); /* DEBUG. too early to print */
}
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, BY2PG);
l1[page->daddr] = Fault;
l2 = &page->next;
}
*l2 = proc->mmul2cache;
proc->mmul2cache = proc->mmul2;
proc->mmul2 = nil;
}
static void
mmul1empty(void)
{
#ifdef notdef /* there's a bug in here */
PTE *l1;
/* clean out any user mappings still in l1 */
if(m->mmul1lo > L1lo){
if(m->mmul1lo == 1)
m->mmul1[L1lo] = Fault;
else
memset(&m->mmul1[L1lo], 0, m->mmul1lo*sizeof(PTE));
m->mmul1lo = L1lo;
}
if(m->mmul1hi < L1hi){
l1 = &m->mmul1[m->mmul1hi];
if((L1hi - m->mmul1hi) == 1)
*l1 = Fault;
else
memset(l1, 0, (L1hi - m->mmul1hi)*sizeof(PTE));
m->mmul1hi = L1hi;
}
#else
memset(&m->mmul1[L1lo], 0, (L1hi - L1lo)*sizeof(PTE));
#endif /* notdef */
}
void
mmuswitch(Proc* proc)
{
int x;
PTE *l1;
Page *page;
/* do kprocs get here and if so, do they need to? */
if(m->mmupid == proc->pid && !proc->newtlb)
return;
m->mmupid = proc->pid;
/* write back dirty and invalidate l1 caches */
cacheuwbinv();
if(proc->newtlb){
mmul2empty(proc, 1);
proc->newtlb = 0;
}
mmul1empty();
/* move in new map */
l1 = m->mmul1;
for(page = proc->mmul2; page != nil; page = page->next){
x = page->daddr;
l1[x] = PPN(page->pa)|Dom0|Coarse;
/* know here that L1lo < x < L1hi */
if(x+1 - m->mmul1lo < m->mmul1hi - x)
m->mmul1lo = x+1;
else
m->mmul1hi = x;
}
/* make sure map is in memory */
/* could be smarter about how much? */
cachedwbse(&l1[L1X(UZERO)], (L1hi - L1lo)*sizeof(PTE));
l2cacheuwbse(&l1[L1X(UZERO)], (L1hi - L1lo)*sizeof(PTE));
/* lose any possible stale tlb entries */
mmuinvalidate();
// mmudump(l1);
//print("mmuswitch l1lo %d l1hi %d %d\n",
// m->mmul1lo, m->mmul1hi, proc->kp);
//print("\n");
}
void
flushmmu(void)
{
int s;
s = splhi();
up->newtlb = 1;
mmuswitch(up);
splx(s);
}
void
mmurelease(Proc* proc)
{
/* write back dirty and invalidate l1 caches */
cacheuwbinv();
mmul2empty(proc, 0);
freepages(proc->mmul2cache, nil, 0);
proc->mmul2cache = nil;
mmul1empty();
/* make sure map is in memory */
/* could be smarter about how much? */
cachedwbse(&m->mmul1[L1X(UZERO)], (L1hi - L1lo)*sizeof(PTE));
l2cacheuwbse(&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;
Page *pg;
PTE *l1, *pte;
x = L1X(va);
l1 = &m->mmul1[x];
//print("putmmu(%#p, %#p, %#p) ", va, pa, page->pa);
//print("mmul1 %#p l1 %#p *l1 %#ux x %d pid %d\n",
// m->mmul1, l1, *l1, x, up->pid);
if(*l1 == Fault){
/* wasteful - l2 pages only have 256 entries - fix */
if(up->mmul2cache == nil){
/* auxpg since we don't need much? memset if so */
pg = newpage(1, 0, 0);
pg->va = VA(kmap(pg));
}
else{
pg = up->mmul2cache;
up->mmul2cache = pg->next;
memset((void*)pg->va, 0, BY2PG);
}
pg->daddr = x;
pg->next = up->mmul2;
up->mmul2 = pg;
/* force l2 page to memory */
cachedwbse((void *)pg->va, BY2PG);
l2cacheuwbse((void *)pg->va, BY2PG);
*l1 = PPN(pg->pa)|Dom0|Coarse;
cachedwbse(l1, sizeof *l1);
l2cacheuwbse(l1, sizeof *l1);
//print("l1 %#p *l1 %#ux x %d pid %d\n", l1, *l1, x, up->pid);
if(x >= m->mmul1lo && x < m->mmul1hi){
if(x+1 - m->mmul1lo < m->mmul1hi - x)
m->mmul1lo = x+1;
else
m->mmul1hi = x;
}
}
pte = (void*)KADDR(PPN(*l1));
//print("pte %#p index %ld %#ux\n", pte, L2X(va), *(pte+L2X(va)));
/* protection bits are
* PTERONLY|PTEVALID;
* PTEWRITE|PTEVALID;
* PTEWRITE|PTEUNCACHED|PTEVALID;
*/
x = Small;
if(!(pa & PTEUNCACHED))
x |= Cached|Buffered;
if(pa & PTEWRITE)
x |= L2AP(Urw);
else
x |= L2AP(Uro);
pte[L2X(va)] = PPN(pa)|x;
cachedwbse(&pte[L2X(va)], sizeof pte[0]);
l2cacheuwbse(&pte[L2X(va)], sizeof pte[0]);
/* clear out the current entry */
mmuinvalidateaddr(PPN(va));
/*
* write back dirty entries - we need this because pio() in
* fault.c is writing via a different virt addr and won't clean
* its changes out of the dcache. Page coloring doesn't work
* on this mmu because the l1 virtual cache is set associative
* rather than direct mapped.
*/
cachedwbinv();
if(needtxtflush(page)){
cacheiinv();
donetxtflush(page);
}
//print("putmmu %#p %#p %#p\n", va, pa, PPN(pa)|x);
}
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 &= ~(Cached|Buffered);
mmuinvalidateaddr(va);
cachedwbse(pte, 4);
l2cacheuwbse(pte, 4);
return v;
}
uintptr
mmukmap(uintptr va, uintptr pa, usize size)
{
int x;
PTE *pte;
/*
* Stub.
*/
assert(!(va & (1*MiB-1)) && !(pa & (1*MiB-1)) && size == 1*MiB);
x = L1X(va);
pte = &m->mmul1[x];
if(*pte != Fault)
return 0;
*pte = pa|Dom0|L1AP(Krw)|Section;
mmuinvalidateaddr(va);
cachedwbse(pte, 4);
l2cacheuwbse(pte, 4);
return va;
}
uintptr
mmukunmap(uintptr va, uintptr pa, usize size)
{
int x;
PTE *pte;
/*
* Stub.
*/
assert(!(va & (1*MiB-1)) && !(pa & (1*MiB-1)) && size == 1*MiB);
x = L1X(va);
pte = &m->mmul1[x];
if(*pte != (pa|Dom0|L1AP(Krw)|Section))
return 0;
*pte = Fault;
mmuinvalidateaddr(va);
cachedwbse(pte, 4);
l2cacheuwbse(pte, 4);
return va;
}
/*
* 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 + 512*MiB) /* assumes PHYSDRAM is 0 */
return PHYSDRAM + 512*MiB - pa;
return 0;
}
/* from 386 */
void*
vmap(uintptr pa, usize size)
{
uintptr pae, va;
usize o, osize;
/*
* XXX - replace with new vm stuff.
* Crock after crock - the first 4MB is mapped with 2MB pages
* so catch that and return good values because the current mmukmap
* will fail.
*/
if(pa+size < 4*MiB)
return (void*)(kseg0|pa);
osize = size;
o = pa & (BY2PG-1);
pa -= o;
size += o;
size = PGROUND(size);
va = kseg0|pa;
pae = mmukmap(va, pa, size);
if(pae == 0 || pae-size != pa)
panic("vmap(%#p, %ld) called from %#p: mmukmap fails %#p",
pa+o, osize, getcallerpc(&pa), pae);
return (void*)(va+o);
}
/* from 386 */
void
vunmap(void* v, usize size)
{
/*
* XXX - replace with new vm stuff.
* Can't do this until do real vmap for all space that
* might be used, e.g. stuff below 1MB which is currently
* mapped automagically at boot but that isn't used (or
* at least shouldn't be used) by the kernel.
upafree(PADDR(v), size);
*/
USED(v, size);
}
/*
* Notes.
* Everything is in domain 0;
* domain 0 access bits in the DAC register are set
* to Client, which means access is controlled by the
* permission values set in the PTE.
*
* L1 access control for the kernel is set to 1 (RW,
* no user mode access);
* L2 access control for the kernel is set to 1 (ditto)
* for all 4 AP sets;
* L1 user mode access is never set;
* L2 access control for user mode is set to either
* 2 (RO) or 3 (RW) depending on whether text or data,
* for all 4 AP sets.
* (To get kernel RO set AP to 0 and S bit in control
* register c1).
* Coarse L1 page-tables are used. They have 256 entries
* and so consume 1024 bytes per table.
* Small L2 page-tables are used. They have 1024 entries
* and so consume 4096 bytes per table.
*
* 4KiB. That's the size of 1) a page, 2) the
* size allocated for an L2 page-table page (note only 1KiB
* is needed per L2 page - to be dealt with later) and
* 3) the size of the area in L1 needed to hold the PTEs
* to map 1GiB of user space (0 -> 0x3fffffff, 1024 entries).
*/