ref: c67d0c699f7b52da534f75d3620776997b1e8d52
dir: /sys/src/9/pc/memory.c/
/*
* Size memory and create the kernel page-tables on the fly while doing so.
* Called from main(), this code should only be run by the bootstrap processor.
*
* MemMin is what the bootstrap code in l.s has already mapped;
* MemMax is the limit of physical memory to scan.
*/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "ureg.h"
#define MEMDEBUG 0
u32int MemMin = 8*MB; /* set in l.s */
enum {
MemUPA = 0, /* unbacked physical address */
MemRAM = 1, /* physical memory */
MemUMB = 2, /* upper memory block (<16MB) */
MemReserved = 3,
NMemType = 4,
KB = 1024,
MemMax = (3*1024+768)*MB,
};
typedef struct Map Map;
struct Map {
ulong size;
ulong addr;
};
typedef struct RMap RMap;
struct RMap {
char* name;
Map* map;
Map* mapend;
Lock;
};
/*
* Memory allocation tracking.
*/
static Map mapupa[16];
static RMap rmapupa = {
"unallocated unbacked physical memory",
mapupa,
&mapupa[nelem(mapupa)-1],
};
static Map mapram[16];
static RMap rmapram = {
"physical memory",
mapram,
&mapram[nelem(mapram)-1],
};
static Map mapumb[64];
static RMap rmapumb = {
"upper memory block",
mapumb,
&mapumb[nelem(mapumb)-1],
};
static Map mapumbrw[16];
static RMap rmapumbrw = {
"UMB device memory",
mapumbrw,
&mapumbrw[nelem(mapumbrw)-1],
};
void
mapprint(RMap *rmap)
{
Map *mp;
print("%s\n", rmap->name);
for(mp = rmap->map; mp->size; mp++)
print("\t%8.8luX %8.8luX (%lud)\n", mp->addr, mp->addr+mp->size, mp->size);
}
void
memdebug(void)
{
ulong maxpa, maxpa1, maxpa2;
maxpa = (nvramread(0x18)<<8)|nvramread(0x17);
maxpa1 = (nvramread(0x31)<<8)|nvramread(0x30);
maxpa2 = (nvramread(0x16)<<8)|nvramread(0x15);
print("maxpa = %luX -> %luX, maxpa1 = %luX maxpa2 = %luX\n",
maxpa, MB+maxpa*KB, maxpa1, maxpa2);
mapprint(&rmapram);
mapprint(&rmapumb);
mapprint(&rmapumbrw);
mapprint(&rmapupa);
}
void
mapfree(RMap* rmap, ulong addr, ulong size)
{
Map *mp;
ulong t;
if(size <= 0)
return;
lock(rmap);
for(mp = rmap->map; mp->addr <= addr && mp->size; mp++)
;
if(mp > rmap->map && (mp-1)->addr+(mp-1)->size == addr){
(mp-1)->size += size;
if(addr+size == mp->addr){
(mp-1)->size += mp->size;
while(mp->size){
mp++;
(mp-1)->addr = mp->addr;
(mp-1)->size = mp->size;
}
}
}
else{
if(addr+size == mp->addr && mp->size){
mp->addr -= size;
mp->size += size;
}
else do{
if(mp >= rmap->mapend){
print("mapfree: %s: losing 0x%luX, %ld\n",
rmap->name, addr, size);
break;
}
t = mp->addr;
mp->addr = addr;
addr = t;
t = mp->size;
mp->size = size;
mp++;
}while(size = t);
}
unlock(rmap);
}
ulong
mapalloc(RMap* rmap, ulong addr, int size, int align)
{
Map *mp;
ulong maddr, oaddr;
lock(rmap);
for(mp = rmap->map; mp->size; mp++){
maddr = mp->addr;
if(addr){
/*
* A specific address range has been given:
* if the current map entry is greater then
* the address is not in the map;
* if the current map entry does not overlap
* the beginning of the requested range then
* continue on to the next map entry;
* if the current map entry does not entirely
* contain the requested range then the range
* is not in the map.
*/
if(maddr > addr)
break;
if(mp->size < addr - maddr) /* maddr+mp->size < addr, but no overflow */
continue;
if(addr - maddr > mp->size - size) /* addr+size > maddr+mp->size, but no overflow */
break;
maddr = addr;
}
if(align > 0)
maddr = ((maddr+align-1)/align)*align;
if(mp->addr+mp->size-maddr < size)
continue;
oaddr = mp->addr;
mp->addr = maddr+size;
mp->size -= maddr-oaddr+size;
if(mp->size == 0){
do{
mp++;
(mp-1)->addr = mp->addr;
}while((mp-1)->size = mp->size);
}
unlock(rmap);
if(oaddr != maddr)
mapfree(rmap, oaddr, maddr-oaddr);
return maddr;
}
unlock(rmap);
return 0;
}
/*
* Allocate from the ram map directly to make page tables.
* Called by mmuwalk during e820scan.
*/
void*
rampage(void)
{
ulong m;
m = mapalloc(&rmapram, 0, BY2PG, BY2PG);
if(m == 0)
return nil;
return KADDR(m);
}
static void
umbexclude(void)
{
int size;
ulong addr;
char *op, *p, *rptr;
if((p = getconf("umbexclude")) == nil)
return;
while(p && *p != '\0' && *p != '\n'){
op = p;
addr = strtoul(p, &rptr, 0);
if(rptr == nil || rptr == p || *rptr != '-'){
print("umbexclude: invalid argument <%s>\n", op);
break;
}
p = rptr+1;
size = strtoul(p, &rptr, 0) - addr + 1;
if(size <= 0){
print("umbexclude: bad range <%s>\n", op);
break;
}
if(rptr != nil && *rptr == ',')
*rptr++ = '\0';
p = rptr;
mapalloc(&rmapumb, addr, size, 0);
}
}
static void
umbscan(void)
{
uchar *p;
/*
* Scan the Upper Memory Blocks (0xA0000->0xF0000) for pieces
* which aren't used; they can be used later for devices which
* want to allocate some virtual address space.
* Check for two things:
* 1) device BIOS ROM. This should start with a two-byte header
* of 0x55 0xAA, followed by a byte giving the size of the ROM
* in 512-byte chunks. These ROM's must start on a 2KB boundary.
* 2) device memory. This is read-write.
* There are some assumptions: there's VGA memory at 0xA0000 and
* the VGA BIOS ROM is at 0xC0000. Also, if there's no ROM signature
* at 0xE0000 then the whole 64KB up to 0xF0000 is theoretically up
* for grabs; check anyway.
*/
p = KADDR(0xD0000);
while(p < (uchar*)KADDR(0xE0000)){
/*
* Test for 0x55 0xAA before poking obtrusively,
* some machines (e.g. Thinkpad X20) seem to map
* something dynamic here (cardbus?) causing weird
* problems if it is changed.
*/
if(p[0] == 0x55 && p[1] == 0xAA){
p += p[2]*512;
continue;
}
p[0] = 0xCC;
p[2*KB-1] = 0xCC;
if(p[0] != 0xCC || p[2*KB-1] != 0xCC){
p[0] = 0x55;
p[1] = 0xAA;
p[2] = 4;
if(p[0] == 0x55 && p[1] == 0xAA){
p += p[2]*512;
continue;
}
if(p[0] == 0xFF && p[1] == 0xFF)
mapfree(&rmapumb, PADDR(p), 2*KB);
}
else
mapfree(&rmapumbrw, PADDR(p), 2*KB);
p += 2*KB;
}
p = KADDR(0xE0000);
if(p[0] != 0x55 || p[1] != 0xAA){
p[0] = 0xCC;
p[64*KB-1] = 0xCC;
if(p[0] != 0xCC && p[64*KB-1] != 0xCC)
mapfree(&rmapumb, PADDR(p), 64*KB);
}
umbexclude();
}
int
checksum(void *v, int n)
{
uchar *p, s;
s = 0;
p = v;
while(n-- > 0)
s += *p++;
return s;
}
static void*
sigscan(uchar* addr, int len, char* signature)
{
int sl;
uchar *e, *p;
e = addr+len;
sl = strlen(signature);
for(p = addr; p+sl < e; p += 16)
if(memcmp(p, signature, sl) == 0)
return p;
return nil;
}
static uintptr
convmemsize(void)
{
uintptr top;
uchar *bda;
bda = KADDR(0x400);
top = ((bda[0x14]<<8) | bda[0x13])*KB;
if(top < 64*KB || top > 640*KB)
top = 640*KB; /* sanity */
/* reserved for bios tables (EBDA) */
top -= 1*KB;
return top;
}
void*
sigsearch(char* signature)
{
uintptr p;
uchar *bda;
void *r;
/*
* Search for the data structure:
* 1) within the first KiB of the Extended BIOS Data Area (EBDA), or
* 2) within the last KiB of system base memory if the EBDA segment
* is undefined, or
* 3) within the BIOS ROM address space between 0xf0000 and 0xfffff
* (but will actually check 0xe0000 to 0xfffff).
*/
bda = KADDR(0x400);
if(memcmp(KADDR(0xfffd9), "EISA", 4) == 0){
if((p = (bda[0x0f]<<8)|bda[0x0e]) != 0){
if((r = sigscan(KADDR(p<<4), 1024, signature)) != nil)
return r;
}
}
if((r = sigscan(KADDR(convmemsize()), 1024, signature)) != nil)
return r;
/* hack for virtualbox: look in KiB below 0xa0000 */
if((r = sigscan(KADDR(0xa0000-1024), 1024, signature)) != nil)
return r;
return sigscan(KADDR(0xe0000), 0x20000, signature);
}
static void
lowraminit(void)
{
uintptr pa, x;
/*
* Initialise the memory bank information for conventional memory
* (i.e. less than 640KB). The base is the first location after the
* bootstrap processor MMU information and the limit is obtained from
* the BIOS data area.
*/
x = PADDR(CPU0END);
pa = convmemsize();
if(x < pa){
mapfree(&rmapram, x, pa-x);
memset(KADDR(x), 0, pa-x); /* keep us honest */
}
x = PADDR(PGROUND((uintptr)end));
pa = MemMin;
if(x > pa)
panic("kernel too big");
mapfree(&rmapram, x, pa-x);
memset(KADDR(x), 0, pa-x); /* keep us honest */
}
static void
ramscan(ulong maxmem)
{
ulong *k0, kzero, map, maxkpa, maxpa, pa, *pte, *table, *va, vbase, x;
int nvalid[NMemType];
/*
* The bootstrap code has has created a prototype page
* table which maps the first MemMin of physical memory to KZERO.
* The page directory is at m->pdb and the first page of
* free memory is after the per-processor MMU information.
*/
pa = MemMin;
/*
* Check if the extended memory size can be obtained from the CMOS.
* If it's 0 then it's either not known or >= 64MB. Always check
* at least 24MB in case there's a memory gap (up to 8MB) below 16MB;
* in this case the memory from the gap is remapped to the top of
* memory.
* The value in CMOS is supposed to be the number of KB above 1MB.
*/
if(maxmem == 0){
x = (nvramread(0x18)<<8)|nvramread(0x17);
if(x == 0 || x >= (63*KB))
maxpa = MemMax;
else
maxpa = MB+x*KB;
if(maxpa < 24*MB)
maxpa = 24*MB;
}else
maxpa = maxmem;
maxkpa = (u32int)-KZERO; /* 2^32 - KZERO */
/*
* March up memory from MemMin to maxpa 1MB at a time,
* mapping the first page and checking the page can
* be written and read correctly. The page tables are created here
* on the fly, allocating from low memory as necessary.
*/
k0 = (ulong*)KADDR(0);
kzero = *k0;
map = 0;
x = 0x12345678;
memset(nvalid, 0, sizeof(nvalid));
/*
* Can't map memory to KADDR(pa) when we're walking because
* can only use KADDR for relatively low addresses.
* Instead, map each 4MB we scan to the virtual address range
* MemMin->MemMin+4MB while we are scanning.
*/
vbase = MemMin;
while(pa < maxpa){
/*
* Map the page. Use mapalloc(&rmapram, ...) to make
* the page table if necessary, it will be returned to the
* pool later if it isn't needed. Map in a fixed range (the second 4M)
* because high physical addresses cannot be passed to KADDR.
*/
va = (void*)(vbase + pa%(4*MB));
table = &m->pdb[PDX(va)];
if(pa%(4*MB) == 0){
if(map == 0 && (map = mapalloc(&rmapram, 0, BY2PG, BY2PG)) == 0)
break;
memset(KADDR(map), 0, BY2PG);
*table = map|PTEWRITE|PTEVALID;
memset(nvalid, 0, sizeof(nvalid));
}
table = KADDR(PPN(*table));
pte = &table[PTX(va)];
*pte = pa|PTEWRITE|PTEUNCACHED|PTEVALID;
mmuflushtlb(PADDR(m->pdb));
/*
* Write a pattern to the page and write a different
* pattern to a possible mirror at KZERO. If the data
* reads back correctly the chunk is some type of RAM (possibly
* a linearly-mapped VGA framebuffer, for instance...) and
* can be cleared and added to the memory pool. If not, the
* chunk is marked uncached and added to the UMB pool if <16MB
* or is marked invalid and added to the UPA pool.
*/
*va = x;
*k0 = ~x;
if(*va == x){
nvalid[MemRAM] += MB/BY2PG;
mapfree(&rmapram, pa, MB);
do{
*pte++ = pa|PTEWRITE|PTEVALID;
pa += BY2PG;
}while(pa % MB);
mmuflushtlb(PADDR(m->pdb));
/* memset(va, 0, MB); so damn slow to memset all of memory */
}
else if(pa < 16*MB){
nvalid[MemUMB] += MB/BY2PG;
mapfree(&rmapumb, pa, MB);
do{
*pte++ = pa|PTEWRITE|PTEUNCACHED|PTEVALID;
pa += BY2PG;
}while(pa % MB);
}
else{
nvalid[MemUPA] += MB/BY2PG;
mapfree(&rmapupa, pa, MB);
*pte = 0;
pa += MB;
}
/*
* Done with this 4MB chunk, review the options:
* 1) not physical memory and >=16MB - invalidate the PDB entry;
* 2) physical memory - use the 4MB page extension if possible;
* 3) not physical memory and <16MB - use the 4MB page extension
* if possible;
* 4) mixed or no 4MB page extension - commit the already
* initialised space for the page table.
*/
if(pa%(4*MB) == 0 && pa >= 32*MB && nvalid[MemUPA] == (4*MB)/BY2PG){
/*
* If we encounter a 4MB chunk of missing memory
* at a sufficiently high offset, call it the end of
* memory. Otherwise we run the risk of thinking
* that video memory is real RAM.
*/
break;
}
if(pa <= maxkpa && pa%(4*MB) == 0){
table = &m->pdb[PDX(KADDR(pa - 4*MB))];
if(nvalid[MemUPA] == (4*MB)/BY2PG)
*table = 0;
else if(nvalid[MemRAM] == (4*MB)/BY2PG && (m->cpuiddx & Pse))
*table = (pa - 4*MB)|PTESIZE|PTEWRITE|PTEVALID;
else if(nvalid[MemUMB] == (4*MB)/BY2PG && (m->cpuiddx & Pse))
*table = (pa - 4*MB)|PTESIZE|PTEWRITE|PTEUNCACHED|PTEVALID;
else{
*table = map|PTEWRITE|PTEVALID;
map = 0;
}
}
mmuflushtlb(PADDR(m->pdb));
x += 0x3141526;
}
/*
* If we didn't reach the end of the 4MB chunk, that part won't
* be mapped. Commit the already initialised space for the page table.
*/
if(pa % (4*MB) && pa <= maxkpa){
m->pdb[PDX(KADDR(pa))] = map|PTEWRITE|PTEVALID;
map = 0;
}
if(map)
mapfree(&rmapram, map, BY2PG);
m->pdb[PDX(vbase)] = 0;
mmuflushtlb(PADDR(m->pdb));
mapfree(&rmapupa, pa, (u32int)-pa);
*k0 = kzero;
}
typedef struct Emap Emap;
struct Emap
{
int type;
uvlong base;
uvlong top;
};
static Emap emap[128];
int nemap;
static int
emapcmp(const void *va, const void *vb)
{
Emap *a, *b;
a = (Emap*)va;
b = (Emap*)vb;
if(a->top < b->top)
return -1;
if(a->top > b->top)
return 1;
if(a->base < b->base)
return -1;
if(a->base > b->base)
return 1;
return 0;
}
static void
map(ulong base, ulong len, int type)
{
ulong e, n;
ulong *table, flags, maxkpa;
/*
* Split any call crossing MemMin to make below simpler.
*/
if(base < MemMin && len > MemMin-base){
n = MemMin - base;
map(base, n, type);
map(MemMin, len-n, type);
}
/*
* Let lowraminit and umbscan hash out the low MemMin.
*/
if(base < MemMin)
return;
/*
* Any non-memory below 16*MB is used as upper mem blocks.
*/
if(type == MemUPA && base < 16*MB && len > 16*MB-base){
map(base, 16*MB-base, MemUMB);
map(16*MB, len-(16*MB-base), MemUPA);
return;
}
/*
* Memory below CPU0END is reserved for the kernel
* and already mapped.
*/
if(base < PADDR(CPU0END)){
n = PADDR(CPU0END) - base;
if(len <= n)
return;
map(PADDR(CPU0END), len-n, type);
return;
}
/*
* Memory between KTZERO and end is the kernel itself
* and is already mapped.
*/
if(base < PADDR(KTZERO) && len > PADDR(KTZERO)-base){
map(base, PADDR(KTZERO)-base, type);
return;
}
if(PADDR(KTZERO) < base && base < PADDR(PGROUND((ulong)end))){
n = PADDR(PGROUND((ulong)end));
if(len <= n)
return;
map(PADDR(PGROUND((ulong)end)), len-n, type);
return;
}
/*
* Now we have a simple case.
*/
// print("map %.8lux %.8lux %d\n", base, base+len, type);
switch(type){
case MemRAM:
mapfree(&rmapram, base, len);
flags = PTEWRITE|PTEVALID;
break;
case MemUMB:
mapfree(&rmapumb, base, len);
flags = PTEWRITE|PTEUNCACHED|PTEVALID;
break;
case MemUPA:
mapfree(&rmapupa, base, len);
flags = 0;
break;
default:
case MemReserved:
flags = 0;
break;
}
/*
* bottom MemMin is already mapped - just twiddle flags.
* (not currently used - see above)
*/
if(base < MemMin){
table = KADDR(PPN(m->pdb[PDX(base)]));
e = base+len;
base = PPN(base);
for(; base<e; base+=BY2PG)
table[PTX(base)] |= flags;
return;
}
/*
* Only map from KZERO to 2^32.
*/
if(flags){
maxkpa = -KZERO;
if(base >= maxkpa)
return;
if(len > maxkpa-base)
len = maxkpa - base;
pdbmap(m->pdb, base|flags, base+KZERO, len);
}
}
static int
e820scan(void)
{
ulong base, len, last;
Emap *e;
char *s;
int i;
/* passed by bootloader */
if((s = getconf("*e820")) == nil)
if((s = getconf("e820")) == nil)
return -1;
nemap = 0;
while(nemap < nelem(emap)){
while(*s == ' ')
s++;
if(*s == 0)
break;
e = emap + nemap;
e->type = 1;
if(s[1] == ' '){ /* new format */
e->type = s[0] - '0';
s += 2;
}
e->base = strtoull(s, &s, 16);
if(*s != ' ')
break;
e->top = strtoull(s, &s, 16);
if(*s != ' ' && *s != 0)
break;
if(e->base < e->top)
nemap++;
}
if(nemap == 0)
return -1;
qsort(emap, nemap, sizeof emap[0], emapcmp);
last = 0;
for(i=0; i<nemap; i++){
e = &emap[i];
/*
* pull out the info but only about the low 32 bits...
*/
if(e->base >= (1ULL<<32))
break;
if(e->top <= last)
continue;
if(e->base < last)
base = last;
else
base = e->base;
if(e->top > (1ULL<<32))
len = -base;
else
len = e->top - base;
/*
* If the map skips addresses, mark them available.
*/
if(last < base)
map(last, base-last, MemUPA);
map(base, len, (e->type == 1) ? MemRAM : MemReserved);
last = base + len;
if(last == 0)
break;
}
if(last != 0)
map(last, -last, MemUPA);
return 0;
}
void
meminit(void)
{
int i;
Map *mp;
Confmem *cm;
ulong pa, *pte;
ulong maxmem, lost;
char *p;
if(p = getconf("*maxmem"))
maxmem = strtoul(p, 0, 0);
else
maxmem = 0;
/*
* Set special attributes for memory between 640KB and 1MB:
* VGA memory is writethrough;
* BIOS ROM's/UMB's are uncached;
* then scan for useful memory.
*/
for(pa = 0xA0000; pa < 0xC0000; pa += BY2PG){
pte = mmuwalk(m->pdb, (ulong)KADDR(pa), 2, 0);
*pte |= PTEWT;
}
for(pa = 0xC0000; pa < 0x100000; pa += BY2PG){
pte = mmuwalk(m->pdb, (ulong)KADDR(pa), 2, 0);
*pte |= PTEUNCACHED;
}
mmuflushtlb(PADDR(m->pdb));
umbscan();
lowraminit();
if(e820scan() < 0)
ramscan(maxmem);
/*
* Set the conf entries describing banks of allocatable memory.
*/
for(i=0; i<nelem(mapram) && i<nelem(conf.mem); i++){
mp = &rmapram.map[i];
cm = &conf.mem[i];
cm->base = mp->addr;
cm->npage = mp->size/BY2PG;
}
lost = 0;
for(; i<nelem(mapram); i++)
lost += rmapram.map[i].size;
if(lost)
print("meminit - lost %lud bytes\n", lost);
if(MEMDEBUG)
memdebug();
}
/*
* Allocate memory from the upper memory blocks.
*/
ulong
umbmalloc(ulong addr, int size, int align)
{
ulong a;
if(a = mapalloc(&rmapumb, addr, size, align))
return (ulong)KADDR(a);
return 0;
}
void
umbfree(ulong addr, int size)
{
mapfree(&rmapumb, PADDR(addr), size);
}
ulong
umbrwmalloc(ulong addr, int size, int align)
{
ulong a;
uchar *p;
if(a = mapalloc(&rmapumbrw, addr, size, align))
return(ulong)KADDR(a);
/*
* Perhaps the memory wasn't visible before
* the interface is initialised, so try again.
*/
if((a = umbmalloc(addr, size, align)) == 0)
return 0;
p = (uchar*)a;
p[0] = 0xCC;
p[size-1] = 0xCC;
if(p[0] == 0xCC && p[size-1] == 0xCC)
return a;
umbfree(a, size);
return 0;
}
void
umbrwfree(ulong addr, int size)
{
mapfree(&rmapumbrw, PADDR(addr), size);
}
/*
* Give out otherwise-unused physical address space
* for use in configuring devices. Note that upaalloc
* does not map the physical address into virtual memory.
* Call vmap to do that.
*/
ulong
upaalloc(int size, int align)
{
ulong a;
a = mapalloc(&rmapupa, 0, size, align);
if(a == 0){
print("out of physical address space allocating %d\n", size);
mapprint(&rmapupa);
}
return a;
}
void
upafree(ulong pa, int size)
{
mapfree(&rmapupa, pa, size);
}
void
upareserve(ulong pa, int size)
{
ulong a;
a = mapalloc(&rmapupa, pa, size, 0);
if(a != pa){
/*
* This can happen when we're using the E820
* map, which might have already reserved some
* of the regions claimed by the pci devices.
*/
// print("upareserve: cannot reserve pa=%#.8lux size=%d\n", pa, size);
if(a != 0)
mapfree(&rmapupa, a, size);
}
}
void
memorysummary(void)
{
memdebug();
}