ref: f39abb2923ac5faf55ce283e925671d639f3b9b9
dir: /sys/src/9/pc/memory.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "ureg.h"
enum {
MemUPA = 0, /* unbacked physical address */
MemUMB = 1, /* upper memory block (<16MB) */
MemRAM = 2, /* physical memory */
MemACPI = 3, /* ACPI tables */
MemReserved = 4, /* don't allocate */
KB = 1024,
};
u32int MemMin; /* set by l.s */
void*
rampage(void)
{
uintptr pa;
if(conf.mem[0].npage != 0)
return xspanalloc(BY2PG, BY2PG, 0);
/*
* Allocate from the map directly to make page tables.
*/
pa = memmapalloc(-1, BY2PG, BY2PG, MemRAM);
if(pa == -1 || cankaddr(pa) == 0)
panic("rampage: out of memory\n");
return KADDR(pa);
}
static void
mapkzero(uintptr base, uintptr len, int type)
{
uintptr flags, n;
if(base < MemMin && base+len > MemMin){
mapkzero(base, MemMin-base, type);
len = base+len-MemMin;
base = MemMin;
}
n = cankaddr(base);
if(n == 0)
return;
if(len > n)
len = n;
switch(type){
default:
return;
case MemRAM:
if(base < MemMin)
return;
flags = PTEWRITE|PTEVALID;
break;
case MemUMB:
if(base < MemMin)
punmap(base+KZERO, len);
flags = PTEWRITE|PTEUNCACHED|PTEVALID;
break;
}
#ifdef PTENOEXEC
flags |= PTENOEXEC;
#endif
pmap(base|flags, base+KZERO, len);
}
static uintptr
ebdaseg(void)
{
uchar *bda;
if(memcmp(KADDR(0xfffd9), "EISA", 4) != 0)
return 0;
bda = KADDR(0x400);
return ((bda[0x0f]<<8)|bda[0x0e]) << 4;
}
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 */
top -= 1*KB;
return top;
}
static void
lowraminit(void)
{
uintptr base, pa, len;
uchar *p;
/*
* Discover 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.
*/
base = PADDR(CPU0END);
pa = convmemsize();
if(base < pa)
memmapadd(base, pa-base, MemRAM);
/* Reserve BIOS tables */
memmapadd(pa, 1*KB, MemReserved);
/* Reserve EBDA */
if((pa = ebdaseg()) != 0)
memmapadd(pa, 1*KB, MemReserved);
memmapadd(0xA0000-1*KB, 1*KB, MemReserved);
/* Reserve the VGA frame buffer */
umballoc(0xA0000, 128*KB, 0);
/* Reserve VGA ROM */
memmapadd(0xC0000, 64*KB, MemReserved);
/*
* Scan the Upper Memory Blocks (0xD0000->0xF0000) for device BIOS ROMs.
* 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.
*/
for(p = (uchar*)KADDR(0xD0000); p < (uchar*)KADDR(0xF0000); p += len){
len = 2*KB;
if(p[0] == 0x55 && p[1] == 0xAA){
if(p[2] != 0)
len = p[2]*512;
memmapadd(PADDR(p), len, MemReserved);
len = ROUND(len, 2*KB);
}
}
/* Reserve BIOS ROM */
memmapadd(0xF0000, 64*KB, MemReserved);
}
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 *sig, int size, int step)
{
uchar *e, *p;
int sl;
sl = strlen(sig);
e = addr+len-(size > sl ? size : sl);
for(p = addr; p <= e; p += step){
if(memcmp(p, sig, sl) != 0)
continue;
if(size && checksum(p, size) != 0)
continue;
return p;
}
return nil;
}
void*
sigsearch(char* signature, int size)
{
uintptr p;
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).
*/
if((p = ebdaseg()) != 0){
if((r = sigscan(KADDR(p), 1*KB, signature, size, 16)) != nil)
return r;
}
if((r = sigscan(KADDR(convmemsize()), 1*KB, signature, size, 16)) != nil)
return r;
/* hack for virtualbox: look in KiB below 0xa0000 */
if((r = sigscan(KADDR(0xA0000-1*KB), 1*KB, signature, size, 16)) != nil)
return r;
return sigscan(KADDR(0xE0000), 128*KB, signature, size, 16);
}
void*
rsdsearch(void)
{
static char signature[] = "RSD PTR ";
uintptr base, size;
uchar *v, *p;
if((p = sigsearch(signature, 36)) != nil)
return p;
if((p = sigsearch(signature, 20)) != nil)
return p;
for(base = memmapnext(-1, MemACPI); base != -1; base = memmapnext(base, MemACPI)){
size = memmapsize(base, 0);
if(size == 0 || size > 0x7fffffff)
continue;
if((v = vmap(base, size)) != nil){
p = sigscan(v, size, signature, 36, 4);
if(p == nil)
p = sigscan(v, size, signature, 20, 4);
vunmap(v, size);
if(p != nil)
return vmap(base + (p - v), 64);
}
}
return nil;
}
/*
* 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.
*/
uvlong
upaalloc(uvlong pa, uvlong size, uvlong align)
{
return memmapalloc(pa, size, align, MemUPA);
}
uvlong
upaallocwin(uvlong pa, uvlong win, uvlong size, uvlong align)
{
uvlong a, base, top = pa + win;
for(base = memmapnext(-1, MemUPA); base != -1 && base < top; base = memmapnext(base, MemUPA)){
if(base < pa){
if(pa >= base + memmapsize(base, 0))
continue;
base = pa;
}
a = upaalloc(base, size, align);
if(a != -1)
return a;
}
return -1ULL;
}
void
upafree(uvlong pa, uvlong size)
{
memmapfree(pa, size, MemUPA);
}
/*
* Allocate memory from the upper memory blocks.
*/
ulong
umballoc(ulong pa, ulong size, ulong align)
{
return (ulong)memmapalloc(pa == -1UL ? -1ULL : (uvlong)pa, size, align, MemUMB);
}
void
umbfree(ulong pa, ulong size)
{
memmapfree(pa, size, MemUMB);
}
static void
umbexclude(void)
{
ulong pa, size;
char *op, *p, *rptr;
if((p = getconf("umbexclude")) == nil)
return;
while(p && *p != '\0' && *p != '\n'){
op = p;
pa = 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) - pa + 1;
if(size <= 0){
print("umbexclude: bad range <%s>\n", op);
break;
}
if(rptr != nil && *rptr == ',')
*rptr++ = '\0';
p = rptr;
memmapalloc(pa, size, 0, MemUMB);
}
}
static void
mtrrexclude(int type, char *expect)
{
uvlong base, top, next, pa;
char *attr;
for(base = memmapnext(-1, type); base != -1; base = memmapnext(base, type)){
top = base + memmapsize(base, 0);
for(pa = base; pa < top; pa = next){
next = top;
attr = mtrrattr(pa, &next);
if(attr != nil && strcmp(attr, expect) != 0){
if(next > top)
next = top;
memmapadd(pa, next - pa, MemReserved);
}
base = pa;
}
}
}
static int
e820scan(void)
{
uvlong base, top, size;
int type;
char *s;
/* passed by bootloader */
if((s = getconf("*e820")) == nil)
if((s = getconf("e820")) == nil)
return -1;
for(;;){
while(*s == ' ')
s++;
if(*s == 0)
break;
type = 1;
if(s[1] == ' '){ /* new format */
type = s[0] - '0';
s += 2;
}
base = strtoull(s, &s, 16);
if(*s != ' ')
break;
top = strtoull(s, &s, 16);
if(*s != ' ' && *s != 0)
break;
if(base >= top)
continue;
switch(type){
case 1:
memmapadd(base, top - base, MemRAM);
break;
case 3:
memmapadd(base, top - base, MemACPI);
break;
default:
memmapadd(base, top - base, MemReserved);
}
}
/* RAM needs to be writeback */
mtrrexclude(MemRAM, "wb");
for(base = memmapnext(-1, MemRAM); base != -1; base = memmapnext(base, MemRAM)){
size = memmapsize(base, BY2PG) & ~(BY2PG-1);
if(size != 0)
mapkzero(PGROUND(base), size, MemRAM);
}
return 0;
}
static void
ramscan(uintptr pa, uintptr top, uintptr chunk)
{
ulong save, pat, seed, *v, *k0;
int i, n, w;
char *attr;
pa += chunk-1;
pa &= ~(chunk-1);
top &= ~(chunk-1);
n = chunk/sizeof(*v);
w = BY2PG/sizeof(*v);
k0 = KADDR(0);
save = *k0;
pat = 0x12345678UL;
for(; pa < top; pa += chunk){
attr = mtrrattr(pa, nil);
if(attr != nil && strcmp(attr, "wb") != 0)
goto Skip;
/* write pattern */
seed = pat;
if((v = vmap(pa, chunk)) == nil)
continue;
for(i = 0; i < n; i += w){
pat += 0x3141526UL;
v[i] = pat;
*k0 = ~pat;
if(v[i] != pat)
goto Bad;
}
vunmap(v, chunk);
/* verify pattern */
pat = seed;
if((v = vmap(pa, chunk)) == nil)
continue;
for(i = 0; i < n; i += w){
pat += 0x3141526UL;
if(v[i] != pat)
goto Bad;
}
vunmap(v, chunk);
memmapadd(pa, chunk, MemRAM);
mapkzero(pa, chunk, MemRAM);
continue;
Bad:
vunmap(v, chunk);
Skip:
if(pa+chunk <= 16*MB)
memmapadd(pa, chunk, MemUMB);
/*
* If we encounter a 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.
*/
if(pa >= 32*MB)
break;
}
*k0 = save;
}
/*
* Sort out initial memory map and discover RAM.
*/
void
meminit0(void)
{
/*
* Add the already mapped memory after the kernel.
*/
if(MemMin < PADDR(PGROUND((uintptr)end)))
panic("kernel too big");
memmapadd(PADDR(PGROUND((uintptr)end)), MemMin-PADDR(PGROUND((uintptr)end)), MemRAM);
/*
* Memory between KTZERO and end is the kernel itself.
*/
memreserve(PADDR(KTZERO), PADDR(PGROUND((uintptr)end))-PADDR(KTZERO));
/*
* Memory below CPU0END is reserved for the kernel.
*/
memreserve(0, PADDR(CPU0END));
/*
* Addresses below 16MB default to be upper
* memory blocks usable for ISA devices.
*/
memmapadd(0, 16*MB, MemUMB);
/*
* Everything between 16MB and 4GB defaults
* to unbacked physical addresses usable for
* device mappings.
*/
memmapadd(16*MB, (u32int)-16*MB, MemUPA);
/*
* On 386, reserve >= 4G as we have no PAE support.
*/
if(sizeof(void*) == 4)
memmapadd((u32int)-BY2PG, -((uvlong)((u32int)-BY2PG)), MemReserved);
/*
* Discover conventional RAM, ROMs and UMBs.
*/
lowraminit();
/*
* Discover more RAM and map to KZERO.
*/
if(e820scan() < 0)
ramscan(MemMin, -((uintptr)MemMin), 4*MB);
/*
* Exclude UMB's and UPA's with unusual cache attributes.
*/
mtrrexclude(MemUMB, "uc");
mtrrexclude(MemUPA, "uc");
}
/*
* Until the memory map is finalized by meminit(),
* archinit() should reserve memory of discovered BIOS
* and ACPI tables by calling memreserve() to prevent
* them from getting allocated and trashed.
* This is due to the UEFI and BIOS memory map being
* unreliable and sometimes marking these ranges as RAM.
*/
void
memreserve(uintptr pa, uintptr size)
{
assert(conf.mem[0].npage == 0);
size += (pa & BY2PG-1);
size &= ~(BY2PG-1);
pa &= ~(BY2PG-1);
memmapadd(pa, size, MemReserved);
}
/*
* Finalize the memory map:
* (re-)map the upper memory blocks
* allocate all usable ram to the conf.mem[] banks
*/
void
meminit(void)
{
uintptr base, size;
Confmem *cm;
umbexclude();
for(base = memmapnext(-1, MemUMB); base != -1; base = memmapnext(base, MemUMB)){
size = memmapsize(base, BY2PG) & ~(BY2PG-1);
if(size != 0)
mapkzero(PGROUND(base), size, MemUMB);
}
cm = &conf.mem[0];
for(base = memmapnext(-1, MemRAM); base != -1; base = memmapnext(base, MemRAM)){
size = memmapsize(base, BY2PG) & ~(BY2PG-1);
if(size == 0)
continue;
if(cm >= &conf.mem[nelem(conf.mem)]){
print("meminit: out of entries, loosing: %#p (%llud)\n", base, (uvlong)size);
continue;
}
cm->base = memmapalloc(base, size, BY2PG, MemRAM);
if(cm->base == -1)
continue;
base = cm->base;
cm->npage = size/BY2PG;
cm++;
}
if(0) memmapdump();
}