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#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "mp.h"
_MP_ *_mp_;
static _MP_*
mpscan(uchar *addr, int len)
{
uchar *e, *p, sum;
int i;
e = addr+len;
for(p = addr; p < e; p += sizeof(_MP_)){
if(memcmp(p, "_MP_", 4))
continue;
sum = 0;
for(i = 0; i < sizeof(_MP_); i++)
sum += p[i];
if(sum == 0)
return (_MP_*)p;
}
return 0;
}
static _MP_*
mpsearch(void)
{
uchar *bda;
ulong p;
_MP_ *mp;
/*
* Search for the MP Floating Pointer Structure:
* 1) in the first KB of the EBDA;
* 2) in the last KB of system base memory;
* 3) in the BIOS ROM between 0xE0000 and 0xFFFFF.
*/
bda = KADDR(0x400);
if((p = (bda[0x0F]<<8)|bda[0x0E])){
if(mp = mpscan(KADDR(p<<4), 1024))
return mp;
}
else{
p = ((bda[0x14]<<8)|bda[0x13])*1024;
if(mp = mpscan(KADDR(p-1024), 1024))
return mp;
}
return mpscan(KADDR(0xF0000), 0x10000);
}
static int identify(void);
PCArch archmp = {
.id= "_MP_",
.ident= identify,
.reset= mpshutdown,
.intrinit= mpinit,
.intrenable= mpintrenable,
.intron= lapicintron,
.introff= lapicintroff,
.fastclock= i8253read,
.timerset= lapictimerset,
};
static int
identify(void)
{
char *cp;
PCMP *pcmp;
uchar *p, sum;
ulong length;
if((cp = getconf("*nomp")) != nil && strtol(cp, 0, 0) != 0)
return 1;
/*
* Search for an MP configuration table. For now,
* don't accept the default configurations (physaddr == 0).
* Check for correct signature, calculate the checksum and,
* if correct, check the version.
* To do: check extended table checksum.
*/
if((_mp_ = mpsearch()) == 0 || _mp_->physaddr == 0)
return 1;
pcmp = KADDR(_mp_->physaddr);
if(memcmp(pcmp, "PCMP", 4))
return 1;
length = pcmp->length;
sum = 0;
for(p = (uchar*)pcmp; length; length--)
sum += *p++;
if(sum || (pcmp->version != 1 && pcmp->version != 4))
return 1;
if(cpuserver && m->havetsc)
archmp.fastclock = tscticks;
return 0;
}
Lock mpsynclock;
void
syncclock(void)
{
uvlong x;
if(arch->fastclock != tscticks)
return;
if(m->machno == 0){
wrmsr(0x10, 0);
m->tscticks = 0;
} else {
x = MACHP(0)->tscticks;
while(x == MACHP(0)->tscticks)
;
wrmsr(0x10, MACHP(0)->tscticks);
cycles(&m->tscticks);
}
}
uvlong
tscticks(uvlong *hz)
{
if(hz != nil)
*hz = m->cpuhz;
cycles(&m->tscticks); /* Uses the rdtsc instruction */
return m->tscticks;
}
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