#include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "io.h" #include "mp.h" #define	cpuserver	1 _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), 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,.fastclock=	i8253read,.timerset=	lapictimerset,}; static intidentify(void){	PCMP *pcmp;	uchar *p, sum;	ulong length; 	if(getconf("*nomp"))		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; voidsyncclock(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);	}} uvlongtscticks(uvlong *hz){	if(hz != nil)		*hz = m->cpuhz; 	cycles(&m->tscticks);	/* Uses the rdtsc instruction */	return m->tscticks;}