142 lines
3.6 KiB
C
142 lines
3.6 KiB
C
// Multiprocessor support
|
|
// Search memory for MP description structures.
|
|
// http://developer.intel.com/design/pentium/datashts/24201606.pdf
|
|
|
|
#include "types.h"
|
|
#include "defs.h"
|
|
#include "param.h"
|
|
#include "memlayout.h"
|
|
#include "mp.h"
|
|
#include "x86.h"
|
|
#include "mmu.h"
|
|
#include "proc.h"
|
|
|
|
struct cpu cpus[NCPU];
|
|
int ncpu;
|
|
uchar ioapicid;
|
|
|
|
static uchar sum(uchar *addr, int len) {
|
|
int i, sum;
|
|
|
|
sum = 0;
|
|
for (i = 0; i < len; i++) {
|
|
sum += addr[i];
|
|
}
|
|
return sum;
|
|
}
|
|
|
|
// Look for an MP structure in the len bytes at addr.
|
|
static struct mp*mpsearch1(uint a, int len) {
|
|
uchar *e, *p, *addr;
|
|
|
|
addr = P2V(a);
|
|
e = addr + len;
|
|
for (p = addr; p < e; p += sizeof(struct mp)) {
|
|
if (memcmp(p, "_MP_", 4) == 0 && sum(p, sizeof(struct mp)) == 0) {
|
|
return (struct mp*)p;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
// Search for the MP Floating Pointer Structure, which according to the
|
|
// spec is in one of the following three locations:
|
|
// 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.
|
|
static struct mp*mpsearch(void) {
|
|
uchar *bda;
|
|
uint p;
|
|
struct mp *mp;
|
|
|
|
bda = (uchar *) P2V(0x400);
|
|
if ((p = ((bda[0x0F] << 8) | bda[0x0E]) << 4)) {
|
|
if ((mp = mpsearch1(p, 1024))) {
|
|
return mp;
|
|
}
|
|
}
|
|
else {
|
|
p = ((bda[0x14] << 8) | bda[0x13]) * 1024;
|
|
if ((mp = mpsearch1(p - 1024, 1024))) {
|
|
return mp;
|
|
}
|
|
}
|
|
return mpsearch1(0xF0000, 0x10000);
|
|
}
|
|
|
|
// 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.
|
|
static struct mpconf*mpconfig(struct mp **pmp) {
|
|
struct mpconf *conf;
|
|
struct mp *mp;
|
|
|
|
if ((mp = mpsearch()) == 0 || mp->physaddr == 0) {
|
|
return 0;
|
|
}
|
|
conf = (struct mpconf*) P2V((uint) mp->physaddr);
|
|
if (memcmp(conf, "PCMP", 4) != 0) {
|
|
return 0;
|
|
}
|
|
if (conf->version != 1 && conf->version != 4) {
|
|
return 0;
|
|
}
|
|
if (sum((uchar*)conf, conf->length) != 0) {
|
|
return 0;
|
|
}
|
|
*pmp = mp;
|
|
return conf;
|
|
}
|
|
|
|
void mpinit(void) {
|
|
uchar *p, *e;
|
|
int ismp;
|
|
struct mp *mp;
|
|
struct mpconf *conf;
|
|
struct mpproc *proc;
|
|
struct mpioapic *ioapic;
|
|
|
|
if ((conf = mpconfig(&mp)) == 0) {
|
|
panic("Expect to run on an SMP");
|
|
}
|
|
ismp = 1;
|
|
lapic = (uint*)conf->lapicaddr;
|
|
for (p = (uchar*)(conf + 1), e = (uchar*)conf + conf->length; p < e;) {
|
|
switch (*p) {
|
|
case MPPROC:
|
|
proc = (struct mpproc*)p;
|
|
if (ncpu < NCPU) {
|
|
cpus[ncpu].apicid = proc->apicid; // apicid may differ from ncpu
|
|
ncpu++;
|
|
}
|
|
p += sizeof(struct mpproc);
|
|
continue;
|
|
case MPIOAPIC:
|
|
ioapic = (struct mpioapic*)p;
|
|
ioapicid = ioapic->apicno;
|
|
p += sizeof(struct mpioapic);
|
|
continue;
|
|
case MPBUS:
|
|
case MPIOINTR:
|
|
case MPLINTR:
|
|
p += 8;
|
|
continue;
|
|
default:
|
|
ismp = 0;
|
|
break;
|
|
}
|
|
}
|
|
if (!ismp) {
|
|
panic("Didn't find a suitable machine");
|
|
}
|
|
|
|
if (mp->imcrp) {
|
|
// Bochs doesn't support IMCR, so this doesn't run on Bochs.
|
|
// But it would on real hardware.
|
|
outb(0x22, 0x70); // Select IMCR
|
|
outb(0x23, inb(0x23) | 1); // Mask external interrupts.
|
|
}
|
|
}
|