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More complete lapic startup (thanks Silas)

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rsc 2007-11-28 20:47:10 +00:00
parent a6c4711a38
commit 4f06ae0d42
1 changed files with 25 additions and 7 deletions
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32
lapic.c
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@ -102,7 +102,8 @@ cpu(void)
if(read_eflags()&FL_IF){
static int n;
if(n++ == 0)
cprintf("cpu called from %x with interrupts enabled\n", ((uint*)read_ebp())[1]);
cprintf("cpu called from %x with interrupts enabled\n",
((uint*)read_ebp())[1]);
}
if(lapic)
@ -129,25 +130,42 @@ microdelay(int us)
for(j=0; j<10000; j++);
}
#define IO_RTC 0x70
// Start additional processor running bootstrap code at addr.
// See Appendix B of MultiProcessor Specification.
void
lapic_startap(uchar apicid, uint addr)
{
int i;
volatile int j = 0;
ushort *wrv;
// Send INIT interrupt to reset other CPU.
// "The BSP must initialize CMOS shutdown code to 0AH
// and the warm reset vector (DWORD based at 40:67) to point at
// the AP startup code prior to the [universal startup algorithm]."
outb(IO_RTC, 0xF); // offset 0xF is shutdown code
outb(IO_RTC+1, 0x0A);
wrv = (ushort*)(0x40<<4 | 0x67); // Warm reset vector
wrv[0] = 0;
wrv[1] = addr >> 4;
// "Universal startup algorithm."
// Send INIT (level-triggered) interrupt to reset other CPU.
lapicw(ICRHI, apicid<<24);
lapicw(ICRLO, INIT | LEVEL | ASSERT);
microdelay(200);
lapicw(ICRLO, INIT | LEVEL);
microdelay(10);
microdelay(100); // should be 10ms, but too slow in Bochs!
// Send startup IPI (twice!) to enter bootstrap code.
// Regular hardware wants it twice, but Bochs complains.
// Too bad for Bochs.
// Regular hardware is supposed to only accept a STARTUP
// when it is in the halted state due to an INIT. So the second
// should be ignored, but it is part of the official Intel algorithm.
// Bochs complains about the second one. Too bad for Bochs.
for(i = 0; i < 2; i++){
lapicw(ICRHI, apicid<<24);
lapicw(ICRLO, STARTUP | (addr>>12));
for(j=0; j<10000; j++); // 200us
microdelay(200);
}
}