Bricoles/xv6-riscv
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Commit to running on an SMP (perhaps with only 1 core). Remove most code

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from picirq.c and remove timer.c completely.  Update runoff.list.
This commit is contained in:
Frans Kaashoek 2017-08-09 07:43:06 -04:00
parent 70705966ad
commit 4f14d8d1e5
10 changed files with 6 additions and 125 deletions
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1
Makefile
View file

@ -22,7 +22,6 @@ OBJS = \
syscall.o\
sysfile.o\
sysproc.o\
timer.o\
trapasm.o\
trap.o\
uart.o\

1
console.c
View file

@ -294,7 +294,6 @@ consoleinit(void)
devsw[CONSOLE].read = consoleread;
cons.locking = 1;
picenable(IRQ_KBD);
ioapicenable(IRQ_KBD, 0);
}

1
ide.c
View file

@ -53,7 +53,6 @@ ideinit(void)
int i;
initlock(&idelock, "ide");
picenable(IRQ_IDE);
ioapicenable(IRQ_IDE, ncpu - 1);
idewait(0);

6
ioapic.c
View file

@ -50,9 +50,6 @@ ioapicinit(void)
{
int i, id, maxintr;
if(!ismp)
return;
ioapic = (volatile struct ioapic*)IOAPIC;
maxintr = (ioapicread(REG_VER) >> 16) & 0xFF;
id = ioapicread(REG_ID) >> 24;
@ -70,9 +67,6 @@ ioapicinit(void)
void
ioapicenable(int irq, int cpunum)
{
if(!ismp)
return;
// Mark interrupt edge-triggered, active high,
// enabled, and routed to the given cpunum,
// which happens to be that cpu's APIC ID.

4
main.c
View file

@ -22,7 +22,7 @@ main(void)
mpinit(); // detect other processors
lapicinit(); // interrupt controller
seginit(); // segment descriptors
picinit(); // another interrupt controller
picinit(); // disable pic
ioapicinit(); // another interrupt controller
consoleinit(); // console hardware
uartinit(); // serial port
@ -31,8 +31,6 @@ main(void)
binit(); // buffer cache
fileinit(); // file table
ideinit(); // disk
if(!ismp)
timerinit(); // uniprocessor timer
startothers(); // start other processors
kinit2(P2V(4*1024*1024), P2V(PHYSTOP)); // must come after startothers()
userinit(); // first user process

13
mp.c
View file

@ -12,7 +12,6 @@
#include "proc.h"
struct cpu cpus[NCPU];
int ismp;
int ncpu;
uchar ioapicid;
@ -93,13 +92,14 @@ 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)
return;
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; ){
@ -127,13 +127,8 @@ mpinit(void)
break;
}
}
if(!ismp){
// Didn't like what we found; fall back to no MP.
ncpu = 1;
lapic = 0;
ioapicid = 0;
return;
}
if(!ismp)
panic("Didn't find a suitable machine");
if(mp->imcrp){
// Bochs doesn't support IMCR, so this doesn't run on Bochs.

70
picirq.c
View file

@ -1,5 +1,3 @@
// Intel 8259A programmable interrupt controllers.
#include "types.h"
#include "x86.h"
#include "traps.h"
@ -8,79 +6,13 @@
#define IO_PIC1 0x20 // Master (IRQs 0-7)
#define IO_PIC2 0xA0 // Slave (IRQs 8-15)
#define IRQ_SLAVE 2 // IRQ at which slave connects to master
// Current IRQ mask.
// Initial IRQ mask has interrupt 2 enabled (for slave 8259A).
static ushort irqmask = 0xFFFF & ~(1<<IRQ_SLAVE);
static void
picsetmask(ushort mask)
{
irqmask = mask;
outb(IO_PIC1+1, mask);
outb(IO_PIC2+1, mask >> 8);
}
void
picenable(int irq)
{
picsetmask(irqmask & ~(1<<irq));
}
// Initialize the 8259A interrupt controllers.
// Don't use the 8259A interrupt controllers. Xv6 assumes SMP hardware.
void
picinit(void)
{
// mask all interrupts
outb(IO_PIC1+1, 0xFF);
outb(IO_PIC2+1, 0xFF);
// Set up master (8259A-1)
// ICW1: 0001g0hi
// g: 0 = edge triggering, 1 = level triggering
// h: 0 = cascaded PICs, 1 = master only
// i: 0 = no ICW4, 1 = ICW4 required
outb(IO_PIC1, 0x11);
// ICW2: Vector offset
outb(IO_PIC1+1, T_IRQ0);
// ICW3: (master PIC) bit mask of IR lines connected to slaves
// (slave PIC) 3-bit # of slave's connection to master
outb(IO_PIC1+1, 1<<IRQ_SLAVE);
// ICW4: 000nbmap
// n: 1 = special fully nested mode
// b: 1 = buffered mode
// m: 0 = slave PIC, 1 = master PIC
// (ignored when b is 0, as the master/slave role
// can be hardwired).
// a: 1 = Automatic EOI mode
// p: 0 = MCS-80/85 mode, 1 = intel x86 mode
outb(IO_PIC1+1, 0x3);
// Set up slave (8259A-2)
outb(IO_PIC2, 0x11); // ICW1
outb(IO_PIC2+1, T_IRQ0 + 8); // ICW2
outb(IO_PIC2+1, IRQ_SLAVE); // ICW3
// NB Automatic EOI mode doesn't tend to work on the slave.
// Linux source code says it's "to be investigated".
outb(IO_PIC2+1, 0x3); // ICW4
// OCW3: 0ef01prs
// ef: 0x = NOP, 10 = clear specific mask, 11 = set specific mask
// p: 0 = no polling, 1 = polling mode
// rs: 0x = NOP, 10 = read IRR, 11 = read ISR
outb(IO_PIC1, 0x68); // clear specific mask
outb(IO_PIC1, 0x0a); // read IRR by default
outb(IO_PIC2, 0x68); // OCW3
outb(IO_PIC2, 0x0a); // OCW3
if(irqmask != 0xFFFF)
picsetmask(irqmask);
}
//PAGEBREAK!

2
runoff.list
View file

@ -60,11 +60,9 @@ mp.h
mp.c
lapic.c
ioapic.c
picirq.c
kbd.h
kbd.c
console.c
timer.c
uart.c
# user-level

32
timer.c
View file

@ -1,32 +0,0 @@
// Intel 8253/8254/82C54 Programmable Interval Timer (PIT).
// Only used on uniprocessors;
// SMP machines use the local APIC timer.
#include "types.h"
#include "defs.h"
#include "traps.h"
#include "x86.h"
#define IO_TIMER1 0x040 // 8253 Timer #1
// Frequency of all three count-down timers;
// (TIMER_FREQ/freq) is the appropriate count
// to generate a frequency of freq Hz.
#define TIMER_FREQ 1193182
#define TIMER_DIV(x) ((TIMER_FREQ+(x)/2)/(x))
#define TIMER_MODE (IO_TIMER1 + 3) // timer mode port
#define TIMER_SEL0 0x00 // select counter 0
#define TIMER_RATEGEN 0x04 // mode 2, rate generator
#define TIMER_16BIT 0x30 // r/w counter 16 bits, LSB first
void
timerinit(void)
{
// Interrupt 100 times/sec.
outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
outb(IO_TIMER1, TIMER_DIV(100) % 256);
outb(IO_TIMER1, TIMER_DIV(100) / 256);
picenable(IRQ_TIMER);
}

1
uart.c
View file

@ -41,7 +41,6 @@ uartinit(void)
// enable interrupts.
inb(COM1+2);
inb(COM1+0);
picenable(IRQ_COM1);
ioapicenable(IRQ_COM1, 0);
// Announce that we're here.