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plan9fox/sys/src/9/imx8/trap.c
cinap_lenrek fff070f2cb imx8: add work in progress i.MX8MQ kernel for the mntreform2 laptop 
This is a work in progress port to the mntreform2 laptop.

Working so far:

- mmu (same as raspberry pi 3b+)
- arm generic timer
- gicv3
- uart1
- enet

With access to the uart, one can netboot this kernel in u-boot
using the following commands:

> dhcp
> bootm
2022-05-08 16:50:29 +00:00

717 lines
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#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "../port/systab.h"
#include <tos.h>
#include "ureg.h"
#include "sysreg.h"
int (*buserror)(Ureg*);
/* SPSR bits user can modify */
#define USPSRMASK (0xFULL<<28)
static void
setupvector(u32int *v, void (*t)(void), void (*f)(void))
{
int i;
for(i = 0; i < 0x80/4; i++){
v[i] = ((u32int*)t)[i];
if(v[i] == 0x14000000){
v[i] |= ((u32int*)f - &v[i]) & 0x3ffffff;
return;
}
}
panic("bug in vector code");
}
void
trapinit(void)
{
extern void vsys(void);
extern void vtrap(void);
extern void virq(void);
extern void vfiq(void);
extern void vserr(void);
extern void vsys0(void);
extern void vtrap0(void);
extern void vtrap1(void);
static u32int *v;
intrcpushutdown();
if(v == nil){
/* disable everything */
intrsoff();
v = mallocalign(0x80*4*4, 1<<11, 0, 0);
if(v == nil)
panic("no memory for vector table");
setupvector(&v[0x000/4], vtrap, vtrap0);
setupvector(&v[0x080/4], virq, vtrap0);
setupvector(&v[0x100/4], vfiq, vtrap0);
setupvector(&v[0x180/4], vserr, vtrap0);
setupvector(&v[0x200/4], vtrap, vtrap1);
setupvector(&v[0x280/4], virq, vtrap1);
setupvector(&v[0x300/4], vfiq, vtrap1);
setupvector(&v[0x380/4], vserr, vtrap1);
setupvector(&v[0x400/4], vsys, vsys0);
setupvector(&v[0x480/4], virq, vtrap0);
setupvector(&v[0x500/4], vfiq, vtrap0);
setupvector(&v[0x580/4], vserr, vtrap0);
setupvector(&v[0x600/4], vtrap, vtrap0);
setupvector(&v[0x680/4], virq, vtrap0);
setupvector(&v[0x700/4], vfiq, vtrap0);
setupvector(&v[0x780/4], vserr, vtrap0);
cacheduwbse(v, 0x80*4*4);
}
cacheiinvse(v, 0x80*4*4);
syswr(VBAR_EL1, (uintptr)v);
splx(0x3<<6); // unmask serr and debug
}
static char *traps[64] = {
[0x00] "sys: trap: unknown",
[0x01] "sys: trap: WFI or WFE instruction execution",
[0x0E] "sys: trap: illegal execution state",
[0x18] "sys: trap: illegal MSR/MRS access",
[0x22] "sys: trap: misaligned pc",
[0x26] "sys: trap: stack pointer misaligned",
[0x30] "sys: trap: breakpoint",
[0x32] "sys: trap: software step",
[0x34] "sys: trap: watchpoint",
[0x3C] "sys: trap: BRK instruction",
};
void
trap(Ureg *ureg)
{
u32int type, intr;
int user;
intr = ureg->type >> 32;
if(intr == 2){
fiq(ureg);
return;
}
splflo();
user = kenter(ureg);
type = (u32int)ureg->type >> 26;
switch(type){
case 0x20: // instruction abort from lower level
case 0x21: // instruction abort from same level
case 0x24: // data abort from lower level
case 0x25: // data abort from same level
faultarm64(ureg);
break;
case 0x07: // SIMD/FP
case 0x2C: // FPU exception (A64 only)
mathtrap(ureg);
break;
case 0x00: // unknown
if(intr == 1){
if(irq(ureg) && up != nil && up->delaysched)
sched();
break;
}
if(intr == 3){
case 0x2F: // SError interrupt
if(buserror != nil && (*buserror)(ureg))
break;
dumpregs(ureg);
panic("SError interrupt");
break;
}
/* wet floor */
case 0x01: // WFI or WFE instruction execution
case 0x03: // MCR or MRC access to CP15 (A32 only)
case 0x04: // MCRR or MRC access to CP15 (A32 only)
case 0x05: // MCR or MRC access to CP14 (A32 only)
case 0x06: // LDC or STD access to CP14 (A32 only)
case 0x08: // MCR or MRC to CP10 (A32 only)
case 0x0C: // MRC access to CP14 (A32 only)
case 0x0E: // Illegal Execution State
case 0x11: // SVC instruction execution (A32 only)
case 0x12: // HVC instruction execution (A32 only)
case 0x13: // SMC instruction execution (A32 only)
case 0x15: // SVC instruction execution (A64 only)
case 0x16: // HVC instruction execution (A64 only)
case 0x17: // SMC instruction execution (A64 only)
case 0x18: // MSR/MRS (A64)
case 0x22: // misaligned pc
case 0x26: // stack pointer misaligned
case 0x28: // FPU exception (A32 only)
case 0x30: // breakpoint from lower level
case 0x31: // breakpoint from same level
case 0x32: // software step from lower level
case 0x33: // software step from same level
case 0x34: // watchpoint execution from lower level
case 0x35: // watchpoint exception from same level
case 0x38: // breapoint (A32 only)
case 0x3A: // vector catch exception (A32 only)
case 0x3C: // BRK instruction (A64 only)
default:
if(!userureg(ureg)){
dumpregs(ureg);
panic("unhandled trap");
}
if(traps[type] == nil) type = 0; // unknown
postnote(up, 1, traps[type], NDebug);
break;
}
splhi();
if(user){
if(up->procctl || up->nnote)
notify(ureg);
kexit(ureg);
}
}
void
syscall(Ureg *ureg)
{
vlong startns, stopns;
uintptr sp, ret;
ulong scallnr;
int i, s;
char *e;
if(!kenter(ureg))
panic("syscall from kernel");
m->syscall++;
up->insyscall = 1;
up->pc = ureg->pc;
sp = ureg->sp;
up->scallnr = scallnr = ureg->r0;
spllo();
up->nerrlab = 0;
startns = 0;
ret = -1;
if(!waserror()){
if(sp < USTKTOP - BY2PG || sp > USTKTOP - sizeof(Sargs) - BY2WD){
validaddr(sp, sizeof(Sargs)+BY2WD, 0);
evenaddr(sp);
}
up->s = *((Sargs*) (sp + BY2WD));
if(up->procctl == Proc_tracesyscall){
syscallfmt(scallnr, ureg->pc, (va_list) up->s.args);
s = splhi();
up->procctl = Proc_stopme;
procctl();
splx(s);
startns = todget(nil);
}
if(scallnr >= nsyscall || systab[scallnr] == nil){
pprint("bad sys call number %lud pc %#p", scallnr, ureg->pc);
postnote(up, 1, "sys: bad sys call", NDebug);
error(Ebadarg);
}
up->psstate = sysctab[scallnr];
ret = systab[scallnr]((va_list)up->s.args);
poperror();
}else{
e = up->syserrstr;
up->syserrstr = up->errstr;
up->errstr = e;
}
if(up->nerrlab){
print("bad errstack [%lud]: %d extra\n", scallnr, up->nerrlab);
for(i = 0; i < NERR; i++)
print("sp=%#p pc=%#p\n", up->errlab[i].sp, up->errlab[i].pc);
panic("error stack");
}
ureg->r0 = ret;
if(up->procctl == Proc_tracesyscall){
stopns = todget(nil);
sysretfmt(scallnr, (va_list) up->s.args, ret, startns, stopns);
s = splhi();
up->procctl = Proc_stopme;
procctl();
splx(s);
}
up->insyscall = 0;
up->psstate = 0;
if(scallnr == NOTED){
noted(ureg, *((ulong*) up->s.args));
/*
* normally, syscall() returns to forkret()
* not restoring general registers when going
* to userspace. to completely restore the
* interrupted context, we have to return thru
* noteret(). we override return pc to jump to
* to it when returning form syscall()
*/
returnto(noteret);
}
if(scallnr != RFORK && (up->procctl || up->nnote)){
splhi();
notify(ureg);
}
if(up->delaysched)
sched();
kexit(ureg);
}
int
notify(Ureg *ureg)
{
int l;
uintptr s, sp;
Note *n;
if(up->procctl)
procctl();
if(up->nnote == 0)
return 0;
if(up->fpstate == FPactive){
fpsave(up->fpsave);
up->fpstate = FPinactive;
}
up->fpstate |= FPillegal;
s = spllo();
qlock(&up->debug);
up->notepending = 0;
n = &up->note[0];
if(strncmp(n->msg, "sys:", 4) == 0){
l = strlen(n->msg);
if(l > ERRMAX-23) /* " pc=0x0123456789abcdef\0" */
l = ERRMAX-23;
sprint(n->msg+l, " pc=%#p", ureg->pc);
}
if(n->flag!=NUser && (up->notified || up->notify==0)){
qunlock(&up->debug);
if(n->flag == NDebug)
pprint("suicide: %s\n", n->msg);
pexit(n->msg, n->flag!=NDebug);
}
if(up->notified){
qunlock(&up->debug);
splhi();
return 0;
}
if(!up->notify){
qunlock(&up->debug);
pexit(n->msg, n->flag!=NDebug);
}
sp = ureg->sp;
sp -= 256; /* debugging: preserve context causing problem */
sp -= sizeof(Ureg);
sp = STACKALIGN(sp);
if(!okaddr((uintptr)up->notify, 1, 0)
|| !okaddr(sp-ERRMAX-4*BY2WD, sizeof(Ureg)+ERRMAX+4*BY2WD, 1)
|| ((uintptr) up->notify & 3) != 0
|| (sp & 7) != 0){
qunlock(&up->debug);
pprint("suicide: bad address in notify: handler=%#p sp=%#p\n",
up->notify, sp);
pexit("Suicide", 0);
}
memmove((Ureg*)sp, ureg, sizeof(Ureg));
*(Ureg**)(sp-BY2WD) = up->ureg; /* word under Ureg is old up->ureg */
up->ureg = (void*)sp;
sp -= BY2WD+ERRMAX;
memmove((char*)sp, up->note[0].msg, ERRMAX);
sp -= 3*BY2WD;
*(uintptr*)(sp+2*BY2WD) = sp+3*BY2WD;
*(uintptr*)(sp+1*BY2WD) = (uintptr)up->ureg;
ureg->r0 = (uintptr) up->ureg;
ureg->sp = sp;
ureg->pc = (uintptr) up->notify;
ureg->link = 0;
up->notified = 1;
up->nnote--;
memmove(&up->lastnote, &up->note[0], sizeof(Note));
memmove(&up->note[0], &up->note[1], up->nnote*sizeof(Note));
qunlock(&up->debug);
splx(s);
return 1;
}
void
noted(Ureg *ureg, ulong arg0)
{
Ureg *nureg;
uintptr oureg, sp;
qlock(&up->debug);
if(arg0 != NRSTR && !up->notified){
qunlock(&up->debug);
pprint("call to noted() when not notified\n");
pexit("Suicide", 0);
}
up->notified = 0;
nureg = up->ureg;
up->fpstate &= ~FPillegal;
oureg = (uintptr) nureg;
if(!okaddr(oureg - BY2WD, BY2WD + sizeof(Ureg), 0) || (oureg & 7) != 0){
qunlock(&up->debug);
pprint("bad ureg in noted or call to noted when not notified\n");
pexit("Suicide", 0);
}
nureg->psr = (nureg->psr & USPSRMASK) | (ureg->psr & ~USPSRMASK);
memmove(ureg, nureg, sizeof(Ureg));
switch(arg0){
case NCONT: case NRSTR:
if(!okaddr(nureg->pc, BY2WD, 0) || !okaddr(nureg->sp, BY2WD, 0) ||
(nureg->pc & 3) != 0 || (nureg->sp & 7) != 0){
qunlock(&up->debug);
pprint("suicide: trap in noted\n");
pexit("Suicide", 0);
}
up->ureg = (Ureg *) (*(uintptr*) (oureg - BY2WD));
qunlock(&up->debug);
break;
case NSAVE:
if(!okaddr(nureg->pc, BY2WD, 0) || !okaddr(nureg->sp, BY2WD, 0) ||
(nureg->pc & 3) != 0 || (nureg->sp & 7) != 0){
qunlock(&up->debug);
pprint("suicide: trap in noted\n");
pexit("Suicide", 0);
}
qunlock(&up->debug);
sp = oureg - 4 * BY2WD - ERRMAX;
splhi();
ureg->sp = sp;
ureg->r0 = (uintptr) oureg;
((uintptr *) sp)[1] = oureg;
((uintptr *) sp)[0] = 0;
break;
default:
up->lastnote.flag = NDebug;
case NDFLT:
qunlock(&up->debug);
if(up->lastnote.flag == NDebug)
pprint("suicide: %s\n", up->lastnote.msg);
pexit(up->lastnote.msg, up->lastnote.flag != NDebug);
}
}
void
faultarm64(Ureg *ureg)
{
extern void checkpages(void);
char buf[ERRMAX];
int read, insyscall;
uintptr addr;
insyscall = up->insyscall;
up->insyscall = 1;
if(!userureg(ureg)){
extern void _peekinst(void);
if(ureg->pc == (uintptr)_peekinst){
ureg->pc = ureg->link;
goto out;
}
if(waserror()){
if(up->nerrlab == 0){
pprint("suicide: sys: %s\n", up->errstr);
pexit(up->errstr, 1);
}
up->insyscall = insyscall;
nexterror();
}
}
addr = getfar();
read = (ureg->type & (1<<6)) == 0;
switch((u32int)ureg->type & 0x3F){
case 4: case 5: case 6: case 7: // Tanslation fault.
case 8: case 9: case 10: case 11: // Access flag fault.
case 12: case 13: case 14: case 15: // Permission fault.
case 48: // tlb conflict fault.
if(fault(addr, ureg->pc, read) == 0)
break;
/* wet floor */
case 0: case 1: case 2: case 3: // Address size fault.
case 16: // synchronous external abort.
case 24: // synchronous parity error on a memory access.
case 20: case 21: case 22: case 23: // synchronous external abort on a table walk.
case 28: case 29: case 30: case 31: // synchronous parity error on table walk.
case 33: // alignment fault.
case 52: // implementation defined, lockdown abort.
case 53: // implementation defined, unsuppoted exclusive.
case 61: // first level domain fault
case 62: // second level domain fault
default:
if(!userureg(ureg)){
dumpregs(ureg);
panic("fault: %s addr=%#p", read ? "read" : "write", addr);
}
checkpages();
sprint(buf, "sys: trap: fault %s addr=%#p", read ? "read" : "write", addr);
postnote(up, 1, buf, NDebug);
}
if(!userureg(ureg))
poperror();
out:
up->insyscall = insyscall;
}
int
userureg(Ureg* ureg)
{
return (ureg->psr & 15) == 0;
}
uintptr
userpc(void)
{
Ureg *ur = up->dbgreg;
return ur->pc;
}
uintptr
dbgpc(Proc *)
{
Ureg *ur = up->dbgreg;
if(ur == nil)
return 0;
return ur->pc;
}
void
procfork(Proc *p)
{
int s;
s = splhi();
switch(up->fpstate & ~FPillegal){
case FPactive:
fpsave(up->fpsave);
up->fpstate = FPinactive;
case FPinactive:
memmove(p->fpsave, up->fpsave, sizeof(FPsave));
p->fpstate = FPinactive;
}
splx(s);
p->tpidr = up->tpidr;
}
void
procsetup(Proc *p)
{
p->fpstate = FPinit;
fpoff();
p->tpidr = 0;
syswr(TPIDR_EL0, p->tpidr);
}
void
procsave(Proc *p)
{
if(p->fpstate == FPactive){
if(p->state == Moribund)
fpclear();
else
fpsave(p->fpsave);
p->fpstate = FPinactive;
}
if(p->kp == 0)
p->tpidr = sysrd(TPIDR_EL0);
putasid(p); // release asid
}
void
procrestore(Proc *p)
{
if(p->kp == 0)
syswr(TPIDR_EL0, p->tpidr);
}
void
kprocchild(Proc *p, void (*entry)(void))
{
p->sched.pc = (uintptr) entry;
p->sched.sp = (uintptr) p->kstack + KSTACK - 16;
*(void**)p->sched.sp = kprocchild; /* fake */
}
void
forkchild(Proc *p, Ureg *ureg)
{
Ureg *cureg;
p->sched.pc = (uintptr) forkret;
p->sched.sp = (uintptr) p->kstack + KSTACK - TRAPFRAMESIZE;
cureg = (Ureg*) (p->sched.sp + 16);
memmove(cureg, ureg, sizeof(Ureg));
cureg->r0 = 0;
}
uintptr
execregs(uintptr entry, ulong ssize, ulong nargs)
{
uintptr *sp;
Ureg *ureg;
sp = (uintptr*)(USTKTOP - ssize);
*--sp = nargs;
ureg = up->dbgreg;
ureg->sp = (uintptr)sp;
ureg->pc = entry;
ureg->link = 0;
return USTKTOP-sizeof(Tos);
}
void
evenaddr(uintptr addr)
{
if(addr & 3){
postnote(up, 1, "sys: odd address", NDebug);
error(Ebadarg);
}
}
void
callwithureg(void (*f) (Ureg *))
{
Ureg u;
u.pc = getcallerpc(&f);
u.sp = (uintptr) &f;
f(&u);
}
void
setkernur(Ureg *ureg, Proc *p)
{
ureg->pc = p->sched.pc;
ureg->sp = p->sched.sp;
ureg->link = (uintptr)sched;
}
void
setupwatchpts(Proc*, Watchpt*, int)
{
}
void
setregisters(Ureg* ureg, char* pureg, char* uva, int n)
{
ulong v;
v = ureg->psr;
memmove(pureg, uva, n);
ureg->psr = (ureg->psr & USPSRMASK) | (v & ~USPSRMASK);
}
static void
dumpstackwithureg(Ureg *ureg)
{
uintptr v, estack, sp;
char *s;
int i;
if((s = getconf("*nodumpstack")) != nil && strcmp(s, "0") != 0){
iprint("dumpstack disabled\n");
return;
}
iprint("ktrace /kernel/path %#p %#p %#p # pc, sp, link\n",
ureg->pc, ureg->sp, ureg->link);
delay(2000);
sp = ureg->sp;
if(sp < KZERO || (sp & 7) != 0)
sp = (uintptr)&ureg;
estack = (uintptr)m+MACHSIZE;
if(up != nil && sp <= (uintptr)up->kstack+KSTACK)
estack = (uintptr)up->kstack+KSTACK;
if(sp > estack){
if(up != nil)
iprint("&up->kstack %#p sp %#p\n", up->kstack, sp);
else
iprint("&m %#p sp %#p\n", m, sp);
return;
}
i = 0;
for(; sp < estack; sp += sizeof(uintptr)){
v = *(uintptr*)sp;
if(KTZERO < v && v < (uintptr)etext && (v & 3) == 0){
iprint("%#8.8lux=%#8.8lux ", (ulong)sp, (ulong)v);
i++;
}
if(i == 4){
i = 0;
iprint("\n");
}
}
if(i)
iprint("\n");
}
void
dumpstack(void)
{
callwithureg(dumpstackwithureg);
}
void
dumpregs(Ureg *ureg)
{
u64int *r;
int i, x;
x = splhi();
if(up != nil)
iprint("cpu%d: dumpregs ureg %#p process %lud: %s\n", m->machno, ureg,
up->pid, up->text);
else
iprint("cpu%d: dumpregs ureg %#p\n", m->machno, ureg);
r = &ureg->r0;
for(i = 0; i < 30; i += 3)
iprint("R%d %.16llux R%d %.16llux R%d %.16llux\n", i, r[i], i+1, r[i+1], i+2, r[i+2]);
iprint("PC %#p SP %#p LR %#p PSR %llux TYPE %llux\n",
ureg->pc, ureg->sp, ureg->link,
ureg->psr, ureg->type);
splx(x);
}
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