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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 <tos.h>
#include "ureg.h"
#include "arm.h"
/*
* A lot of this stuff doesn't belong here
* but this is a convenient dumping ground for
* later sorting into the appropriate buckets.
*/
/* Give enough context in the ureg to produce a kernel stack for
* a sleeping process
*/
void
setkernur(Ureg* ureg, Proc* p)
{
ureg->pc = p->sched.pc;
ureg->sp = p->sched.sp+4;
ureg->r14 = (uintptr)sched;
}
/*
* called in sysfile.c
*/
void
evenaddr(uintptr addr)
{
if(addr & 3){
postnote(up, 1, "sys: odd address", NDebug);
error(Ebadarg);
}
}
/* go to user space */
void
kexit(Ureg*)
{
uvlong t;
Tos *tos;
/* precise time accounting, kernel exit */
tos = (Tos*)(USTKTOP-sizeof(Tos));
cycles(&t);
tos->kcycles += t - up->kentry;
tos->pcycles = t + up->pcycles;
tos->cyclefreq = m->cpuhz;
tos->pid = up->pid;
/* make visible immediately to user proc */
cachedwbinvse(tos, sizeof *tos);
}
/*
* return the userpc the last exception happened at
*/
uintptr
userpc(void)
{
Ureg *ureg = up->dbgreg;
return ureg->pc;
}
/* This routine must save the values of registers the user is not permitted
* to write from devproc and then restore the saved values before returning.
*/
void
setregisters(Ureg* ureg, char* pureg, char* uva, int n)
{
ulong v = ureg->psr;
memmove(pureg, uva, n);
ureg->psr = ureg->psr & ~(PsrMask|PsrDfiq|PsrDirq) | v & (PsrMask|PsrDfiq|PsrDirq);
}
/*
* this is the body for all kproc's
*/
static void
linkproc(void)
{
spllo();
up->kpfun(up->kparg);
pexit("kproc exiting", 0);
}
/*
* setup stack and initial PC for a new kernel proc. This is architecture
* dependent because of the starting stack location
*/
void
kprocchild(Proc *p, void (*func)(void*), void *arg)
{
p->sched.pc = (uintptr)linkproc;
p->sched.sp = (uintptr)p->kstack+KSTACK;
p->kpfun = func;
p->kparg = arg;
}
/*
* pc output by dumpaproc
*/
uintptr
dbgpc(Proc* p)
{
Ureg *ureg;
ureg = p->dbgreg;
if(ureg == 0)
return 0;
return ureg->pc;
}
/*
* set mach dependent process state for a new process
*/
void
procsetup(Proc* p)
{
fpusysprocsetup(p);
cycles(&p->kentry);
p->pcycles = -p->kentry;
}
void
procfork(Proc* p)
{
p->kentry = up->kentry;
p->pcycles = -p->kentry;
fpuprocfork(p);
}
/*
* Save the mach dependent part of the process state.
*/
void
procsave(Proc* p)
{
uvlong t;
cycles(&t);
p->pcycles += t;
p->kentry -= t;
// TODO: save and restore VFPv3 FP state once 5[cal] know the new registers.
fpuprocsave(p);
/*
* Prevent the following scenario:
* pX sleeps on cpuA, leaving its page tables in mmul1
* pX wakes up on cpuB, and exits, freeing its page tables
* pY on cpuB allocates a freed page table page and overwrites with data
* cpuA takes an interrupt, and is now running with bad page tables
* In theory this shouldn't hurt because only user address space tables
* are affected, and mmuswitch will clear mmul1 before a user process is
* dispatched. But empirically it correlates with weird problems, eg
* resetting of the core clock at 0x4000001C which confuses local timers.
*/
if(conf.nmach > 1)
mmuswitch(nil);
}
void
procrestore(Proc* p)
{
uvlong t;
if(p->kp)
return;
cycles(&t);
p->pcycles -= t;
p->kentry += t;
fpuprocrestore(p);
}
int
userureg(Ureg* ureg)
{
return (ureg->psr & PsrMask) == PsrMusr;
}
int
cas32(void* addr, u32int old, u32int new)
{
int r, s;
s = splhi();
if(r = (*(u32int*)addr == old))
*(u32int*)addr = new;
splx(s);
if (r)
coherence();
return r;
}
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