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#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "portfns.h"
#include "ureg.h"
#include "../port/error.h"
//
// These bits used to be in port/devdbg but were removed in
// order to allow for using hardware debug features on certain
// architectures
//
extern void breakset(Bkpt *b);
extern void breakrestore(Bkpt *b);
extern Bkpt* breakclear(int id);
extern void breaknotify(Bkpt *b, Proc *p);
extern int breakmatch(BkptCond *cond, Ureg *ur, Proc *p);
void skipfree(Bkpt *b);
Bkpt*newskip(ulong addr, Bkpt *skipb, Proc *skipp);
Bkpt *skipalloc;
extern Bkpt *breakpoints;
typedef struct SkipArg SkipArg;
struct SkipArg
{
Bkpt *b;
Proc *p;
};
void
skiphandler(Bkpt *b)
{
SkipArg *a = b->aux;
Bkpt *l;
if(breakclear(b->id) == nil)
panic("skiphandler: breakclear() failed");
breakrestore(a->b);
l = a->b->link;
while(l != nil) {
breakrestore(l);
l = l->link;
}
skipfree(b);
a->p->dbgstop = 0; // Whoo!
if(a->p->state == Stopped)
ready(a->p);
}
Bkpt*
newskip(ulong addr, Bkpt *skipb, Proc *skipp)
{
Bkpt *b;
SkipArg *a;
b = skipalloc;
if(b == nil)
panic("newskip(): no free skips\n");
skipalloc = b->next;
b->addr = addr;
b->conditions->val = addr;
b->link = nil;
a = b->aux;
a->b = skipb;
a->p = skipp;
return b;
}
void
skipfree(Bkpt *b)
{
b->next = skipalloc;
skipalloc = b;
}
//
// Called from the exception handler when a breakpoint instruction has been
// hit. This cannot not be called unless at least one breakpoint with this
// address is in the list of breakpoints. (All breakpoint notifications must
// previously have been set via setbreak())
//
// foreach breakpoint in list
// if breakpoint matches conditions
// notify the break handler
// if no breakpoints matched the conditions
// pick a random breakpoint set to this address
//
// set a breakpoint at the next instruction to be executed,
// and pass the current breakpoint to the "skiphandler"
//
// clear the current breakpoint
//
// Tell the scheduler to stop scheduling, so the caller is
// guaranteed to execute the instruction, followed by the
// added breakpoint.
//
//
int
breakhit(Ureg *ur, Proc *p)
{
Bkpt *b;
int nmatched;
Bkpt *skip;
nmatched = 0;
for(b = breakpoints; b != nil; b = b->next) {
if(breakmatch(b->conditions, ur, p)) {
breaknotify(b, p);
++nmatched;
}
}
if(nmatched)
return BrkSched;
skip = nil;
for(b = breakpoints; b != nil; b = b->next) {
if(b->addr == ur->pc) {
if(breakclear(b->id) == nil)
panic("breakhit: breakclear() failed");
if(skip == nil)
skip = newskip(machnextaddr(ur), b, p);
else {
b->link = skip->link;
skip->link = b;
}
}
}
if(skip == nil)
return BrkSched;
breakset(skip);
return BrkNoSched;
}
void
portbreakinit(void)
{
Bkpt *b;
int i;
skipalloc = mallocz(conf.nproc*(sizeof(Bkpt)+sizeof(BkptCond)+sizeof(SkipArg)), 1);
if(skipalloc == nil)
error(Enomem);
b = skipalloc;
for(i=0; i < conf.nproc-1; i++) {
b->id = -(i+1);
b->conditions = (BkptCond*)((uchar*)b + sizeof(Bkpt));
b->conditions->op = 'b';
b->handler = skiphandler;
b->aux = (SkipArg*)((uchar*)b+sizeof(Bkpt)+sizeof(BkptCond));
b->next = (Bkpt*)((uchar*)b+sizeof(Bkpt)+sizeof(BkptCond)+sizeof(SkipArg));
b = b->next;
}
b->next = nil;
}
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