ref: b548687a8ed1d0a159c9d3f3f921d93bbb56908e
dir: /os/port/portbreak.c/
#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; }