dtrace_isa.c

Sun Solaris 10 中的 DTrace 组件的源代码。请参看: http://www.sun.com/software/solaris/observability.jsp

	if (lwp == NULL || p == NULL || lwp->lwp_regs == NULL)
		return;

	if (pcstack_limit <= 0)
		return;

	*pcstack++ = (uint64_t)p->p_pid;
	pcstack_limit--;

	if (pcstack_limit <= 0)
		return;

	rp = lwp->lwp_regs;

	if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) {
		*fpstack++ = 0;
		*pcstack++ = (uint64_t)rp->r_pc;
		pcstack_limit--;
		if (pcstack_limit <= 0)
			return;

		*fpstack++ = (uint64_t)rp->r_sp;
		*pcstack++ = (uint64_t)rp->r_o7;
		pcstack_limit--;
	} else {
		*fpstack++ = (uint64_t)rp->r_sp;
		*pcstack++ = (uint64_t)rp->r_pc;
		pcstack_limit--;
	}

	if (pcstack_limit <= 0)
		return;

	sp = rp->r_sp;

	dtrace_flush_user_windows();

	if (p->p_model == DATAMODEL_NATIVE) {
		while (pcstack_limit > 0) {
			struct frame *fr = (struct frame *)(sp + STACK_BIAS);
			uintptr_t pc;

			if (sp == 0 || fr == NULL ||
			    ((uintptr_t)&fr->fr_savpc & 3) != 0 ||
			    ((uintptr_t)&fr->fr_savfp & 3) != 0)
				break;

			pc = dtrace_fulword(&fr->fr_savpc);
			sp = dtrace_fulword(&fr->fr_savfp);

			if (pc == 0)
				break;

			*fpstack++ = sp;
			*pcstack++ = pc;
			pcstack_limit--;
		}
	} else {
		while (pcstack_limit > 0) {
			struct frame32 *fr = (struct frame32 *)sp;
			uint32_t pc;

			if (sp == 0 ||
			    ((uintptr_t)&fr->fr_savpc & 3) != 0 ||
			    ((uintptr_t)&fr->fr_savfp & 3) != 0)
				break;

			pc = dtrace_fuword32(&fr->fr_savpc);
			sp = dtrace_fuword32(&fr->fr_savfp);

			*fpstack++ = sp;
			*pcstack++ = pc;
			pcstack_limit--;
		}
	}

	while (pcstack_limit-- > 0)
		*pcstack++ = NULL;
}

uint64_t
dtrace_getarg(int arg, int aframes)
{
	uintptr_t val;
	struct frame *fp;
	uint64_t rval;

	/*
	 * Account for the fact that dtrace_getarg() consumes an additional
	 * stack frame.
	 */
	aframes++;

	if (arg < 6) {
		if (dtrace_fish(aframes, DTRACE_REG_I0 + arg, &val) == 0)
			return (val);
	} else {
		if (dtrace_fish(aframes, DTRACE_REG_I6, &val) == 0) {
			/*
			 * We have a stack pointer; grab the argument.
			 */
			fp = (struct frame *)(val + STACK_BIAS);

			DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
			rval = fp->fr_argx[arg - 6];
			DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);

			return (rval);
		}
	}

	/*
	 * There are other ways to do this.  But the slow, painful way works
	 * just fine.  Because this requires some loads, we need to set
	 * CPU_DTRACE_NOFAULT to protect against looking for an argument that
	 * isn't there.
	 */
	fp = (struct frame *)((caddr_t)dtrace_getfp() + STACK_BIAS);
	dtrace_flush_windows();

	DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);

	for (aframes -= 1; aframes; aframes--)
		fp = (struct frame *)((caddr_t)fp->fr_savfp + STACK_BIAS);

	if (arg < 6) {
		rval = fp->fr_arg[arg];
	} else {
		fp = (struct frame *)((caddr_t)fp->fr_savfp + STACK_BIAS);
		rval = fp->fr_argx[arg - 6];
	}

	DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);

	return (rval);
}

int
dtrace_getstackdepth(int aframes)
{
	struct frame *fp, *nextfp, *minfp, *stacktop;
	int depth = 0;
	int on_intr;

	fp = (struct frame *)((caddr_t)dtrace_getfp() + STACK_BIAS);
	dtrace_flush_windows();

	if ((on_intr = CPU_ON_INTR(CPU)) != 0)
		stacktop = (struct frame *)CPU->cpu_intr_stack + SA(MINFRAME);
	else
		stacktop = (struct frame *)curthread->t_stk;
	minfp = fp;

	for (;;) {
		nextfp = (struct frame *)((caddr_t)fp->fr_savfp + STACK_BIAS);
		if (nextfp <= minfp || nextfp >= stacktop) {
			if (on_intr) {
				/*
				 * Hop from interrupt stack to thread stack.
				 */
				stacktop = (struct frame *)curthread->t_stk;
				minfp = (struct frame *)curthread->t_stkbase;
				on_intr = 0;
				continue;
			}

			return (++depth);
		}

		if (aframes > 0) {
			aframes--;
		} else {
			depth++;
		}

		fp = nextfp;
		minfp = fp;
	}
}

/*
 * This uses the same register numbering scheme as in sys/procfs_isa.h.
 */
ulong_t
dtrace_getreg(struct regs *rp, uint_t reg)
{
	ulong_t value;
	uintptr_t fp;
	struct machpcb *mpcb;

	if (reg == R_G0)
		return (0);

	if (reg <= R_G7)
		return ((&rp->r_g1)[reg - 1]);

	if (reg > R_I7) {
		switch (reg) {
		case R_CCR:
			return ((rp->r_tstate >> TSTATE_CCR_SHIFT) &
			    TSTATE_CCR_MASK);
		case R_PC:
			return (rp->r_pc);
		case R_nPC:
			return (rp->r_npc);
		case R_Y:
			return (rp->r_y);
		case R_ASI:
			return ((rp->r_tstate >> TSTATE_ASI_SHIFT) &
			    TSTATE_ASI_MASK);
		case R_FPRS:
			return (dtrace_getfprs());
		default:
			DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
			return (0);
		}
	}

	/*
	 * We reach go to the fake restore case if the probe we hit was a pid
	 * return probe on a restore instruction. We partially emulate the
	 * restore in the kernel and then execute a simple restore
	 * instruction that we've secreted away to do the actual register
	 * window manipulation. We need to go one register window further
	 * down to get at the %ls, and %is and we need to treat %os like %is
	 * to pull them out of the topmost user frame.
	 */
	if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_FAKERESTORE)) {
		if (reg > R_O7)
			goto fake_restore;
		else
			reg += R_I0 - R_O0;

	} else if (reg <= R_O7) {
		return ((&rp->r_g1)[reg - 1]);
	}

	if (dtrace_getotherwin() > 0)
		return (dtrace_getreg_win(reg, 1));

	mpcb = (struct machpcb *)((caddr_t)rp - REGOFF);

	if (curproc->p_model == DATAMODEL_NATIVE) {
		struct frame *fr = (void *)(rp->r_sp + STACK_BIAS);

		if (mpcb->mpcb_wbcnt > 0) {
			struct rwindow *rwin = (void *)mpcb->mpcb_wbuf;
			int i = mpcb->mpcb_wbcnt;
			do {
				i--;
				if ((long)mpcb->mpcb_spbuf[i] == rp->r_sp)
					return (rwin[i].rw_local[reg - 16]);
			} while (i > 0);
		}

		DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
		value = dtrace_fulword(&fr->fr_local[reg - 16]);
		DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
	} else {
		struct frame32 *fr = (void *)(caddr32_t)rp->r_sp;

		if (mpcb->mpcb_wbcnt > 0) {
			struct rwindow32 *rwin = (void *)mpcb->mpcb_wbuf;
			int i = mpcb->mpcb_wbcnt;
			do {
				i--;
				if ((long)mpcb->mpcb_spbuf[i] == rp->r_sp)
					return (rwin[i].rw_local[reg - 16]);
			} while (i > 0);
		}

		DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
		value = dtrace_fuword32(&fr->fr_local[reg - 16]);
		DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
	}

	return (value);

fake_restore:
	ASSERT(R_L0 <= reg && reg <= R_I7);

	/*
	 * We first look two user windows down to see if we can dig out
	 * the register we're looking for.
	 */
	if (dtrace_getotherwin() > 1)
		return (dtrace_getreg_win(reg, 2));

	/*
	 * First we need to get the frame pointer and then we perform
	 * the same computation as in the non-fake-o-restore case.
	 */

	mpcb = (struct machpcb *)((caddr_t)rp - REGOFF);

	if (dtrace_getotherwin() > 0) {
		fp = dtrace_getreg_win(R_FP, 1);
		goto got_fp;
	}

	if (curproc->p_model == DATAMODEL_NATIVE) {
		struct frame *fr = (void *)(rp->r_sp + STACK_BIAS);

		if (mpcb->mpcb_wbcnt > 0) {
			struct rwindow *rwin = (void *)mpcb->mpcb_wbuf;
			int i = mpcb->mpcb_wbcnt;
			do {
				i--;
				if ((long)mpcb->mpcb_spbuf[i] == rp->r_sp) {
					fp = rwin[i].rw_fp;
					goto got_fp;
				}
			} while (i > 0);
		}

		DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
		fp = dtrace_fulword(&fr->fr_savfp);
		DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
		if (cpu_core[CPU->cpu_id].cpuc_dtrace_flags & CPU_DTRACE_FAULT)
			return (0);
	} else {
		struct frame32 *fr = (void *)(caddr32_t)rp->r_sp;

		if (mpcb->mpcb_wbcnt > 0) {
			struct rwindow32 *rwin = (void *)mpcb->mpcb_wbuf;
			int i = mpcb->mpcb_wbcnt;
			do {
				i--;
				if ((long)mpcb->mpcb_spbuf[i] == rp->r_sp) {
					fp = rwin[i].rw_fp;
					goto got_fp;
				}
			} while (i > 0);
		}

		DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
		fp = dtrace_fuword32(&fr->fr_savfp);
		DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
		if (cpu_core[CPU->cpu_id].cpuc_dtrace_flags & CPU_DTRACE_FAULT)
			return (0);
	}
got_fp:

	if (curproc->p_model == DATAMODEL_NATIVE) {
		struct frame *fr = (void *)(fp + STACK_BIAS);

		if (mpcb->mpcb_wbcnt > 0) {
			struct rwindow *rwin = (void *)mpcb->mpcb_wbuf;
			int i = mpcb->mpcb_wbcnt;
			do {
				i--;
				if ((long)mpcb->mpcb_spbuf[i] == fp)
					return (rwin[i].rw_local[reg - 16]);
			} while (i > 0);
		}

		DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
		value = dtrace_fulword(&fr->fr_local[reg - 16]);
		DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
	} else {
		struct frame32 *fr = (void *)(caddr32_t)fp;

		if (mpcb->mpcb_wbcnt > 0) {
			struct rwindow32 *rwin = (void *)mpcb->mpcb_wbuf;
			int i = mpcb->mpcb_wbcnt;
			do {
				i--;
				if ((long)mpcb->mpcb_spbuf[i] == fp)
					return (rwin[i].rw_local[reg - 16]);
			} while (i > 0);
		}

		DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
		value = dtrace_fuword32(&fr->fr_local[reg - 16]);
		DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
	}

	return (value);
}