perfmon.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

#if 0
	/*
	 * in case of non blocking mode, then it's just a matter of
	 * of reseting the sampling buffer (if any) index. The PMU
	 * is already active.
	 */

	/*
	 * must reset the header count first
	 */
	if (CTX_HAS_SMPL(ctx)) {
		DBprintk(("resetting sampling indexes for %d \n", task->pid));
		ctx->ctx_psb->psb_hdr->hdr_count = 0;
		ctx->ctx_psb->psb_index = 0;
	}
#endif
	return 0;
}

static int
pfm_stop(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, 
	 struct pt_regs *regs)
{
	/* we don't quite support this right now */
	if (task != current) return -EINVAL;

	/* 
	 * Cannot do anything before PMU is enabled 
	 */
	if (!CTX_IS_ENABLED(ctx)) return -EINVAL;

	DBprintk(("[%d] fl_system=%d owner=%p current=%p\n",
				current->pid,
				ctx->ctx_fl_system, PMU_OWNER(),
				current));

	/* simply stop monitoring but not the PMU */
	if (ctx->ctx_fl_system) {

		/* disable dcr pp */
		ia64_set_dcr(ia64_get_dcr() & ~IA64_DCR_PP);

		/* stop monitoring */
		__asm__ __volatile__ ("rsm psr.pp;;"::: "memory");

		ia64_srlz_i();

		local_cpu_data->pfm_dcr_pp  = 0;

		ia64_psr(regs)->pp = 0;

	} else {

		/* stop monitoring */
		__asm__ __volatile__ ("rum psr.up;;"::: "memory");

		ia64_srlz_i();

		/*
		 * clear user level psr.up
		 */
		ia64_psr(regs)->up = 0;
	}
	return 0;
}

static int
pfm_disable(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, 
	   struct pt_regs *regs)
{	
	/* we don't quite support this right now */
	if (task != current) return -EINVAL;

	if (!CTX_IS_ENABLED(ctx)) return -EINVAL;

	/*
	 * stop monitoring, freeze PMU, and save state in context
	 * this call will clear IA64_THREAD_PM_VALID for per-task sessions.
	 */
	pfm_flush_regs(task);

	if (ctx->ctx_fl_system) {	
		ia64_psr(regs)->pp = 0;
	} else {
		ia64_psr(regs)->up = 0;
	}
	/* 
	 * goes back to default behavior: no user level control
	 * no need to change live psr.sp because useless at the kernel level
	 */
	ia64_psr(regs)->sp = 1;

	DBprintk(("enabling psr.sp for [%d]\n", current->pid));

	ctx->ctx_flags.state = PFM_CTX_DISABLED;

	return 0;
}

static int
pfm_context_destroy(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, 
	 struct pt_regs *regs)
{
	/* we don't quite support this right now */
	if (task != current) return -EINVAL;

	/*
	 * if context was never enabled, then there is not much
	 * to do
	 */
	if (!CTX_IS_ENABLED(ctx)) goto skipped_stop;

	/*
	 * Disable context: stop monitoring, flush regs to software state (useless here), 
	 * and freeze PMU
	 * 
	 * The IA64_THREAD_PM_VALID is cleared by pfm_flush_regs() called from pfm_disable()
	 */
	pfm_disable(task, ctx, arg, count, regs);

	if (ctx->ctx_fl_system) {	
		ia64_psr(regs)->pp = 0;
	} else {
		ia64_psr(regs)->up = 0;
	}

skipped_stop:
	/*
	 * remove sampling buffer mapping, if any
	 */
	if (ctx->ctx_smpl_vaddr) {
		pfm_remove_smpl_mapping(task);
		ctx->ctx_smpl_vaddr = 0UL;
	}
	/* now free context and related state */
	pfm_context_exit(task);

	return 0;
}

/*
 * does nothing at the moment
 */
static int
pfm_context_unprotect(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, 
	 struct pt_regs *regs)
{
	return 0;
}

static int
pfm_protect_context(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, 
	 struct pt_regs *regs)
{
	DBprintk(("context from [%d] is protected\n", task->pid));
	/*
	 * from now on, only the creator of the context has access to it
	 */
	ctx->ctx_fl_protected = 1;

	/*
	 * reinforce secure monitoring: cannot toggle psr.up
	 */
	ia64_psr(regs)->sp = 1;

	return 0;
}

static int
pfm_debug(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, 
	 struct pt_regs *regs)
{
	unsigned int mode = *(unsigned int *)arg;

	pfm_sysctl.debug = mode == 0 ? 0 : 1;

	printk("perfmon debugging %s\n", pfm_sysctl.debug ? "on" : "off");

	return 0;
}

#ifdef PFM_PMU_USES_DBR

typedef struct {
	unsigned long ibr_mask:56;
	unsigned long ibr_plm:4;
	unsigned long ibr_ig:3;
	unsigned long ibr_x:1;
} ibr_mask_reg_t;

typedef struct {
	unsigned long dbr_mask:56;
	unsigned long dbr_plm:4;
	unsigned long dbr_ig:2;
	unsigned long dbr_w:1;
	unsigned long dbr_r:1;
} dbr_mask_reg_t;

typedef union {
	unsigned long  val;
	ibr_mask_reg_t ibr;
	dbr_mask_reg_t dbr;
} dbreg_t;


static int
pfm_write_ibr_dbr(int mode, struct task_struct *task, void *arg, int count, struct pt_regs *regs)
{
	struct thread_struct *thread = &task->thread;
	pfm_context_t *ctx = task->thread.pfm_context;
	pfarg_dbreg_t tmp, *req = (pfarg_dbreg_t *)arg;
	dbreg_t dbreg;
	unsigned int rnum;
	int first_time;
	int i, ret = 0;

	/*
	 * we do not need to check for ipsr.db because we do clear ibr.x, dbr.r, and dbr.w
	 * ensuring that no real breakpoint can be installed via this call.
	 */

	first_time = ctx->ctx_fl_using_dbreg == 0;

	/*
	 * check for debug registers in system wide mode
	 *
	 */
	LOCK_PFS();
	if (ctx->ctx_fl_system && first_time) {
		if (pfm_sessions.pfs_ptrace_use_dbregs) 
			ret = -EBUSY;
		else
			pfm_sessions.pfs_sys_use_dbregs++;
	}
	UNLOCK_PFS();

	if (ret != 0) return ret;

	if (ctx->ctx_fl_system) {
		/* we mark ourselves as owner  of the debug registers */
		ctx->ctx_fl_using_dbreg = 1;
		DBprintk(("system-wide setting fl_using_dbreg for [%d]\n", task->pid));
	} else if (first_time) {
			ret= -EBUSY;
			if ((thread->flags & IA64_THREAD_DBG_VALID) != 0) {
				DBprintk(("debug registers already in use for [%d]\n", task->pid));
				goto abort_mission;
			}
			/* we mark ourselves as owner  of the debug registers */
			ctx->ctx_fl_using_dbreg = 1;

			DBprintk(("setting fl_using_dbreg for [%d]\n", task->pid));
			/* 
			 * Given debug registers cannot be used for both debugging 
			 * and performance monitoring at the same time, we reuse
			 * the storage area to save and restore the registers on ctxsw.
			 */
			memset(task->thread.dbr, 0, sizeof(task->thread.dbr));
			memset(task->thread.ibr, 0, sizeof(task->thread.ibr));
	}

	if (first_time) {
		DBprintk(("[%d] clearing ibrs,dbrs\n", task->pid));
		/*
	 	 * clear hardware registers to make sure we don't
	 	 * pick up stale state. 
		 *
		 * for a system wide session, we do not use
		 * thread.dbr, thread.ibr because this process
		 * never leaves the current CPU and the state
		 * is shared by all processes running on it
	 	 */
		for (i=0; i < pmu_conf.num_ibrs; i++) {
			ia64_set_ibr(i, 0UL);
		}
		ia64_srlz_i();
		for (i=0; i < pmu_conf.num_dbrs; i++) {
			ia64_set_dbr(i, 0UL);
		}
		ia64_srlz_d();
	}

	ret = -EFAULT;

	/*
	 * Now install the values into the registers
	 */
	for (i = 0; i < count; i++, req++) {
		
		if (__copy_from_user(&tmp, req, sizeof(tmp))) goto abort_mission;
		
		rnum      = tmp.dbreg_num;
		dbreg.val = tmp.dbreg_value;
		
		ret = -EINVAL;

		if ((mode == 0 && !IBR_IS_IMPL(rnum)) || ((mode == 1) && !DBR_IS_IMPL(rnum))) {
			DBprintk(("invalid register %u val=0x%lx mode=%d i=%d count=%d\n", 
				  rnum, dbreg.val, mode, i, count));

			goto abort_mission;
		}

		/*
		 * make sure we do not install enabled breakpoint
		 */
		if (rnum & 0x1) {
			if (mode == 0) 
				dbreg.ibr.ibr_x = 0;
			else
				dbreg.dbr.dbr_r = dbreg.dbr.dbr_w = 0;
		}

		/*
		 * clear return flags and copy back to user
		 *
		 * XXX: fix once EAGAIN is implemented
		 */
		ret = -EFAULT;

		PFM_REG_RETFLAG_SET(tmp.dbreg_flags, 0);

		if (__copy_to_user(req, &tmp, sizeof(tmp))) goto abort_mission;

		/*
		 * Debug registers, just like PMC, can only be modified
		 * by a kernel call. Moreover, perfmon() access to those
		 * registers are centralized in this routine. The hardware
		 * does not modify the value of these registers, therefore,
		 * if we save them as they are written, we can avoid having
		 * to save them on context switch out. This is made possible
		 * by the fact that when perfmon uses debug registers, ptrace()
		 * won't be able to modify them concurrently.
		 */
		if (mode == 0) {
			CTX_USED_IBR(ctx, rnum);

			ia64_set_ibr(rnum, dbreg.val);
			ia64_srlz_i();

			thread->ibr[rnum] = dbreg.val;

			DBprintk(("write ibr%u=0x%lx used_ibrs=0x%lx\n", rnum, dbreg.val, ctx->ctx_used_ibrs[0]));
		} else {
			CTX_USED_DBR(ctx, rnum);

			ia64_set_dbr(rnum, dbreg.val);
			ia64_srlz_d();

			thread->dbr[rnum] = dbreg.val;

			DBprintk(("write dbr%u=0x%lx used_dbrs=0x%lx\n", rnum, dbreg.val, ctx->ctx_used_dbrs[0]));
		}
	}

	return 0;

abort_mission:
	/*
	 * in case it was our first attempt, we undo the global modifications
	 */
	if (first_time) {
		LOCK_PFS();
		if (ctx->ctx_fl_system) {
			pfm_sessions.pfs_sys_use_dbregs--;
		}
		UNLOCK_PFS();
		ctx->ctx_fl_using_dbreg = 0;
	}
	/*
	 * install error return flag
	 */
	if (ret != -EFAULT) {
		/*
		 * XXX: for now we can only come here on EINVAL
		 */
		PFM_REG_RETFLAG_SET(tmp.dbreg_flags, PFM_REG_RETFL_EINVAL);
		if (__put_user(tmp.dbreg_flags, &req->dbreg_flags)) ret = -EFAULT;
	}
	return ret;
}

static int
pfm_write_ibrs(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, 
	 struct pt_regs *regs)
{	
	/* we don't quite support this right now */
	if (task != current) return -EINVAL;

	if (!CTX_IS_ENABLED(ctx)) return -EINVAL;

	return pfm_write_ibr_dbr(0, task, arg, count, regs);
}

static int
pfm_write_dbrs(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, 
	 struct pt_regs *regs)
{	
	/* we don't quite support this right now */
	if (task != current) return -EINVAL;

	if (!CTX_IS_ENABLED(ctx)) return -EINVAL;

	return pfm_write_ibr_dbr(1, task, arg, count, regs);
}

#endif /* PFM_PMU_USES_DBR */

static int
pfm_get_features(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	pfarg_features_t tmp;

	memset(&tmp, 0, sizeof(tmp));

	tmp.ft_version      = PFM_VERSION;
	tmp.ft_smpl_version = PFM_SMPL_VERSION;

	if (__copy_to_user(arg, &tmp, sizeof(tmp))) return -EFAULT;

	return 0;
}

static int
pfm_start(struct task_struct *task, pfm_context_t *ctx, void *arg, int count, 
	  struct pt_regs *regs)
{
	/* we don't quite support this right now */
	if (task != current) return -EINVAL;

	/* 
	 * Cannot do anything before PMU is enabled 
	 */
	if (!CTX_IS_ENABLED(ctx)) return -EINVAL;

	DBprintk(("[%d] fl_system=%d owner=%p current=%p\n",
				current->pid,
				ctx->ctx_fl_system, PMU_OWNER(),
				current));

	if (PMU_OWNER() != task) {
		printk("perfmon: pfm_start task [%d] not pmu owner\n", task->pid);
		return -EINVAL;
	}

	if (ctx->ctx_fl_system) {
		
		local_cpu_data->pfm_dcr_pp  = 1;

		/* set user level psr.pp */
		ia64_psr(regs)->pp = 1;

		/* start monitoring at kernel level */
		__asm__ __volatile__ ("ssm psr.pp;;"::: "memory");

		/* enable dcr pp */
		ia64_set_dcr(ia64_get_dcr()|IA64_DCR_PP);

		ia64_srlz_i();

	} else {
		if ((task->thread.flags & IA64_THREAD_PM_VALID) == 0) {
			printk("perfmon: pfm_start task flag not set for [%d]\n", task->pid