Commit da5f7d2c authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon
Browse files

perf/arm-cmn: Streamline node iteration 



Refactor the places where we scan through the set of nodes to switch
from explicit array indexing to pointer-based iteration. This leads to
slightly simpler object code, but also makes the source less dense and
more pleasant for further development. It also unearths an almost-bug
in arm_cmn_event_init() where we've been depending on the "array index"
of NULL relative to cmn->dns being a sufficiently large number, yuck.

Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/ee0c9eda9a643f46001ac43aadf3f0b1fd5660dd.1638530442.git.robin.murphy@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 5f167eab

drivers/perf/arm-cmn.c

+20 −13
Original line number Original line Diff line number Diff line
@@ -299,11 +299,11 @@ static struct arm_cmn_node *arm_cmn_node_to_xp(struct arm_cmn_node *dn) 
static struct arm_cmn_node *arm_cmn_node(const struct arm_cmn *cmn,

static struct arm_cmn_node *arm_cmn_node(const struct arm_cmn *cmn,

					 enum cmn_node_type type)

					 enum cmn_node_type type)

{

{

	int i;

	struct arm_cmn_node *dn;





	for (i = 0; i < cmn->num_dns; i++)

	for (dn = cmn->dns; dn->type; dn++)

		if (cmn->dns[i].type == type)

		if (dn->type == type)

			return &cmn->dns[i];

			return dn;

	return NULL;

	return NULL;

}

}
@@ -941,8 +941,8 @@ static int arm_cmn_event_init(struct perf_event *event) 
{

{

	struct arm_cmn *cmn = to_cmn(event->pmu);

	struct arm_cmn *cmn = to_cmn(event->pmu);

	struct arm_cmn_hw_event *hw = to_cmn_hw(event);

	struct arm_cmn_hw_event *hw = to_cmn_hw(event);

	struct arm_cmn_node *dn;

	enum cmn_node_type type;

	enum cmn_node_type type;

	unsigned int i;

	bool bynodeid;

	bool bynodeid;

	u16 nodeid, eventid;

	u16 nodeid, eventid;
@@ -974,10 +974,12 @@ static int arm_cmn_event_init(struct perf_event *event) 
	nodeid = CMN_EVENT_NODEID(event);

	nodeid = CMN_EVENT_NODEID(event);





	hw->dn = arm_cmn_node(cmn, type);

	hw->dn = arm_cmn_node(cmn, type);

	for (i = hw->dn - cmn->dns; i < cmn->num_dns && cmn->dns[i].type == type; i++) {

	if (!hw->dn)

		return -EINVAL;

	for (dn = hw->dn; dn->type == type; dn++) {

		if (!bynodeid) {

		if (!bynodeid) {

			hw->num_dns++;

			hw->num_dns++;

		} else if (cmn->dns[i].id != nodeid) {

		} else if (dn->id != nodeid) {

			hw->dn++;

			hw->dn++;

		} else {

		} else {

			hw->num_dns = 1;

			hw->num_dns = 1;
@@ -1332,7 +1334,7 @@ static int arm_cmn_init_dtcs(struct arm_cmn *cmn) 




	cmn->xps = arm_cmn_node(cmn, CMN_TYPE_XP);

	cmn->xps = arm_cmn_node(cmn, CMN_TYPE_XP);





	for (dn = cmn->dns; dn < cmn->dns + cmn->num_dns; dn++) {

	for (dn = cmn->dns; dn->type; dn++) {

		if (dn->type != CMN_TYPE_XP)

		if (dn->type != CMN_TYPE_XP)

			arm_cmn_init_node_to_xp(cmn, dn);

			arm_cmn_init_node_to_xp(cmn, dn);

		else if (cmn->num_dtcs == 1)

		else if (cmn->num_dtcs == 1)
@@ -1382,6 +1384,7 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset) 
	u32 xp_offset[CMN_MAX_XPS];

	u32 xp_offset[CMN_MAX_XPS];

	u64 reg;

	u64 reg;

	int i, j;

	int i, j;

	size_t sz;





	cfg_region = cmn->base + rgn_offset;

	cfg_region = cmn->base + rgn_offset;

	reg = readl_relaxed(cfg_region + CMN_CFGM_PERIPH_ID_2);

	reg = readl_relaxed(cfg_region + CMN_CFGM_PERIPH_ID_2);
@@ -1408,14 +1411,13 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset) 
		cmn->num_dns += FIELD_GET(CMN_CI_CHILD_COUNT, reg);

		cmn->num_dns += FIELD_GET(CMN_CI_CHILD_COUNT, reg);

	}

	}





	/* Cheeky +1 to help terminate pointer-based iteration */

	/* Cheeky +1 to help terminate pointer-based iteration later */

	cmn->dns = devm_kcalloc(cmn->dev, cmn->num_dns + 1,

	dn = devm_kcalloc(cmn->dev, cmn->num_dns + 1, sizeof(*dn), GFP_KERNEL);

				sizeof(*cmn->dns), GFP_KERNEL);

	if (!dn)

	if (!cmn->dns)

		return -ENOMEM;

		return -ENOMEM;





	/* Pass 2: now we can actually populate the nodes */

	/* Pass 2: now we can actually populate the nodes */

	dn = cmn->dns;

	cmn->dns = dn;

	for (i = 0; i < cmn->num_xps; i++) {

	for (i = 0; i < cmn->num_xps; i++) {

		void __iomem *xp_region = cmn->base + xp_offset[i];

		void __iomem *xp_region = cmn->base + xp_offset[i];

		struct arm_cmn_node *xp = dn++;

		struct arm_cmn_node *xp = dn++;
@@ -1484,6 +1486,11 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset) 
	/* Correct for any nodes we skipped */

	/* Correct for any nodes we skipped */

	cmn->num_dns = dn - cmn->dns;

	cmn->num_dns = dn - cmn->dns;





	sz = (void *)(dn + 1) - (void *)cmn->dns;

	dn = devm_krealloc(cmn->dev, cmn->dns, sz, GFP_KERNEL);

	if (dn)

		cmn->dns = dn;



	/*

	/*

	 * If mesh_x wasn't set during discovery then we never saw

	 * If mesh_x wasn't set during discovery then we never saw

	 * an XP at (0,1), thus we must have an Nx1 configuration.

	 * an XP at (0,1), thus we must have an Nx1 configuration.