From 5c183fe66a3a75373fee1c5283b1b1d5a888a10e Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Fri, 3 Dec 2021 11:44:58 +0000 Subject: [PATCH] perf/arm-cmn: Move group validation data off-stack With the value of CMN_MAX_DTMS increasing significantly, our validation data structure is set to get quite big. Technically we could pack it at least twice as densely, since we only need around 19 bits of information per DTM, but that makes the code even more mind-bogglingly impenetrable, and even half of "quite big" may still be uncomfortably large for a stack frame (~1KB). Just move it to an off-stack allocation instead. Signed-off-by: Robin Murphy Link: https://lore.kernel.org/r/0cabff2e5839ddc0979e757c55515966f65359e4.1638530442.git.robin.murphy@arm.com Signed-off-by: Will Deacon --- drivers/perf/arm-cmn.c | 43 ++++++++++++++++++++++++------------------ 1 file changed, 25 insertions(+), 18 deletions(-) diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index acff8683af2c2..d2dd02f040b8c 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -876,8 +876,8 @@ static int arm_cmn_validate_group(struct perf_event *event) struct arm_cmn_node *dn; struct perf_event *sibling, *leader = event->group_leader; enum cmn_node_type type; - struct arm_cmn_val val; - int i; + struct arm_cmn_val *val; + int i, ret = -EINVAL; u8 occupid; if (leader == event) @@ -886,18 +886,22 @@ static int arm_cmn_validate_group(struct perf_event *event) if (event->pmu != leader->pmu && !is_software_event(leader)) return -EINVAL; - memset(&val, 0, sizeof(val)); + val = kzalloc(sizeof(*val), GFP_KERNEL); + if (!val) + return -ENOMEM; - arm_cmn_val_add_event(&val, leader); + arm_cmn_val_add_event(val, leader); for_each_sibling_event(sibling, leader) - arm_cmn_val_add_event(&val, sibling); + arm_cmn_val_add_event(val, sibling); type = CMN_EVENT_TYPE(event); - if (type == CMN_TYPE_DTC) - return val.cycles ? -EINVAL : 0; + if (type == CMN_TYPE_DTC) { + ret = val->cycles ? -EINVAL : 0; + goto done; + } - if (val.dtc_count == CMN_DT_NUM_COUNTERS) - return -EINVAL; + if (val->dtc_count == CMN_DT_NUM_COUNTERS) + goto done; if (arm_cmn_is_occup_event(type, CMN_EVENT_EVENTID(event))) occupid = CMN_EVENT_OCCUPID(event) + 1; @@ -907,25 +911,28 @@ static int arm_cmn_validate_group(struct perf_event *event) for_each_hw_dn(hw, dn, i) { int wp_idx, wp_cmb, dtm = dn->dtm; - if (val.dtm_count[dtm] == CMN_DTM_NUM_COUNTERS) - return -EINVAL; + if (val->dtm_count[dtm] == CMN_DTM_NUM_COUNTERS) + goto done; - if (occupid && val.occupid[dtm] && occupid != val.occupid[dtm]) - return -EINVAL; + if (occupid && val->occupid[dtm] && occupid != val->occupid[dtm]) + goto done; if (type != CMN_TYPE_WP) continue; wp_idx = arm_cmn_wp_idx(event); - if (val.wp[dtm][wp_idx]) - return -EINVAL; + if (val->wp[dtm][wp_idx]) + goto done; - wp_cmb = val.wp[dtm][wp_idx ^ 1]; + wp_cmb = val->wp[dtm][wp_idx ^ 1]; if (wp_cmb && wp_cmb != CMN_EVENT_WP_COMBINE(event) + 1) - return -EINVAL; + goto done; } - return 0; + ret = 0; +done: + kfree(val); + return ret; } static int arm_cmn_event_init(struct perf_event *event) -- 2.39.5