From: Kees Cook <keescook@chromium.org>
To: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] perf/arm-cci: Remove VLA usage
Date: Fri, 29 Jun 2018 11:45:36 -0700 [thread overview]
Message-ID: <20180629184536.GA37337@beast> (raw)
In the quest to remove all stack VLA usage from the kernel[1], this
removes the VLA in favor of a maximum size and adds a sanity check
at registration time. The sizes are all explicitly enumerated already,
so this just collects them into macros.
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/perf/arm-cci.c | 38 ++++++++++++++++++++++++++------------
1 file changed, 26 insertions(+), 12 deletions(-)
diff --git a/drivers/perf/arm-cci.c b/drivers/perf/arm-cci.c
index 0d09d8e669cd..1bfeb160c5b1 100644
--- a/drivers/perf/arm-cci.c
+++ b/drivers/perf/arm-cci.c
@@ -53,6 +53,16 @@ enum {
CCI_IF_MAX,
};
+#define NUM_HW_CNTRS_CII_4XX 4
+#define NUM_HW_CNTRS_CII_5XX 8
+#define NUM_HW_CNTRS_MAX NUM_HW_CNTRS_CII_5XX
+
+#define FIXED_HW_CNTRS_CII_4XX 1
+#define FIXED_HW_CNTRS_CII_5XX 0
+#define FIXED_HW_CNTRS_MAX FIXED_HW_CNTRS_CII_4XX
+
+#define HW_CNTRS_MAX (NUM_HW_CNTRS_MAX + FIXED_HW_CNTRS_MAX)
+
struct event_range {
u32 min;
u32 max;
@@ -633,8 +643,7 @@ static void cci_pmu_sync_counters(struct cci_pmu *cci_pmu)
{
int i;
struct cci_pmu_hw_events *cci_hw = &cci_pmu->hw_events;
-
- DECLARE_BITMAP(mask, cci_pmu->num_cntrs);
+ DECLARE_BITMAP(mask, HW_CNTRS_MAX);
bitmap_zero(mask, cci_pmu->num_cntrs);
for_each_set_bit(i, cci_pmu->hw_events.used_mask, cci_pmu->num_cntrs) {
@@ -940,7 +949,7 @@ static void pmu_write_counters(struct cci_pmu *cci_pmu, unsigned long *mask)
static void cci5xx_pmu_write_counters(struct cci_pmu *cci_pmu, unsigned long *mask)
{
int i;
- DECLARE_BITMAP(saved_mask, cci_pmu->num_cntrs);
+ DECLARE_BITMAP(saved_mask, HW_CNTRS_MAX);
bitmap_zero(saved_mask, cci_pmu->num_cntrs);
pmu_save_counters(cci_pmu, saved_mask);
@@ -1245,7 +1254,7 @@ static int validate_group(struct perf_event *event)
{
struct perf_event *sibling, *leader = event->group_leader;
struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
- unsigned long mask[BITS_TO_LONGS(cci_pmu->num_cntrs)];
+ unsigned long mask[BITS_TO_LONGS(HW_CNTRS_MAX)];
struct cci_pmu_hw_events fake_pmu = {
/*
* Initialise the fake PMU. We only need to populate the
@@ -1403,6 +1412,11 @@ static int cci_pmu_init(struct cci_pmu *cci_pmu, struct platform_device *pdev)
char *name = model->name;
u32 num_cntrs;
+ if (WARN_ON(model->num_hw_cntrs > NUM_HW_CNTRS_MAX))
+ return -EINVAL;
+ if (WARN_ON(model->fixed_hw_cntrs > FIXED_HW_CNTRS_MAX))
+ return -EINVAL;
+
pmu_event_attr_group.attrs = model->event_attrs;
pmu_format_attr_group.attrs = model->format_attrs;
@@ -1455,8 +1469,8 @@ static __maybe_unused struct cci_pmu_model cci_pmu_models[] = {
#ifdef CONFIG_ARM_CCI400_PMU
[CCI400_R0] = {
.name = "CCI_400",
- .fixed_hw_cntrs = 1, /* Cycle counter */
- .num_hw_cntrs = 4,
+ .fixed_hw_cntrs = FIXED_HW_CNTRS_CII_4XX, /* Cycle counter */
+ .num_hw_cntrs = NUM_HW_CNTRS_CII_4XX,
.cntr_size = SZ_4K,
.format_attrs = cci400_pmu_format_attrs,
.event_attrs = cci400_r0_pmu_event_attrs,
@@ -1475,8 +1489,8 @@ static __maybe_unused struct cci_pmu_model cci_pmu_models[] = {
},
[CCI400_R1] = {
.name = "CCI_400_r1",
- .fixed_hw_cntrs = 1, /* Cycle counter */
- .num_hw_cntrs = 4,
+ .fixed_hw_cntrs = FIXED_HW_CNTRS_CII_4XX, /* Cycle counter */
+ .num_hw_cntrs = NUM_HW_CNTRS_CII_4XX,
.cntr_size = SZ_4K,
.format_attrs = cci400_pmu_format_attrs,
.event_attrs = cci400_r1_pmu_event_attrs,
@@ -1497,8 +1511,8 @@ static __maybe_unused struct cci_pmu_model cci_pmu_models[] = {
#ifdef CONFIG_ARM_CCI5xx_PMU
[CCI500_R0] = {
.name = "CCI_500",
- .fixed_hw_cntrs = 0,
- .num_hw_cntrs = 8,
+ .fixed_hw_cntrs = FIXED_HW_CNTRS_CII_5XX,
+ .num_hw_cntrs = NUM_HW_CNTRS_CII_5XX,
.cntr_size = SZ_64K,
.format_attrs = cci5xx_pmu_format_attrs,
.event_attrs = cci5xx_pmu_event_attrs,
@@ -1521,8 +1535,8 @@ static __maybe_unused struct cci_pmu_model cci_pmu_models[] = {
},
[CCI550_R0] = {
.name = "CCI_550",
- .fixed_hw_cntrs = 0,
- .num_hw_cntrs = 8,
+ .fixed_hw_cntrs = FIXED_HW_CNTRS_CII_5XX,
+ .num_hw_cntrs = NUM_HW_CNTRS_CII_5XX,
.cntr_size = SZ_64K,
.format_attrs = cci5xx_pmu_format_attrs,
.event_attrs = cci5xx_pmu_event_attrs,
--
2.17.1
--
Kees Cook
Pixel Security
next reply other threads:[~2018-06-29 18:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-29 18:45 Kees Cook [this message]
2018-06-29 21:26 ` [PATCH] perf/arm-cci: Remove VLA usage Arnd Bergmann
2018-07-02 16:50 ` Will Deacon
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