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Commit 1201a5a2 authored by Kees Cook's avatar Kees Cook Committed by Will Deacon
Browse files

perf/arm-cci: Remove VLA usage 

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: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent ce397d21

drivers/perf/arm-cci.c

+26 −12
Original line number Diff line number Diff line
@@ -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,