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AMU: Add hooks to save/restore AMU context

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On some systems, the AMU counters might reset to 0 when a CPU
powerdown happens.  This behaviour conflicts with the intended
use-case of AMU as lower ELs are only expected to see non-decreasing
counter values.

Change-Id: If25519965d4e6e47e09225d0e732947986cbb5ec
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
This commit is contained in:
Dimitris Papastamos 2017-11-28 13:47:06 +00:00
parent 0767d50e69
commit b6eb39327c
3 changed files with 156 additions and 0 deletions
include/lib/aarch32
arch_helpers.h
lib/extensions/amu
aarch32
amu.c
aarch64
amu.c

5
include/lib/aarch32/arch_helpers.h
View file

@ -287,6 +287,11 @@ DEFINE_COPROCR_RW_FUNCS(amcntenset1, AMCNTENSET1)
DEFINE_COPROCR_RW_FUNCS(amcntenclr0, AMCNTENCLR0)
DEFINE_COPROCR_RW_FUNCS(amcntenclr1, AMCNTENCLR1)
DEFINE_COPROCR_RW_FUNCS_64(amevcntr00, AMEVCNTR00)
DEFINE_COPROCR_RW_FUNCS_64(amevcntr01, AMEVCNTR01)
DEFINE_COPROCR_RW_FUNCS_64(amevcntr02, AMEVCNTR02)
DEFINE_COPROCR_RW_FUNCS_64(amevcntr03, AMEVCNTR03)
/*
* TLBI operation prototypes
*/

73
lib/extensions/amu/aarch32/amu.c
View file

@ -8,6 +8,16 @@
#include <arch.h>
#include <arch_helpers.h>
#include <debug.h>
#include <platform.h>
#include <pubsub_events.h>
#define AMU_GROUP0_NR_COUNTERS 4
struct amu_ctx {
uint64_t group0_cnts[AMU_GROUP0_NR_COUNTERS];
};
static struct amu_ctx amu_ctxs[PLATFORM_CORE_COUNT];
void amu_enable(int el2_unused)
{
@ -34,3 +44,66 @@ void amu_enable(int el2_unused)
/* Enable group 0 counters */
write_amcntenset0(AMU_GROUP0_COUNTERS_MASK);
}
static void *amu_context_save(const void *arg)
{
struct amu_ctx *ctx;
uint64_t features;
features = read_id_pfr0() >> ID_PFR0_AMU_SHIFT;
if ((features & ID_PFR0_AMU_MASK) != 1)
return (void *)-1;
ctx = &amu_ctxs[plat_my_core_pos()];
/* Assert that group 0 counter configuration is what we expect */
assert(read_amcntenset0() == AMU_GROUP0_COUNTERS_MASK);
/*
* Disable group 0 counters to avoid other observers like SCP sampling
* counter values from the future via the memory mapped view.
*/
write_amcntenclr0(AMU_GROUP0_COUNTERS_MASK);
isb();
ctx->group0_cnts[0] = read64_amevcntr00();
ctx->group0_cnts[1] = read64_amevcntr01();
ctx->group0_cnts[2] = read64_amevcntr02();
ctx->group0_cnts[3] = read64_amevcntr03();
return 0;
}
static void *amu_context_restore(const void *arg)
{
struct amu_ctx *ctx;
uint64_t features;
features = read_id_pfr0() >> ID_PFR0_AMU_SHIFT;
if ((features & ID_PFR0_AMU_MASK) != 1)
return (void *)-1;
ctx = &amu_ctxs[plat_my_core_pos()];
/* Counters were disabled in `amu_context_save()` */
assert(read_amcntenset0() == 0);
/* Restore group 0 counters */
if (AMU_GROUP0_COUNTERS_MASK & (1U << 0))
write64_amevcntr00(ctx->group0_cnts[0]);
if (AMU_GROUP0_COUNTERS_MASK & (1U << 1))
write64_amevcntr01(ctx->group0_cnts[1]);
if (AMU_GROUP0_COUNTERS_MASK & (1U << 2))
write64_amevcntr02(ctx->group0_cnts[2]);
if (AMU_GROUP0_COUNTERS_MASK & (1U << 3))
write64_amevcntr03(ctx->group0_cnts[3]);
isb();
/* Enable group 0 counters */
write_amcntenset0(AMU_GROUP0_COUNTERS_MASK);
return 0;
}
SUBSCRIBE_TO_EVENT(psci_suspend_pwrdown_start, amu_context_save);
SUBSCRIBE_TO_EVENT(psci_suspend_pwrdown_finish, amu_context_restore);

78
lib/extensions/amu/aarch64/amu.c
View file

@ -10,9 +10,18 @@
#include <arch_helpers.h>
#include <assert.h>
#include <debug.h>
#include <platform.h>
#include <pubsub_events.h>
#define AMU_GROUP0_NR_COUNTERS 4
struct amu_ctx {
uint64_t group0_cnts[AMU_GROUP0_NR_COUNTERS];
uint64_t group1_cnts[AMU_GROUP1_NR_COUNTERS];
};
static struct amu_ctx amu_ctxs[PLATFORM_CORE_COUNT];
int amu_supported(void)
{
uint64_t features;
@ -108,3 +117,72 @@ void amu_group1_set_evtype(int idx, unsigned int val)
amu_group1_set_evtype_internal(idx, val);
isb();
}
static void *amu_context_save(const void *arg)
{
struct amu_ctx *ctx = &amu_ctxs[plat_my_core_pos()];
int i;
if (!amu_supported())
return (void *)-1;
/* Assert that group 0/1 counter configuration is what we expect */
assert(read_amcntenset0_el0() == AMU_GROUP0_COUNTERS_MASK &&
read_amcntenset1_el0() == AMU_GROUP1_COUNTERS_MASK);
assert((sizeof(int) * 8) - __builtin_clz(AMU_GROUP1_COUNTERS_MASK)
<= AMU_GROUP1_NR_COUNTERS);
/*
* Disable group 0/1 counters to avoid other observers like SCP sampling
* counter values from the future via the memory mapped view.
*/
write_amcntenclr0_el0(AMU_GROUP0_COUNTERS_MASK);
write_amcntenclr1_el0(AMU_GROUP1_COUNTERS_MASK);
isb();
/* Save group 0 counters */
for (i = 0; i < AMU_GROUP0_NR_COUNTERS; i++)
ctx->group0_cnts[i] = amu_group0_cnt_read(i);
/* Save group 1 counters */
for (i = 0; i < AMU_GROUP1_NR_COUNTERS; i++)
ctx->group1_cnts[i] = amu_group1_cnt_read(i);
return 0;
}
static void *amu_context_restore(const void *arg)
{
struct amu_ctx *ctx = &amu_ctxs[plat_my_core_pos()];
int i;
if (!amu_supported())
return (void *)-1;
/* Counters were disabled in `amu_context_save()` */
assert(read_amcntenset0_el0() == 0 && read_amcntenset1_el0() == 0);
assert((sizeof(int) * 8) - __builtin_clz(AMU_GROUP1_COUNTERS_MASK)
<= AMU_GROUP1_NR_COUNTERS);
/* Restore group 0 counters */
for (i = 0; i < AMU_GROUP0_NR_COUNTERS; i++)
if (AMU_GROUP0_COUNTERS_MASK & (1U << i))
amu_group0_cnt_write(i, ctx->group0_cnts[i]);
/* Restore group 1 counters */
for (i = 0; i < AMU_GROUP1_NR_COUNTERS; i++)
if (AMU_GROUP1_COUNTERS_MASK & (1U << i))
amu_group1_cnt_write(i, ctx->group1_cnts[i]);
isb();
/* Restore group 0/1 counter configuration */
write_amcntenset0_el0(AMU_GROUP0_COUNTERS_MASK);
write_amcntenset1_el0(AMU_GROUP1_COUNTERS_MASK);
return 0;
}
SUBSCRIBE_TO_EVENT(psci_suspend_pwrdown_start, amu_context_save);
SUBSCRIBE_TO_EVENT(psci_suspend_pwrdown_finish, amu_context_restore);