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Subject[PATCH 9/9] oprofile/x86: implement perfctr reservation for IBS
Date
For sharing IBS with oprofile and perf a resource allocation is
needed. This patch implements IBS allocation by extending the perfctr
reservation code.

Signed-off-by: Robert Richter <robert.richter@amd.com>
---
arch/x86/include/asm/perf_event.h | 3 +
arch/x86/oprofile/op_model_amd.c | 104 +++++++++++++++++++++++++------------
2 files changed, 74 insertions(+), 33 deletions(-)
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 80e6936..2a95e01 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -117,6 +117,9 @@ union cpuid10_edx {
*/
#define X86_PMC_IDX_FIXED_BTS (X86_PMC_IDX_FIXED + 16)

+#define X86_PMC_IDX_SPECIAL_IBS_FETCH (X86_PMC_IDX_FIXED + 17)
+#define X86_PMC_IDX_SPECIAL_IBS_OP (X86_PMC_IDX_FIXED + 18)
+
/* IbsFetchCtl bits/masks */
#define IBS_FETCH_RAND_EN (1ULL<<57)
#define IBS_FETCH_VAL (1ULL<<49)
diff --git a/arch/x86/oprofile/op_model_amd.c b/arch/x86/oprofile/op_model_amd.c
index 9c0d978..9bd040d 100644
--- a/arch/x86/oprofile/op_model_amd.c
+++ b/arch/x86/oprofile/op_model_amd.c
@@ -61,6 +61,7 @@ struct op_ibs_config {
};

static struct op_ibs_config ibs_config;
+static u64 ibs_fetch_ctl;
static u64 ibs_op_ctl;

/*
@@ -105,6 +106,63 @@ static u32 get_ibs_caps(void)
return ibs_caps;
}

+static void shutdown_ibs(void)
+{
+ if (ibs_fetch_ctl) {
+ ibs_fetch_ctl = 0;
+ release_perfctr(X86_PMC_IDX_SPECIAL_IBS_FETCH);
+ }
+
+ if (ibs_op_ctl) {
+ ibs_op_ctl = 0;
+ release_perfctr(X86_PMC_IDX_SPECIAL_IBS_OP);
+ }
+}
+
+static int setup_ibs(void)
+{
+ ibs_fetch_ctl = 0;
+ if (ibs_caps && ibs_config.fetch_enabled) {
+ if (!reserve_perfctr(X86_PMC_IDX_SPECIAL_IBS_FETCH))
+ goto fail;
+ ibs_fetch_ctl =
+ ((ibs_config.max_cnt_fetch >> 4) & IBS_FETCH_MAX_CNT)
+ | (ibs_config.rand_en ? IBS_FETCH_RAND_EN : 0)
+ | IBS_FETCH_ENABLE;
+ }
+
+ ibs_op_ctl = 0;
+ if (ibs_caps && ibs_config.op_enabled) {
+ if (!reserve_perfctr(X86_PMC_IDX_SPECIAL_IBS_OP))
+ goto fail;
+ ibs_op_ctl = ibs_config.max_cnt_op >> 4;
+ if (!(ibs_caps & IBS_CAPS_RDWROPCNT)) {
+ /*
+ * IbsOpCurCnt not supported. See
+ * op_amd_randomize_ibs_op() for details.
+ */
+ ibs_op_ctl = clamp(ibs_op_ctl, 0x0081ULL, 0xFF80ULL);
+ } else {
+ /*
+ * The start value is randomized with a
+ * positive offset, we need to compensate it
+ * with the half of the randomized range. Also
+ * avoid underflows.
+ */
+ ibs_op_ctl = min(ibs_op_ctl + IBS_RANDOM_MAXCNT_OFFSET,
+ IBS_OP_MAX_CNT);
+ }
+ if (ibs_caps & IBS_CAPS_OPCNT && ibs_config.dispatched_ops)
+ ibs_op_ctl |= IBS_OP_CNT_CTL;
+ ibs_op_ctl |= IBS_OP_ENABLE;
+ }
+
+ return 0;
+fail:
+ shutdown_ibs();
+ return -EBUSY;
+}
+
/*
* 16-bit Linear Feedback Shift Register (LFSR)
*
@@ -170,7 +228,7 @@ op_amd_handle_ibs(struct pt_regs * const regs,
if (!ibs_caps)
return;

- if (ibs_config.fetch_enabled) {
+ if (ibs_fetch_ctl) {
rdmsrl(MSR_AMD64_IBSFETCHCTL, ctl);
if (ctl & IBS_FETCH_VAL) {
rdmsrl(MSR_AMD64_IBSFETCHLINAD, val);
@@ -183,13 +241,11 @@ op_amd_handle_ibs(struct pt_regs * const regs,
oprofile_write_commit(&entry);

/* reenable the IRQ */
- ctl &= ~(IBS_FETCH_VAL | IBS_FETCH_CNT);
- ctl |= IBS_FETCH_ENABLE;
- wrmsrl(MSR_AMD64_IBSFETCHCTL, ctl);
+ wrmsrl(MSR_AMD64_IBSFETCHCTL, ibs_fetch_ctl);
}
}

- if (ibs_config.op_enabled) {
+ if (ibs_op_ctl) {
rdmsrl(MSR_AMD64_IBSOPCTL, ctl);
if (ctl & IBS_OP_VAL) {
rdmsrl(MSR_AMD64_IBSOPRIP, val);
@@ -222,34 +278,10 @@ static inline void op_amd_start_ibs(void)
if (!ibs_caps)
return;

- if (ibs_config.fetch_enabled) {
- val = (ibs_config.max_cnt_fetch >> 4) & IBS_FETCH_MAX_CNT;
- val |= ibs_config.rand_en ? IBS_FETCH_RAND_EN : 0;
- val |= IBS_FETCH_ENABLE;
- wrmsrl(MSR_AMD64_IBSFETCHCTL, val);
- }
+ if (ibs_fetch_ctl)
+ wrmsrl(MSR_AMD64_IBSFETCHCTL, ibs_fetch_ctl);

- if (ibs_config.op_enabled) {
- ibs_op_ctl = ibs_config.max_cnt_op >> 4;
- if (!(ibs_caps & IBS_CAPS_RDWROPCNT)) {
- /*
- * IbsOpCurCnt not supported. See
- * op_amd_randomize_ibs_op() for details.
- */
- ibs_op_ctl = clamp(ibs_op_ctl, 0x0081ULL, 0xFF80ULL);
- } else {
- /*
- * The start value is randomized with a
- * positive offset, we need to compensate it
- * with the half of the randomized range. Also
- * avoid underflows.
- */
- ibs_op_ctl = min(ibs_op_ctl + IBS_RANDOM_MAXCNT_OFFSET,
- IBS_OP_MAX_CNT);
- }
- if (ibs_caps & IBS_CAPS_OPCNT && ibs_config.dispatched_ops)
- ibs_op_ctl |= IBS_OP_CNT_CTL;
- ibs_op_ctl |= IBS_OP_ENABLE;
+ if (ibs_op_ctl) {
val = op_amd_randomize_ibs_op(ibs_op_ctl);
wrmsrl(MSR_AMD64_IBSOPCTL, val);
}
@@ -297,7 +329,11 @@ static void op_amd_shutdown(struct op_msrs const * const msrs);

static int op_amd_fill_in_addresses(struct op_msrs * const msrs)
{
- int i;
+ int err, i;
+
+ err = setup_ibs();
+ if (err)
+ return err;

for (i = 0; i < NUM_COUNTERS; i++) {
if (reserve_perfctr(i)) {
@@ -438,6 +474,8 @@ static void op_amd_shutdown(struct op_msrs const * const msrs)
if (msrs->counters[i].addr)
release_perfctr(i);
}
+
+ shutdown_ibs();
}

static u8 ibs_eilvt_off;
--
1.7.0



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