Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 MPAM fixes from Catalin Marinas: - Fix NULL dereference and a false-positive warning when the driver probes hardware with surprising version numbers - Fix writing values to the wrong registers when probing cache-utilisation counters. Replace 'NRDY' probing with a version that is robust for platforms where the bit is writeable by both hardware and software * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm_mpam: Check whether the config array is allocated before destroying it arm_mpam: Fix false positive assert failure during mpam_disable() arm_mpam: Improve check for whether or not NRDY is hardware managed arm_mpam: Pretend that NRDY is always hardware managed arm_mpam: Fix monitor instance selection when checking for hardware NRDY

Linus Torvalds committed 6 months ago

Commit 36343a82 parents 30e0ff6 6ccbb612 files · +40 −43Browse files

Unified · Split

2 files

drivers/resctrl/mpam_devices.c +40 −41
drivers/resctrl/mpam_internal.h +0 −2

drivers/resctrl/mpam_devices.c+40−41

 /*
  * Once mpam is enabled, new requestors cannot further reduce the available
  * partid. Assert that the size is fixed, and new requestors will be turned
- * away.
+ * away. This is needed when walking over structures sized by PARTID.
+ *
+ * During mpam_disable() these structures are not fixed, but the MSC state
+ * is still reset using whatever sizes have been discovered so far. As only
+ * PARTID 0 will be used after mpam_disable(), any race would be benign.
+ * Skip the check if a mpam_disable_reason has been set.
  */
 static void mpam_assert_partid_sizes_fixed(void)
 {
-	WARN_ON_ONCE(!partid_max_published);
+	if (!mpam_disable_reason)
+		WARN_ON_ONCE(!partid_max_published);
 }
 static u32 __mpam_read_reg(struct mpam_msc *msc, u16 reg)
  * Try and see what values stick in this bit. If we can write either value,
  * its probably not implemented by hardware.
  */
-static bool _mpam_ris_hw_probe_hw_nrdy(struct mpam_msc_ris *ris, u32 mon_reg)
+static bool mpam_ris_hw_probe_csu_nrdy(struct mpam_msc_ris *ris)
 {
-	u32 now;
+	u32 now, mon_sel, ctl_val;
-	u64 mon_sel;
 	bool can_set, can_clear;
 	struct mpam_msc *msc = ris->vmsc->msc;
 	mon_sel = FIELD_PREP(MSMON_CFG_MON_SEL_MON_SEL, 0) |
 		  FIELD_PREP(MSMON_CFG_MON_SEL_RIS, ris->ris_idx);
-	_mpam_write_monsel_reg(msc, mon_reg, mon_sel);
+	mpam_write_monsel_reg(msc, CFG_MON_SEL, mon_sel);
+	/* Hardware might ignore nrdy if it's not enabled */
+	ctl_val = MSMON_CFG_CSU_CTL_TYPE_CSU;
+	ctl_val |= MSMON_CFG_x_CTL_MATCH_PARTID;
+	ctl_val |= MSMON_CFG_x_CTL_MATCH_PMG;
+	ctl_val |= MSMON_CFG_x_CTL_EN;
+	mpam_write_monsel_reg(msc, CFG_CSU_FLT, 0);
+	mpam_write_monsel_reg(msc, CFG_CSU_CTL, ctl_val);
-	_mpam_write_monsel_reg(msc, mon_reg, MSMON___NRDY);
+	_mpam_write_monsel_reg(msc, MSMON_CSU, MSMON___NRDY);
-	now = _mpam_read_monsel_reg(msc, mon_reg);
+	now = _mpam_read_monsel_reg(msc, MSMON_CSU);
 	can_set = now & MSMON___NRDY;
-	_mpam_write_monsel_reg(msc, mon_reg, 0);
+	_mpam_write_monsel_reg(msc, MSMON_CSU, 0);
-	now = _mpam_read_monsel_reg(msc, mon_reg);
+	/* Configuration change to try and coax hardware into setting nrdy */
+	mpam_write_monsel_reg(msc, CFG_CSU_FLT, 0x1);
+	now = _mpam_read_monsel_reg(msc, MSMON_CSU);
 	can_clear = !(now & MSMON___NRDY);
 	mpam_mon_sel_unlock(msc);
 	return (!can_set || !can_clear);
 }
-#define mpam_ris_hw_probe_hw_nrdy(_ris, _mon_reg)			\
-	_mpam_ris_hw_probe_hw_nrdy(_ris, MSMON_##_mon_reg)
 static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
 {
 	int err;
 					mpam_set_feature(mpam_feat_msmon_csu_xcl, props);
 				/* Is NRDY hardware managed? */
-				hw_managed = mpam_ris_hw_probe_hw_nrdy(ris, CSU);
+				hw_managed = mpam_ris_hw_probe_csu_nrdy(ris);
-				if (hw_managed)
-					mpam_set_feature(mpam_feat_msmon_csu_hw_nrdy, props);
-			}
-			/*
+				/*
-			 * Accept the missing firmware property if NRDY appears
+				 * Accept the missing firmware property if NRDY appears
-			 * un-implemented.
+				 * un-implemented.
-			 */
+				 */
-			if (err && mpam_has_feature(mpam_feat_msmon_csu_hw_nrdy, props))
+				if (err && hw_managed)
-				dev_err_once(dev, "Counters are not usable because not-ready timeout was not provided by firmware.");
+					dev_err_once(dev, "Counters are not usable because not-ready timeout was not provided by firmware.");
+			}
 		}
 		if (FIELD_GET(MPAMF_MSMON_IDR_MSMON_MBWU, msmon_features)) {
-			bool has_long, hw_managed;
+			bool has_long;
 			u32 mbwumon_idr = mpam_read_partsel_reg(msc, MBWUMON_IDR);
 			props->num_mbwu_mon = FIELD_GET(MPAMF_MBWUMON_IDR_NUM_MON, mbwumon_idr);
 				} else {
 					mpam_set_feature(mpam_feat_msmon_mbwu_31counter, props);
 				}
-				/* Is NRDY hardware managed? */
-				hw_managed = mpam_ris_hw_probe_hw_nrdy(ris, MBWU);
-				if (hw_managed)
-					mpam_set_feature(mpam_feat_msmon_mbwu_hw_nrdy, props);
-				/*
-				 * Don't warn about any missing firmware property for
-				 * MBWU NRDY - it doesn't make any sense!
-				 */
 			}
 		}
 	}
 	bool reset_on_next_read = false;
 	struct mpam_msc_ris *ris = m->ris;
 	struct msmon_mbwu_state *mbwu_state;
-	struct mpam_props *rprops = &ris->props;
 	struct mpam_msc *msc = m->ris->vmsc->msc;
 	u32 mon_sel, ctl_val, flt_val, cur_ctl, cur_flt;
 	switch (m->type) {
 	case mpam_feat_msmon_csu:
 		now = mpam_read_monsel_reg(msc, CSU);
-		if (mpam_has_feature(mpam_feat_msmon_csu_hw_nrdy, rprops))
+		nrdy = now & MSMON___NRDY;
-			nrdy = now & MSMON___NRDY;
 		now = FIELD_GET(MSMON___VALUE, now);
 		if (mpam_has_quirk(IGNORE_CSU_NRDY, msc) && m->waited_timeout)
 	case mpam_feat_msmon_mbwu_63counter:
 		if (m->type != mpam_feat_msmon_mbwu_31counter) {
 			now = mpam_msc_read_mbwu_l(msc);
-			if (mpam_has_feature(mpam_feat_msmon_mbwu_hw_nrdy, rprops))
+			nrdy = now & MSMON___L_NRDY;
-				nrdy = now & MSMON___L_NRDY;
 			if (m->type == mpam_feat_msmon_mbwu_63counter)
 				now = FIELD_GET(MSMON___LWD_VALUE, now);
 				now = FIELD_GET(MSMON___L_VALUE, now);
 		} else {
 			now = mpam_read_monsel_reg(msc, MBWU);
-			if (mpam_has_feature(mpam_feat_msmon_mbwu_hw_nrdy, rprops))
+			nrdy = now & MSMON___NRDY;
-				nrdy = now & MSMON___NRDY;
 			now = FIELD_GET(MSMON___VALUE, now);
 		}
 	lockdep_assert_held(&mpam_list_lock);
+	if (!comp->cfg)
+		return;
 	add_to_garbage(comp->cfg);
 	list_for_each_entry(vmsc, &comp->vmsc, comp_list) {
 		msc = vmsc->msc;

drivers/resctrl/mpam_internal.h+0−2

 	mpam_feat_msmon_csu,
 	mpam_feat_msmon_csu_capture,
 	mpam_feat_msmon_csu_xcl,
-	mpam_feat_msmon_csu_hw_nrdy,
 	mpam_feat_msmon_mbwu,
 	mpam_feat_msmon_mbwu_31counter,
 	mpam_feat_msmon_mbwu_44counter,
 	mpam_feat_msmon_mbwu_63counter,
 	mpam_feat_msmon_mbwu_capture,
 	mpam_feat_msmon_mbwu_rwbw,
-	mpam_feat_msmon_mbwu_hw_nrdy,
 	mpam_feat_partid_nrw,
 	MPAM_FEATURE_LAST
 };