[PATCH 18/27] arm_mpam: propagate MSC access errors for msmon helpers

[James Morse <james.morse@arm.com>]

From: Andre Przywara <andre.przywara@arm.com>

Allow the helper functions for msmon accesses to return an error, and
propagate read and write errors from the lower level up.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Reviewed-by: Ben Horgan <ben.horgan@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Gavin Shan <gshan@redhat.com> # on NVIDIA Grace Hopper
Tested-by: Ritwick Sharma <ritwick.sharma@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
---
 drivers/resctrl/mpam_devices.c | 72 ++++++++++++++++++++++------------
 1 file changed, 47 insertions(+), 25 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index c573fe08ce01..72a5d1ab9684 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -1177,15 +1177,20 @@ static int mpam_msc_read_mbwu_l(struct mpam_msc *msc, u64 *res)
 	return 0;
 }
 
-static void mpam_msc_zero_mbwu_l(struct mpam_msc *msc)
+static int mpam_msc_zero_mbwu_l(struct mpam_msc *msc)
 {
+	int ret;
+
 	mpam_mon_sel_lock_held(msc);
 
 	WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz);
 	WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility));
 
-	__mpam_write_reg(msc, MSMON_MBWU_L, 0);
-	__mpam_write_reg(msc, MSMON_MBWU_L + 4, 0);
+	ret = __mpam_write_reg(msc, MSMON_MBWU_L, 0);
+	if (ret)
+		return ret;
+
+	return __mpam_write_reg(msc, MSMON_MBWU_L + 4, 0);
 }
 
 static void gen_msmon_ctl_flt_vals(struct mon_read *m, u32 *ctl_val,
@@ -1228,24 +1233,28 @@ static void gen_msmon_ctl_flt_vals(struct mon_read *m, u32 *ctl_val,
 	}
 }
 
-static void read_msmon_ctl_flt_vals(struct mon_read *m, u32 *ctl_val,
-				    u32 *flt_val)
+static int read_msmon_ctl_flt_vals(struct mon_read *m, u32 *ctl_val,
+				   u32 *flt_val)
 {
 	struct mpam_msc *msc = m->ris->vmsc->msc;
+	int ret;
 
 	switch (m->type) {
 	case mpam_feat_msmon_csu:
-		mpam_read_monsel_reg(msc, CFG_CSU_CTL, ctl_val);
-		mpam_read_monsel_reg(msc, CFG_CSU_FLT, flt_val);
-		break;
+		ret = mpam_read_monsel_reg(msc, CFG_CSU_CTL, ctl_val);
+		if (ret)
+			return ret;
+		return mpam_read_monsel_reg(msc, CFG_CSU_FLT, flt_val);
 	case mpam_feat_msmon_mbwu_31counter:
 	case mpam_feat_msmon_mbwu_44counter:
 	case mpam_feat_msmon_mbwu_63counter:
-		mpam_read_monsel_reg(msc, CFG_MBWU_CTL, ctl_val);
-		mpam_read_monsel_reg(msc, CFG_MBWU_FLT, flt_val);
-		break;
+		ret = mpam_read_monsel_reg(msc, CFG_MBWU_CTL, ctl_val);
+		if (ret)
+			return ret;
+		return mpam_read_monsel_reg(msc, CFG_MBWU_FLT, flt_val);
 	default:
 		pr_warn("Unexpected monitor type %d\n", m->type);
+		return -EINVAL;
 	}
 }
 
@@ -1258,10 +1267,11 @@ static inline void clean_msmon_ctl_val(u32 *cur_ctl)
 		*cur_ctl &= ~MSMON_CFG_MBWU_CTL_OFLOW_STATUS_L;
 }
 
-static void write_msmon_ctl_flt_vals(struct mon_read *m, u32 ctl_val,
-				     u32 flt_val)
+static int write_msmon_ctl_flt_vals(struct mon_read *m, u32 ctl_val,
+				    u32 flt_val)
 {
 	struct mpam_msc *msc = m->ris->vmsc->msc;
+	int ret;
 
 	/*
 	 * Write the ctl_val with the enable bit cleared, reset the counter,
@@ -1269,25 +1279,37 @@ static void write_msmon_ctl_flt_vals(struct mon_read *m, u32 ctl_val,
 	 */
 	switch (m->type) {
 	case mpam_feat_msmon_csu:
-		mpam_write_monsel_reg(msc, CFG_CSU_FLT, flt_val);
-		mpam_write_monsel_reg(msc, CFG_CSU_CTL, ctl_val);
-		mpam_write_monsel_reg(msc, CSU, 0);
-		mpam_write_monsel_reg(msc, CFG_CSU_CTL, ctl_val | MSMON_CFG_x_CTL_EN);
-		break;
+		ret = mpam_write_monsel_reg(msc, CFG_CSU_FLT, flt_val);
+		if (ret)
+			return ret;
+		ret = mpam_write_monsel_reg(msc, CFG_CSU_CTL, ctl_val);
+		if (ret)
+			return ret;
+		ret = mpam_write_monsel_reg(msc, CSU, 0);
+		if (ret)
+			return ret;
+		return mpam_write_monsel_reg(msc, CFG_CSU_CTL, ctl_val | MSMON_CFG_x_CTL_EN);
 	case mpam_feat_msmon_mbwu_31counter:
 	case mpam_feat_msmon_mbwu_44counter:
 	case mpam_feat_msmon_mbwu_63counter:
-		mpam_write_monsel_reg(msc, CFG_MBWU_FLT, flt_val);
-		mpam_write_monsel_reg(msc, CFG_MBWU_CTL, ctl_val);
-		mpam_write_monsel_reg(msc, CFG_MBWU_CTL, ctl_val | MSMON_CFG_x_CTL_EN);
+		ret = mpam_write_monsel_reg(msc, CFG_MBWU_FLT, flt_val);
+		if (ret)
+			return ret;
+		ret = mpam_write_monsel_reg(msc, CFG_MBWU_CTL, ctl_val);
+		if (ret)
+			return ret;
+		ret = mpam_write_monsel_reg(msc, CFG_MBWU_CTL,
+					    ctl_val | MSMON_CFG_x_CTL_EN);
+		if (ret)
+			return ret;
 		/* Counting monitors require NRDY to be reset by software */
 		if (m->type == mpam_feat_msmon_mbwu_31counter)
-			mpam_write_monsel_reg(msc, MBWU, 0);
-		else
-			mpam_msc_zero_mbwu_l(m->ris->vmsc->msc);
-		break;
+			return mpam_write_monsel_reg(msc, MBWU, 0);
+
+		return mpam_msc_zero_mbwu_l(m->ris->vmsc->msc);
 	default:
 		pr_warn("Unexpected monitor type %d\n", m->type);
+		return -EINVAL;
 	}
 }
 
-- 
2.53.0