linux-kernel - [RFC PATCH v2 08/11] arm_mpam: [NFU] Development diagnostics for MPAM ID assignments

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Message-Id: <20250117151033.1517882-21-Dave.Martin@arm.com>
Date: Fri, 17 Jan 2025 15:10:30 +0000
From: Dave Martin <Dave.Martin@....com>
To: linux-kernel@...r.kernel.org
Cc: linux-arm-kernel@...ts.infradead.org,
	Zeng Heng <zengheng4@...wei.com>,
	Shaopeng Tan <tan.shaopeng@...itsu.com>,
	James Morse <james.morse@....com>
Subject: [RFC PATCH v2 08/11] arm_mpam: [NFU] Development diagnostics for MPAM ID assignments

Purely for development purposes, add some printks to show what MPAM
IDs actually get assigned and configured.

This would otherwise be observable only though statistical
measurements of performance (or not observable at all).

This change is not intended for upstream.

Signed-off-by: Dave Martin <Dave.Martin@....com>
---
 arch/arm64/include/asm/mpam.h              | 7 +++++++
 drivers/platform/arm64/mpam/mpam_devices.c | 6 ++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/arm64/include/asm/mpam.h b/arch/arm64/include/asm/mpam.h
index df725d2d9d05..4ae2e635e261 100644
--- a/arch/arm64/include/asm/mpam.h
+++ b/arch/arm64/include/asm/mpam.h
@@ -66,6 +66,9 @@ static inline void mpam_set_cpu_defaults(int cpu, u16 partid_d, u16 partid_i,
 	default_val |= FIELD_PREP(MPAM1_EL1_PMG_I, pmg_i);
 
 	WRITE_ONCE(per_cpu(arm64_mpam_default, cpu), default_val);
+
+	pr_info("MPAM: CPU%d -> (D=%d:%d, I=%d:%d)\n",
+		cpu, partid_d, pmg_d, partid_i, pmg_i);
 }
 
 static inline void mpam_set_task_partid_pmg(struct task_struct *tsk,
@@ -81,6 +84,10 @@ static inline void mpam_set_task_partid_pmg(struct task_struct *tsk,
 	regval |= FIELD_PREP(MPAM1_EL1_PMG_I, pmg_i);
 
 	WRITE_ONCE(task_thread_info(tsk)->mpam_partid_pmg, regval);
+
+	pr_info("MPAM: task %s[%d/%d] -> (D=%d:%d, I=%d:%d)\n",
+		current->comm, current->pid, current->tgid,
+		partid_d, pmg_d, partid_i, pmg_i);
 #endif
 }
 
diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/mpam_devices.c
index f965e6639e0d..6b326506c359 100644
--- a/drivers/platform/arm64/mpam/mpam_devices.c
+++ b/drivers/platform/arm64/mpam/mpam_devices.c
@@ -3149,6 +3149,12 @@ int mpam_apply_config(struct mpam_component *comp, u16 partid,
 
 	mpam_extend_config(comp->class, cfg);
 
+	pr_info("mpam_apply_config(): comp %d partid %d cfg={0x%x: 0x%lx, 0x%lx, %u, %u}\n",
+		comp->comp_id, partid, cfg->features,
+		(unsigned long)cfg->cpbm,
+		(unsigned long)cfg->mbw_pbm,
+		cfg->mbw_min, cfg->mbw_max);
+
 	if (!mpam_update_config(&comp->cfg[partid], cfg))
 		return 0;
 
-- 
2.34.1