linux-kernel - [PATCH v2 2/2] drm/etnaviv: print MMU exception cause

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Message-Id: <20190913055052.25599-2-christian.gmeiner@gmail.com>
Date:   Fri, 13 Sep 2019 07:50:37 +0200
From:   Christian Gmeiner <christian.gmeiner@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     Christian Gmeiner <christian.gmeiner@...il.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Russell King <linux+etnaviv@...linux.org.uk>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, etnaviv@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH v2 2/2] drm/etnaviv: print MMU exception cause

Might be useful when debugging MMU exceptions.

Changes in V2:
 - Use a static array of string for error message as suggested
   by Lucas Stach.

Signed-off-by: Christian Gmeiner <christian.gmeiner@...il.com>
---
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index d47d1a8e0219..b8cd85153fe0 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1351,6 +1351,15 @@ static void sync_point_worker(struct work_struct *work)
 
 static void dump_mmu_fault(struct etnaviv_gpu *gpu)
 {
+	static const char *errors[] = {
+		"slave not present",
+		"page not present",
+		"write violation",
+		"out of bound",
+		"read security violation",
+		"write security violation",
+	};
+
 	u32 status_reg, status;
 	int i;
 
@@ -1364,10 +1373,16 @@ static void dump_mmu_fault(struct etnaviv_gpu *gpu)
 
 	for (i = 0; i < 4; i++) {
 		u32 address_reg;
+		const char *error = "unknown state";
 
 		if (!(status & (VIVS_MMUv2_STATUS_EXCEPTION0__MASK << (i * 4))))
 			continue;
 
+		if (status < ARRAY_SIZE(errors))
+			error = errors[status];
+
+		dev_err_ratelimited(gpu->dev, "MMU %d %s\n", i, error);
+
 		if (gpu->sec_mode == ETNA_SEC_NONE)
 			address_reg = VIVS_MMUv2_EXCEPTION_ADDR(i);
 		else
-- 
2.21.0