[PATCH v3 0/2] arm64: Add decode of ISS2 to data abort reports

[PATCH v3 0/2] arm64: Add decode of ISS2 to data abort reports

[Mark Brown]

We provide fairly detailed decode of ESR for data aborts but do not
currently cover the information reported in ISS2 which has had quite a
bit of additional information added to it by recent architecture
extensions.  Add decode for this information to aid in debugging, for
completeness including features we don't actually use yet.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
Changes in v3:
- Correct ISS->ISS2 typo.
- Link to v2: https://lore.kernel.org/r/20230417-arm64-iss2-dabt-decode-v2-0-84e1c1463d30@kernel.org

Changes in v2:
- Rebase onto v6.4-rc1.
- Link to v1: https://lore.kernel.org/r/20230417-arm64-iss2-dabt-decode-v1-0-2138b5668777@kernel.org

---
Mark Brown (2):
      arm64/esr: Use GENMASK() for the ISS mask
      arm64/esr: Add decode of ISS2 to data abort reporting

 arch/arm64/include/asm/esr.h | 19 ++++++++++++++++++-
 arch/arm64/mm/fault.c        | 17 ++++++++++++++---
 2 files changed, 32 insertions(+), 4 deletions(-)
---
base-commit: ac9a78681b921877518763ba0e89202254349d1b
change-id: 20230417-arm64-iss2-dabt-decode-ec9b46c98a91

Best regards,
-- 
Mark Brown,,, <broonie@kernel.org>

[PATCH v3 1/2] arm64/esr: Use GENMASK() for the ISS mask

[Mark Brown]

We express the mask for ESR_ELx.ISS in a non-standard manner, not using
the standard helpers. In preparation for adding decode for ISS2 convert to
use GENMASK(). No functional change.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/esr.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index 8487aec9b658..0bd879007168 100644
--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -75,7 +75,7 @@
 
 #define ESR_ELx_IL_SHIFT	(25)
 #define ESR_ELx_IL		(UL(1) << ESR_ELx_IL_SHIFT)
-#define ESR_ELx_ISS_MASK	(ESR_ELx_IL - 1)
+#define ESR_ELx_ISS_MASK	(GENMASK(24, 0))
 #define ESR_ELx_ISS(esr)	((esr) & ESR_ELx_ISS_MASK)
 
 /* ISS field definitions shared by different classes */

-- 
2.39.2

[PATCH v3 2/2] arm64/esr: Add decode of ISS2 to data abort reporting

[Mark Brown]

The architecture has added more information about faults to ISS2 within
ESR. Add decode of this to our data abort fault decode to aid diagnostics.
Features that are not currently enabled are included here for completeness.

Since the architecture specifies the values of bits within ISS2 in terms
of ISS2 rather than in terms of the register as a whole we do so for our
definitions as well, this makes it easier to review bitfield definitions.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/esr.h | 17 +++++++++++++++++
 arch/arm64/mm/fault.c        | 17 ++++++++++++++---
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index 0bd879007168..0552a29f026b 100644
--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -77,6 +77,9 @@
 #define ESR_ELx_IL		(UL(1) << ESR_ELx_IL_SHIFT)
 #define ESR_ELx_ISS_MASK	(GENMASK(24, 0))
 #define ESR_ELx_ISS(esr)	((esr) & ESR_ELx_ISS_MASK)
+#define ESR_ELx_ISS2_SHIFT	(32)
+#define ESR_ELx_ISS2_MASK	(GENMASK_ULL(55, 32))
+#define ESR_ELx_ISS2(esr)	(((esr) & ESR_ELx_ISS2_MASK) >> ESR_ELx_ISS2_SHIFT)
 
 /* ISS field definitions shared by different classes */
 #define ESR_ELx_WNR_SHIFT	(6)
@@ -140,6 +143,20 @@
 #define ESR_ELx_CM_SHIFT	(8)
 #define ESR_ELx_CM 		(UL(1) << ESR_ELx_CM_SHIFT)
 
+/* ISS2 field definitions for Data Aborts */
+#define ESR_ELx_TnD_SHIFT	(10)
+#define ESR_ELx_TnD 		(UL(1) << ESR_ELx_TnD_SHIFT)
+#define ESR_ELx_TagAccess_SHIFT	(9)
+#define ESR_ELx_TagAccess	(UL(1) << ESR_ELx_TagAccess_SHIFT)
+#define ESR_ELx_GCS_SHIFT	(8)
+#define ESR_ELx_GCS 		(UL(1) << ESR_ELx_GCS_SHIFT)
+#define ESR_ELx_Overlay_SHIFT	(6)
+#define ESR_ELx_Overlay		(UL(1) << ESR_ELx_Overlay_SHIFT)
+#define ESR_ELx_DirtyBit_SHIFT	(5)
+#define ESR_ELx_DirtyBit	(UL(1) << ESR_ELx_DirtyBit_SHIFT)
+#define ESR_ELx_Xs_SHIFT	(0)
+#define ESR_ELx_Xs_MASK		(GENMASK_ULL(4, 0))
+
 /* ISS field definitions for exceptions taken in to Hyp */
 #define ESR_ELx_CV		(UL(1) << 24)
 #define ESR_ELx_COND_SHIFT	(20)
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 9e0db5c387e3..6f08fd9686be 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -66,6 +66,8 @@ static inline const struct fault_info *esr_to_debug_fault_info(unsigned long esr
 
 static void data_abort_decode(unsigned long esr)
 {
+	unsigned long iss2 = ESR_ELx_ISS2(esr);
+
 	pr_alert("Data abort info:\n");
 
 	if (esr & ESR_ELx_ISV) {
@@ -78,12 +80,21 @@ static void data_abort_decode(unsigned long esr)
 			 (esr & ESR_ELx_SF) >> ESR_ELx_SF_SHIFT,
 			 (esr & ESR_ELx_AR) >> ESR_ELx_AR_SHIFT);
 	} else {
-		pr_alert("  ISV = 0, ISS = 0x%08lx\n", esr & ESR_ELx_ISS_MASK);
+		pr_alert("  ISV = 0, ISS = 0x%08lx, ISS2 = 0x%08lx\n",
+			 esr & ESR_ELx_ISS_MASK, iss2);
 	}
 
-	pr_alert("  CM = %lu, WnR = %lu\n",
+	pr_alert("  CM = %lu, WnR = %lu, TnD = %lu, TagAccess = %lu\n",
 		 (esr & ESR_ELx_CM) >> ESR_ELx_CM_SHIFT,
-		 (esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT);
+		 (esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT,
+		 (iss2 & ESR_ELx_TnD) >> ESR_ELx_TnD_SHIFT,
+		 (iss2 & ESR_ELx_TagAccess) >> ESR_ELx_TagAccess_SHIFT);
+
+	pr_alert("  GCS = %ld, Overlay = %lu, DirtyBit = %lu, Xs = %llu\n",
+		 (iss2 & ESR_ELx_GCS) >> ESR_ELx_GCS_SHIFT,
+		 (iss2 & ESR_ELx_Overlay) >> ESR_ELx_Overlay_SHIFT,
+		 (iss2 & ESR_ELx_DirtyBit) >> ESR_ELx_DirtyBit_SHIFT,
+		 (iss2 & ESR_ELx_Xs_MASK) >> ESR_ELx_Xs_SHIFT);
 }
 
 static void mem_abort_decode(unsigned long esr)

-- 
2.39.2

Re: [PATCH v3 0/2] arm64: Add decode of ISS2 to data abort reports

[Catalin Marinas]

On Thu, 11 May 2023 15:05:13 +0900, Mark Brown wrote:
> We provide fairly detailed decode of ESR for data aborts but do not
> currently cover the information reported in ISS2 which has had quite a
> bit of additional information added to it by recent architecture
> extensions.  Add decode for this information to aid in debugging, for
> completeness including features we don't actually use yet.
> 
> 
> [...]

Applied to arm64 (for-next/iss2-decode), thanks!

[1/2] arm64/esr: Use GENMASK() for the ISS mask
      https://git.kernel.org/arm64/c/de847275449a
[2/2] arm64/esr: Add decode of ISS2 to data abort reporting
      https://git.kernel.org/arm64/c/1f9d4ba6839c

-- 
Catalin