linux-kernel - [PATCH V2] arm64/hw_breakpoint: Directly use ESR_ELx

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Message-Id: <20240229083431.356578-1-anshuman.khandual@arm.com>
Date: Thu, 29 Feb 2024 14:04:31 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: linux-arm-kernel@...ts.infradead.org,
	catalin.marinas@....com
Cc: Anshuman Khandual <anshuman.khandual@....com>,
	Will Deacon <will@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	linux-kernel@...r.kernel.org,
	Mark Brown <broonie@...nel.org>
Subject: [PATCH V2] arm64/hw_breakpoint: Directly use ESR_ELx_WNR for an watchpoint exception

Let's use existing ISS encoding for an watchpoint exception i.e ESR_ELx_WNR
This represents an instruction's either writing to or reading from a memory
location during an watchpoint exception. While here this drops non-standard
macro AARCH64_ESR_ACCESS_MASK.

Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Reviewed-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
This applies on v6.8-rc5

Changes in V2:

- Dropped new ISS encoding details ESR_ELx_WnR and ESR_ELx_WnR_SHIFT
- Directly used existing ESR_ELx_WNR per Catalin
- Updated the commit message as required

Changes in V1:

https://lore.kernel.org/all/20240223094615.3977323-1-anshuman.khandual@arm.com/ 

 arch/arm64/include/asm/hw_breakpoint.h | 1 -
 arch/arm64/kernel/hw_breakpoint.c      | 3 ++-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/hw_breakpoint.h b/arch/arm64/include/asm/hw_breakpoint.h
index 84055329cd8b..bd81cf17744a 100644
--- a/arch/arm64/include/asm/hw_breakpoint.h
+++ b/arch/arm64/include/asm/hw_breakpoint.h
@@ -59,7 +59,6 @@ static inline void decode_ctrl_reg(u32 reg,
 /* Watchpoints */
 #define ARM_BREAKPOINT_LOAD	1
 #define ARM_BREAKPOINT_STORE	2
-#define AARCH64_ESR_ACCESS_MASK	(1 << 6)
 
 /* Lengths */
 #define ARM_BREAKPOINT_LEN_1	0x1
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index 35225632d70a..2f5755192c2b 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c
@@ -21,6 +21,7 @@
 
 #include <asm/current.h>
 #include <asm/debug-monitors.h>
+#include <asm/esr.h>
 #include <asm/hw_breakpoint.h>
 #include <asm/traps.h>
 #include <asm/cputype.h>
@@ -779,7 +780,7 @@ static int watchpoint_handler(unsigned long addr, unsigned long esr,
 		 * Check that the access type matches.
 		 * 0 => load, otherwise => store
 		 */
-		access = (esr & AARCH64_ESR_ACCESS_MASK) ? HW_BREAKPOINT_W :
+		access = (esr & ESR_ELx_WNR) ? HW_BREAKPOINT_W :
 			 HW_BREAKPOINT_R;
 		if (!(access & hw_breakpoint_type(wp)))
 			continue;
-- 
2.25.1