arm64: add macro to extract ESR_ELx.EC

Several places open-code extraction of the EC field from an ESR_ELx
value, in subtly different ways. This is unfortunate duplication and
variation, and the precise logic used to extract the field is a
distraction.

This patch adds a new macro, ESR_ELx_EC(), to extract the EC field from
an ESR_ELx value in a consistent fashion.

Existing open-coded extractions in core arm64 code are moved over to the
new helper. KVM code is left as-is for the moment.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Huang Shijie <shijie.huang@arm.com>
Cc: Dave P Martin <dave.martin@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

3 files changed, 3 insertions, 2 deletions

diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index 77eeb2cc648f..f772e15c4766 100644
--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -74,6 +74,7 @@
 
 #define ESR_ELx_EC_SHIFT        (26)
 #define ESR_ELx_EC_MASK         (UL(0x3F) << ESR_ELx_EC_SHIFT)
+#define ESR_ELx_EC(esr)         (((esr) & ESR_ELx_EC_MASK) >> ESR_ELx_EC_SHIFT)
 
 #define ESR_ELx_IL              (UL(1) << 25)
 #define ESR_ELx_ISS_MASK        (ESR_ELx_IL - 1)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index d9da2c56e4f8..a4250a59f2b9 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -456,7 +456,7 @@ static const char *esr_class_str[] = {
 
 const char *esr_get_class_string(u32 esr)
 {
-        return esr_class_str[esr >> ESR_ELx_EC_SHIFT];
+        return esr_class_str[ESR_ELx_EC(esr)];
 }
 
 /*
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 013e2cbe7924..d2c124cbd18c 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -244,7 +244,7 @@ out:
 
 static inline int permission_fault(unsigned int esr)
 {
-        unsigned int ec       = (esr & ESR_ELx_EC_MASK) >> ESR_ELx_EC_SHIFT;
+        unsigned int ec       = ESR_ELx_EC(esr);
         unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
 
         return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM);