As of today we enable unaligned access unconditionally on ARCv2.
Lets move it under Kconfig option so we can disable it in case of
using HW configuration which lacks of it.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
arch/arc/Kconfig | 8 ++++++++
arch/arc/include/asm/irqflags-arcv2.h | 4 ++++
arch/arc/kernel/head.S | 14 +++++++++-----
arch/arc/kernel/intc-arcv2.c | 2 +-
4 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 376366a7db81..37c8aeefa3a5 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -387,6 +387,14 @@ config ARC_HAS_SWAPE
if ISA_ARCV2
+config ARC_USE_UNALIGNED_MEM_ACCESS
+ bool "Handle unaligned access in HW and use it"
+ default y
+ help
+ The ARC HS architecture supports unaligned memory access
+ which is disabled by default. Enable unaligned access in
+ hardware and use it in software.
+
config ARC_HAS_LL64
bool "Insn: 64bit LDD/STD"
help
diff --git a/arch/arc/include/asm/irqflags-arcv2.h b/arch/arc/include/asm/irqflags-arcv2.h
index 8a4f77ea3238..9b911e2c6b31 100644
--- a/arch/arc/include/asm/irqflags-arcv2.h
+++ b/arch/arc/include/asm/irqflags-arcv2.h
@@ -44,8 +44,12 @@
#define ARCV2_IRQ_DEF_PRIO 1
/* seed value for status register */
+#ifdef CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS
#define ISA_INIT_STATUS_BITS (STATUS_IE_MASK | STATUS_AD_MASK | \
(ARCV2_IRQ_DEF_PRIO << 1))
+#else
+#define ISA_INIT_STATUS_BITS (STATUS_IE_MASK | (ARCV2_IRQ_DEF_PRIO << 1))
+#endif /* CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS */
#ifndef __ASSEMBLY__
diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 25b3a247e11c..bd24ba0e0264 100644
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -49,11 +49,15 @@
1:
-#ifdef CONFIG_ISA_ARCV2
- ; Enable unaligned access as disabled by default in hw while
- ; gcc 8.1.0 onwards (ARC GNU 2018.03) unconditionally generates
- ; code for unaligned accesses
- flag 1 << STATUS_AD_BIT
+ ; Enable / disable HW handling of unaligned access in the CPU.
+#ifdef CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS
+ kflag STATUS_AD_MASK
+#else
+ ; Handling of unaligned access is disabled by default but we disable it
+ ; manually in case of any bootloader enabled it earlier.
+ lr r5, [ARC_REG_STATUS32]
+ bclr r5, r5, STATUS_AD_BIT
+ kflag r5
#endif
.endm
diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c
index 067ea362fb3e..6359896da1ea 100644
--- a/arch/arc/kernel/intc-arcv2.c
+++ b/arch/arc/kernel/intc-arcv2.c
@@ -93,7 +93,7 @@ void arc_init_IRQ(void)
/* setup status32, don't enable intr yet as kernel doesn't want */
tmp = read_aux_reg(ARC_REG_STATUS32);
- tmp |= STATUS_AD_MASK | (ARCV2_IRQ_DEF_PRIO << 1);
+ tmp |= ARCV2_IRQ_DEF_PRIO << 1;
tmp &= ~STATUS_IE_MASK;
asm volatile("kflag %0 \n"::"r"(tmp));
}
--
2.14.5
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