Even though we do enable AD bit in arc_init_IRQ() we need to do
it in early ASM code otherwise we may face unaligned data until
we reach arc_init_IRQ() because GCC starting from v8.1.0 actively
generates unaligned data as it assumes that:
* ARCv2 always has support of unaliged data
* This support is turned on in runtime
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
arch/arc/kernel/head.S | 14 ++++++++++++++
arch/arc/kernel/intc-arcv2.c | 2 --
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 8b90d25a15cc..ffe3d384fca5 100644
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -17,6 +17,9 @@
#include <asm/entry.h>
#include <asm/arcregs.h>
#include <asm/cache.h>
+#ifdef CONFIG_ISA_ARCV2
+#include <asm/irqflags-arcv2.h>
+#endif
.macro CPU_EARLY_SETUP
@@ -47,6 +50,17 @@
sr r5, [ARC_REG_DC_CTRL]
1:
+
+ ; 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
.section .init.text, "ax",@progbits
diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c
index 84b1c7157d1b..6359896da1ea 100644
--- a/arch/arc/kernel/intc-arcv2.c
+++ b/arch/arc/kernel/intc-arcv2.c
@@ -93,8 +93,6 @@ void arc_init_IRQ(void)
/* setup status32, don't enable intr yet as kernel doesn't want */
tmp = read_aux_reg(ARC_REG_STATUS32);
- if (IS_ENABLED(ARC_USE_UNALIGNED_MEM_ACCESS))
- tmp |= STATUS_AD_MASK;
tmp |= ARCV2_IRQ_DEF_PRIO << 1;
tmp &= ~STATUS_IE_MASK;
asm volatile("kflag %0 \n"::"r"(tmp));
--
2.14.5
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