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SubjectRe: [PATCH 2/5] ARCv2: introduce unaligned access under a Kconfig option
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On 1/29/19 2:49 AM, Eugeniy Paltsev wrote:
> 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@synopsys.com>
> ---
> arch/arc/Kconfig | 8 ++++++++
> arch/arc/include/asm/irqflags-arcv2.h | 4 ++++
> arch/arc/kernel/intc-arcv2.c | 4 +++-
> 3 files changed, 15 insertions(+), 1 deletion(-)
>
> 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 */

I'd prefer to change the define of STATUS_AD_MASK itself and keep all of this
unchanged !

>
> #ifndef __ASSEMBLY__
>
> diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c
> index 067ea362fb3e..84b1c7157d1b 100644
> --- a/arch/arc/kernel/intc-arcv2.c
> +++ b/arch/arc/kernel/intc-arcv2.c
> @@ -93,7 +93,9 @@ 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);
> + if (IS_ENABLED(ARC_USE_UNALIGNED_MEM_ACCESS))
> + tmp |= STATUS_AD_MASK;
> + tmp |= ARCV2_IRQ_DEF_PRIO << 1;

This will change after rebase as we just need to delete the code here, done in head.S

> tmp &= ~STATUS_IE_MASK;
> asm volatile("kflag %0 \n"::"r"(tmp));
> }


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