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SubjectRe: [RFC PATCH] ARM: Add imprecise abort enable/disable macro
On Fri, Feb 07, 2014 at 04:19:15PM +0000, Fabrice GASNIER wrote:
> This patch adds imprecise abort enable/disable macros.
> It also enables imprecise aborts when starting kernel.
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
> ---
> arch/arm/include/asm/irqflags.h | 33 +++++++++++++++++++++++++++++++++
> arch/arm/kernel/smp.c | 1 +
> arch/arm/kernel/traps.c | 4 ++++
> 3 files changed, 38 insertions(+)
>
> diff --git a/arch/arm/include/asm/irqflags.h b/arch/arm/include/asm/irqflags.h
> index 3b763d6..82e3834 100644
> --- a/arch/arm/include/asm/irqflags.h
> +++ b/arch/arm/include/asm/irqflags.h
> @@ -51,6 +51,9 @@ static inline void arch_local_irq_disable(void)
>
> #define local_fiq_enable() __asm__("cpsie f @ __stf" : : : "memory", "cc")
> #define local_fiq_disable() __asm__("cpsid f @ __clf" : : : "memory", "cc")
> +
> +#define local_abt_enable() __asm__("cpsie a @ __sta" : : : "memory", "cc")
> +#define local_abt_disable() __asm__("cpsid a @ __cla" : : : "memory", "cc")
> #else
>
> /*
> @@ -130,6 +133,36 @@ static inline void arch_local_irq_disable(void)
> : "memory", "cc"); \
> })
>
> +/*
> + * Enable Aborts
> + */
> +#define local_abt_enable() \
> + ({ \
> + unsigned long temp; \
> + __asm__ __volatile__( \
> + "mrs %0, cpsr @ sta\n" \
> +" bic %0, %0, %1\n" \
> +" msr cpsr_c, %0" \
> + : "=r" (temp) \
> + : "r" (PSR_A_BIT) \

Can you use "i" instead of a register for this constant?

> + : "memory", "cc"); \

You don't need the "cc" clobber.

> + })
> +
> +/*
> + * Disable Aborts
> + */
> +#define local_abt_disable() \
> + ({ \
> + unsigned long temp; \
> + __asm__ __volatile__( \
> + "mrs %0, cpsr @ cla\n" \
> +" orr %0, %0, %1\n" \
> +" msr cpsr_c, %0" \
> + : "=r" (temp) \
> + : "r" (PSR_A_BIT) \
> + : "memory", "cc"); \
> + })

Same comments here.

> #endif
> /*
> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> index dc894ab..c2093cb 100644
> --- a/arch/arm/kernel/smp.c
> +++ b/arch/arm/kernel/smp.c
> @@ -377,6 +377,7 @@ asmlinkage void secondary_start_kernel(void)
>
> local_irq_enable();
> local_fiq_enable();
> + local_abt_enable();
>
> /*
> * OK, it's off to the idle thread for us
> diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
> index 4636d56..ef15709 100644
> --- a/arch/arm/kernel/traps.c
> +++ b/arch/arm/kernel/traps.c
> @@ -900,6 +900,10 @@ void __init early_trap_init(void *vectors_base)
>
> flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
> modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
> +
> + /* Enable imprecise aborts */
> + local_abt_enable();

Surely we want to enable this as early as possible? Now, putting this into
head.S is ugly, as it duplicating it across all the proc*.S files, so why
not setup_arch?

Will


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