On Fri, Feb 07, 2014 at 05:19:15PM +0100, Fabrice GASNIER wrote: > This patch adds imprecise abort enable/disable macros. > It also enables imprecise aborts when starting kernel.
Relying on imprecise aborts for hardware probing would be considered bad hardware and/or software design for ARM-specific stuff. PCI is more generic though, so we may have to put up with this to some extent. Can you point me to the affected probing code? I'm not very familiar with that stuff... > > Signed-off-by: Fabrice Gasnier <fabrice.gasn...@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" \ I suggest you use "cpsie/cpsid a" instead. This requires ARMv6, but the CPSR.A bit only exists on ARMv6 and later anyway. Poking that bit on earlier CPUs may cause unpredictable behaviour, so these macros should be no-ops for v5 and earlier. > + : "=r" (temp) \ > + : "r" (PSR_A_BIT) \ > + : "memory", "cc"); \ > + }) > + > +/* > + * 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"); \ > + }) > + > #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(); It would be good to clean up why aborts are not being consistently enabled on boot. Really, they should be enabled, except for a brief window during boot when the vectors are not mapped and the abort can't be dispatched. Cheers ---Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/