Messages in this thread | | | From | Tim Sander <> | Subject | Re: [PATCH 3.18-rc3 v9 5/5] arm: smp: Handle ipi_cpu_backtrace() using FIQ (if available) | Date | Wed, 26 Nov 2014 13:46:52 +0100 |
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Hi Daniel
Am Dienstag, 25. November 2014, 17:26:41 schrieb Daniel Thompson: > Previous changes have introduced both a replacement default FIQ handler > and an implementation of arch_trigger_all_cpu_backtrace for ARM but > these are currently independent of each other. > > This patch plumbs together these features making it possible, on platforms > that support it, to trigger backtrace using FIQ. Does this ipi handler interfere in any way with set_fiq_handler?
As far as i know there is only one FIQ handler vector so i guess there is a potential conflict. But i have not worked with IPI's so i might be completley wrong.
Regards Tim
> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> > --- > arch/arm/include/asm/smp.h | 3 +++ > arch/arm/kernel/smp.c | 4 +++- > arch/arm/kernel/traps.c | 3 +++ > 3 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h > index 18f5a554134f..b076584ac0fa 100644 > --- a/arch/arm/include/asm/smp.h > +++ b/arch/arm/include/asm/smp.h > @@ -18,6 +18,8 @@ > # error "<asm/smp.h> included in non-SMP build" > #endif > > +#define SMP_IPI_FIQ_MASK 0x0100 > + > #define raw_smp_processor_id() (current_thread_info()->cpu) > > struct seq_file; > @@ -79,6 +81,7 @@ extern void arch_send_call_function_single_ipi(int cpu); > extern void arch_send_call_function_ipi_mask(const struct cpumask *mask); > extern void arch_send_wakeup_ipi_mask(const struct cpumask *mask); > > +extern void ipi_cpu_backtrace(struct pt_regs *regs); > extern int register_ipi_completion(struct completion *completion, int cpu); > > struct smp_operations { > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > index 14c594a12bef..e923843562d9 100644 > --- a/arch/arm/kernel/smp.c > +++ b/arch/arm/kernel/smp.c > @@ -539,7 +539,7 @@ static void ipi_cpu_stop(unsigned int cpu) > cpu_relax(); > } > > -static void ipi_cpu_backtrace(struct pt_regs *regs) > +void ipi_cpu_backtrace(struct pt_regs *regs) > { > int cpu = smp_processor_id(); > > @@ -580,6 +580,8 @@ void handle_IPI(int ipinr, struct pt_regs *regs) > unsigned int cpu = smp_processor_id(); > struct pt_regs *old_regs = set_irq_regs(regs); > > + BUILD_BUG_ON(SMP_IPI_FIQ_MASK != BIT(IPI_CPU_BACKTRACE)); > + > if ((unsigned)ipinr < NR_IPI) { > trace_ipi_entry(ipi_types[ipinr]); > __inc_irq_stat(cpu, ipi_irqs[ipinr]); > diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c > index 4dc45b38e56e..9eb05be9526e 100644 > --- a/arch/arm/kernel/traps.c > +++ b/arch/arm/kernel/traps.c > @@ -483,6 +483,9 @@ asmlinkage void __exception_irq_entry > handle_fiq_as_nmi(struct pt_regs *regs) #ifdef CONFIG_ARM_GIC > gic_handle_fiq_ipi(); > #endif > +#ifdef CONFIG_SMP > + ipi_cpu_backtrace(regs); > +#endif > > nmi_exit();
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