Messages in this thread | | | Subject | Re: [PATCH v9 09/26] arm64: Unmask PMR before going idle | From | Julien Thierry <> | Date | Wed, 23 Jan 2019 08:56:20 +0000 |
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On 22/01/2019 20:18, Ard Biesheuvel wrote: > On Mon, 21 Jan 2019 at 16:36, Julien Thierry <julien.thierry@arm.com> wrote: >> >> CPU does not received signals for interrupts with a priority masked by >> ICC_PMR_EL1. This means the CPU might not come back from a WFI >> instruction. >> >> Make sure ICC_PMR_EL1 does not mask interrupts when doing a WFI. >> >> Since the logic of cpu_do_idle is becoming a bit more complex than just >> two instructions, lets turn it from ASM to C. >> >> Signed-off-by: Julien Thierry <julien.thierry@arm.com> >> Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Will Deacon <will.deacon@arm.com> >> --- >> arch/arm64/kernel/process.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ >> arch/arm64/mm/proc.S | 11 ----------- >> 2 files changed, 45 insertions(+), 11 deletions(-) >> >> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c >> index 6d410fc..f05b63f 100644 >> --- a/arch/arm64/kernel/process.c >> +++ b/arch/arm64/kernel/process.c >> @@ -51,6 +51,7 @@ >> #include <linux/thread_info.h> >> >> #include <asm/alternative.h> >> +#include <asm/arch_gicv3.h> >> #include <asm/compat.h> >> #include <asm/cacheflush.h> >> #include <asm/exec.h> >> @@ -74,6 +75,50 @@ >> >> void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); >> >> +static inline void __cpu_do_idle(void) >> +{ >> + dsb(sy); >> + wfi(); >> +} >> + >> +static inline void __cpu_do_idle_irqprio(void) > > Can we drop the 'inline's from all the function definitions in .c > files? (not just in this patch) > We tend to leave that to the compiler. >
Sure, I guess cpu_do_idle() isn't a performance critical path anyway.
Unless anyone argues against it, I'll drop these inlines for the next version.
Thanks,
Julien
>> +{ >> + unsigned long pmr; >> + unsigned long daif_bits; >> + >> + daif_bits = read_sysreg(daif); >> + write_sysreg(daif_bits | PSR_I_BIT, daif); >> + >> + /* >> + * Unmask PMR before going idle to make sure interrupts can >> + * be raised. >> + */ >> + pmr = gic_read_pmr(); >> + gic_write_pmr(GIC_PRIO_IRQON); >> + >> + __cpu_do_idle(); >> + >> + gic_write_pmr(pmr); >> + write_sysreg(daif_bits, daif); >> +} >> + >> +/* >> + * cpu_do_idle() >> + * >> + * Idle the processor (wait for interrupt). >> + * >> + * If the CPU supports priority masking we must do additional work to >> + * ensure that interrupts are not masked at the PMR (because the core will >> + * not wake up if we block the wake up signal in the interrupt controller). >> + */ >> +void cpu_do_idle(void) >> +{ >> + if (system_uses_irq_prio_masking()) >> + __cpu_do_idle_irqprio(); >> + else >> + __cpu_do_idle(); >> +} >> + >> /* >> * This is our default idle handler. >> */ >> diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S >> index 73886a5..3ea4f3b 100644 >> --- a/arch/arm64/mm/proc.S >> +++ b/arch/arm64/mm/proc.S >> @@ -55,17 +55,6 @@ >> >> #define MAIR(attr, mt) ((attr) << ((mt) * 8)) >> >> -/* >> - * cpu_do_idle() >> - * >> - * Idle the processor (wait for interrupt). >> - */ >> -ENTRY(cpu_do_idle) >> - dsb sy // WFI may enter a low-power mode >> - wfi >> - ret >> -ENDPROC(cpu_do_idle) >> - >> #ifdef CONFIG_CPU_PM >> /** >> * cpu_do_suspend - save CPU registers context >> -- >> 1.9.1 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
-- Julien Thierry
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