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arm64: Unmask PMR before going idle 

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>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Julien Thierry 2019-01-31 14:58:47 +00:00 committed by Catalin Marinas
parent 133d051863
commit a9806aa259
2 changed files with 45 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
arch/arm64/kernel/process.c
View File

@ -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 @@ EXPORT_SYMBOL_GPL(pm_power_off);
void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
static void __cpu_do_idle(void)
{
dsb(sy);
wfi();
}
static void __cpu_do_idle_irqprio(void)
{
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.
*/

11
arch/arm64/mm/proc.S
View File

@ -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