From e462919413547dcfe84e785380d0f47f1359878a Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Fri, 27 Nov 2015 16:26:41 +0300 Subject: xtensa: make fake NMI configurable Do not always use fake NMI when safe, provide Kconfig option instead. Print a warning if fake NMI is chosen in unsafe configuration, but allow it, because it may work if the user knows that interrupts with priorities at or above PMM IRQ are not used. Add a check to NMI handler that BUGs if any of these IRQs fire. Signed-off-by: Max Filippov --- arch/xtensa/kernel/traps.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'arch/xtensa/kernel/traps.c') diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c index 42d441f7898b..be0cae8082c7 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -205,6 +205,32 @@ extern void do_IRQ(int, struct pt_regs *); #if XTENSA_FAKE_NMI +#define IS_POW2(v) (((v) & ((v) - 1)) == 0) + +#if !(PROFILING_INTLEVEL == XCHAL_EXCM_LEVEL && \ + IS_POW2(XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL))) +#warning "Fake NMI is requested for PMM, but there are other IRQs at or above its level." +#warning "Fake NMI will be used, but there will be a bugcheck if one of those IRQs fire." + +static inline void check_valid_nmi(void) +{ + unsigned intread = get_sr(interrupt); + unsigned intenable = get_sr(intenable); + + BUG_ON(intread & intenable & + ~(XTENSA_INTLEVEL_ANDBELOW_MASK(PROFILING_INTLEVEL) ^ + XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL) ^ + BIT(XCHAL_PROFILING_INTERRUPT))); +} + +#else + +static inline void check_valid_nmi(void) +{ +} + +#endif + irqreturn_t xtensa_pmu_irq_handler(int irq, void *dev_id); DEFINE_PER_CPU(unsigned long, nmi_count); @@ -219,6 +245,7 @@ void do_nmi(struct pt_regs *regs) old_regs = set_irq_regs(regs); nmi_enter(); ++*this_cpu_ptr(&nmi_count); + check_valid_nmi(); xtensa_pmu_irq_handler(0, NULL); nmi_exit(); set_irq_regs(old_regs); -- cgit v1.2.3