From d3afc7f12987581eb0d1215b518d719fb9d762da Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Sat, 25 Apr 2020 15:03:47 +0100 Subject: arm64: Allow IPIs to be handled as normal interrupts In order to deal with IPIs as normal interrupts, let's add a new way to register them with the architecture code. set_smp_ipi_range() takes a range of interrupts, and allows the arch code to request them as if the were normal interrupts. A standard handler is then called by the core IRQ code to deal with the IPI. This means that we don't need to call irq_enter/irq_exit, and that we don't need to deal with set_irq_regs either. So let's move the dispatcher into its own function, and leave handle_IPI() as a compatibility function. On the sending side, let's make use of ipi_send_mask, which already exists for this purpose. One of the major difference is that we end up, in some cases (such as when performing IRQ time accounting on the scheduler IPI), end up with nested irq_enter()/irq_exit() pairs. Other than the (relatively small) overhead, there should be no consequences to it (these pairs are designed to nest correctly, and the accounting shouldn't be off). Reviewed-by: Valentin Schneider Acked-by: Catalin Marinas Signed-off-by: Marc Zyngier --- arch/arm64/kernel/smp.c | 93 ++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 81 insertions(+), 12 deletions(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 355ee9eed4dd..00c9db1b61b5 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -75,6 +75,13 @@ enum ipi_msg_type { IPI_WAKEUP }; +static int ipi_irq_base __read_mostly; +static int nr_ipi __read_mostly = NR_IPI; +static struct irq_desc *ipi_desc[NR_IPI] __read_mostly; + +static void ipi_setup(int cpu); +static void ipi_teardown(int cpu); + #ifdef CONFIG_HOTPLUG_CPU static int op_cpu_kill(unsigned int cpu); #else @@ -237,6 +244,8 @@ asmlinkage notrace void secondary_start_kernel(void) */ notify_cpu_starting(cpu); + ipi_setup(cpu); + store_cpu_topology(cpu); numa_add_cpu(cpu); @@ -302,6 +311,7 @@ int __cpu_disable(void) * and we must not schedule until we're ready to give up the cpu. */ set_cpu_online(cpu, false); + ipi_teardown(cpu); /* * OK - migrate IRQs away from this CPU @@ -890,10 +900,9 @@ static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs) /* * Main handler for inter-processor interrupts */ -void handle_IPI(int ipinr, struct pt_regs *regs) +static void do_handle_IPI(int ipinr) { unsigned int cpu = smp_processor_id(); - struct pt_regs *old_regs = set_irq_regs(regs); if ((unsigned)ipinr < NR_IPI) { trace_ipi_entry_rcuidle(ipi_types[ipinr]); @@ -906,21 +915,16 @@ void handle_IPI(int ipinr, struct pt_regs *regs) break; case IPI_CALL_FUNC: - irq_enter(); generic_smp_call_function_interrupt(); - irq_exit(); break; case IPI_CPU_STOP: - irq_enter(); local_cpu_stop(); - irq_exit(); break; case IPI_CPU_CRASH_STOP: if (IS_ENABLED(CONFIG_KEXEC_CORE)) { - irq_enter(); - ipi_cpu_crash_stop(cpu, regs); + ipi_cpu_crash_stop(cpu, get_irq_regs()); unreachable(); } @@ -928,17 +932,13 @@ void handle_IPI(int ipinr, struct pt_regs *regs) #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST case IPI_TIMER: - irq_enter(); tick_receive_broadcast(); - irq_exit(); break; #endif #ifdef CONFIG_IRQ_WORK case IPI_IRQ_WORK: - irq_enter(); irq_work_run(); - irq_exit(); break; #endif @@ -957,9 +957,78 @@ void handle_IPI(int ipinr, struct pt_regs *regs) if ((unsigned)ipinr < NR_IPI) trace_ipi_exit_rcuidle(ipi_types[ipinr]); +} + +/* Legacy version, should go away once all irqchips have been converted */ +void handle_IPI(int ipinr, struct pt_regs *regs) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + + irq_enter(); + do_handle_IPI(ipinr); + irq_exit(); + set_irq_regs(old_regs); } +static irqreturn_t ipi_handler(int irq, void *data) +{ + do_handle_IPI(irq - ipi_irq_base); + return IRQ_HANDLED; +} + +static void ipi_send(const struct cpumask *target, unsigned int ipi) +{ + __ipi_send_mask(ipi_desc[ipi], target); +} + +static void ipi_setup(int cpu) +{ + int i; + + if (!ipi_irq_base) + return; + + for (i = 0; i < nr_ipi; i++) + enable_percpu_irq(ipi_irq_base + i, 0); +} + +static void ipi_teardown(int cpu) +{ + int i; + + if (!ipi_irq_base) + return; + + for (i = 0; i < nr_ipi; i++) + disable_percpu_irq(ipi_irq_base + i); +} + +void __init set_smp_ipi_range(int ipi_base, int n) +{ + int i; + + WARN_ON(n < NR_IPI); + nr_ipi = min(n, NR_IPI); + + for (i = 0; i < nr_ipi; i++) { + int err; + + err = request_percpu_irq(ipi_base + i, ipi_handler, + "IPI", &irq_stat); + WARN_ON(err); + + ipi_desc[i] = irq_to_desc(ipi_base + i); + irq_set_status_flags(ipi_base + i, IRQ_HIDDEN); + } + + ipi_irq_base = ipi_base; + __smp_cross_call = ipi_send; + + /* Setup the boot CPU immediately */ + ipi_setup(smp_processor_id()); +} + void smp_send_reschedule(int cpu) { smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); -- cgit v1.2.3 From 5cebfd2d47c214f69d918e3d34ad183c061eddb2 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Sat, 9 May 2020 14:00:23 +0100 Subject: arm64: Kill __smp_cross_call and co The old IPI registration interface is now unused on arm64, so let's get rid of it. Reviewed-by: Valentin Schneider Acked-by: Catalin Marinas Signed-off-by: Marc Zyngier --- arch/arm64/kernel/smp.c | 38 +++++++------------------------------- 1 file changed, 7 insertions(+), 31 deletions(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 00c9db1b61b5..58fb155fb0ab 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -782,13 +782,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus) } } -void (*__smp_cross_call)(const struct cpumask *, unsigned int); - -void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int)) -{ - __smp_cross_call = fn; -} - static const char *ipi_types[NR_IPI] __tracepoint_string = { #define S(x,s) [x] = s S(IPI_RESCHEDULE, "Rescheduling interrupts"), @@ -800,11 +793,7 @@ static const char *ipi_types[NR_IPI] __tracepoint_string = { S(IPI_WAKEUP, "CPU wake-up interrupts"), }; -static void smp_cross_call(const struct cpumask *target, unsigned int ipinr) -{ - trace_ipi_raise(target, ipi_types[ipinr]); - __smp_cross_call(target, ipinr); -} +static void smp_cross_call(const struct cpumask *target, unsigned int ipinr); void show_ipi_list(struct seq_file *p, int prec) { @@ -851,8 +840,7 @@ void arch_send_wakeup_ipi_mask(const struct cpumask *mask) #ifdef CONFIG_IRQ_WORK void arch_irq_work_raise(void) { - if (__smp_cross_call) - smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK); + smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK); } #endif @@ -959,34 +947,23 @@ static void do_handle_IPI(int ipinr) trace_ipi_exit_rcuidle(ipi_types[ipinr]); } -/* Legacy version, should go away once all irqchips have been converted */ -void handle_IPI(int ipinr, struct pt_regs *regs) -{ - struct pt_regs *old_regs = set_irq_regs(regs); - - irq_enter(); - do_handle_IPI(ipinr); - irq_exit(); - - set_irq_regs(old_regs); -} - static irqreturn_t ipi_handler(int irq, void *data) { do_handle_IPI(irq - ipi_irq_base); return IRQ_HANDLED; } -static void ipi_send(const struct cpumask *target, unsigned int ipi) +static void smp_cross_call(const struct cpumask *target, unsigned int ipinr) { - __ipi_send_mask(ipi_desc[ipi], target); + trace_ipi_raise(target, ipi_types[ipinr]); + __ipi_send_mask(ipi_desc[ipinr], target); } static void ipi_setup(int cpu) { int i; - if (!ipi_irq_base) + if (WARN_ON_ONCE(!ipi_irq_base)) return; for (i = 0; i < nr_ipi; i++) @@ -997,7 +974,7 @@ static void ipi_teardown(int cpu) { int i; - if (!ipi_irq_base) + if (WARN_ON_ONCE(!ipi_irq_base)) return; for (i = 0; i < nr_ipi; i++) @@ -1023,7 +1000,6 @@ void __init set_smp_ipi_range(int ipi_base, int n) } ipi_irq_base = ipi_base; - __smp_cross_call = ipi_send; /* Setup the boot CPU immediately */ ipi_setup(smp_processor_id()); -- cgit v1.2.3 From a263881525310e10ecd46ae8e8531ac9e968b1b4 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Sat, 20 Jun 2020 17:19:00 +0100 Subject: arm64: Remove custom IRQ stat accounting Let's switch the arm64 code to the core accounting, which already does everything we need. Reviewed-by: Valentin Schneider Acked-by: Catalin Marinas Signed-off-by: Marc Zyngier --- arch/arm64/kernel/irq.c | 11 +---------- arch/arm64/kernel/smp.c | 30 ++++++++++++------------------ 2 files changed, 13 insertions(+), 28 deletions(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c index 04a327ccf84d..9cf2fb87584a 100644 --- a/arch/arm64/kernel/irq.c +++ b/arch/arm64/kernel/irq.c @@ -10,10 +10,10 @@ * Copyright (C) 2012 ARM Ltd. */ -#include #include #include #include +#include #include #include #include @@ -22,20 +22,11 @@ #include #include -unsigned long irq_err_count; - /* Only access this in an NMI enter/exit */ DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts); DEFINE_PER_CPU(unsigned long *, irq_stack_ptr); -int arch_show_interrupts(struct seq_file *p, int prec) -{ - show_ipi_list(p, prec); - seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count); - return 0; -} - #ifdef CONFIG_VMAP_STACK static void init_irq_stacks(void) { diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 58fb155fb0ab..b6bde2675ccc 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -72,7 +73,8 @@ enum ipi_msg_type { IPI_CPU_CRASH_STOP, IPI_TIMER, IPI_IRQ_WORK, - IPI_WAKEUP + IPI_WAKEUP, + NR_IPI }; static int ipi_irq_base __read_mostly; @@ -795,29 +797,23 @@ static const char *ipi_types[NR_IPI] __tracepoint_string = { static void smp_cross_call(const struct cpumask *target, unsigned int ipinr); -void show_ipi_list(struct seq_file *p, int prec) +unsigned long irq_err_count; + +int arch_show_interrupts(struct seq_file *p, int prec) { unsigned int cpu, i; for (i = 0; i < NR_IPI; i++) { + unsigned int irq = irq_desc_get_irq(ipi_desc[i]); seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, prec >= 4 ? " " : ""); for_each_online_cpu(cpu) - seq_printf(p, "%10u ", - __get_irq_stat(cpu, ipi_irqs[i])); + seq_printf(p, "%10u ", kstat_irqs_cpu(irq, cpu)); seq_printf(p, " %s\n", ipi_types[i]); } -} - -u64 smp_irq_stat_cpu(unsigned int cpu) -{ - u64 sum = 0; - int i; - for (i = 0; i < NR_IPI; i++) - sum += __get_irq_stat(cpu, ipi_irqs[i]); - - return sum; + seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count); + return 0; } void arch_send_call_function_ipi_mask(const struct cpumask *mask) @@ -892,10 +888,8 @@ static void do_handle_IPI(int ipinr) { unsigned int cpu = smp_processor_id(); - if ((unsigned)ipinr < NR_IPI) { + if ((unsigned)ipinr < NR_IPI) trace_ipi_entry_rcuidle(ipi_types[ipinr]); - __inc_irq_stat(cpu, ipi_irqs[ipinr]); - } switch (ipinr) { case IPI_RESCHEDULE: @@ -992,7 +986,7 @@ void __init set_smp_ipi_range(int ipi_base, int n) int err; err = request_percpu_irq(ipi_base + i, ipi_handler, - "IPI", &irq_stat); + "IPI", &cpu_number); WARN_ON(err); ipi_desc[i] = irq_to_desc(ipi_base + i); -- cgit v1.2.3