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-rw-r--r--arch/powerpc/kernel/irq_64.c522
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diff --git a/arch/powerpc/kernel/irq_64.c b/arch/powerpc/kernel/irq_64.c
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+++ b/arch/powerpc/kernel/irq_64.c
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Derived from arch/i386/kernel/irq.c
+ * Copyright (C) 1992 Linus Torvalds
+ * Adapted from arch/i386 by Gary Thomas
+ * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ * Updated and modified by Cort Dougan <cort@fsmlabs.com>
+ * Copyright (C) 1996-2001 Cort Dougan
+ * Adapted for Power Macintosh by Paul Mackerras
+ * Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
+ *
+ * This file contains the code used by various IRQ handling routines:
+ * asking for different IRQ's should be done through these routines
+ * instead of just grabbing them. Thus setups with different IRQ numbers
+ * shouldn't result in any weird surprises, and installing new handlers
+ * should be easier.
+ */
+
+#undef DEBUG
+
+#include <linux/export.h>
+#include <linux/threads.h>
+#include <linux/kernel_stat.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/ptrace.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/timex.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/seq_file.h>
+#include <linux/cpumask.h>
+#include <linux/profile.h>
+#include <linux/bitops.h>
+#include <linux/list.h>
+#include <linux/radix-tree.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/debugfs.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/vmalloc.h>
+#include <linux/pgtable.h>
+#include <linux/static_call.h>
+
+#include <linux/uaccess.h>
+#include <asm/interrupt.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/cache.h>
+#include <asm/ptrace.h>
+#include <asm/machdep.h>
+#include <asm/udbg.h>
+#include <asm/smp.h>
+#include <asm/hw_irq.h>
+#include <asm/softirq_stack.h>
+#include <asm/ppc_asm.h>
+
+#include <asm/paca.h>
+#include <asm/firmware.h>
+#include <asm/lv1call.h>
+#include <asm/dbell.h>
+#include <asm/trace.h>
+#include <asm/cpu_has_feature.h>
+
+int distribute_irqs = 1;
+
+static inline void next_interrupt(struct pt_regs *regs)
+{
+ if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)) {
+ WARN_ON(!(local_paca->irq_happened & PACA_IRQ_HARD_DIS));
+ WARN_ON(irq_soft_mask_return() != IRQS_ALL_DISABLED);
+ }
+
+ /*
+ * We are responding to the next interrupt, so interrupt-off
+ * latencies should be reset here.
+ */
+ lockdep_hardirq_exit();
+ trace_hardirqs_on();
+ trace_hardirqs_off();
+ lockdep_hardirq_enter();
+}
+
+static inline bool irq_happened_test_and_clear(u8 irq)
+{
+ if (local_paca->irq_happened & irq) {
+ local_paca->irq_happened &= ~irq;
+ return true;
+ }
+ return false;
+}
+
+static __no_kcsan void __replay_soft_interrupts(void)
+{
+ struct pt_regs regs;
+
+ /*
+ * We use local_paca rather than get_paca() to avoid all the
+ * debug_smp_processor_id() business in this low level function.
+ */
+
+ if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)) {
+ WARN_ON_ONCE(mfmsr() & MSR_EE);
+ WARN_ON(!(local_paca->irq_happened & PACA_IRQ_HARD_DIS));
+ WARN_ON(local_paca->irq_happened & PACA_IRQ_REPLAYING);
+ }
+
+ /*
+ * PACA_IRQ_REPLAYING prevents interrupt handlers from enabling
+ * MSR[EE] to get PMIs, which can result in more IRQs becoming
+ * pending.
+ */
+ local_paca->irq_happened |= PACA_IRQ_REPLAYING;
+
+ ppc_save_regs(&regs);
+ regs.softe = IRQS_ENABLED;
+ regs.msr |= MSR_EE;
+
+ /*
+ * Force the delivery of pending soft-disabled interrupts on PS3.
+ * Any HV call will have this side effect.
+ */
+ if (firmware_has_feature(FW_FEATURE_PS3_LV1)) {
+ u64 tmp, tmp2;
+ lv1_get_version_info(&tmp, &tmp2);
+ }
+
+ /*
+ * Check if an hypervisor Maintenance interrupt happened.
+ * This is a higher priority interrupt than the others, so
+ * replay it first.
+ */
+ if (IS_ENABLED(CONFIG_PPC_BOOK3S) &&
+ irq_happened_test_and_clear(PACA_IRQ_HMI)) {
+ regs.trap = INTERRUPT_HMI;
+ handle_hmi_exception(&regs);
+ next_interrupt(&regs);
+ }
+
+ if (irq_happened_test_and_clear(PACA_IRQ_DEC)) {
+ regs.trap = INTERRUPT_DECREMENTER;
+ timer_interrupt(&regs);
+ next_interrupt(&regs);
+ }
+
+ if (irq_happened_test_and_clear(PACA_IRQ_EE)) {
+ regs.trap = INTERRUPT_EXTERNAL;
+ do_IRQ(&regs);
+ next_interrupt(&regs);
+ }
+
+ if (IS_ENABLED(CONFIG_PPC_DOORBELL) &&
+ irq_happened_test_and_clear(PACA_IRQ_DBELL)) {
+ regs.trap = INTERRUPT_DOORBELL;
+ doorbell_exception(&regs);
+ next_interrupt(&regs);
+ }
+
+ /* Book3E does not support soft-masking PMI interrupts */
+ if (IS_ENABLED(CONFIG_PPC_BOOK3S) &&
+ irq_happened_test_and_clear(PACA_IRQ_PMI)) {
+ regs.trap = INTERRUPT_PERFMON;
+ performance_monitor_exception(&regs);
+ next_interrupt(&regs);
+ }
+
+ local_paca->irq_happened &= ~PACA_IRQ_REPLAYING;
+}
+
+__no_kcsan void replay_soft_interrupts(void)
+{
+ irq_enter(); /* See comment in arch_local_irq_restore */
+ __replay_soft_interrupts();
+ irq_exit();
+}
+
+#if defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_PPC_KUAP)
+static inline __no_kcsan void replay_soft_interrupts_irqrestore(void)
+{
+ unsigned long kuap_state = get_kuap();
+
+ /*
+ * Check if anything calls local_irq_enable/restore() when KUAP is
+ * disabled (user access enabled). We handle that case here by saving
+ * and re-locking AMR but we shouldn't get here in the first place,
+ * hence the warning.
+ */
+ kuap_assert_locked();
+
+ if (kuap_state != AMR_KUAP_BLOCKED)
+ set_kuap(AMR_KUAP_BLOCKED);
+
+ __replay_soft_interrupts();
+
+ if (kuap_state != AMR_KUAP_BLOCKED)
+ set_kuap(kuap_state);
+}
+#else
+#define replay_soft_interrupts_irqrestore() __replay_soft_interrupts()
+#endif
+
+notrace __no_kcsan void arch_local_irq_restore(unsigned long mask)
+{
+ unsigned char irq_happened;
+
+ /* Write the new soft-enabled value if it is a disable */
+ if (mask) {
+ irq_soft_mask_set(mask);
+ return;
+ }
+
+ if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)) {
+ WARN_ON_ONCE(in_nmi());
+ WARN_ON_ONCE(in_hardirq());
+ WARN_ON_ONCE(local_paca->irq_happened & PACA_IRQ_REPLAYING);
+ }
+
+again:
+ /*
+ * After the stb, interrupts are unmasked and there are no interrupts
+ * pending replay. The restart sequence makes this atomic with
+ * respect to soft-masked interrupts. If this was just a simple code
+ * sequence, a soft-masked interrupt could become pending right after
+ * the comparison and before the stb.
+ *
+ * This allows interrupts to be unmasked without hard disabling, and
+ * also without new hard interrupts coming in ahead of pending ones.
+ */
+ asm_volatile_goto(
+"1: \n"
+" lbz 9,%0(13) \n"
+" cmpwi 9,0 \n"
+" bne %l[happened] \n"
+" stb 9,%1(13) \n"
+"2: \n"
+ RESTART_TABLE(1b, 2b, 1b)
+ : : "i" (offsetof(struct paca_struct, irq_happened)),
+ "i" (offsetof(struct paca_struct, irq_soft_mask))
+ : "cr0", "r9"
+ : happened);
+
+ if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))
+ WARN_ON_ONCE(!(mfmsr() & MSR_EE));
+
+ /*
+ * If we came here from the replay below, we might have a preempt
+ * pending (due to preempt_enable_no_resched()). Have to check now.
+ */
+ preempt_check_resched();
+
+ return;
+
+happened:
+ irq_happened = READ_ONCE(local_paca->irq_happened);
+ if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))
+ WARN_ON_ONCE(!irq_happened);
+
+ if (irq_happened == PACA_IRQ_HARD_DIS) {
+ if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))
+ WARN_ON_ONCE(mfmsr() & MSR_EE);
+ irq_soft_mask_set(IRQS_ENABLED);
+ local_paca->irq_happened = 0;
+ __hard_irq_enable();
+ preempt_check_resched();
+ return;
+ }
+
+ /* Have interrupts to replay, need to hard disable first */
+ if (!(irq_happened & PACA_IRQ_HARD_DIS)) {
+ if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)) {
+ if (!(mfmsr() & MSR_EE)) {
+ /*
+ * An interrupt could have come in and cleared
+ * MSR[EE] and set IRQ_HARD_DIS, so check
+ * IRQ_HARD_DIS again and warn if it is still
+ * clear.
+ */
+ irq_happened = READ_ONCE(local_paca->irq_happened);
+ WARN_ON_ONCE(!(irq_happened & PACA_IRQ_HARD_DIS));
+ }
+ }
+ __hard_irq_disable();
+ local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
+ } else {
+ if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)) {
+ if (WARN_ON_ONCE(mfmsr() & MSR_EE))
+ __hard_irq_disable();
+ }
+ }
+
+ /*
+ * Disable preempt here, so that the below preempt_enable will
+ * perform resched if required (a replayed interrupt may set
+ * need_resched).
+ */
+ preempt_disable();
+ irq_soft_mask_set(IRQS_ALL_DISABLED);
+ trace_hardirqs_off();
+
+ /*
+ * Now enter interrupt context. The interrupt handlers themselves
+ * also call irq_enter/exit (which is okay, they can nest). But call
+ * it here now to hold off softirqs until the below irq_exit(). If
+ * we allowed replayed handlers to run softirqs, that enables irqs,
+ * which must replay interrupts, which recurses in here and makes
+ * things more complicated. The recursion is limited to 2, and it can
+ * be made to work, but it's complicated.
+ *
+ * local_bh_disable can not be used here because interrupts taken in
+ * idle are not in the right context (RCU, tick, etc) to run softirqs
+ * so irq_enter must be called.
+ */
+ irq_enter();
+
+ replay_soft_interrupts_irqrestore();
+
+ irq_exit();
+
+ if (unlikely(local_paca->irq_happened != PACA_IRQ_HARD_DIS)) {
+ /*
+ * The softirq processing in irq_exit() may enable interrupts
+ * temporarily, which can result in MSR[EE] being enabled and
+ * more irqs becoming pending. Go around again if that happens.
+ */
+ trace_hardirqs_on();
+ preempt_enable_no_resched();
+ goto again;
+ }
+
+ trace_hardirqs_on();
+ irq_soft_mask_set(IRQS_ENABLED);
+ local_paca->irq_happened = 0;
+ __hard_irq_enable();
+ preempt_enable();
+}
+EXPORT_SYMBOL(arch_local_irq_restore);
+
+/*
+ * This is a helper to use when about to go into idle low-power
+ * when the latter has the side effect of re-enabling interrupts
+ * (such as calling H_CEDE under pHyp).
+ *
+ * You call this function with interrupts soft-disabled (this is
+ * already the case when ppc_md.power_save is called). The function
+ * will return whether to enter power save or just return.
+ *
+ * In the former case, it will have generally sanitized the lazy irq
+ * state, and in the latter case it will leave with interrupts hard
+ * disabled and marked as such, so the local_irq_enable() call
+ * in arch_cpu_idle() will properly re-enable everything.
+ */
+__cpuidle bool prep_irq_for_idle(void)
+{
+ /*
+ * First we need to hard disable to ensure no interrupt
+ * occurs before we effectively enter the low power state
+ */
+ __hard_irq_disable();
+ local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
+
+ /*
+ * If anything happened while we were soft-disabled,
+ * we return now and do not enter the low power state.
+ */
+ if (lazy_irq_pending())
+ return false;
+
+ /*
+ * Mark interrupts as soft-enabled and clear the
+ * PACA_IRQ_HARD_DIS from the pending mask since we
+ * are about to hard enable as well as a side effect
+ * of entering the low power state.
+ */
+ local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
+ irq_soft_mask_set(IRQS_ENABLED);
+
+ /* Tell the caller to enter the low power state */
+ return true;
+}
+
+#ifdef CONFIG_PPC_BOOK3S
+/*
+ * This is for idle sequences that return with IRQs off, but the
+ * idle state itself wakes on interrupt. Tell the irq tracer that
+ * IRQs are enabled for the duration of idle so it does not get long
+ * off times. Must be paired with fini_irq_for_idle_irqsoff.
+ */
+bool prep_irq_for_idle_irqsoff(void)
+{
+ WARN_ON(!irqs_disabled());
+
+ /*
+ * First we need to hard disable to ensure no interrupt
+ * occurs before we effectively enter the low power state
+ */
+ __hard_irq_disable();
+ local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
+
+ /*
+ * If anything happened while we were soft-disabled,
+ * we return now and do not enter the low power state.
+ */
+ if (lazy_irq_pending())
+ return false;
+
+ /* Tell lockdep we are about to re-enable */
+ trace_hardirqs_on();
+
+ return true;
+}
+
+/*
+ * Take the SRR1 wakeup reason, index into this table to find the
+ * appropriate irq_happened bit.
+ *
+ * Sytem reset exceptions taken in idle state also come through here,
+ * but they are NMI interrupts so do not need to wait for IRQs to be
+ * restored, and should be taken as early as practical. These are marked
+ * with 0xff in the table. The Power ISA specifies 0100b as the system
+ * reset interrupt reason.
+ */
+#define IRQ_SYSTEM_RESET 0xff
+
+static const u8 srr1_to_lazyirq[0x10] = {
+ 0, 0, 0,
+ PACA_IRQ_DBELL,
+ IRQ_SYSTEM_RESET,
+ PACA_IRQ_DBELL,
+ PACA_IRQ_DEC,
+ 0,
+ PACA_IRQ_EE,
+ PACA_IRQ_EE,
+ PACA_IRQ_HMI,
+ 0, 0, 0, 0, 0 };
+
+void replay_system_reset(void)
+{
+ struct pt_regs regs;
+
+ ppc_save_regs(&regs);
+ regs.trap = 0x100;
+ get_paca()->in_nmi = 1;
+ system_reset_exception(&regs);
+ get_paca()->in_nmi = 0;
+}
+EXPORT_SYMBOL_GPL(replay_system_reset);
+
+void irq_set_pending_from_srr1(unsigned long srr1)
+{
+ unsigned int idx = (srr1 & SRR1_WAKEMASK_P8) >> 18;
+ u8 reason = srr1_to_lazyirq[idx];
+
+ /*
+ * Take the system reset now, which is immediately after registers
+ * are restored from idle. It's an NMI, so interrupts need not be
+ * re-enabled before it is taken.
+ */
+ if (unlikely(reason == IRQ_SYSTEM_RESET)) {
+ replay_system_reset();
+ return;
+ }
+
+ if (reason == PACA_IRQ_DBELL) {
+ /*
+ * When doorbell triggers a system reset wakeup, the message
+ * is not cleared, so if the doorbell interrupt is replayed
+ * and the IPI handled, the doorbell interrupt would still
+ * fire when EE is enabled.
+ *
+ * To avoid taking the superfluous doorbell interrupt,
+ * execute a msgclr here before the interrupt is replayed.
+ */
+ ppc_msgclr(PPC_DBELL_MSGTYPE);
+ }
+
+ /*
+ * The 0 index (SRR1[42:45]=b0000) must always evaluate to 0,
+ * so this can be called unconditionally with the SRR1 wake
+ * reason as returned by the idle code, which uses 0 to mean no
+ * interrupt.
+ *
+ * If a future CPU was to designate this as an interrupt reason,
+ * then a new index for no interrupt must be assigned.
+ */
+ local_paca->irq_happened |= reason;
+}
+#endif /* CONFIG_PPC_BOOK3S */
+
+/*
+ * Force a replay of the external interrupt handler on this CPU.
+ */
+void force_external_irq_replay(void)
+{
+ /*
+ * This must only be called with interrupts soft-disabled,
+ * the replay will happen when re-enabling.
+ */
+ WARN_ON(!arch_irqs_disabled());
+
+ /*
+ * Interrupts must always be hard disabled before irq_happened is
+ * modified (to prevent lost update in case of interrupt between
+ * load and store).
+ */
+ __hard_irq_disable();
+ local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
+
+ /* Indicate in the PACA that we have an interrupt to replay */
+ local_paca->irq_happened |= PACA_IRQ_EE;
+}
+
+static int __init setup_noirqdistrib(char *str)
+{
+ distribute_irqs = 0;
+ return 1;
+}
+
+__setup("noirqdistrib", setup_noirqdistrib);