Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 526 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/irq_64.c b/arch/powerpc/kernel/irq_64.c
new file mode 100644
index 000000000..9dc0ad3c5
--- /dev/null
+++ b/arch/powerpc/kernel/irq_64.c
@@ -0,0 +1,526 @@
+// 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 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;
+}
+
+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 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 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 notified lockdep of interrupts
+ * being re-enabled and 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.
+ */
+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;
+
+	/* Tell lockdep we are about to re-enable */
+	trace_hardirqs_on();
+
+	/*
+	 * 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);