Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 916ddc4..5645bc9 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  Derived from arch/i386/kernel/irq.c
  *    Copyright (C) 1992 Linus Torvalds
@@ -8,11 +9,6 @@
  *  Adapted for Power Macintosh by Paul Mackerras
  *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- *
  * 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
@@ -81,10 +77,7 @@
 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
 EXPORT_PER_CPU_SYMBOL(irq_stat);
 
-int __irq_offset_value;
-
 #ifdef CONFIG_PPC32
-EXPORT_SYMBOL(__irq_offset_value);
 atomic_t ppc_n_lost_interrupts;
 
 #ifdef CONFIG_TAU_INT
@@ -261,16 +254,9 @@
 	 */
 	irq_happened = get_irq_happened();
 	if (!irq_happened) {
-		/*
-		 * FIXME. Here we'd like to be able to do:
-		 *
-		 * #ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
-		 *   WARN_ON(!(mfmsr() & MSR_EE));
-		 * #endif
-		 *
-		 * But currently it hits in a few paths, we should fix those and
-		 * enable the warning.
-		 */
+#ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
+		WARN_ON_ONCE(!(mfmsr() & MSR_EE));
+#endif
 		return;
 	}
 
@@ -282,7 +268,7 @@
 	 */
 	if (!(irq_happened & PACA_IRQ_HARD_DIS)) {
 #ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
-		WARN_ON(!(mfmsr() & MSR_EE));
+		WARN_ON_ONCE(!(mfmsr() & MSR_EE));
 #endif
 		__hard_irq_disable();
 #ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
@@ -293,7 +279,7 @@
 		 * warn if we are wrong. Only do that when IRQ tracing
 		 * is enabled as mfmsr() can be costly.
 		 */
-		if (WARN_ON(mfmsr() & MSR_EE))
+		if (WARN_ON_ONCE(mfmsr() & MSR_EE))
 			__hard_irq_disable();
 #endif
 	}
@@ -618,9 +604,8 @@
 	sp = current_stack_pointer() & (THREAD_SIZE-1);
 
 	/* check for stack overflow: is there less than 2KB free? */
-	if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
-		pr_err("do_IRQ: stack overflow: %ld\n",
-			sp - sizeof(struct thread_info));
+	if (unlikely(sp < 2048)) {
+		pr_err("do_IRQ: stack overflow: %ld\n", sp);
 		dump_stack();
 	}
 #endif
@@ -660,36 +645,21 @@
 void do_IRQ(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
-	struct thread_info *curtp, *irqtp, *sirqtp;
+	void *cursp, *irqsp, *sirqsp;
 
 	/* Switch to the irq stack to handle this */
-	curtp = current_thread_info();
-	irqtp = hardirq_ctx[raw_smp_processor_id()];
-	sirqtp = softirq_ctx[raw_smp_processor_id()];
+	cursp = (void *)(current_stack_pointer() & ~(THREAD_SIZE - 1));
+	irqsp = hardirq_ctx[raw_smp_processor_id()];
+	sirqsp = softirq_ctx[raw_smp_processor_id()];
 
 	/* Already there ? */
-	if (unlikely(curtp == irqtp || curtp == sirqtp)) {
+	if (unlikely(cursp == irqsp || cursp == sirqsp)) {
 		__do_irq(regs);
 		set_irq_regs(old_regs);
 		return;
 	}
-
-	/* Prepare the thread_info in the irq stack */
-	irqtp->task = curtp->task;
-	irqtp->flags = 0;
-
-	/* Copy the preempt_count so that the [soft]irq checks work. */
-	irqtp->preempt_count = curtp->preempt_count;
-
 	/* Switch stack and call */
-	call_do_irq(regs, irqtp);
-
-	/* Restore stack limit */
-	irqtp->task = NULL;
-
-	/* Copy back updates to the thread_info */
-	if (irqtp->flags)
-		set_bits(irqtp->flags, &curtp->flags);
+	call_do_irq(regs, irqsp);
 
 	set_irq_regs(old_regs);
 }
@@ -698,90 +668,20 @@
 {
 	if (ppc_md.init_IRQ)
 		ppc_md.init_IRQ();
-
-	exc_lvl_ctx_init();
-
-	irq_ctx_init();
 }
 
 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
-struct thread_info   *critirq_ctx[NR_CPUS] __read_mostly;
-struct thread_info    *dbgirq_ctx[NR_CPUS] __read_mostly;
-struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;
-
-void exc_lvl_ctx_init(void)
-{
-	struct thread_info *tp;
-	int i, cpu_nr;
-
-	for_each_possible_cpu(i) {
-#ifdef CONFIG_PPC64
-		cpu_nr = i;
-#else
-#ifdef CONFIG_SMP
-		cpu_nr = get_hard_smp_processor_id(i);
-#else
-		cpu_nr = 0;
-#endif
+void   *critirq_ctx[NR_CPUS] __read_mostly;
+void    *dbgirq_ctx[NR_CPUS] __read_mostly;
+void *mcheckirq_ctx[NR_CPUS] __read_mostly;
 #endif
 
-		memset((void *)critirq_ctx[cpu_nr], 0, THREAD_SIZE);
-		tp = critirq_ctx[cpu_nr];
-		tp->cpu = cpu_nr;
-		tp->preempt_count = 0;
-
-#ifdef CONFIG_BOOKE
-		memset((void *)dbgirq_ctx[cpu_nr], 0, THREAD_SIZE);
-		tp = dbgirq_ctx[cpu_nr];
-		tp->cpu = cpu_nr;
-		tp->preempt_count = 0;
-
-		memset((void *)mcheckirq_ctx[cpu_nr], 0, THREAD_SIZE);
-		tp = mcheckirq_ctx[cpu_nr];
-		tp->cpu = cpu_nr;
-		tp->preempt_count = HARDIRQ_OFFSET;
-#endif
-	}
-}
-#endif
-
-struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;
-struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly;
-
-void irq_ctx_init(void)
-{
-	struct thread_info *tp;
-	int i;
-
-	for_each_possible_cpu(i) {
-		memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
-		tp = softirq_ctx[i];
-		tp->cpu = i;
-		klp_init_thread_info(tp);
-
-		memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
-		tp = hardirq_ctx[i];
-		tp->cpu = i;
-		klp_init_thread_info(tp);
-	}
-}
+void *softirq_ctx[NR_CPUS] __read_mostly;
+void *hardirq_ctx[NR_CPUS] __read_mostly;
 
 void do_softirq_own_stack(void)
 {
-	struct thread_info *curtp, *irqtp;
-
-	curtp = current_thread_info();
-	irqtp = softirq_ctx[smp_processor_id()];
-	irqtp->task = curtp->task;
-	irqtp->flags = 0;
-	call_do_softirq(irqtp);
-	irqtp->task = NULL;
-
-	/* Set any flag that may have been set on the
-	 * alternate stack
-	 */
-	if (irqtp->flags)
-		set_bits(irqtp->flags, &curtp->flags);
+	call_do_softirq(softirq_ctx[smp_processor_id()]);
 }
 
 irq_hw_number_t virq_to_hw(unsigned int virq)
@@ -827,11 +727,6 @@
 }
 #endif
 
-int arch_early_irq_init(void)
-{
-	return 0;
-}
-
 #ifdef CONFIG_PPC64
 static int __init setup_noirqdistrib(char *str)
 {