Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/csky/mm/tlb.c b/arch/csky/mm/tlb.c
new file mode 100644
index 0000000..eb3ba6c
--- /dev/null
+++ b/arch/csky/mm/tlb.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
+#include <asm/setup.h>
+
+/*
+ * One C-SKY MMU TLB entry contain two PFN/page entry, ie:
+ * 1VPN -> 2PFN
+ */
+#define TLB_ENTRY_SIZE		(PAGE_SIZE * 2)
+#define TLB_ENTRY_SIZE_MASK	(PAGE_MASK << 1)
+
+void flush_tlb_all(void)
+{
+	tlb_invalid_all();
+}
+
+void flush_tlb_mm(struct mm_struct *mm)
+{
+#ifdef CONFIG_CPU_HAS_TLBI
+	asm volatile("tlbi.asids %0"::"r"(cpu_asid(mm)));
+#else
+	tlb_invalid_all();
+#endif
+}
+
+/*
+ * MMU operation regs only could invalid tlb entry in jtlb and we
+ * need change asid field to invalid I-utlb & D-utlb.
+ */
+#ifndef CONFIG_CPU_HAS_TLBI
+#define restore_asid_inv_utlb(oldpid, newpid) \
+do { \
+	if (oldpid == newpid) \
+		write_mmu_entryhi(oldpid + 1); \
+	write_mmu_entryhi(oldpid); \
+} while (0)
+#endif
+
+void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
+			unsigned long end)
+{
+	unsigned long newpid = cpu_asid(vma->vm_mm);
+
+	start &= TLB_ENTRY_SIZE_MASK;
+	end   += TLB_ENTRY_SIZE - 1;
+	end   &= TLB_ENTRY_SIZE_MASK;
+
+#ifdef CONFIG_CPU_HAS_TLBI
+	while (start < end) {
+		asm volatile("tlbi.vas %0"::"r"(start | newpid));
+		start += 2*PAGE_SIZE;
+	}
+	sync_is();
+#else
+	{
+	unsigned long flags, oldpid;
+
+	local_irq_save(flags);
+	oldpid = read_mmu_entryhi() & ASID_MASK;
+	while (start < end) {
+		int idx;
+
+		write_mmu_entryhi(start | newpid);
+		start += 2*PAGE_SIZE;
+		tlb_probe();
+		idx = read_mmu_index();
+		if (idx >= 0)
+			tlb_invalid_indexed();
+	}
+	restore_asid_inv_utlb(oldpid, newpid);
+	local_irq_restore(flags);
+	}
+#endif
+}
+
+void flush_tlb_kernel_range(unsigned long start, unsigned long end)
+{
+	start &= TLB_ENTRY_SIZE_MASK;
+	end   += TLB_ENTRY_SIZE - 1;
+	end   &= TLB_ENTRY_SIZE_MASK;
+
+#ifdef CONFIG_CPU_HAS_TLBI
+	while (start < end) {
+		asm volatile("tlbi.vaas %0"::"r"(start));
+		start += 2*PAGE_SIZE;
+	}
+	sync_is();
+#else
+	{
+	unsigned long flags, oldpid;
+
+	local_irq_save(flags);
+	oldpid = read_mmu_entryhi() & ASID_MASK;
+	while (start < end) {
+		int idx;
+
+		write_mmu_entryhi(start | oldpid);
+		start += 2*PAGE_SIZE;
+		tlb_probe();
+		idx = read_mmu_index();
+		if (idx >= 0)
+			tlb_invalid_indexed();
+	}
+	restore_asid_inv_utlb(oldpid, oldpid);
+	local_irq_restore(flags);
+	}
+#endif
+}
+
+void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
+{
+	int newpid = cpu_asid(vma->vm_mm);
+
+	addr &= TLB_ENTRY_SIZE_MASK;
+
+#ifdef CONFIG_CPU_HAS_TLBI
+	asm volatile("tlbi.vas %0"::"r"(addr | newpid));
+	sync_is();
+#else
+	{
+	int oldpid, idx;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	oldpid = read_mmu_entryhi() & ASID_MASK;
+	write_mmu_entryhi(addr | newpid);
+	tlb_probe();
+	idx = read_mmu_index();
+	if (idx >= 0)
+		tlb_invalid_indexed();
+
+	restore_asid_inv_utlb(oldpid, newpid);
+	local_irq_restore(flags);
+	}
+#endif
+}
+
+void flush_tlb_one(unsigned long addr)
+{
+	addr &= TLB_ENTRY_SIZE_MASK;
+
+#ifdef CONFIG_CPU_HAS_TLBI
+	asm volatile("tlbi.vaas %0"::"r"(addr));
+	sync_is();
+#else
+	{
+	int oldpid, idx;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	oldpid = read_mmu_entryhi() & ASID_MASK;
+	write_mmu_entryhi(addr | oldpid);
+	tlb_probe();
+	idx = read_mmu_index();
+	if (idx >= 0)
+		tlb_invalid_indexed();
+
+	restore_asid_inv_utlb(oldpid, oldpid);
+	local_irq_restore(flags);
+	}
+#endif
+}
+EXPORT_SYMBOL(flush_tlb_one);