Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/arc/mm/Makefile b/arch/arc/mm/Makefile
index 3703a49..633a773 100644
--- a/arch/arc/mm/Makefile
+++ b/arch/arc/mm/Makefile
@@ -1,10 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 #
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 as
-# published by the Free Software Foundation.
-#
 
 obj-y	:= extable.o ioremap.o dma.o fault.o init.o
 obj-y	+= tlb.o tlbex.o cache.o mmap.o
diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index f2701c1..a2fbea3 100644
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * ARC Cache Management
  *
  * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/module.h>
@@ -113,10 +110,24 @@
 	}
 
 	READ_BCR(ARC_REG_CLUSTER_BCR, cbcr);
-	if (cbcr.c)
+	if (cbcr.c) {
 		ioc_exists = 1;
-	else
+
+		/*
+		 * As for today we don't support both IOC and ZONE_HIGHMEM enabled
+		 * simultaneously. This happens because as of today IOC aperture covers
+		 * only ZONE_NORMAL (low mem) and any dma transactions outside this
+		 * region won't be HW coherent.
+		 * If we want to use both IOC and ZONE_HIGHMEM we can use
+		 * bounce_buffer to handle dma transactions to HIGHMEM.
+		 * Also it is possible to modify dma_direct cache ops or increase IOC
+		 * aperture size if we are planning to use HIGHMEM without PAE.
+		 */
+		if (IS_ENABLED(CONFIG_HIGHMEM) || is_pae40_enabled())
+			ioc_enable = 0;
+	} else {
 		ioc_enable = 0;
+	}
 
 	/* HS 2.0 didn't have AUX_VOL */
 	if (cpuinfo_arc700[cpu].core.family > 0x51) {
@@ -1145,17 +1156,18 @@
 	unsigned int ioc_base, mem_sz;
 
 	/*
-	 * As for today we don't support both IOC and ZONE_HIGHMEM enabled
-	 * simultaneously. This happens because as of today IOC aperture covers
-	 * only ZONE_NORMAL (low mem) and any dma transactions outside this
-	 * region won't be HW coherent.
-	 * If we want to use both IOC and ZONE_HIGHMEM we can use
-	 * bounce_buffer to handle dma transactions to HIGHMEM.
-	 * Also it is possible to modify dma_direct cache ops or increase IOC
-	 * aperture size if we are planning to use HIGHMEM without PAE.
+	 * If IOC was already enabled (due to bootloader) it technically needs to
+	 * be reconfigured with aperture base,size corresponding to Linux memory map
+	 * which will certainly be different than uboot's. But disabling and
+	 * reenabling IOC when DMA might be potentially active is tricky business.
+	 * To avoid random memory issues later, just panic here and ask user to
+	 * upgrade bootloader to one which doesn't enable IOC
 	 */
-	if (IS_ENABLED(CONFIG_HIGHMEM))
-		panic("IOC and HIGHMEM can't be used simultaneously");
+	if (read_aux_reg(ARC_REG_IO_COH_ENABLE) & ARC_IO_COH_ENABLE_BIT)
+		panic("IOC already enabled, please upgrade bootloader!\n");
+
+	if (!ioc_enable)
+		return;
 
 	/* Flush + invalidate + disable L1 dcache */
 	__dc_disable();
@@ -1187,8 +1199,8 @@
 		panic("IOC Aperture start must be aligned to the size of the aperture");
 
 	write_aux_reg(ARC_REG_IO_COH_AP0_BASE, ioc_base >> 12);
-	write_aux_reg(ARC_REG_IO_COH_PARTIAL, 1);
-	write_aux_reg(ARC_REG_IO_COH_ENABLE, 1);
+	write_aux_reg(ARC_REG_IO_COH_PARTIAL, ARC_IO_COH_PARTIAL_BIT);
+	write_aux_reg(ARC_REG_IO_COH_ENABLE, ARC_IO_COH_ENABLE_BIT);
 
 	/* Re-enable L1 dcache */
 	__dc_enable();
@@ -1265,7 +1277,7 @@
 	if (is_isa_arcv2() && l2_line_sz && !slc_enable)
 		arc_slc_disable();
 
-	if (is_isa_arcv2() && ioc_enable)
+	if (is_isa_arcv2() && ioc_exists)
 		arc_ioc_setup();
 
 	if (is_isa_arcv2() && l2_line_sz && slc_enable) {
@@ -1280,7 +1292,7 @@
 	/*
 	 * In case of IOC (say IOC+SLC case), pointers above could still be set
 	 * but end up not being relevant as the first function in chain is not
-	 * called at all for @dma_direct_ops
+	 * called at all for devices using coherent DMA.
 	 *     arch_sync_dma_for_cpu() -> dma_cache_*() -> __dma_cache_*()
 	 */
 }
diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index c75d5c3..73a7e88 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/dma-noncoherent.h>
@@ -11,51 +8,15 @@
 #include <asm/cacheflush.h>
 
 /*
- * ARCH specific callbacks for generic noncoherent DMA ops (dma/noncoherent.c)
+ * ARCH specific callbacks for generic noncoherent DMA ops
  *  - hardware IOC not available (or "dma-coherent" not set for device in DT)
  *  - But still handle both coherent and non-coherent requests from caller
  *
  * For DMA coherent hardware (IOC) generic code suffices
  */
-void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
-		gfp_t gfp, unsigned long attrs)
+
+void arch_dma_prep_coherent(struct page *page, size_t size)
 {
-	unsigned long order = get_order(size);
-	struct page *page;
-	phys_addr_t paddr;
-	void *kvaddr;
-	bool need_coh = !(attrs & DMA_ATTR_NON_CONSISTENT);
-
-	/*
-	 * __GFP_HIGHMEM flag is cleared by upper layer functions
-	 * (in include/linux/dma-mapping.h) so we should never get a
-	 * __GFP_HIGHMEM here.
-	 */
-	BUG_ON(gfp & __GFP_HIGHMEM);
-
-	page = alloc_pages(gfp, order);
-	if (!page)
-		return NULL;
-
-	/* This is linear addr (0x8000_0000 based) */
-	paddr = page_to_phys(page);
-
-	*dma_handle = paddr;
-
-	/*
-	 * A coherent buffer needs MMU mapping to enforce non-cachability.
-	 * kvaddr is kernel Virtual address (0x7000_0000 based).
-	 */
-	if (need_coh) {
-		kvaddr = ioremap_nocache(paddr, size);
-		if (kvaddr == NULL) {
-			__free_pages(page, order);
-			return NULL;
-		}
-	} else {
-		kvaddr = (void *)(u32)paddr;
-	}
-
 	/*
 	 * Evict any existing L1 and/or L2 lines for the backing page
 	 * in case it was used earlier as a normal "cached" page.
@@ -66,47 +27,7 @@
 	 * Currently flush_cache_vmap nukes the L1 cache completely which
 	 * will be optimized as a separate commit
 	 */
-	if (need_coh)
-		dma_cache_wback_inv(paddr, size);
-
-	return kvaddr;
-}
-
-void arch_dma_free(struct device *dev, size_t size, void *vaddr,
-		dma_addr_t dma_handle, unsigned long attrs)
-{
-	phys_addr_t paddr = dma_handle;
-	struct page *page = virt_to_page(paddr);
-
-	if (!(attrs & DMA_ATTR_NON_CONSISTENT))
-		iounmap((void __force __iomem *)vaddr);
-
-	__free_pages(page, get_order(size));
-}
-
-int arch_dma_mmap(struct device *dev, struct vm_area_struct *vma,
-		void *cpu_addr, dma_addr_t dma_addr, size_t size,
-		unsigned long attrs)
-{
-	unsigned long user_count = vma_pages(vma);
-	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-	unsigned long pfn = __phys_to_pfn(dma_addr);
-	unsigned long off = vma->vm_pgoff;
-	int ret = -ENXIO;
-
-	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-
-	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
-		return ret;
-
-	if (off < count && user_count <= (count - off)) {
-		ret = remap_pfn_range(vma, vma->vm_start,
-				      pfn + off,
-				      user_count << PAGE_SHIFT,
-				      vma->vm_page_prot);
-	}
-
-	return ret;
+	dma_cache_wback_inv(page_to_phys(page), size);
 }
 
 /*
@@ -167,7 +88,7 @@
 }
 
 /*
- * Plug in coherent or noncoherent dma ops
+ * Plug in direct dma map ops.
  */
 void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 			const struct iommu_ops *iommu, bool coherent)
@@ -175,13 +96,11 @@
 	/*
 	 * IOC hardware snoops all DMA traffic keeping the caches consistent
 	 * with memory - eliding need for any explicit cache maintenance of
-	 * DMA buffers - so we can use dma_direct cache ops.
+	 * DMA buffers.
 	 */
-	if (is_isa_arcv2() && ioc_enable && coherent) {
-		set_dma_ops(dev, &dma_direct_ops);
-		dev_info(dev, "use dma_direct_ops cache ops\n");
-	} else {
-		set_dma_ops(dev, &dma_noncoherent_ops);
-		dev_info(dev, "use dma_noncoherent_ops cache ops\n");
-	}
+	if (is_isa_arcv2() && ioc_enable && coherent)
+		dev->dma_coherent = true;
+
+	dev_info(dev, "use %scoherent DMA ops\n",
+		 dev->dma_coherent ? "" : "non");
 }
diff --git a/arch/arc/mm/extable.c b/arch/arc/mm/extable.c
index 72125a3..b06b09d 100644
--- a/arch/arc/mm/extable.c
+++ b/arch/arc/mm/extable.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  * Borrowed heavily from MIPS
  */
 
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index db69130..3861543 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Page Fault Handling for ARC (TLB Miss / ProtV)
  *
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/signal.h>
@@ -66,33 +63,24 @@
 	struct vm_area_struct *vma = NULL;
 	struct task_struct *tsk = current;
 	struct mm_struct *mm = tsk->mm;
-	siginfo_t info;
-	int ret;
-	vm_fault_t fault;
-	int write = regs->ecr_cause & ECR_C_PROTV_STORE;  /* ST/EX */
-	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
-
-	clear_siginfo(&info);
+	int sig, si_code = SEGV_MAPERR;
+	unsigned int write = 0, exec = 0, mask;
+	vm_fault_t fault = VM_FAULT_SIGSEGV;	/* handle_mm_fault() output */
+	unsigned int flags;			/* handle_mm_fault() input */
 
 	/*
-	 * We fault-in kernel-space virtual memory on-demand. The
-	 * 'reference' page table is init_mm.pgd.
-	 *
 	 * NOTE! We MUST NOT take any locks for this case. We may
 	 * be in an interrupt or a critical region, and should
 	 * only copy the information from the master page table,
 	 * nothing more.
 	 */
-	if (address >= VMALLOC_START) {
-		ret = handle_kernel_vaddr_fault(address);
-		if (unlikely(ret))
-			goto bad_area_nosemaphore;
+	if (address >= VMALLOC_START && !user_mode(regs)) {
+		if (unlikely(handle_kernel_vaddr_fault(address)))
+			goto no_context;
 		else
 			return;
 	}
 
-	info.si_code = SEGV_MAPERR;
-
 	/*
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
@@ -100,147 +88,117 @@
 	if (faulthandler_disabled() || !mm)
 		goto no_context;
 
+	if (regs->ecr_cause & ECR_C_PROTV_STORE)	/* ST/EX */
+		write = 1;
+	else if ((regs->ecr_vec == ECR_V_PROTV) &&
+	         (regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
+		exec = 1;
+
+	flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
 	if (user_mode(regs))
 		flags |= FAULT_FLAG_USER;
+	if (write)
+		flags |= FAULT_FLAG_WRITE;
+
 retry:
 	down_read(&mm->mmap_sem);
+
 	vma = find_vma(mm, address);
 	if (!vma)
 		goto bad_area;
-	if (vma->vm_start <= address)
-		goto good_area;
-	if (!(vma->vm_flags & VM_GROWSDOWN))
-		goto bad_area;
-	if (expand_stack(vma, address))
-		goto bad_area;
-
-	/*
-	 * Ok, we have a good vm_area for this memory access, so
-	 * we can handle it..
-	 */
-good_area:
-	info.si_code = SEGV_ACCERR;
-
-	/* Handle protection violation, execute on heap or stack */
-
-	if ((regs->ecr_vec == ECR_V_PROTV) &&
-	    (regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
-		goto bad_area;
-
-	if (write) {
-		if (!(vma->vm_flags & VM_WRITE))
-			goto bad_area;
-		flags |= FAULT_FLAG_WRITE;
-	} else {
-		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+	if (unlikely(address < vma->vm_start)) {
+		if (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack(vma, address))
 			goto bad_area;
 	}
 
 	/*
-	 * If for any reason at all we couldn't handle the fault,
-	 * make sure we exit gracefully rather than endlessly redo
-	 * the fault.
+	 * vm_area is good, now check permissions for this memory access
 	 */
+	mask = VM_READ;
+	if (write)
+		mask = VM_WRITE;
+	if (exec)
+		mask = VM_EXEC;
+
+	if (!(vma->vm_flags & mask)) {
+		si_code = SEGV_ACCERR;
+		goto bad_area;
+	}
+
 	fault = handle_mm_fault(vma, address, flags);
 
-	/* If Pagefault was interrupted by SIGKILL, exit page fault "early" */
-	if (unlikely(fatal_signal_pending(current))) {
-		if ((fault & VM_FAULT_ERROR) && !(fault & VM_FAULT_RETRY))
-			up_read(&mm->mmap_sem);
-		if (user_mode(regs))
-			return;
-	}
-
-	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
-
-	if (likely(!(fault & VM_FAULT_ERROR))) {
-		if (flags & FAULT_FLAG_ALLOW_RETRY) {
-			/* To avoid updating stats twice for retry case */
-			if (fault & VM_FAULT_MAJOR) {
-				tsk->maj_flt++;
-				perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
-					      regs, address);
-			} else {
-				tsk->min_flt++;
-				perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
-					      regs, address);
-			}
-
-			if (fault & VM_FAULT_RETRY) {
-				flags &= ~FAULT_FLAG_ALLOW_RETRY;
-				flags |= FAULT_FLAG_TRIED;
-				goto retry;
-			}
-		}
-
-		/* Fault Handled Gracefully */
-		up_read(&mm->mmap_sem);
-		return;
-	}
-
-	if (fault & VM_FAULT_OOM)
-		goto out_of_memory;
-	else if (fault & VM_FAULT_SIGSEGV)
-		goto bad_area;
-	else if (fault & VM_FAULT_SIGBUS)
-		goto do_sigbus;
-
-	/* no man's land */
-	BUG();
-
 	/*
-	 * Something tried to access memory that isn't in our memory map..
-	 * Fix it, but check if it's kernel or user first..
+	 * Fault retry nuances
 	 */
+	if (unlikely(fault & VM_FAULT_RETRY)) {
+
+		/*
+		 * If fault needs to be retried, handle any pending signals
+		 * first (by returning to user mode).
+		 * mmap_sem already relinquished by core mm for RETRY case
+		 */
+		if (fatal_signal_pending(current)) {
+			if (!user_mode(regs))
+				goto no_context;
+			return;
+		}
+		/*
+		 * retry state machine
+		 */
+		if (flags & FAULT_FLAG_ALLOW_RETRY) {
+			flags &= ~FAULT_FLAG_ALLOW_RETRY;
+			flags |= FAULT_FLAG_TRIED;
+			goto retry;
+		}
+	}
+
 bad_area:
 	up_read(&mm->mmap_sem);
 
-bad_area_nosemaphore:
-	/* User mode accesses just cause a SIGSEGV */
-	if (user_mode(regs)) {
-		tsk->thread.fault_address = address;
-		info.si_signo = SIGSEGV;
-		info.si_errno = 0;
-		/* info.si_code has been set above */
-		info.si_addr = (void __user *)address;
-		force_sig_info(SIGSEGV, &info, tsk);
-		return;
-	}
-
-no_context:
-	/* Are we prepared to handle this kernel fault?
-	 *
-	 * (The kernel has valid exception-points in the source
-	 *  when it accesses user-memory. When it fails in one
-	 *  of those points, we find it in a table and do a jump
-	 *  to some fixup code that loads an appropriate error
-	 *  code)
+	/*
+	 * Major/minor page fault accounting
+	 * (in case of retry we only land here once)
 	 */
-	if (fixup_exception(regs))
-		return;
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 
-	die("Oops", regs, address);
+	if (likely(!(fault & VM_FAULT_ERROR))) {
+		if (fault & VM_FAULT_MAJOR) {
+			tsk->maj_flt++;
+			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
+				      regs, address);
+		} else {
+			tsk->min_flt++;
+			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
+				      regs, address);
+		}
 
-out_of_memory:
-	up_read(&mm->mmap_sem);
-
-	if (user_mode(regs)) {
-		pagefault_out_of_memory();
+		/* Normal return path: fault Handled Gracefully */
 		return;
 	}
 
-	goto no_context;
-
-do_sigbus:
-	up_read(&mm->mmap_sem);
-
 	if (!user_mode(regs))
 		goto no_context;
 
+	if (fault & VM_FAULT_OOM) {
+		pagefault_out_of_memory();
+		return;
+	}
+
+	if (fault & VM_FAULT_SIGBUS) {
+		sig = SIGBUS;
+		si_code = BUS_ADRERR;
+	}
+	else {
+		sig = SIGSEGV;
+	}
+
 	tsk->thread.fault_address = address;
-	info.si_signo = SIGBUS;
-	info.si_errno = 0;
-	info.si_code = BUS_ADRERR;
-	info.si_addr = (void __user *)address;
-	force_sig_info(SIGBUS, &info, tsk);
+	force_sig_fault(sig, si_code, (void __user *)address);
+	return;
+
+no_context:
+	if (fixup_exception(regs))
+		return;
+
+	die("Oops", regs, address);
 }
diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c
index 77ff64a..a4856bf 100644
--- a/arch/arc/mm/highmem.c
+++ b/arch/arc/mm/highmem.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2015 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
-#include <linux/bootmem.h>
+#include <linux/memblock.h>
 #include <linux/export.h>
 #include <linux/highmem.h>
 #include <asm/processor.h>
@@ -123,7 +119,11 @@
 	pud_k = pud_offset(pgd_k, kvaddr);
 	pmd_k = pmd_offset(pud_k, kvaddr);
 
-	pte_k = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
+	pte_k = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
+	if (!pte_k)
+		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
+		      __func__, PAGE_SIZE, PAGE_SIZE);
+
 	pmd_populate_kernel(&init_mm, pmd_k, pte_k);
 	return pte_k;
 }
diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index ba14506..0920c96 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c
@@ -1,14 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/kernel.h>
 #include <linux/mm.h>
-#include <linux/bootmem.h>
 #include <linux/memblock.h>
 #ifdef CONFIG_BLK_DEV_INITRD
 #include <linux/initrd.h>
@@ -79,24 +75,6 @@
 		base, TO_MB(size), !in_use ? "Not used":"");
 }
 
-#ifdef CONFIG_BLK_DEV_INITRD
-static int __init early_initrd(char *p)
-{
-	unsigned long start, size;
-	char *endp;
-
-	start = memparse(p, &endp);
-	if (*endp == ',') {
-		size = memparse(endp + 1, NULL);
-
-		initrd_start = (unsigned long)__va(start);
-		initrd_end = (unsigned long)__va(start + size);
-	}
-	return 0;
-}
-early_param("initrd", early_initrd);
-#endif
-
 /*
  * First memory setup routine called from setup_arch()
  * 1. setup swapper's mm @init_mm
@@ -138,11 +116,15 @@
 	 */
 
 	memblock_add_node(low_mem_start, low_mem_sz, 0);
-	memblock_reserve(low_mem_start, __pa(_end) - low_mem_start);
+	memblock_reserve(CONFIG_LINUX_LINK_BASE,
+			 __pa(_end) - CONFIG_LINUX_LINK_BASE);
 
 #ifdef CONFIG_BLK_DEV_INITRD
-	if (initrd_start)
-		memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
+	if (phys_initrd_size) {
+		memblock_reserve(phys_initrd_start, phys_initrd_size);
+		initrd_start = (unsigned long)__va(phys_initrd_start);
+		initrd_end = initrd_start + phys_initrd_size;
+	}
 #endif
 
 	early_init_fdt_reserve_self();
@@ -218,21 +200,6 @@
 		free_highmem_page(pfn_to_page(tmp));
 #endif
 
-	free_all_bootmem();
+	memblock_free_all();
 	mem_init_print_info(NULL);
 }
-
-/*
- * free_initmem: Free all the __init memory.
- */
-void __ref free_initmem(void)
-{
-	free_initmem_default(-1);
-}
-
-#ifdef CONFIG_BLK_DEV_INITRD
-void __init free_initrd_mem(unsigned long start, unsigned long end)
-{
-	free_reserved_area((void *)start, (void *)end, -1, "initrd");
-}
-#endif
diff --git a/arch/arc/mm/ioremap.c b/arch/arc/mm/ioremap.c
index 9881bd7..fac4adc 100644
--- a/arch/arc/mm/ioremap.c
+++ b/arch/arc/mm/ioremap.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/vmalloc.h>
diff --git a/arch/arc/mm/mmap.c b/arch/arc/mm/mmap.c
index 2e13683..722d26b 100644
--- a/arch/arc/mm/mmap.c
+++ b/arch/arc/mm/mmap.c
@@ -1,13 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * ARC700 mmap
  *
  * (started from arm version - for VIPT alias handling)
  *
  * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/fs.h>
diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
index 4097764..10025e1 100644
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * TLB Management (flush/create/diagnostics) for ARC700
  *
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  * vineetg: Aug 2011
  *  -Reintroduce duplicate PD fixup - some customer chips still have the issue
  *
@@ -911,9 +908,11 @@
 			  struct pt_regs *regs)
 {
 	struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
-	unsigned int pd0[mmu->ways];
 	unsigned long flags;
-	int set;
+	int set, n_ways = mmu->ways;
+
+	n_ways = min(n_ways, 4);
+	BUG_ON(mmu->ways > 4);
 
 	local_irq_save(flags);
 
@@ -921,9 +920,10 @@
 	for (set = 0; set < mmu->sets; set++) {
 
 		int is_valid, way;
+		unsigned int pd0[4];
 
 		/* read out all the ways of current set */
-		for (way = 0, is_valid = 0; way < mmu->ways; way++) {
+		for (way = 0, is_valid = 0; way < n_ways; way++) {
 			write_aux_reg(ARC_REG_TLBINDEX,
 					  SET_WAY_TO_IDX(mmu, set, way));
 			write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead);
@@ -937,14 +937,14 @@
 			continue;
 
 		/* Scan the set for duplicate ways: needs a nested loop */
-		for (way = 0; way < mmu->ways - 1; way++) {
+		for (way = 0; way < n_ways - 1; way++) {
 
 			int n;
 
 			if (!pd0[way])
 				continue;
 
-			for (n = way + 1; n < mmu->ways; n++) {
+			for (n = way + 1; n < n_ways; n++) {
 				if (pd0[way] != pd0[n])
 					continue;
 
diff --git a/arch/arc/mm/tlbex.S b/arch/arc/mm/tlbex.S
index 0e1e47a..c55d95d 100644
--- a/arch/arc/mm/tlbex.S
+++ b/arch/arc/mm/tlbex.S
@@ -1,12 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * TLB Exception Handling for ARC
  *
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  * Vineetg: April 2011 :
  *  -MMU v1: moved out legacy code into a seperate file
  *  -MMU v3: PD{0,1} bits layout changed: They don't overlap anymore,
@@ -396,6 +393,17 @@
 ;-------- Common routine to call Linux Page Fault Handler -----------
 do_slow_path_pf:
 
+#ifdef CONFIG_ISA_ARCV2
+	; Set Z flag if exception in U mode. Hardware micro-ops do this on any
+	; taken interrupt/exception, and thus is already the case at the entry
+	; above, but ensuing code would have already clobbered.
+	; EXCEPTION_PROLOGUE called in slow path, relies on correct Z flag set
+
+	lr	r2, [erstatus]
+	and	r2, r2, STATUS_U_MASK
+	bxor.f	0, r2, STATUS_U_BIT
+#endif
+
 	; Restore the 4-scratch regs saved by fast path miss handler
 	TLBMISS_RESTORE_REGS