Merge tag 'arc-4.13-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC fixes from Vineet Gupta:

 - PAE40 related updates

 - SLC errata for region ops

 - intc line masking by default

* tag 'arc-4.13-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  arc: Mask individual IRQ lines during core INTC init
  ARCv2: PAE40: set MSB even if !CONFIG_ARC_HAS_PAE40 but PAE exists in SoC
  ARCv2: PAE40: Explicitly set MSB counterpart of SLC region ops addresses
  ARC: dma: implement dma_unmap_page and sg variant
  ARCv2: SLC: Make sure busy bit is set properly for region ops
  ARC: [plat-sim] Include this platform unconditionally
  ARC: [plat-axs10x]: prepare dts files for enabling PAE40 on axs103
  ARC: defconfig: Cleanup from old Kconfig options

arch/arc/Kconfig

@@ -96,7 +96,6 @@ menu "ARC Architecture Configuration"
 
 menu "ARC Platform/SoC/Board"
 
-source "arch/arc/plat-sim/Kconfig"
 source "arch/arc/plat-tb10x/Kconfig"
 source "arch/arc/plat-axs10x/Kconfig"
 #New platform adds here

arch/arc/Makefile

@@ -107,7 +107,7 @@ core-y		+= arch/arc/
 # w/o this dtb won't embed into kernel binary
 core-y		+= arch/arc/boot/dts/
 
-core-$(CONFIG_ARC_PLAT_SIM)	+= arch/arc/plat-sim/
+core-y				+= arch/arc/plat-sim/
 core-$(CONFIG_ARC_PLAT_TB10X)	+= arch/arc/plat-tb10x/
 core-$(CONFIG_ARC_PLAT_AXS10X)	+= arch/arc/plat-axs10x/
 core-$(CONFIG_ARC_PLAT_EZNPS)	+= arch/arc/plat-eznps/

arch/arc/boot/dts/axc001.dtsi

@@ -15,15 +15,15 @@
 
 / {
 	compatible = "snps,arc";
-	#address-cells = <1>;
-	#size-cells = <1>;
+	#address-cells = <2>;
+	#size-cells = <2>;
 
 	cpu_card {
 		compatible = "simple-bus";
 		#address-cells = <1>;
 		#size-cells = <1>;
 
-		ranges = <0x00000000 0xf0000000 0x10000000>;
+		ranges = <0x00000000 0x0 0xf0000000 0x10000000>;
 
 		core_clk: core_clk {
 			#clock-cells = <0>;
@@ -91,23 +91,21 @@ arcpct0: pct {
 	mb_intc: dw-apb-ictl@0xe0012000 {
 		#interrupt-cells = <1>;
 		compatible = "snps,dw-apb-ictl";
-		reg = < 0xe0012000 0x200 >;
+		reg = < 0x0 0xe0012000 0x0 0x200 >;
 		interrupt-controller;
 		interrupt-parent = <&core_intc>;
 		interrupts = < 7 >;
 	};
 
 	memory {
-		#address-cells = <1>;
-		#size-cells = <1>;
-		ranges = <0x00000000 0x80000000 0x20000000>;
 		device_type = "memory";
-		reg = <0x80000000 0x1b000000>;	/* (512 - 32) MiB */
+		/* CONFIG_KERNEL_RAM_BASE_ADDRESS needs to match low mem start */
+		reg = <0x0 0x80000000 0x0 0x1b000000>;	/* (512 - 32) MiB */
 	};
 
 	reserved-memory {
-		#address-cells = <1>;
-		#size-cells = <1>;
+		#address-cells = <2>;
+		#size-cells = <2>;
 		ranges;
 		/*
 		 * We just move frame buffer area to the very end of
@@ -118,7 +116,7 @@ reserved-memory {
 		 */
 		frame_buffer: frame_buffer@9e000000 {
 			compatible = "shared-dma-pool";
-			reg = <0x9e000000 0x2000000>;
+			reg = <0x0 0x9e000000 0x0 0x2000000>;
 			no-map;
 		};
 	};

arch/arc/boot/dts/axc003.dtsi

@@ -14,15 +14,15 @@
 
 / {
 	compatible = "snps,arc";
-	#address-cells = <1>;
-	#size-cells = <1>;
+	#address-cells = <2>;
+	#size-cells = <2>;
 
 	cpu_card {
 		compatible = "simple-bus";
 		#address-cells = <1>;
 		#size-cells = <1>;
 
-		ranges = <0x00000000 0xf0000000 0x10000000>;
+		ranges = <0x00000000 0x0 0xf0000000 0x10000000>;
 
 		core_clk: core_clk {
 			#clock-cells = <0>;
@@ -94,30 +94,29 @@ arcpct0: pct {
 	mb_intc: dw-apb-ictl@0xe0012000 {
 		#interrupt-cells = <1>;
 		compatible = "snps,dw-apb-ictl";
-		reg = < 0xe0012000 0x200 >;
+		reg = < 0x0 0xe0012000 0x0 0x200 >;
 		interrupt-controller;
 		interrupt-parent = <&core_intc>;
 		interrupts = < 24 >;
 	};
 
 	memory {
-		#address-cells = <1>;
-		#size-cells = <1>;
-		ranges = <0x00000000 0x80000000 0x40000000>;
 		device_type = "memory";
-		reg = <0x80000000 0x20000000>;	/* 512MiB */
+		/* CONFIG_KERNEL_RAM_BASE_ADDRESS needs to match low mem start */
+		reg = <0x0 0x80000000 0x0 0x20000000	/* 512 MiB low mem */
+		       0x1 0xc0000000 0x0 0x40000000>;	/* 1 GiB highmem */
 	};
 
 	reserved-memory {
-		#address-cells = <1>;
-		#size-cells = <1>;
+		#address-cells = <2>;
+		#size-cells = <2>;
 		ranges;
 		/*
 		 * Move frame buffer out of IOC aperture (0x8z-0xAz).
 		 */
 		frame_buffer: frame_buffer@be000000 {
 			compatible = "shared-dma-pool";
-			reg = <0xbe000000 0x2000000>;
+			reg = <0x0 0xbe000000 0x0 0x2000000>;
 			no-map;
 		};
 	};

arch/arc/boot/dts/axc003_idu.dtsi

@@ -14,15 +14,15 @@
 
 / {
 	compatible = "snps,arc";
-	#address-cells = <1>;
-	#size-cells = <1>;
+	#address-cells = <2>;
+	#size-cells = <2>;
 
 	cpu_card {
 		compatible = "simple-bus";
 		#address-cells = <1>;
 		#size-cells = <1>;
 
-		ranges = <0x00000000 0xf0000000 0x10000000>;
+		ranges = <0x00000000 0x0 0xf0000000 0x10000000>;
 
 		core_clk: core_clk {
 			#clock-cells = <0>;
@@ -100,30 +100,29 @@ arcpct0: pct {
 	mb_intc: dw-apb-ictl@0xe0012000 {
 		#interrupt-cells = <1>;
 		compatible = "snps,dw-apb-ictl";
-		reg = < 0xe0012000 0x200 >;
+		reg = < 0x0 0xe0012000 0x0 0x200 >;
 		interrupt-controller;
 		interrupt-parent = <&idu_intc>;
 		interrupts = <0>;
 	};
 
 	memory {
-		#address-cells = <1>;
-		#size-cells = <1>;
-		ranges = <0x00000000 0x80000000 0x40000000>;
 		device_type = "memory";
-		reg = <0x80000000 0x20000000>;	/* 512MiB */
+		/* CONFIG_KERNEL_RAM_BASE_ADDRESS needs to match low mem start */
+		reg = <0x0 0x80000000 0x0 0x20000000	/* 512 MiB low mem */
+		       0x1 0xc0000000 0x0 0x40000000>;	/* 1 GiB highmem */
 	};
 
 	reserved-memory {
-		#address-cells = <1>;
-		#size-cells = <1>;
+		#address-cells = <2>;
+		#size-cells = <2>;
 		ranges;
 		/*
 		 * Move frame buffer out of IOC aperture (0x8z-0xAz).
 		 */
 		frame_buffer: frame_buffer@be000000 {
 			compatible = "shared-dma-pool";
-			reg = <0xbe000000 0x2000000>;
+			reg = <0x0 0xbe000000 0x0 0x2000000>;
 			no-map;
 		};
 	};

arch/arc/boot/dts/axs10x_mb.dtsi

@@ -13,7 +13,7 @@ axs10x_mb {
 		compatible = "simple-bus";
 		#address-cells = <1>;
 		#size-cells = <1>;
-		ranges = <0x00000000 0xe0000000 0x10000000>;
+		ranges = <0x00000000 0x0 0xe0000000 0x10000000>;
 		interrupt-parent = <&mb_intc>;
 
 		i2sclk: i2sclk@100a0 {

arch/arc/configs/haps_hs_defconfig

@@ -21,7 +21,6 @@ CONFIG_MODULES=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
-CONFIG_ARC_PLAT_SIM=y
 CONFIG_ISA_ARCV2=y
 CONFIG_ARC_BUILTIN_DTB_NAME="haps_hs"
 CONFIG_PREEMPT=y

arch/arc/configs/haps_hs_smp_defconfig

@@ -23,7 +23,6 @@ CONFIG_MODULES=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
-CONFIG_ARC_PLAT_SIM=y
 CONFIG_ISA_ARCV2=y
 CONFIG_SMP=y
 CONFIG_ARC_BUILTIN_DTB_NAME="haps_hs_idu"

arch/arc/configs/nps_defconfig

@@ -39,7 +39,6 @@ CONFIG_IP_PNP=y
 # CONFIG_INET_XFRM_MODE_TRANSPORT is not set
 # CONFIG_INET_XFRM_MODE_TUNNEL is not set
 # CONFIG_INET_XFRM_MODE_BEET is not set
-# CONFIG_INET_LRO is not set
 # CONFIG_INET_DIAG is not set
 # CONFIG_IPV6 is not set
 # CONFIG_WIRELESS is not set

arch/arc/configs/nsim_700_defconfig

@@ -23,7 +23,6 @@ CONFIG_MODULES=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
-CONFIG_ARC_PLAT_SIM=y
 CONFIG_ARC_BUILTIN_DTB_NAME="nsim_700"
 CONFIG_PREEMPT=y
 # CONFIG_COMPACTION is not set

arch/arc/configs/nsim_hs_defconfig

@@ -26,7 +26,6 @@ CONFIG_MODULE_FORCE_UNLOAD=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
-CONFIG_ARC_PLAT_SIM=y
 CONFIG_ISA_ARCV2=y
 CONFIG_ARC_BUILTIN_DTB_NAME="nsim_hs"
 CONFIG_PREEMPT=y

arch/arc/configs/nsim_hs_smp_defconfig

@@ -24,7 +24,6 @@ CONFIG_MODULE_FORCE_UNLOAD=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
-CONFIG_ARC_PLAT_SIM=y
 CONFIG_ISA_ARCV2=y
 CONFIG_SMP=y
 CONFIG_ARC_BUILTIN_DTB_NAME="nsim_hs_idu"

arch/arc/configs/nsimosci_defconfig

@@ -23,7 +23,6 @@ CONFIG_MODULES=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
-CONFIG_ARC_PLAT_SIM=y
 CONFIG_ARC_BUILTIN_DTB_NAME="nsimosci"
 # CONFIG_COMPACTION is not set
 CONFIG_NET=y

arch/arc/configs/nsimosci_hs_defconfig

@@ -23,7 +23,6 @@ CONFIG_MODULES=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
-CONFIG_ARC_PLAT_SIM=y
 CONFIG_ISA_ARCV2=y
 CONFIG_ARC_BUILTIN_DTB_NAME="nsimosci_hs"
 # CONFIG_COMPACTION is not set

arch/arc/configs/nsimosci_hs_smp_defconfig

@@ -18,7 +18,6 @@ CONFIG_MODULES=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
-CONFIG_ARC_PLAT_SIM=y
 CONFIG_ISA_ARCV2=y
 CONFIG_SMP=y
 # CONFIG_ARC_TIMERS_64BIT is not set

arch/arc/configs/tb10x_defconfig

@@ -38,7 +38,6 @@ CONFIG_IP_MULTICAST=y
 # CONFIG_INET_XFRM_MODE_TRANSPORT is not set
 # CONFIG_INET_XFRM_MODE_TUNNEL is not set
 # CONFIG_INET_XFRM_MODE_BEET is not set
-# CONFIG_INET_LRO is not set
 # CONFIG_INET_DIAG is not set
 # CONFIG_IPV6 is not set
 # CONFIG_WIRELESS is not set

arch/arc/include/asm/cache.h

@@ -96,7 +96,9 @@ extern unsigned long perip_base, perip_end;
 #define ARC_REG_SLC_FLUSH	0x904
 #define ARC_REG_SLC_INVALIDATE	0x905
 #define ARC_REG_SLC_RGN_START	0x914
+#define ARC_REG_SLC_RGN_START1	0x915
 #define ARC_REG_SLC_RGN_END	0x916
+#define ARC_REG_SLC_RGN_END1	0x917
 
 /* Bit val in SLC_CONTROL */
 #define SLC_CTRL_DIS		0x001

arch/arc/include/asm/mmu.h

@@ -94,6 +94,8 @@ static inline int is_pae40_enabled(void)
 	return IS_ENABLED(CONFIG_ARC_HAS_PAE40);
 }
 
+extern int pae40_exist_but_not_enab(void);
+
 #endif	/* !__ASSEMBLY__ */
 
 #endif

arch/arc/kernel/intc-arcv2.c

@@ -75,10 +75,13 @@ void arc_init_IRQ(void)
 	 * Set a default priority for all available interrupts to prevent
 	 * switching of register banks if Fast IRQ and multiple register banks
 	 * are supported by CPU.
+	 * Also disable all IRQ lines so faulty external hardware won't
+	 * trigger interrupt that kernel is not ready to handle.
 	 */
 	for (i = NR_EXCEPTIONS; i < irq_bcr.irqs + NR_EXCEPTIONS; i++) {
 		write_aux_reg(AUX_IRQ_SELECT, i);
 		write_aux_reg(AUX_IRQ_PRIORITY, ARCV2_IRQ_DEF_PRIO);
+		write_aux_reg(AUX_IRQ_ENABLE, 0);
 	}
 
 	/* setup status32, don't enable intr yet as kernel doesn't want */

arch/arc/kernel/intc-compact.c

@@ -27,7 +27,7 @@
  */
 void arc_init_IRQ(void)
 {
-	int level_mask = 0;
+	int level_mask = 0, i;
 
        /* Is timer high priority Interrupt (Level2 in ARCompact jargon) */
 	level_mask |= IS_ENABLED(CONFIG_ARC_COMPACT_IRQ_LEVELS) << TIMER0_IRQ;
@@ -40,6 +40,18 @@ void arc_init_IRQ(void)
 
 	if (level_mask)
 		pr_info("Level-2 interrupts bitset %x\n", level_mask);
+
+	/*
+	 * Disable all IRQ lines so faulty external hardware won't
+	 * trigger interrupt that kernel is not ready to handle.
+	 */
+	for (i = TIMER0_IRQ; i < NR_CPU_IRQS; i++) {
+		unsigned int ienb;
+
+		ienb = read_aux_reg(AUX_IENABLE);
+		ienb &= ~(1 << i);
+		write_aux_reg(AUX_IENABLE, ienb);
+	}
 }
 
 /*

arch/arc/mm/cache.c

@@ -665,6 +665,7 @@ noinline void slc_op(phys_addr_t paddr, unsigned long sz, const int op)
 	static DEFINE_SPINLOCK(lock);
 	unsigned long flags;
 	unsigned int ctrl;
+	phys_addr_t end;
 
 	spin_lock_irqsave(&lock, flags);
 
@@ -694,8 +695,19 @@ noinline void slc_op(phys_addr_t paddr, unsigned long sz, const int op)
 	 * END needs to be setup before START (latter triggers the operation)
 	 * END can't be same as START, so add (l2_line_sz - 1) to sz
 	 */
-	write_aux_reg(ARC_REG_SLC_RGN_END, (paddr + sz + l2_line_sz - 1));
-	write_aux_reg(ARC_REG_SLC_RGN_START, paddr);
+	end = paddr + sz + l2_line_sz - 1;
+	if (is_pae40_enabled())
+		write_aux_reg(ARC_REG_SLC_RGN_END1, upper_32_bits(end));
+
+	write_aux_reg(ARC_REG_SLC_RGN_END, lower_32_bits(end));
+
+	if (is_pae40_enabled())
+		write_aux_reg(ARC_REG_SLC_RGN_START1, upper_32_bits(paddr));
+
+	write_aux_reg(ARC_REG_SLC_RGN_START, lower_32_bits(paddr));
+
+	/* Make sure "busy" bit reports correct stataus, see STAR 9001165532 */
+	read_aux_reg(ARC_REG_SLC_CTRL);
 
 	while (read_aux_reg(ARC_REG_SLC_CTRL) & SLC_CTRL_BUSY);
 
@@ -1111,6 +1123,13 @@ noinline void __init arc_ioc_setup(void)
 	__dc_enable();
 }
 
+/*
+ * Cache related boot time checks/setups only needed on master CPU:
+ *  - Geometry checks (kernel build and hardware agree: e.g. L1_CACHE_BYTES)
+ *    Assume SMP only, so all cores will have same cache config. A check on
+ *    one core suffices for all
+ *  - IOC setup / dma callbacks only need to be done once
+ */
 void __init arc_cache_init_master(void)
 {
 	unsigned int __maybe_unused cpu = smp_processor_id();
@@ -1190,12 +1209,27 @@ void __ref arc_cache_init(void)
 
 	printk(arc_cache_mumbojumbo(0, str, sizeof(str)));
 
-	/*
-	 * Only master CPU needs to execute rest of function:
-	 *  - Assume SMP so all cores will have same cache config so
-	 *    any geomtry checks will be same for all
-	 *  - IOC setup / dma callbacks only need to be setup once
-	 */
 	if (!cpu)
 		arc_cache_init_master();
+
+	/*
+	 * In PAE regime, TLB and cache maintenance ops take wider addresses
+	 * And even if PAE is not enabled in kernel, the upper 32-bits still need
+	 * to be zeroed to keep the ops sane.
+	 * As an optimization for more common !PAE enabled case, zero them out
+	 * once at init, rather than checking/setting to 0 for every runtime op
+	 */
+	if (is_isa_arcv2() && pae40_exist_but_not_enab()) {
+
+		if (IS_ENABLED(CONFIG_ARC_HAS_ICACHE))
+			write_aux_reg(ARC_REG_IC_PTAG_HI, 0);
+
+		if (IS_ENABLED(CONFIG_ARC_HAS_DCACHE))
+			write_aux_reg(ARC_REG_DC_PTAG_HI, 0);
+
+		if (l2_line_sz) {
+			write_aux_reg(ARC_REG_SLC_RGN_END1, 0);
+			write_aux_reg(ARC_REG_SLC_RGN_START1, 0);
+		}
+	}
 }

arch/arc/mm/dma.c

@@ -153,6 +153,19 @@ static void _dma_cache_sync(phys_addr_t paddr, size_t size,
 	}
 }
 
+/*
+ * arc_dma_map_page - map a portion of a page for streaming DMA
+ *
+ * Ensure that any data held in the cache is appropriately discarded
+ * or written back.
+ *
+ * The device owns this memory once this call has completed.  The CPU
+ * can regain ownership by calling dma_unmap_page().
+ *
+ * Note: while it takes struct page as arg, caller can "abuse" it to pass
+ * a region larger than PAGE_SIZE, provided it is physically contiguous
+ * and this still works correctly
+ */
 static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
 		unsigned long offset, size_t size, enum dma_data_direction dir,
 		unsigned long attrs)
@@ -165,6 +178,24 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
 	return plat_phys_to_dma(dev, paddr);
 }
 
+/*
+ * arc_dma_unmap_page - unmap a buffer previously mapped through dma_map_page()
+ *
+ * After this call, reads by the CPU to the buffer are guaranteed to see
+ * whatever the device wrote there.
+ *
+ * Note: historically this routine was not implemented for ARC
+ */
+static void arc_dma_unmap_page(struct device *dev, dma_addr_t handle,
+			       size_t size, enum dma_data_direction dir,
+			       unsigned long attrs)
+{
+	phys_addr_t paddr = plat_dma_to_phys(dev, handle);
+
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		_dma_cache_sync(paddr, size, dir);
+}
+
 static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
 	   int nents, enum dma_data_direction dir, unsigned long attrs)
 {
@@ -178,6 +209,18 @@ static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
 	return nents;
 }
 
+static void arc_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
+			     int nents, enum dma_data_direction dir,
+			     unsigned long attrs)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nents, i)
+		arc_dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir,
+				   attrs);
+}
+
 static void arc_dma_sync_single_for_cpu(struct device *dev,
 		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
 {
@@ -223,7 +266,9 @@ const struct dma_map_ops arc_dma_ops = {
 	.free			= arc_dma_free,
 	.mmap			= arc_dma_mmap,
 	.map_page		= arc_dma_map_page,
+	.unmap_page		= arc_dma_unmap_page,
 	.map_sg			= arc_dma_map_sg,
+	.unmap_sg		= arc_dma_unmap_sg,
 	.sync_single_for_device	= arc_dma_sync_single_for_device,
 	.sync_single_for_cpu	= arc_dma_sync_single_for_cpu,
 	.sync_sg_for_cpu	= arc_dma_sync_sg_for_cpu,

arch/arc/mm/tlb.c

@@ -104,6 +104,8 @@
 /* A copy of the ASID from the PID reg is kept in asid_cache */
 DEFINE_PER_CPU(unsigned int, asid_cache) = MM_CTXT_FIRST_CYCLE;
 
+static int __read_mostly pae_exists;
+
 /*
  * Utility Routine to erase a J-TLB entry
  * Caller needs to setup Index Reg (manually or via getIndex)
@@ -784,7 +786,7 @@ void read_decode_mmu_bcr(void)
 		mmu->u_dtlb = mmu4->u_dtlb * 4;
 		mmu->u_itlb = mmu4->u_itlb * 4;
 		mmu->sasid = mmu4->sasid;
-		mmu->pae = mmu4->pae;
+		pae_exists = mmu->pae = mmu4->pae;
 	}
 }
 
@@ -809,6 +811,11 @@ char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len)
 	return buf;
 }
 
+int pae40_exist_but_not_enab(void)
+{
+	return pae_exists && !is_pae40_enabled();
+}
+
 void arc_mmu_init(void)
 {
 	char str[256];
@@ -859,6 +866,9 @@ void arc_mmu_init(void)
 	/* swapper_pg_dir is the pgd for the kernel, used by vmalloc */
 	write_aux_reg(ARC_REG_SCRATCH_DATA0, swapper_pg_dir);
 #endif
+
+	if (pae40_exist_but_not_enab())
+		write_aux_reg(ARC_REG_TLBPD1HI, 0);
 }
 
 /*

arch/arc/plat-sim/Kconfig

-#
-# Copyright (C) 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.
-#
-
-menuconfig ARC_PLAT_SIM
-	bool "ARC nSIM based simulation virtual platforms"
-	help
-	  Support for nSIM based ARC simulation platforms
-	  This includes the standalone nSIM (uart only) vs. System C OSCI VP

arch/arc/plat-sim/platform.c

@@ -20,11 +20,14 @@
  */
 
 static const char *simulation_compat[] __initconst = {
+#ifdef CONFIG_ISA_ARCOMPACT
 	"snps,nsim",
-	"snps,nsim_hs",
 	"snps,nsimosci",
+#else
+	"snps,nsim_hs",
 	"snps,nsimosci_hs",
 	"snps,zebu_hs",
+#endif
 	NULL,
 };