17 files changed, 167 insertions, 281 deletions

diff --git a/arch/arc/boot/dts/angel4.dts b/arch/arc/boot/dts/angel4.dts
index 5bb2fdaca02f..6b57475967a6 100644
--- a/arch/arc/boot/dts/angel4.dts
+++ b/arch/arc/boot/dts/angel4.dts
@@ -17,7 +17,7 @@
         interrupt-parent = <&intc>;
 
         chosen {
-                bootargs = "console=ttyARC0,115200n8 earlyprintk=ttyARC0";
+                bootargs = "earlycon=arc_uart,mmio32,0xc0fc1000,115200n8 console=ttyARC0,115200n8";
         };
 
         aliases {
diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
index 355cb470c2a4..372466b371bf 100644
--- a/arch/arc/include/asm/arcregs.h
+++ b/arch/arc/include/asm/arcregs.h
@@ -296,7 +296,7 @@ struct cpuinfo_arc_mmu {
 };
 
 struct cpuinfo_arc_cache {
-        unsigned int sz, line_len, assoc, ver;
+        unsigned int sz_k:8, line_len:8, assoc:4, ver:4, alias:1, vipt:1, pad:6;
 };
 
 struct cpuinfo_arc_ccm {
diff --git a/arch/arc/include/asm/irq.h b/arch/arc/include/asm/irq.h
index fb4efb648971..f38652fb2ed7 100644
--- a/arch/arc/include/asm/irq.h
+++ b/arch/arc/include/asm/irq.h
@@ -16,9 +16,13 @@
 #define TIMER0_IRQ      3
 #define TIMER1_IRQ      4
 
+#include <linux/interrupt.h>
 #include <asm-generic/irq.h>
 
 extern void arc_init_IRQ(void);
 void arc_local_timer_setup(void);
+void arc_request_percpu_irq(int irq, int cpu,
+                            irqreturn_t (*isr)(int irq, void *dev),
+                            const char *irq_nm, void *percpu_dev);
 
 #endif
diff --git a/arch/arc/include/asm/irqflags.h b/arch/arc/include/asm/irqflags.h
index cb7efc29f16f..587df8236e8b 100644
--- a/arch/arc/include/asm/irqflags.h
+++ b/arch/arc/include/asm/irqflags.h
@@ -131,24 +131,6 @@ static inline int arch_irqs_disabled(void)
         return arch_irqs_disabled_flags(arch_local_save_flags());
 }
 
-static inline void arch_mask_irq(unsigned int irq)
-{
-        unsigned int ienb;
-
-        ienb = read_aux_reg(AUX_IENABLE);
-        ienb &= ~(1 << irq);
-        write_aux_reg(AUX_IENABLE, ienb);
-}
-
-static inline void arch_unmask_irq(unsigned int irq)
-{
-        unsigned int ienb;
-
-        ienb = read_aux_reg(AUX_IENABLE);
-        ienb |= (1 << irq);
-        write_aux_reg(AUX_IENABLE, ienb);
-}
-
 #else
 
 #ifdef CONFIG_TRACE_IRQFLAGS
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index d99f9b37cd15..82588f3ba77f 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -62,6 +62,8 @@ unsigned long thread_saved_pc(struct task_struct *t);
 #define cpu_relax()     do { } while (0)
 #endif
 
+#define cpu_relax_lowlatency() cpu_relax()
+
 #define copy_segments(tsk, mm)      do { } while (0)
 #define release_segments(mm)        do { } while (0)
 
diff --git a/arch/arc/kernel/irq.c b/arch/arc/kernel/irq.c
index 7d653c0d0773..620ec2fe32a9 100644
--- a/arch/arc/kernel/irq.c
+++ b/arch/arc/kernel/irq.c
@@ -19,21 +19,16 @@
 
 /*
  * Early Hardware specific Interrupt setup
+ * -Platform independent, needed for each CPU (not foldable into init_IRQ)
  * -Called very early (start_kernel -> setup_arch -> setup_processor)
- * -Platform Independent (must for any ARC700)
- * -Needed for each CPU (hence not foldable into init_IRQ)
  *
  * what it does ?
- * -Disable all IRQs (on CPU side)
  * -Optionally, setup the High priority Interrupts as Level 2 IRQs
  */
 void arc_init_IRQ(void)
 {
         int level_mask = 0;
 
-        /* Disable all IRQs: enable them as devices request */
-        write_aux_reg(AUX_IENABLE, 0);
-
        /* setup any high priority Interrupts (Level2 in ARCompact jargon) */
         level_mask |= IS_ENABLED(CONFIG_ARC_IRQ3_LV2) << 3;
         level_mask |= IS_ENABLED(CONFIG_ARC_IRQ5_LV2) << 5;
@@ -60,20 +55,28 @@ void arc_init_IRQ(void)
  * below, per IRQ.
  */
 
-static void arc_mask_irq(struct irq_data *data)
+static void arc_irq_mask(struct irq_data *data)
 {
-        arch_mask_irq(data->irq);
+        unsigned int ienb;
+
+        ienb = read_aux_reg(AUX_IENABLE);
+        ienb &= ~(1 << data->irq);
+        write_aux_reg(AUX_IENABLE, ienb);
 }
 
-static void arc_unmask_irq(struct irq_data *data)
+static void arc_irq_unmask(struct irq_data *data)
 {
-        arch_unmask_irq(data->irq);
+        unsigned int ienb;
+
+        ienb = read_aux_reg(AUX_IENABLE);
+        ienb |= (1 << data->irq);
+        write_aux_reg(AUX_IENABLE, ienb);
 }
 
 static struct irq_chip onchip_intc = {
         .name           = "ARC In-core Intc",
-        .irq_mask       = arc_mask_irq,
-        .irq_unmask     = arc_unmask_irq,
+        .irq_mask       = arc_irq_mask,
+        .irq_unmask     = arc_irq_unmask,
 };
 
 static int arc_intc_domain_map(struct irq_domain *d, unsigned int irq,
@@ -150,6 +153,32 @@ void arch_do_IRQ(unsigned int irq, struct pt_regs *regs)
         set_irq_regs(old_regs);
 }
 
+void arc_request_percpu_irq(int irq, int cpu,
+                            irqreturn_t (*isr)(int irq, void *dev),
+                            const char *irq_nm,
+                            void *percpu_dev)
+{
+        /* Boot cpu calls request, all call enable */
+        if (!cpu) {
+                int rc;
+
+                /*
+                 * These 2 calls are essential to making percpu IRQ APIs work
+                 * Ideally these details could be hidden in irq chip map function
+                 * but the issue is IPIs IRQs being static (non-DT) and platform
+                 * specific, so we can't identify them there.
+                 */
+                irq_set_percpu_devid(irq);
+                irq_modify_status(irq, IRQ_NOAUTOEN, 0);  /* @irq, @clr, @set */
+
+                rc = request_percpu_irq(irq, isr, irq_nm, percpu_dev);
+                if (rc)
+                        panic("Percpu IRQ request failed for %d\n", irq);
+        }
+
+        enable_percpu_irq(irq, 0);
+}
+
 /*
  * arch_local_irq_enable - Enable interrupts.
  *
diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
index 63177e4cb66d..b9a5685a990e 100644
--- a/arch/arc/kernel/perf_event.c
+++ b/arch/arc/kernel/perf_event.c
@@ -99,10 +99,6 @@ static int arc_pmu_event_init(struct perf_event *event)
         struct hw_perf_event *hwc = &event->hw;
         int ret;
 
-        /* ARC 700 PMU does not support sampling events */
-        if (is_sampling_event(event))
-                return -ENOENT;
-
         switch (event->attr.type) {
         case PERF_TYPE_HARDWARE:
                 if (event->attr.config >= PERF_COUNT_HW_MAX)
@@ -298,6 +294,9 @@ static int arc_pmu_device_probe(struct platform_device *pdev)
                 .read           = arc_pmu_read,
         };
 
+        /* ARC 700 PMU does not support sampling events */
+        arc_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
+
         ret = perf_pmu_register(&arc_pmu->pmu, pdev->name, PERF_TYPE_RAW);
 
         return ret;
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index c802bb500602..dcd317c47d09 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -12,23 +12,15 @@
  *    -- Initial Write (Borrowed heavily from ARM)
  */
 
-#include <linux/module.h>
-#include <linux/init.h>
 #include <linux/spinlock.h>
 #include <linux/sched.h>
 #include <linux/interrupt.h>
 #include <linux/profile.h>
-#include <linux/errno.h>
-#include <linux/err.h>
 #include <linux/mm.h>
 #include <linux/cpu.h>
-#include <linux/smp.h>
 #include <linux/irq.h>
-#include <linux/delay.h>
 #include <linux/atomic.h>
-#include <linux/percpu.h>
 #include <linux/cpumask.h>
-#include <linux/spinlock_types.h>
 #include <linux/reboot.h>
 #include <asm/processor.h>
 #include <asm/setup.h>
@@ -136,7 +128,7 @@ void start_kernel_secondary(void)
         pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
 
         if (machine_desc->init_smp)
-                machine_desc->init_smp(smp_processor_id());
+                machine_desc->init_smp(cpu);
 
         arc_local_timer_setup();
 
@@ -338,18 +330,11 @@ irqreturn_t do_IPI(int irq, void *dev_id)
  */
 static DEFINE_PER_CPU(int, ipi_dev);
 
-static struct irqaction arc_ipi_irq = {
-        .name    = "IPI Interrupt",
-        .flags   = IRQF_PERCPU,
-        .handler = do_IPI,
-};
-
 int smp_ipi_irq_setup(int cpu, int irq)
 {
-        if (!cpu)
-                return setup_irq(irq, &arc_ipi_irq);
-        else
-                arch_unmask_irq(irq);
+        int *dev = per_cpu_ptr(&ipi_dev, cpu);
+
+        arc_request_percpu_irq(irq, cpu, do_IPI, "IPI Interrupt", dev);
 
         return 0;
 }
diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c
index 36c2aa99436f..dbe74f418019 100644
--- a/arch/arc/kernel/time.c
+++ b/arch/arc/kernel/time.c
@@ -144,12 +144,12 @@ static struct clocksource arc_counter = {
 /********** Clock Event Device *********/
 
 /*
- * Arm the timer to interrupt after @limit cycles
+ * Arm the timer to interrupt after @cycles
  * The distinction for oneshot/periodic is done in arc_event_timer_ack() below
  */
-static void arc_timer_event_setup(unsigned int limit)
+static void arc_timer_event_setup(unsigned int cycles)
 {
-        write_aux_reg(ARC_REG_TIMER0_LIMIT, limit);
+        write_aux_reg(ARC_REG_TIMER0_LIMIT, cycles);
         write_aux_reg(ARC_REG_TIMER0_CNT, 0);   /* start from 0 */
 
         write_aux_reg(ARC_REG_TIMER0_CTRL, TIMER_CTRL_IE | TIMER_CTRL_NH);
@@ -168,6 +168,10 @@ static void arc_clkevent_set_mode(enum clock_event_mode mode,
 {
         switch (mode) {
         case CLOCK_EVT_MODE_PERIODIC:
+                /*
+                 * At X Hz, 1 sec = 1000ms -> X cycles;
+                 *                    10ms -> X / 100 cycles
+                 */
                 arc_timer_event_setup(arc_get_core_freq() / HZ);
                 break;
         case CLOCK_EVT_MODE_ONESHOT:
@@ -210,12 +214,6 @@ static irqreturn_t timer_irq_handler(int irq, void *dev_id)
         return IRQ_HANDLED;
 }
 
-static struct irqaction arc_timer_irq = {
-        .name    = "Timer0 (clock-evt-dev)",
-        .flags   = IRQF_TIMER | IRQF_PERCPU,
-        .handler = timer_irq_handler,
-};
-
 /*
  * Setup the local event timer for @cpu
  */
@@ -228,15 +226,9 @@ void arc_local_timer_setup()
         clockevents_config_and_register(evt, arc_get_core_freq(),
                                         0, ARC_TIMER_MAX);
 
-        /*
-         * setup the per-cpu timer IRQ handler - for all cpus
-         * For non boot CPU explicitly unmask at intc
-         * setup_irq() -> .. -> irq_startup() already does this on boot-cpu
-         */
-        if (!cpu)
-                setup_irq(TIMER0_IRQ, &arc_timer_irq);
-        else
-                arch_unmask_irq(TIMER0_IRQ);
+        /* setup the per-cpu timer IRQ handler - for all cpus */
+        arc_request_percpu_irq(TIMER0_IRQ, cpu, timer_irq_handler,
+                               "Timer0 (per-cpu-tick)", evt);
 }
 
 /*
diff --git a/arch/arc/mm/cache_arc700.c b/arch/arc/mm/cache_arc700.c
index 353b202c37c9..4670afc3b971 100644
--- a/arch/arc/mm/cache_arc700.c
+++ b/arch/arc/mm/cache_arc700.c
@@ -77,21 +77,19 @@ char *arc_cache_mumbojumbo(int c, char *buf, int len)
 {
         int n = 0;
 
-#define PR_CACHE(p, enb, str)                                           \
-{                                                                       \
+#define PR_CACHE(p, cfg, str)                                           \
         if (!(p)->ver)                                                  \
                 n += scnprintf(buf + n, len - n, str"\t\t: N/A\n");     \
         else                                                            \
                 n += scnprintf(buf + n, len - n,                        \
-                        str"\t\t: (%uK) VIPT, %dway set-asc, %ub Line %s\n", \
-                        TO_KB((p)->sz), (p)->assoc, (p)->line_len,      \
-                        enb ?  "" : "DISABLED (kernel-build)");         \
-}
+                        str"\t\t: %uK, %dway/set, %uB Line, %s%s%s\n",  \
+                        (p)->sz_k, (p)->assoc, (p)->line_len,           \
+                        (p)->vipt ? "VIPT" : "PIPT",                    \
+                        (p)->alias ? " aliasing" : "",                  \
+                        IS_ENABLED(cfg) ? "" : " (not used)");
 
-        PR_CACHE(&cpuinfo_arc700[c].icache, IS_ENABLED(CONFIG_ARC_HAS_ICACHE),
-                        "I-Cache");
-        PR_CACHE(&cpuinfo_arc700[c].dcache, IS_ENABLED(CONFIG_ARC_HAS_DCACHE),
-                        "D-Cache");
+        PR_CACHE(&cpuinfo_arc700[c].icache, CONFIG_ARC_HAS_ICACHE, "I-Cache");
+        PR_CACHE(&cpuinfo_arc700[c].dcache, CONFIG_ARC_HAS_DCACHE, "D-Cache");
 
         return buf;
 }
@@ -116,20 +114,31 @@ void read_decode_cache_bcr(void)
         p_ic = &cpuinfo_arc700[cpu].icache;
         READ_BCR(ARC_REG_IC_BCR, ibcr);
 
+        if (!ibcr.ver)
+                goto dc_chk;
+
         BUG_ON(ibcr.config != 3);
         p_ic->assoc = 2;                /* Fixed to 2w set assoc */
         p_ic->line_len = 8 << ibcr.line_len;
-        p_ic->sz = 0x200 << ibcr.sz;
+        p_ic->sz_k = 1 << (ibcr.sz - 1);
         p_ic->ver = ibcr.ver;
+        p_ic->vipt = 1;
+        p_ic->alias = p_ic->sz_k/p_ic->assoc/TO_KB(PAGE_SIZE) > 1;
 
+dc_chk:
         p_dc = &cpuinfo_arc700[cpu].dcache;
         READ_BCR(ARC_REG_DC_BCR, dbcr);
 
+        if (!dbcr.ver)
+                return;
+
         BUG_ON(dbcr.config != 2);
         p_dc->assoc = 4;                /* Fixed to 4w set assoc */
         p_dc->line_len = 16 << dbcr.line_len;
-        p_dc->sz = 0x200 << dbcr.sz;
+        p_dc->sz_k = 1 << (dbcr.sz - 1);
         p_dc->ver = dbcr.ver;
+        p_dc->vipt = 1;
+        p_dc->alias = p_dc->sz_k/p_dc->assoc/TO_KB(PAGE_SIZE) > 1;
 }
 
 /*
@@ -142,14 +151,16 @@ void read_decode_cache_bcr(void)
 void arc_cache_init(void)
 {
         unsigned int __maybe_unused cpu = smp_processor_id();
-        struct cpuinfo_arc_cache __maybe_unused *ic, __maybe_unused *dc;
         char str[256];
 
         printk(arc_cache_mumbojumbo(0, str, sizeof(str)));
 
-#ifdef CONFIG_ARC_HAS_ICACHE
-        ic = &cpuinfo_arc700[cpu].icache;
-        if (ic->ver) {
+        if (IS_ENABLED(CONFIG_ARC_HAS_ICACHE)) {
+                struct cpuinfo_arc_cache *ic = &cpuinfo_arc700[cpu].icache;
+
+                if (!ic->ver)
+                        panic("cache support enabled but non-existent cache\n");
+
                 if (ic->line_len != L1_CACHE_BYTES)
                         panic("ICache line [%d] != kernel Config [%d]",
                               ic->line_len, L1_CACHE_BYTES);
@@ -158,26 +169,26 @@ void arc_cache_init(void)
                         panic("Cache ver [%d] doesn't match MMU ver [%d]\n",
                               ic->ver, CONFIG_ARC_MMU_VER);
         }
-#endif
 
-#ifdef CONFIG_ARC_HAS_DCACHE
-        dc = &cpuinfo_arc700[cpu].dcache;
-        if (dc->ver) {
-                unsigned int dcache_does_alias;
+        if (IS_ENABLED(CONFIG_ARC_HAS_DCACHE)) {
+                struct cpuinfo_arc_cache *dc = &cpuinfo_arc700[cpu].dcache;
+                int handled;
+
+                if (!dc->ver)
+                        panic("cache support enabled but non-existent cache\n");
 
                 if (dc->line_len != L1_CACHE_BYTES)
                         panic("DCache line [%d] != kernel Config [%d]",
                               dc->line_len, L1_CACHE_BYTES);
 
                 /* check for D-Cache aliasing */
-                dcache_does_alias = (dc->sz / dc->assoc) > PAGE_SIZE;
+                handled = IS_ENABLED(CONFIG_ARC_CACHE_VIPT_ALIASING);
 
-                if (dcache_does_alias && !cache_is_vipt_aliasing())
+                if (dc->alias && !handled)
                         panic("Enable CONFIG_ARC_CACHE_VIPT_ALIASING\n");
-                else if (!dcache_does_alias && cache_is_vipt_aliasing())
+                else if (!dc->alias && handled)
                         panic("Don't need CONFIG_ARC_CACHE_VIPT_ALIASING\n");
         }
-#endif
 }
 
 #define OP_INV          0x1
@@ -255,10 +266,32 @@ static inline void __cache_line_loop(unsigned long paddr, unsigned long vaddr,
  * Machine specific helpers for Entire D-Cache or Per Line ops
  */
 
-static inline void wait_for_flush(void)
+static unsigned int __before_dc_op(const int op)
+{
+        unsigned int reg = reg;
+
+        if (op == OP_FLUSH_N_INV) {
+                /* Dcache provides 2 cmd: FLUSH or INV
+                 * INV inturn has sub-modes: DISCARD or FLUSH-BEFORE
+                 * flush-n-inv is achieved by INV cmd but with IM=1
+                 * So toggle INV sub-mode depending on op request and default
+                 */
+                reg = read_aux_reg(ARC_REG_DC_CTRL);
+                write_aux_reg(ARC_REG_DC_CTRL, reg | DC_CTRL_INV_MODE_FLUSH)
+                        ;
+        }
+
+        return reg;
+}
+
+static void __after_dc_op(const int op, unsigned int reg)
 {
-        while (read_aux_reg(ARC_REG_DC_CTRL) & DC_CTRL_FLUSH_STATUS)
-                ;
+        if (op & OP_FLUSH)      /* flush / flush-n-inv both wait */
+                while (read_aux_reg(ARC_REG_DC_CTRL) & DC_CTRL_FLUSH_STATUS);
+
+        /* Switch back to default Invalidate mode */
+        if (op == OP_FLUSH_N_INV)
+                write_aux_reg(ARC_REG_DC_CTRL, reg & ~DC_CTRL_INV_MODE_FLUSH);
 }
 
 /*
@@ -269,18 +302,10 @@ static inline void wait_for_flush(void)
  */
 static inline void __dc_entire_op(const int cacheop)
 {
-        unsigned int tmp = tmp;
+        unsigned int ctrl_reg;
         int aux;
 
-        if (cacheop == OP_FLUSH_N_INV) {
-                /* Dcache provides 2 cmd: FLUSH or INV
-                 * INV inturn has sub-modes: DISCARD or FLUSH-BEFORE
-                 * flush-n-inv is achieved by INV cmd but with IM=1
-                 * Default INV sub-mode is DISCARD, which needs to be toggled
-                 */
-                tmp = read_aux_reg(ARC_REG_DC_CTRL);
-                write_aux_reg(ARC_REG_DC_CTRL, tmp | DC_CTRL_INV_MODE_FLUSH);
-        }
+        ctrl_reg = __before_dc_op(cacheop);
 
         if (cacheop & OP_INV)   /* Inv or flush-n-inv use same cmd reg */
                 aux = ARC_REG_DC_IVDC;
@@ -289,12 +314,7 @@ static inline void __dc_entire_op(const int cacheop)
 
         write_aux_reg(aux, 0x1);
 
-        if (cacheop & OP_FLUSH) /* flush / flush-n-inv both wait */
-                wait_for_flush();
-
-        /* Switch back the DISCARD ONLY Invalidate mode */
-        if (cacheop == OP_FLUSH_N_INV)
-                write_aux_reg(ARC_REG_DC_CTRL, tmp & ~DC_CTRL_INV_MODE_FLUSH);
+        __after_dc_op(cacheop, ctrl_reg);
 }
 
 /* For kernel mappings cache operation: index is same as paddr */
@@ -306,29 +326,16 @@ static inline void __dc_entire_op(const int cacheop)
 static inline void __dc_line_op(unsigned long paddr, unsigned long vaddr,
                                 unsigned long sz, const int cacheop)
 {
-        unsigned long flags, tmp = tmp;
+        unsigned long flags;
+        unsigned int ctrl_reg;
 
         local_irq_save(flags);
 
-        if (cacheop == OP_FLUSH_N_INV) {
-                /*
-                 * Dcache provides 2 cmd: FLUSH or INV
-                 * INV inturn has sub-modes: DISCARD or FLUSH-BEFORE
-                 * flush-n-inv is achieved by INV cmd but with IM=1
-                 * Default INV sub-mode is DISCARD, which needs to be toggled
-                 */
-                tmp = read_aux_reg(ARC_REG_DC_CTRL);
-                write_aux_reg(ARC_REG_DC_CTRL, tmp | DC_CTRL_INV_MODE_FLUSH);
-        }
+        ctrl_reg = __before_dc_op(cacheop);
 
         __cache_line_loop(paddr, vaddr, sz, cacheop);
 
-        if (cacheop & OP_FLUSH) /* flush / flush-n-inv both wait */
-                wait_for_flush();
-
-        /* Switch back the DISCARD ONLY Invalidate mode */
-        if (cacheop == OP_FLUSH_N_INV)
-                write_aux_reg(ARC_REG_DC_CTRL, tmp & ~DC_CTRL_INV_MODE_FLUSH);
+        __after_dc_op(cacheop, ctrl_reg);
 
         local_irq_restore(flags);
 }
@@ -389,8 +396,16 @@ static inline void __dc_line_op(unsigned long paddr, unsigned long vaddr,
 /***********************************************************
  * Machine specific helper for per line I-Cache invalidate.
  */
-static void __ic_line_inv_vaddr_local(unsigned long paddr, unsigned long vaddr,
-                                unsigned long sz)
+
+static inline void __ic_entire_inv(void)
+{
+        write_aux_reg(ARC_REG_IC_IVIC, 1);
+        read_aux_reg(ARC_REG_IC_CTRL);  /* blocks */
+}
+
+static inline void
+__ic_line_inv_vaddr_local(unsigned long paddr, unsigned long vaddr,
+                          unsigned long sz)
 {
         unsigned long flags;
 
@@ -399,30 +414,39 @@ static void __ic_line_inv_vaddr_local(unsigned long paddr, unsigned long vaddr,
         local_irq_restore(flags);
 }
 
-static inline void __ic_entire_inv(void)
-{
-        write_aux_reg(ARC_REG_IC_IVIC, 1);
-        read_aux_reg(ARC_REG_IC_CTRL);  /* blocks */
-}
+#ifndef CONFIG_SMP
+
+#define __ic_line_inv_vaddr(p, v, s)    __ic_line_inv_vaddr_local(p, v, s)
 
-struct ic_line_inv_vaddr_ipi {
+#else
+
+struct ic_inv_args {
         unsigned long paddr, vaddr;
         int sz;
 };
 
 static void __ic_line_inv_vaddr_helper(void *info)
 {
-        struct ic_line_inv_vaddr_ipi *ic_inv = (struct ic_line_inv_vaddr_ipi*) info;
+        struct ic_inv *ic_inv_args = (struct ic_inv_args *) info;
+
         __ic_line_inv_vaddr_local(ic_inv->paddr, ic_inv->vaddr, ic_inv->sz);
 }
 
 static void __ic_line_inv_vaddr(unsigned long paddr, unsigned long vaddr,
                                 unsigned long sz)
 {
-        struct ic_line_inv_vaddr_ipi ic_inv = { paddr, vaddr , sz};
+        struct ic_inv_args ic_inv = {
+                .paddr = paddr,
+                .vaddr = vaddr,
+                .sz    = sz
+        };
+
         on_each_cpu(__ic_line_inv_vaddr_helper, &ic_inv, 1);
 }
-#else
+
+#endif  /* CONFIG_SMP */
+
+#else   /* !CONFIG_ARC_HAS_ICACHE */
 
 #define __ic_entire_inv()
 #define __ic_line_inv_vaddr(pstart, vstart, sz)
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index 9c69552350c4..6f7e3a68803a 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -159,7 +159,6 @@ good_area:
                 return;
         }
 
-        /* TBD: switch to pagefault_out_of_memory() */
         if (fault & VM_FAULT_OOM)
                 goto out_of_memory;
         else if (fault & VM_FAULT_SIGBUS)
diff --git a/arch/arc/mm/tlbex.S b/arch/arc/mm/tlbex.S
index 79bfc81358c9..d572f1c2c724 100644
--- a/arch/arc/mm/tlbex.S
+++ b/arch/arc/mm/tlbex.S
@@ -220,9 +220,9 @@ ex_saved_reg1:
 
 .macro CONV_PTE_TO_TLB
         and    r3, r0, PTE_BITS_RWX     ;       r w x
-        lsl    r2, r3, 3                ; r w x 0 0 0
+        lsl    r2, r3, 3                ; r w x 0 0 0 (GLOBAL, kernel only)
         and.f  0,  r0, _PAGE_GLOBAL
-        or.z   r2, r2, r3               ; r w x r w x
+        or.z   r2, r2, r3               ; r w x r w x (!GLOBAL, user page)
 
         and r3, r0, PTE_BITS_NON_RWX_IN_PD1 ; Extract PFN+cache bits from PTE
         or  r3, r3, r2
diff --git a/arch/arc/plat-arcfpga/Kconfig b/arch/arc/plat-arcfpga/Kconfig
index e27bb5cc3c1e..b9f34cf55acf 100644
--- a/arch/arc/plat-arcfpga/Kconfig
+++ b/arch/arc/plat-arcfpga/Kconfig
@@ -41,11 +41,4 @@ config ISS_SMP_EXTN
           -XTL (To enable CPU start/stop/set-PC for another CPU)
           It doesn't provide coherent Caches and/or Atomic Ops (LLOCK/SCOND)
 
-config ARC_SERIAL_BAUD
-        int "UART Baud rate"
-        default "115200"
-        depends on SERIAL_ARC || SERIAL_ARC_CONSOLE
-        help
-          Baud rate for the ARC UART
-
 endif
diff --git a/arch/arc/plat-arcfpga/Makefile b/arch/arc/plat-arcfpga/Makefile
index 4d1bddc34b5b..66fd0ecd68b3 100644
--- a/arch/arc/plat-arcfpga/Makefile
+++ b/arch/arc/plat-arcfpga/Makefile
@@ -8,5 +8,5 @@
 
 KBUILD_CFLAGS   += -Iarch/arc/plat-arcfpga/include
 
-obj-y := platform.o irq.o
+obj-y := platform.o
 obj-$(CONFIG_ISS_SMP_EXTN)              += smp.o
diff --git a/arch/arc/plat-arcfpga/include/plat/irq.h b/arch/arc/plat-arcfpga/include/plat/irq.h
index 6adbc53c3a5b..2c9dea690ac4 100644
--- a/arch/arc/plat-arcfpga/include/plat/irq.h
+++ b/arch/arc/plat-arcfpga/include/plat/irq.h
@@ -24,6 +24,4 @@
 #define IDU_INTERRUPT_0 16
 #endif
 
-extern void __init plat_fpga_init_IRQ(void);
-
 #endif
diff --git a/arch/arc/plat-arcfpga/irq.c b/arch/arc/plat-arcfpga/irq.c
deleted file mode 100644
index d2215fd889c2..000000000000
--- a/arch/arc/plat-arcfpga/irq.c
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * ARC FPGA Platform IRQ hookups
- *
- * Copyright (C) 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/interrupt.h>
-#include <plat/irq.h>
-
-void __init plat_fpga_init_IRQ(void)
-{
-        /*
-         * SMP Hack because UART IRQ hardwired to cpu0 (boot-cpu) but if the
-         * request_irq() comes from any other CPU, the low level IRQ unamsking
-         * essential for getting Interrupts won't be enabled on cpu0, locking
-         * up the UART state machine.
-         */
-#ifdef CONFIG_SMP
-        arch_unmask_irq(UART0_IRQ);
-#endif
-}
diff --git a/arch/arc/plat-arcfpga/platform.c b/arch/arc/plat-arcfpga/platform.c
index 61c7e5997387..1038949a99a1 100644
--- a/arch/arc/plat-arcfpga/platform.c
+++ b/arch/arc/plat-arcfpga/platform.c
@@ -22,115 +22,22 @@
 #include <plat/smp.h>
 #include <plat/irq.h>
 
-/*----------------------- Platform Devices -----------------------------*/
-
-#if IS_ENABLED(CONFIG_SERIAL_ARC)
-static unsigned long arc_uart_info[] = {
-        0,      /* uart->is_emulated (runtime @running_on_hw) */
-        0,      /* uart->port.uartclk */
-        0,      /* uart->baud */
-        0
-};
-
-#if defined(CONFIG_SERIAL_ARC_CONSOLE)
-/*
- * static platform data - but only for early serial
- * TBD: derive this from a special DT node
- */
-static struct resource arc_uart0_res[] = {
-        {
-                .start = UART0_BASE,
-                .end   = UART0_BASE + 0xFF,
-                .flags = IORESOURCE_MEM,
-        },
-        {
-                .start = UART0_IRQ,
-                .end   = UART0_IRQ,
-                .flags = IORESOURCE_IRQ,
-        },
-};
-
-static struct platform_device arc_uart0_dev = {
-        .name = "arc-uart",
-        .id = 0,
-        .num_resources = ARRAY_SIZE(arc_uart0_res),
-        .resource = arc_uart0_res,
-        .dev = {
-                .platform_data = &arc_uart_info,
-        },
-};
-
-static struct platform_device *fpga_early_devs[] __initdata = {
-        &arc_uart0_dev,
-};
-#endif  /* CONFIG_SERIAL_ARC_CONSOLE */
-
-static void arc_fpga_serial_init(void)
-{
-        /* To let driver workaround ISS bug: baudh Reg can't be set to 0 */
-        arc_uart_info[0] = !running_on_hw;
-
-        arc_uart_info[1] = arc_get_core_freq();
-
-        arc_uart_info[2] = CONFIG_ARC_SERIAL_BAUD;
-
-#if defined(CONFIG_SERIAL_ARC_CONSOLE)
-        early_platform_add_devices(fpga_early_devs,
-                                   ARRAY_SIZE(fpga_early_devs));
-
-        /*
-         * ARC console driver registers (build time) as an early platform driver
-         * of class "earlyprintk". However it needs explicit cmdline toggle
-         * "earlyprintk=ttyARC0" to be successfuly runtime registered.
-         * Otherwise the early probe below fails to find the driver
-         */
-        early_platform_driver_probe("earlyprintk", 1, 0);
-
-        /*
-         * This is to make sure that arc uart would be preferred console
-         * despite one/more of following:
-         *   -command line lacked "console=ttyARC0" or
-         *   -CONFIG_VT_CONSOLE was enabled (for no reason whatsoever)
-         * Note that this needs to be done after above early console is reg,
-         * otherwise the early console never gets a chance to run.
-         */
-        add_preferred_console("ttyARC", 0, "115200");
-#endif  /* CONFIG_SERIAL_ARC_CONSOLE */
-}
-#else   /* !IS_ENABLED(CONFIG_SERIAL_ARC) */
-static void arc_fpga_serial_init(void)
-{
-}
-#endif
-
 static void __init plat_fpga_early_init(void)
 {
         pr_info("[plat-arcfpga]: registering early dev resources\n");
 
-        arc_fpga_serial_init();
-
 #ifdef CONFIG_ISS_SMP_EXTN
         iss_model_init_early_smp();
 #endif
 }
 
-static struct of_dev_auxdata plat_auxdata_lookup[] __initdata = {
-#if IS_ENABLED(CONFIG_SERIAL_ARC)
-        OF_DEV_AUXDATA("snps,arc-uart", UART0_BASE, "arc-uart", arc_uart_info),
-#endif
-        {}
-};
-
 static void __init plat_fpga_populate_dev(void)
 {
-        pr_info("[plat-arcfpga]: registering device resources\n");
-
         /*
          * Traverses flattened DeviceTree - registering platform devices
-         * complete with their resources
+         * (if any) complete with their resources
          */
-        of_platform_populate(NULL, of_default_bus_match_table,
-                             plat_auxdata_lookup, NULL);
+        of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }
 
 /*----------------------- Machine Descriptions ------------------------------
@@ -150,7 +57,6 @@ MACHINE_START(ANGEL4, "angel4")
         .dt_compat      = aa4_compat,
         .init_early     = plat_fpga_early_init,
         .init_machine   = plat_fpga_populate_dev,
-        .init_irq       = plat_fpga_init_IRQ,
 #ifdef CONFIG_ISS_SMP_EXTN
         .init_smp       = iss_model_init_smp,
 #endif
@@ -165,7 +71,6 @@ MACHINE_START(ML509, "ml509")
         .dt_compat      = ml509_compat,
         .init_early     = plat_fpga_early_init,
         .init_machine   = plat_fpga_populate_dev,
-        .init_irq       = plat_fpga_init_IRQ,
 #ifdef CONFIG_SMP
         .init_smp       = iss_model_init_smp,
 #endif
@@ -180,5 +85,4 @@ MACHINE_START(NSIMOSCI, "nsimosci")
         .dt_compat      = nsimosci_compat,
         .init_early     = NULL,
         .init_machine   = plat_fpga_populate_dev,
-        .init_irq       = NULL,
 MACHINE_END