diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index 18158be62a2bfbb9f82250f889b61ea4d91f2da7..970460a0b492efe9fcf6bc126e06ab11074641ce 100644
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -40,6 +40,7 @@ generic-y += resource.h
 generic-y += scatterlist.h
 generic-y += sections.h
 generic-y += sembuf.h
+generic-y += serial.h
 generic-y += setup.h
 generic-y += shmbuf.h
 generic-y += shmparam.h
diff --git a/arch/riscv/include/asm/asm.h b/arch/riscv/include/asm/asm.h
index 6cbbb6a68d76c2ba846fbcdeb65d91cf27e04f05..5ad4cb622bedf02f8b77bc27e7867c3cec6c7aca 100644
--- a/arch/riscv/include/asm/asm.h
+++ b/arch/riscv/include/asm/asm.h
@@ -58,17 +58,17 @@
 #endif
 
 #if (__SIZEOF_INT__ == 4)
-#define INT		__ASM_STR(.word)
-#define SZINT		__ASM_STR(4)
-#define LGINT		__ASM_STR(2)
+#define RISCV_INT		__ASM_STR(.word)
+#define RISCV_SZINT		__ASM_STR(4)
+#define RISCV_LGINT		__ASM_STR(2)
 #else
 #error "Unexpected __SIZEOF_INT__"
 #endif
 
 #if (__SIZEOF_SHORT__ == 2)
-#define SHORT		__ASM_STR(.half)
-#define SZSHORT		__ASM_STR(2)
-#define LGSHORT		__ASM_STR(1)
+#define RISCV_SHORT		__ASM_STR(.half)
+#define RISCV_SZSHORT		__ASM_STR(2)
+#define RISCV_LGSHORT		__ASM_STR(1)
 #else
 #error "Unexpected __SIZEOF_SHORT__"
 #endif
diff --git a/arch/riscv/include/asm/atomic.h b/arch/riscv/include/asm/atomic.h
index e2e37c57cbeb24e19c6c48422818abb8f32af130..e65d1cd89e28bb5ae52291e8fa2d13937f28e1a9 100644
--- a/arch/riscv/include/asm/atomic.h
+++ b/arch/riscv/include/asm/atomic.h
@@ -50,30 +50,30 @@ static __always_inline void atomic64_set(atomic64_t *v, long i)
  * have the AQ or RL bits set.  These don't return anything, so there's only
  * one version to worry about.
  */
-#define ATOMIC_OP(op, asm_op, c_op, I, asm_type, c_type, prefix)				\
-static __always_inline void atomic##prefix##_##op(c_type i, atomic##prefix##_t *v)		\
-{												\
-	__asm__ __volatile__ (									\
-		"amo" #asm_op "." #asm_type " zero, %1, %0"					\
-		: "+A" (v->counter)								\
-		: "r" (I)									\
-		: "memory");									\
+#define ATOMIC_OP(op, asm_op, I, asm_type, c_type, prefix)				\
+static __always_inline void atomic##prefix##_##op(c_type i, atomic##prefix##_t *v)	\
+{											\
+	__asm__ __volatile__ (								\
+		"amo" #asm_op "." #asm_type " zero, %1, %0"				\
+		: "+A" (v->counter)							\
+		: "r" (I)								\
+		: "memory");								\
 }
 
 #ifdef CONFIG_GENERIC_ATOMIC64
-#define ATOMIC_OPS(op, asm_op, c_op, I)			\
-        ATOMIC_OP (op, asm_op, c_op, I, w,  int,   )
+#define ATOMIC_OPS(op, asm_op, I)			\
+        ATOMIC_OP (op, asm_op, I, w,  int,   )
 #else
-#define ATOMIC_OPS(op, asm_op, c_op, I)			\
-        ATOMIC_OP (op, asm_op, c_op, I, w,  int,   )	\
-        ATOMIC_OP (op, asm_op, c_op, I, d, long, 64)
+#define ATOMIC_OPS(op, asm_op, I)			\
+        ATOMIC_OP (op, asm_op, I, w,  int,   )	\
+        ATOMIC_OP (op, asm_op, I, d, long, 64)
 #endif
 
-ATOMIC_OPS(add, add, +,  i)
-ATOMIC_OPS(sub, add, +, -i)
-ATOMIC_OPS(and, and, &,  i)
-ATOMIC_OPS( or,  or, |,  i)
-ATOMIC_OPS(xor, xor, ^,  i)
+ATOMIC_OPS(add, add,  i)
+ATOMIC_OPS(sub, add, -i)
+ATOMIC_OPS(and, and,  i)
+ATOMIC_OPS( or,  or,  i)
+ATOMIC_OPS(xor, xor,  i)
 
 #undef ATOMIC_OP
 #undef ATOMIC_OPS
@@ -83,7 +83,7 @@ ATOMIC_OPS(xor, xor, ^,  i)
  * There's two flavors of these: the arithmatic ops have both fetch and return
  * versions, while the logical ops only have fetch versions.
  */
-#define ATOMIC_FETCH_OP(op, asm_op, c_op, I, asm_or, c_or, asm_type, c_type, prefix)			\
+#define ATOMIC_FETCH_OP(op, asm_op, I, asm_or, c_or, asm_type, c_type, prefix)				\
 static __always_inline c_type atomic##prefix##_fetch_##op##c_or(c_type i, atomic##prefix##_t *v)	\
 {													\
 	register c_type ret;										\
@@ -103,13 +103,13 @@ static __always_inline c_type atomic##prefix##_##op##_return##c_or(c_type i, ato
 
 #ifdef CONFIG_GENERIC_ATOMIC64
 #define ATOMIC_OPS(op, asm_op, c_op, I, asm_or, c_or)				\
-        ATOMIC_FETCH_OP (op, asm_op, c_op, I, asm_or, c_or, w,  int,   )	\
+        ATOMIC_FETCH_OP (op, asm_op,       I, asm_or, c_or, w,  int,   )	\
         ATOMIC_OP_RETURN(op, asm_op, c_op, I, asm_or, c_or, w,  int,   )
 #else
 #define ATOMIC_OPS(op, asm_op, c_op, I, asm_or, c_or)				\
-        ATOMIC_FETCH_OP (op, asm_op, c_op, I, asm_or, c_or, w,  int,   )	\
+        ATOMIC_FETCH_OP (op, asm_op,       I, asm_or, c_or, w,  int,   )	\
         ATOMIC_OP_RETURN(op, asm_op, c_op, I, asm_or, c_or, w,  int,   )	\
-        ATOMIC_FETCH_OP (op, asm_op, c_op, I, asm_or, c_or, d, long, 64)	\
+        ATOMIC_FETCH_OP (op, asm_op,       I, asm_or, c_or, d, long, 64)	\
         ATOMIC_OP_RETURN(op, asm_op, c_op, I, asm_or, c_or, d, long, 64)
 #endif
 
@@ -126,28 +126,28 @@ ATOMIC_OPS(sub, add, +, -i, .aqrl,         )
 #undef ATOMIC_OPS
 
 #ifdef CONFIG_GENERIC_ATOMIC64
-#define ATOMIC_OPS(op, asm_op, c_op, I, asm_or, c_or)				\
-        ATOMIC_FETCH_OP(op, asm_op, c_op, I, asm_or, c_or, w,  int,   )
+#define ATOMIC_OPS(op, asm_op, I, asm_or, c_or)				\
+        ATOMIC_FETCH_OP(op, asm_op, I, asm_or, c_or, w,  int,   )
 #else
-#define ATOMIC_OPS(op, asm_op, c_op, I, asm_or, c_or)				\
-        ATOMIC_FETCH_OP(op, asm_op, c_op, I, asm_or, c_or, w,  int,   )		\
-        ATOMIC_FETCH_OP(op, asm_op, c_op, I, asm_or, c_or, d, long, 64)
+#define ATOMIC_OPS(op, asm_op, I, asm_or, c_or)				\
+        ATOMIC_FETCH_OP(op, asm_op, I, asm_or, c_or, w,  int,   )	\
+        ATOMIC_FETCH_OP(op, asm_op, I, asm_or, c_or, d, long, 64)
 #endif
 
-ATOMIC_OPS(and, and, &,  i,      , _relaxed)
-ATOMIC_OPS(and, and, &,  i, .aq  , _acquire)
-ATOMIC_OPS(and, and, &,  i, .rl  , _release)
-ATOMIC_OPS(and, and, &,  i, .aqrl,         )
+ATOMIC_OPS(and, and, i,      , _relaxed)
+ATOMIC_OPS(and, and, i, .aq  , _acquire)
+ATOMIC_OPS(and, and, i, .rl  , _release)
+ATOMIC_OPS(and, and, i, .aqrl,         )
 
-ATOMIC_OPS( or,  or, |,  i,      , _relaxed)
-ATOMIC_OPS( or,  or, |,  i, .aq  , _acquire)
-ATOMIC_OPS( or,  or, |,  i, .rl  , _release)
-ATOMIC_OPS( or,  or, |,  i, .aqrl,         )
+ATOMIC_OPS( or,  or, i,      , _relaxed)
+ATOMIC_OPS( or,  or, i, .aq  , _acquire)
+ATOMIC_OPS( or,  or, i, .rl  , _release)
+ATOMIC_OPS( or,  or, i, .aqrl,         )
 
-ATOMIC_OPS(xor, xor, ^,  i,      , _relaxed)
-ATOMIC_OPS(xor, xor, ^,  i, .aq  , _acquire)
-ATOMIC_OPS(xor, xor, ^,  i, .rl  , _release)
-ATOMIC_OPS(xor, xor, ^,  i, .aqrl,         )
+ATOMIC_OPS(xor, xor, i,      , _relaxed)
+ATOMIC_OPS(xor, xor, i, .aq  , _acquire)
+ATOMIC_OPS(xor, xor, i, .rl  , _release)
+ATOMIC_OPS(xor, xor, i, .aqrl,         )
 
 #undef ATOMIC_OPS
 
@@ -182,13 +182,13 @@ ATOMIC_OPS(add_negative, add,  <, 0)
 #undef ATOMIC_OP
 #undef ATOMIC_OPS
 
-#define ATOMIC_OP(op, func_op, c_op, I, c_type, prefix)				\
+#define ATOMIC_OP(op, func_op, I, c_type, prefix)				\
 static __always_inline void atomic##prefix##_##op(atomic##prefix##_t *v)	\
 {										\
 	atomic##prefix##_##func_op(I, v);					\
 }
 
-#define ATOMIC_FETCH_OP(op, func_op, c_op, I, c_type, prefix)				\
+#define ATOMIC_FETCH_OP(op, func_op, I, c_type, prefix)					\
 static __always_inline c_type atomic##prefix##_fetch_##op(atomic##prefix##_t *v)	\
 {											\
 	return atomic##prefix##_fetch_##func_op(I, v);					\
@@ -202,16 +202,16 @@ static __always_inline c_type atomic##prefix##_##op##_return(atomic##prefix##_t
 
 #ifdef CONFIG_GENERIC_ATOMIC64
 #define ATOMIC_OPS(op, asm_op, c_op, I)						\
-        ATOMIC_OP       (op, asm_op, c_op, I,  int,   )				\
-        ATOMIC_FETCH_OP (op, asm_op, c_op, I,  int,   )				\
+        ATOMIC_OP       (op, asm_op,       I,  int,   )				\
+        ATOMIC_FETCH_OP (op, asm_op,       I,  int,   )				\
         ATOMIC_OP_RETURN(op, asm_op, c_op, I,  int,   )
 #else
 #define ATOMIC_OPS(op, asm_op, c_op, I)						\
-        ATOMIC_OP       (op, asm_op, c_op, I,  int,   )				\
-        ATOMIC_FETCH_OP (op, asm_op, c_op, I,  int,   )				\
+        ATOMIC_OP       (op, asm_op,       I,  int,   )				\
+        ATOMIC_FETCH_OP (op, asm_op,       I,  int,   )				\
         ATOMIC_OP_RETURN(op, asm_op, c_op, I,  int,   )				\
-        ATOMIC_OP       (op, asm_op, c_op, I, long, 64)				\
-        ATOMIC_FETCH_OP (op, asm_op, c_op, I, long, 64)				\
+        ATOMIC_OP       (op, asm_op,       I, long, 64)				\
+        ATOMIC_FETCH_OP (op, asm_op,       I, long, 64)				\
         ATOMIC_OP_RETURN(op, asm_op, c_op, I, long, 64)
 #endif
 
@@ -300,8 +300,13 @@ static __always_inline long atomic64_inc_not_zero(atomic64_t *v)
 
 /*
  * atomic_{cmp,}xchg is required to have exactly the same ordering semantics as
- * {cmp,}xchg and the operations that return, so they need a barrier.  We just
- * use the other implementations directly.
+ * {cmp,}xchg and the operations that return, so they need a barrier.
+ */
+/*
+ * FIXME: atomic_cmpxchg_{acquire,release,relaxed} are all implemented by
+ * assigning the same barrier to both the LR and SC operations, but that might
+ * not make any sense.  We're waiting on a memory model specification to
+ * determine exactly what the right thing to do is here.
  */
 #define ATOMIC_OP(c_t, prefix, c_or, size, asm_or)						\
 static __always_inline c_t atomic##prefix##_cmpxchg##c_or(atomic##prefix##_t *v, c_t o, c_t n) 	\
diff --git a/arch/riscv/include/asm/barrier.h b/arch/riscv/include/asm/barrier.h
index 183534b7c39b7d663ea757b2d0ff346e58bae15c..773c4e039cd7288bcd25ed53ce831db84c766f26 100644
--- a/arch/riscv/include/asm/barrier.h
+++ b/arch/riscv/include/asm/barrier.h
@@ -38,29 +38,6 @@
 #define smp_rmb()	RISCV_FENCE(r,r)
 #define smp_wmb()	RISCV_FENCE(w,w)
 
-/*
- * These fences exist to enforce ordering around the relaxed AMOs.  The
- * documentation defines that
- * "
- *     atomic_fetch_add();
- *   is equivalent to:
- *     smp_mb__before_atomic();
- *     atomic_fetch_add_relaxed();
- *     smp_mb__after_atomic();
- * "
- * So we emit full fences on both sides.
- */
-#define __smb_mb__before_atomic()	smp_mb()
-#define __smb_mb__after_atomic()	smp_mb()
-
-/*
- * These barriers prevent accesses performed outside a spinlock from being moved
- * inside a spinlock.  Since RISC-V sets the aq/rl bits on our spinlock only
- * enforce release consistency, we need full fences here.
- */
-#define smb_mb__before_spinlock()	smp_mb()
-#define smb_mb__after_spinlock()	smp_mb()
-
 #include <asm-generic/barrier.h>
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/riscv/include/asm/bitops.h b/arch/riscv/include/asm/bitops.h
index 7c281ef1d58320d24caf33d4d1af2c57f4c75d9b..f30daf26f08f44bbb1028640c0d8e2539220ab0f 100644
--- a/arch/riscv/include/asm/bitops.h
+++ b/arch/riscv/include/asm/bitops.h
@@ -67,7 +67,7 @@
 		: "memory");
 
 #define __test_and_op_bit(op, mod, nr, addr) 			\
-	__test_and_op_bit_ord(op, mod, nr, addr, )
+	__test_and_op_bit_ord(op, mod, nr, addr, .aqrl)
 #define __op_bit(op, mod, nr, addr)				\
 	__op_bit_ord(op, mod, nr, addr, )
 
diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h
index c3e13764a943c6f66b80dfe54f92abb10da87962..bfc7f099ab1fea28981d2a3a1ffce8aa25e4ea4d 100644
--- a/arch/riscv/include/asm/bug.h
+++ b/arch/riscv/include/asm/bug.h
@@ -27,8 +27,8 @@
 typedef u32 bug_insn_t;
 
 #ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
-#define __BUG_ENTRY_ADDR	INT " 1b - 2b"
-#define __BUG_ENTRY_FILE	INT " %0 - 2b"
+#define __BUG_ENTRY_ADDR	RISCV_INT " 1b - 2b"
+#define __BUG_ENTRY_FILE	RISCV_INT " %0 - 2b"
 #else
 #define __BUG_ENTRY_ADDR	RISCV_PTR " 1b"
 #define __BUG_ENTRY_FILE	RISCV_PTR " %0"
@@ -38,7 +38,7 @@ typedef u32 bug_insn_t;
 #define __BUG_ENTRY			\
 	__BUG_ENTRY_ADDR "\n\t"		\
 	__BUG_ENTRY_FILE "\n\t"		\
-	SHORT " %1"
+	RISCV_SHORT " %1"
 #else
 #define __BUG_ENTRY			\
 	__BUG_ENTRY_ADDR
diff --git a/arch/riscv/include/asm/cacheflush.h b/arch/riscv/include/asm/cacheflush.h
index 0595585013b07d899bccbe98598f3750bdd39bca..efd89a88d2d0e9b2bcd639a436a6143440a24d77 100644
--- a/arch/riscv/include/asm/cacheflush.h
+++ b/arch/riscv/include/asm/cacheflush.h
@@ -18,22 +18,44 @@
 
 #undef flush_icache_range
 #undef flush_icache_user_range
+#undef flush_dcache_page
 
 static inline void local_flush_icache_all(void)
 {
 	asm volatile ("fence.i" ::: "memory");
 }
 
+#define PG_dcache_clean PG_arch_1
+
+static inline void flush_dcache_page(struct page *page)
+{
+	if (test_bit(PG_dcache_clean, &page->flags))
+		clear_bit(PG_dcache_clean, &page->flags);
+}
+
+/*
+ * RISC-V doesn't have an instruction to flush parts of the instruction cache,
+ * so instead we just flush the whole thing.
+ */
+#define flush_icache_range(start, end) flush_icache_all()
+#define flush_icache_user_range(vma, pg, addr, len) flush_icache_all()
+
 #ifndef CONFIG_SMP
 
-#define flush_icache_range(start, end) local_flush_icache_all()
-#define flush_icache_user_range(vma, pg, addr, len) local_flush_icache_all()
+#define flush_icache_all() local_flush_icache_all()
+#define flush_icache_mm(mm, local) flush_icache_all()
 
 #else /* CONFIG_SMP */
 
-#define flush_icache_range(start, end) sbi_remote_fence_i(0)
-#define flush_icache_user_range(vma, pg, addr, len) sbi_remote_fence_i(0)
+#define flush_icache_all() sbi_remote_fence_i(0)
+void flush_icache_mm(struct mm_struct *mm, bool local);
 
 #endif /* CONFIG_SMP */
 
+/*
+ * Bits in sys_riscv_flush_icache()'s flags argument.
+ */
+#define SYS_RISCV_FLUSH_ICACHE_LOCAL 1UL
+#define SYS_RISCV_FLUSH_ICACHE_ALL   (SYS_RISCV_FLUSH_ICACHE_LOCAL)
+
 #endif /* _ASM_RISCV_CACHEFLUSH_H */
diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h
index c1f32cfcc79bbb7f35786e3ab9b9ab5b8f683df8..a82ce599b639813c9ed3ad697f217cb09a6538e1 100644
--- a/arch/riscv/include/asm/io.h
+++ b/arch/riscv/include/asm/io.h
@@ -19,6 +19,8 @@
 #ifndef _ASM_RISCV_IO_H
 #define _ASM_RISCV_IO_H
 
+#include <linux/types.h>
+
 #ifdef CONFIG_MMU
 
 extern void __iomem *ioremap(phys_addr_t offset, unsigned long size);
@@ -32,7 +34,7 @@ extern void __iomem *ioremap(phys_addr_t offset, unsigned long size);
 #define ioremap_wc(addr, size) ioremap((addr), (size))
 #define ioremap_wt(addr, size) ioremap((addr), (size))
 
-extern void iounmap(void __iomem *addr);
+extern void iounmap(volatile void __iomem *addr);
 
 #endif /* CONFIG_MMU */
 
@@ -250,7 +252,7 @@ static inline u64 __raw_readq(const volatile void __iomem *addr)
 			const ctype *buf = buffer;				\
 										\
 			do {							\
-				__raw_writeq(*buf++, addr);			\
+				__raw_write ## len(*buf++, addr);		\
 			} while (--count);					\
 		}								\
 		afence;								\
@@ -266,9 +268,9 @@ __io_reads_ins(reads, u32, l, __io_br(), __io_ar())
 __io_reads_ins(ins,  u8, b, __io_pbr(), __io_par())
 __io_reads_ins(ins, u16, w, __io_pbr(), __io_par())
 __io_reads_ins(ins, u32, l, __io_pbr(), __io_par())
-#define insb(addr, buffer, count) __insb((void __iomem *)addr, buffer, count)
-#define insw(addr, buffer, count) __insw((void __iomem *)addr, buffer, count)
-#define insl(addr, buffer, count) __insl((void __iomem *)addr, buffer, count)
+#define insb(addr, buffer, count) __insb((void __iomem *)(long)addr, buffer, count)
+#define insw(addr, buffer, count) __insw((void __iomem *)(long)addr, buffer, count)
+#define insl(addr, buffer, count) __insl((void __iomem *)(long)addr, buffer, count)
 
 __io_writes_outs(writes,  u8, b, __io_bw(), __io_aw())
 __io_writes_outs(writes, u16, w, __io_bw(), __io_aw())
@@ -280,9 +282,9 @@ __io_writes_outs(writes, u32, l, __io_bw(), __io_aw())
 __io_writes_outs(outs,  u8, b, __io_pbw(), __io_paw())
 __io_writes_outs(outs, u16, w, __io_pbw(), __io_paw())
 __io_writes_outs(outs, u32, l, __io_pbw(), __io_paw())
-#define outsb(addr, buffer, count) __outsb((void __iomem *)addr, buffer, count)
-#define outsw(addr, buffer, count) __outsw((void __iomem *)addr, buffer, count)
-#define outsl(addr, buffer, count) __outsl((void __iomem *)addr, buffer, count)
+#define outsb(addr, buffer, count) __outsb((void __iomem *)(long)addr, buffer, count)
+#define outsw(addr, buffer, count) __outsw((void __iomem *)(long)addr, buffer, count)
+#define outsl(addr, buffer, count) __outsl((void __iomem *)(long)addr, buffer, count)
 
 #ifdef CONFIG_64BIT
 __io_reads_ins(reads, u64, q, __io_br(), __io_ar())
diff --git a/arch/riscv/include/asm/mmu.h b/arch/riscv/include/asm/mmu.h
index 66805cba9a27ad819a8cfc938e93f705fe432943..5df2dccdba122c4d5d02ffff7d82e8727b735ba6 100644
--- a/arch/riscv/include/asm/mmu.h
+++ b/arch/riscv/include/asm/mmu.h
@@ -19,6 +19,10 @@
 
 typedef struct {
 	void *vdso;
+#ifdef CONFIG_SMP
+	/* A local icache flush is needed before user execution can resume. */
+	cpumask_t icache_stale_mask;
+#endif
 } mm_context_t;
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/riscv/include/asm/mmu_context.h b/arch/riscv/include/asm/mmu_context.h
index de1fc1631fc4367b439ce96ff21e2137ee8aa797..97424834dce2a7706bccebe505602d21fa78834b 100644
--- a/arch/riscv/include/asm/mmu_context.h
+++ b/arch/riscv/include/asm/mmu_context.h
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2017 SiFive
  *
  *   This program is free software; you can redistribute it and/or
  *   modify it under the terms of the GNU General Public License
@@ -14,11 +15,13 @@
 #ifndef _ASM_RISCV_MMU_CONTEXT_H
 #define _ASM_RISCV_MMU_CONTEXT_H
 
+#include <linux/mm_types.h>
 #include <asm-generic/mm_hooks.h>
 
 #include <linux/mm.h>
 #include <linux/sched.h>
 #include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
 
 static inline void enter_lazy_tlb(struct mm_struct *mm,
 	struct task_struct *task)
@@ -46,12 +49,54 @@ static inline void set_pgdir(pgd_t *pgd)
 	csr_write(sptbr, virt_to_pfn(pgd) | SPTBR_MODE);
 }
 
+/*
+ * When necessary, performs a deferred icache flush for the given MM context,
+ * on the local CPU.  RISC-V has no direct mechanism for instruction cache
+ * shoot downs, so instead we send an IPI that informs the remote harts they
+ * need to flush their local instruction caches.  To avoid pathologically slow
+ * behavior in a common case (a bunch of single-hart processes on a many-hart
+ * machine, ie 'make -j') we avoid the IPIs for harts that are not currently
+ * executing a MM context and instead schedule a deferred local instruction
+ * cache flush to be performed before execution resumes on each hart.  This
+ * actually performs that local instruction cache flush, which implicitly only
+ * refers to the current hart.
+ */
+static inline void flush_icache_deferred(struct mm_struct *mm)
+{
+#ifdef CONFIG_SMP
+	unsigned int cpu = smp_processor_id();
+	cpumask_t *mask = &mm->context.icache_stale_mask;
+
+	if (cpumask_test_cpu(cpu, mask)) {
+		cpumask_clear_cpu(cpu, mask);
+		/*
+		 * Ensure the remote hart's writes are visible to this hart.
+		 * This pairs with a barrier in flush_icache_mm.
+		 */
+		smp_mb();
+		local_flush_icache_all();
+	}
+#endif
+}
+
 static inline void switch_mm(struct mm_struct *prev,
 	struct mm_struct *next, struct task_struct *task)
 {
 	if (likely(prev != next)) {
+		/*
+		 * Mark the current MM context as inactive, and the next as
+		 * active.  This is at least used by the icache flushing
+		 * routines in order to determine who should
+		 */
+		unsigned int cpu = smp_processor_id();
+
+		cpumask_clear_cpu(cpu, mm_cpumask(prev));
+		cpumask_set_cpu(cpu, mm_cpumask(next));
+
 		set_pgdir(next->pgd);
 		local_flush_tlb_all();
+
+		flush_icache_deferred(next);
 	}
 }
 
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 3399257780b2cc219b7c6a29a48e54f67d342865..2cbd92ed1629c00df42b8ceaffd2250b6de7413a 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -178,28 +178,6 @@ static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long addr)
 #define pte_offset_map(dir, addr)	pte_offset_kernel((dir), (addr))
 #define pte_unmap(pte)			((void)(pte))
 
-/*
- * Certain architectures need to do special things when PTEs within
- * a page table are directly modified.  Thus, the following hook is
- * made available.
- */
-static inline void set_pte(pte_t *ptep, pte_t pteval)
-{
-	*ptep = pteval;
-}
-
-static inline void set_pte_at(struct mm_struct *mm,
-	unsigned long addr, pte_t *ptep, pte_t pteval)
-{
-	set_pte(ptep, pteval);
-}
-
-static inline void pte_clear(struct mm_struct *mm,
-	unsigned long addr, pte_t *ptep)
-{
-	set_pte_at(mm, addr, ptep, __pte(0));
-}
-
 static inline int pte_present(pte_t pte)
 {
 	return (pte_val(pte) & _PAGE_PRESENT);
@@ -210,21 +188,22 @@ static inline int pte_none(pte_t pte)
 	return (pte_val(pte) == 0);
 }
 
-/* static inline int pte_read(pte_t pte) */
-
 static inline int pte_write(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_WRITE;
 }
 
+static inline int pte_exec(pte_t pte)
+{
+	return pte_val(pte) & _PAGE_EXEC;
+}
+
 static inline int pte_huge(pte_t pte)
 {
 	return pte_present(pte)
 		&& (pte_val(pte) & (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC));
 }
 
-/* static inline int pte_exec(pte_t pte) */
-
 static inline int pte_dirty(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_DIRTY;
@@ -311,6 +290,33 @@ static inline int pte_same(pte_t pte_a, pte_t pte_b)
 	return pte_val(pte_a) == pte_val(pte_b);
 }
 
+/*
+ * Certain architectures need to do special things when PTEs within
+ * a page table are directly modified.  Thus, the following hook is
+ * made available.
+ */
+static inline void set_pte(pte_t *ptep, pte_t pteval)
+{
+	*ptep = pteval;
+}
+
+void flush_icache_pte(pte_t pte);
+
+static inline void set_pte_at(struct mm_struct *mm,
+	unsigned long addr, pte_t *ptep, pte_t pteval)
+{
+	if (pte_present(pteval) && pte_exec(pteval))
+		flush_icache_pte(pteval);
+
+	set_pte(ptep, pteval);
+}
+
+static inline void pte_clear(struct mm_struct *mm,
+	unsigned long addr, pte_t *ptep)
+{
+	set_pte_at(mm, addr, ptep, __pte(0));
+}
+
 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 static inline int ptep_set_access_flags(struct vm_area_struct *vma,
 					unsigned long address, pte_t *ptep,
diff --git a/arch/riscv/include/asm/spinlock.h b/arch/riscv/include/asm/spinlock.h
index 04c71d938afdbf40f93d0d5d9d89229fa5f72c56..2fd27e8ef1fd686d8cf234143174a538223acc79 100644
--- a/arch/riscv/include/asm/spinlock.h
+++ b/arch/riscv/include/asm/spinlock.h
@@ -24,7 +24,7 @@
 
 /* FIXME: Replace this with a ticket lock, like MIPS. */
 
-#define arch_spin_is_locked(x)	((x)->lock != 0)
+#define arch_spin_is_locked(x)	(READ_ONCE((x)->lock) != 0)
 
 static inline void arch_spin_unlock(arch_spinlock_t *lock)
 {
@@ -58,15 +58,6 @@ static inline void arch_spin_lock(arch_spinlock_t *lock)
 	}
 }
 
-static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
-{
-	smp_rmb();
-	do {
-		cpu_relax();
-	} while (arch_spin_is_locked(lock));
-	smp_acquire__after_ctrl_dep();
-}
-
 /***********************************************************/
 
 static inline void arch_read_lock(arch_rwlock_t *lock)
diff --git a/arch/riscv/include/asm/timex.h b/arch/riscv/include/asm/timex.h
index 3df4932d8964faad964d0d3a3894ee0f0425c9d7..2f26989cb864bedaa1eb0bd53456ae33fcdcaabe 100644
--- a/arch/riscv/include/asm/timex.h
+++ b/arch/riscv/include/asm/timex.h
@@ -18,7 +18,7 @@
 
 typedef unsigned long cycles_t;
 
-static inline cycles_t get_cycles(void)
+static inline cycles_t get_cycles_inline(void)
 {
 	cycles_t n;
 
@@ -27,6 +27,7 @@ static inline cycles_t get_cycles(void)
 		: "=r" (n));
 	return n;
 }
+#define get_cycles get_cycles_inline
 
 #ifdef CONFIG_64BIT
 static inline uint64_t get_cycles64(void)
diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index 5ee4ae370b5e54d49f3c062d1a19c30ca3ddfec2..715b0f10af580811dfca3ba067819e07fe1e7374 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -17,7 +17,12 @@
 
 #ifdef CONFIG_MMU
 
-/* Flush entire local TLB */
+#include <linux/mm_types.h>
+
+/*
+ * Flush entire local TLB.  'sfence.vma' implicitly fences with the instruction
+ * cache as well, so a 'fence.i' is not necessary.
+ */
 static inline void local_flush_tlb_all(void)
 {
 	__asm__ __volatile__ ("sfence.vma" : : : "memory");
diff --git a/arch/riscv/include/asm/vdso-syscalls.h b/arch/riscv/include/asm/vdso-syscalls.h
new file mode 100644
index 0000000000000000000000000000000000000000..a2ccf189492958e475cc7cc6664d86559124f001
--- /dev/null
+++ b/arch/riscv/include/asm/vdso-syscalls.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2017 SiFive
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _ASM_RISCV_VDSO_SYSCALLS_H
+#define _ASM_RISCV_VDSO_SYSCALLS_H
+
+#ifdef CONFIG_SMP
+
+/* These syscalls are only used by the vDSO and are not in the uapi. */
+#define __NR_riscv_flush_icache (__NR_arch_specific_syscall + 15)
+__SYSCALL(__NR_riscv_flush_icache, sys_riscv_flush_icache)
+
+#endif
+
+#endif /* _ASM_RISCV_VDSO_H */
diff --git a/arch/riscv/include/asm/vdso.h b/arch/riscv/include/asm/vdso.h
index 602f61257553727ff87a9b077702a6407e240c30..541544d64c33b2f95a0d2f3a1f7f3e80498ea006 100644
--- a/arch/riscv/include/asm/vdso.h
+++ b/arch/riscv/include/asm/vdso.h
@@ -38,4 +38,8 @@ struct vdso_data {
 	(void __user *)((unsigned long)(base) + __vdso_##name);			\
 })
 
+#ifdef CONFIG_SMP
+asmlinkage long sys_riscv_flush_icache(uintptr_t, uintptr_t, uintptr_t);
+#endif
+
 #endif /* _ASM_RISCV_VDSO_H */
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 76af908f87c18b76502c71d31ed12925790ce816..78f670d701339055c11c8cbeef409f9edf08ba3a 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -152,6 +152,3 @@ END(_start)
 __PAGE_ALIGNED_BSS
 	/* Empty zero page */
 	.balign PAGE_SIZE
-ENTRY(empty_zero_page)
-	.fill (empty_zero_page + PAGE_SIZE) - ., 1, 0x00
-END(empty_zero_page)
diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c
index 23cc81ec9e9444be312a2714b8aed2a06c5eee68..5517342487489b6ee35c4a95bbfa3d5c4a31f2aa 100644
--- a/arch/riscv/kernel/riscv_ksyms.c
+++ b/arch/riscv/kernel/riscv_ksyms.c
@@ -12,4 +12,7 @@
 /*
  * Assembly functions that may be used (directly or indirectly) by modules
  */
+EXPORT_SYMBOL(__clear_user);
 EXPORT_SYMBOL(__copy_user);
+EXPORT_SYMBOL(memset);
+EXPORT_SYMBOL(memcpy);
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index de7db114c31531ba244cb45c765b3fb2e1c559eb..8fbb6749910d42473d814b37eb255f812d4d206b 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -58,7 +58,12 @@ static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
 #endif /* CONFIG_CMDLINE_BOOL */
 
 unsigned long va_pa_offset;
+EXPORT_SYMBOL(va_pa_offset);
 unsigned long pfn_base;
+EXPORT_SYMBOL(pfn_base);
+
+unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
+EXPORT_SYMBOL(empty_zero_page);
 
 /* The lucky hart to first increment this variable will boot the other cores */
 atomic_t hart_lottery;
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index b4a71ec5906f64089e7ec613daaade6bd3fef95a..6d3962435720d1ee7fe84bf74d50ffbe16d49219 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -38,6 +38,13 @@ enum ipi_message_type {
 	IPI_MAX
 };
 
+
+/* Unsupported */
+int setup_profiling_timer(unsigned int multiplier)
+{
+	return -EINVAL;
+}
+
 irqreturn_t handle_ipi(void)
 {
 	unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
@@ -108,3 +115,51 @@ void smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
+
+/*
+ * Performs an icache flush for the given MM context.  RISC-V has no direct
+ * mechanism for instruction cache shoot downs, so instead we send an IPI that
+ * informs the remote harts they need to flush their local instruction caches.
+ * To avoid pathologically slow behavior in a common case (a bunch of
+ * single-hart processes on a many-hart machine, ie 'make -j') we avoid the
+ * IPIs for harts that are not currently executing a MM context and instead
+ * schedule a deferred local instruction cache flush to be performed before
+ * execution resumes on each hart.
+ */
+void flush_icache_mm(struct mm_struct *mm, bool local)
+{
+	unsigned int cpu;
+	cpumask_t others, *mask;
+
+	preempt_disable();
+
+	/* Mark every hart's icache as needing a flush for this MM. */
+	mask = &mm->context.icache_stale_mask;
+	cpumask_setall(mask);
+	/* Flush this hart's I$ now, and mark it as flushed. */
+	cpu = smp_processor_id();
+	cpumask_clear_cpu(cpu, mask);
+	local_flush_icache_all();
+
+	/*
+	 * Flush the I$ of other harts concurrently executing, and mark them as
+	 * flushed.
+	 */
+	cpumask_andnot(&others, mm_cpumask(mm), cpumask_of(cpu));
+	local |= cpumask_empty(&others);
+	if (mm != current->active_mm || !local)
+		sbi_remote_fence_i(others.bits);
+	else {
+		/*
+		 * It's assumed that at least one strongly ordered operation is
+		 * performed on this hart between setting a hart's cpumask bit
+		 * and scheduling this MM context on that hart.  Sending an SBI
+		 * remote message will do this, but in the case where no
+		 * messages are sent we still need to order this hart's writes
+		 * with flush_icache_deferred().
+		 */
+		smp_mb();
+	}
+
+	preempt_enable();
+}
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
index 4351be7d0533a6e3857169fd1de5d6cfdbd1bafc..a2ae936a093e4f91d4def96fff0dd46e6e0226c0 100644
--- a/arch/riscv/kernel/sys_riscv.c
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -14,8 +14,8 @@
  */
 
 #include <linux/syscalls.h>
-#include <asm/cmpxchg.h>
 #include <asm/unistd.h>
+#include <asm/cacheflush.h>
 
 static long riscv_sys_mmap(unsigned long addr, unsigned long len,
 			   unsigned long prot, unsigned long flags,
@@ -47,3 +47,34 @@ SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
 	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 12);
 }
 #endif /* !CONFIG_64BIT */
+
+#ifdef CONFIG_SMP
+/*
+ * Allows the instruction cache to be flushed from userspace.  Despite RISC-V
+ * having a direct 'fence.i' instruction available to userspace (which we
+ * can't trap!), that's not actually viable when running on Linux because the
+ * kernel might schedule a process on another hart.  There is no way for
+ * userspace to handle this without invoking the kernel (as it doesn't know the
+ * thread->hart mappings), so we've defined a RISC-V specific system call to
+ * flush the instruction cache.
+ *
+ * sys_riscv_flush_icache() is defined to flush the instruction cache over an
+ * address range, with the flush applying to either all threads or just the
+ * caller.  We don't currently do anything with the address range, that's just
+ * in there for forwards compatibility.
+ */
+SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
+	uintptr_t, flags)
+{
+	struct mm_struct *mm = current->mm;
+	bool local = (flags & SYS_RISCV_FLUSH_ICACHE_LOCAL) != 0;
+
+	/* Check the reserved flags. */
+	if (unlikely(flags & !SYS_RISCV_FLUSH_ICACHE_ALL))
+		return -EINVAL;
+
+	flush_icache_mm(mm, local);
+
+	return 0;
+}
+#endif
diff --git a/arch/riscv/kernel/syscall_table.c b/arch/riscv/kernel/syscall_table.c
index 4e30dc5fb593580e67eef62f8ea61c797c498cf6..a5bd6401f95e6988a376406f02b7e39cb7c1352e 100644
--- a/arch/riscv/kernel/syscall_table.c
+++ b/arch/riscv/kernel/syscall_table.c
@@ -15,6 +15,7 @@
 #include <linux/linkage.h>
 #include <linux/syscalls.h>
 #include <asm-generic/syscalls.h>
+#include <asm/vdso.h>
 
 #undef __SYSCALL
 #define __SYSCALL(nr, call)	[nr] = (call),
@@ -22,4 +23,5 @@
 void *sys_call_table[__NR_syscalls] = {
 	[0 ... __NR_syscalls - 1] = sys_ni_syscall,
 #include <asm/unistd.h>
+#include <asm/vdso-syscalls.h>
 };
diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 523d0a8ac8db7f37750cf45496132d1156aceb38..324568d3392130fe5beba7bd03928a762848d377 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -1,7 +1,12 @@
 # Copied from arch/tile/kernel/vdso/Makefile
 
 # Symbols present in the vdso
-vdso-syms = rt_sigreturn
+vdso-syms  = rt_sigreturn
+vdso-syms += gettimeofday
+vdso-syms += clock_gettime
+vdso-syms += clock_getres
+vdso-syms += getcpu
+vdso-syms += flush_icache
 
 # Files to link into the vdso
 obj-vdso = $(patsubst %, %.o, $(vdso-syms))
diff --git a/arch/riscv/kernel/vdso/clock_getres.S b/arch/riscv/kernel/vdso/clock_getres.S
new file mode 100644
index 0000000000000000000000000000000000000000..edf7e2339648a3b36afa5c1f8df30f7592d1938a
--- /dev/null
+++ b/arch/riscv/kernel/vdso/clock_getres.S
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2017 SiFive
+ *
+ *   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, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/linkage.h>
+#include <asm/unistd.h>
+
+	.text
+/* int __vdso_clock_getres(clockid_t clock_id, struct timespec *res); */
+ENTRY(__vdso_clock_getres)
+	.cfi_startproc
+	/* For now, just do the syscall. */
+	li a7, __NR_clock_getres
+	ecall
+	ret
+	.cfi_endproc
+ENDPROC(__vdso_clock_getres)
diff --git a/arch/riscv/kernel/vdso/clock_gettime.S b/arch/riscv/kernel/vdso/clock_gettime.S
new file mode 100644
index 0000000000000000000000000000000000000000..aac65676c6d5547a67f8833d8d119b87c7b1174c
--- /dev/null
+++ b/arch/riscv/kernel/vdso/clock_gettime.S
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2017 SiFive
+ *
+ *   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, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/linkage.h>
+#include <asm/unistd.h>
+
+	.text
+/* int __vdso_clock_gettime(clockid_t clock_id, struct timespec *tp); */
+ENTRY(__vdso_clock_gettime)
+	.cfi_startproc
+	/* For now, just do the syscall. */
+	li a7, __NR_clock_gettime
+	ecall
+	ret
+	.cfi_endproc
+ENDPROC(__vdso_clock_gettime)
diff --git a/arch/riscv/kernel/vdso/flush_icache.S b/arch/riscv/kernel/vdso/flush_icache.S
new file mode 100644
index 0000000000000000000000000000000000000000..b0fbad74e873ea9fff553424b975502b589d7097
--- /dev/null
+++ b/arch/riscv/kernel/vdso/flush_icache.S
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2017 SiFive
+ *
+ *   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, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/linkage.h>
+#include <asm/unistd.h>
+#include <asm/vdso-syscalls.h>
+
+	.text
+/* int __vdso_flush_icache(void *start, void *end, unsigned long flags); */
+ENTRY(__vdso_flush_icache)
+	.cfi_startproc
+#ifdef CONFIG_SMP
+	li a7, __NR_riscv_flush_icache
+	ecall
+#else
+	fence.i
+	li a0, 0
+#endif
+	ret
+	.cfi_endproc
+ENDPROC(__vdso_flush_icache)
diff --git a/arch/riscv/kernel/vdso/getcpu.S b/arch/riscv/kernel/vdso/getcpu.S
new file mode 100644
index 0000000000000000000000000000000000000000..cc7e98924484ad8cf32db65aac9fb8043797fa05
--- /dev/null
+++ b/arch/riscv/kernel/vdso/getcpu.S
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2017 SiFive
+ *
+ *   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, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/linkage.h>
+#include <asm/unistd.h>
+
+	.text
+/* int __vdso_getcpu(unsigned *cpu, unsigned *node, void *unused); */
+ENTRY(__vdso_getcpu)
+	.cfi_startproc
+	/* For now, just do the syscall. */
+	li a7, __NR_getcpu
+	ecall
+	ret
+	.cfi_endproc
+ENDPROC(__vdso_getcpu)
diff --git a/arch/riscv/kernel/vdso/gettimeofday.S b/arch/riscv/kernel/vdso/gettimeofday.S
new file mode 100644
index 0000000000000000000000000000000000000000..da85d33e8990c8a012d29e5638e01851c7446c6e
--- /dev/null
+++ b/arch/riscv/kernel/vdso/gettimeofday.S
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2017 SiFive
+ *
+ *   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, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/linkage.h>
+#include <asm/unistd.h>
+
+	.text
+/* int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz); */
+ENTRY(__vdso_gettimeofday)
+	.cfi_startproc
+	/* For now, just do the syscall. */
+	li a7, __NR_gettimeofday
+	ecall
+	ret
+	.cfi_endproc
+ENDPROC(__vdso_gettimeofday)
diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S
index 8c9dce95c11d4f472c4b555c644c8caa63294345..cd1d47e0724ba0bd811101e0fa0eb59f7841bd5c 100644
--- a/arch/riscv/kernel/vdso/vdso.lds.S
+++ b/arch/riscv/kernel/vdso/vdso.lds.S
@@ -70,8 +70,11 @@ VERSION
 	LINUX_4.15 {
 	global:
 		__vdso_rt_sigreturn;
-		__vdso_cmpxchg32;
-		__vdso_cmpxchg64;
+		__vdso_gettimeofday;
+		__vdso_clock_gettime;
+		__vdso_clock_getres;
+		__vdso_getcpu;
+		__vdso_flush_icache;
 	local: *;
 	};
 }
diff --git a/arch/riscv/lib/delay.c b/arch/riscv/lib/delay.c
index 1cc4ac3964b4c124864b72f3c807560d28df1461..dce8ae24c6d33b4ca3ebd0c19c3650f1ce890bde 100644
--- a/arch/riscv/lib/delay.c
+++ b/arch/riscv/lib/delay.c
@@ -84,6 +84,7 @@ void __delay(unsigned long cycles)
 	while ((unsigned long)(get_cycles() - t0) < cycles)
 		cpu_relax();
 }
+EXPORT_SYMBOL(__delay);
 
 void udelay(unsigned long usecs)
 {
diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
index 81f7d9ce6d881df0da157b0913275f49517495d4..eb22ab49b3e008ec4ab677778302d5dbbea358b1 100644
--- a/arch/riscv/mm/Makefile
+++ b/arch/riscv/mm/Makefile
@@ -2,3 +2,4 @@ obj-y += init.o
 obj-y += fault.o
 obj-y += extable.o
 obj-y += ioremap.o
+obj-y += cacheflush.o
diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
new file mode 100644
index 0000000000000000000000000000000000000000..498c0a0814fe3fa2ddaa59cd0de0831aa94eba87
--- /dev/null
+++ b/arch/riscv/mm/cacheflush.c
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2017 SiFive
+ *
+ *   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, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <asm/pgtable.h>
+#include <asm/cacheflush.h>
+
+void flush_icache_pte(pte_t pte)
+{
+	struct page *page = pte_page(pte);
+
+	if (!test_and_set_bit(PG_dcache_clean, &page->flags))
+		flush_icache_all();
+}
diff --git a/arch/riscv/mm/ioremap.c b/arch/riscv/mm/ioremap.c
index e99194a4077ec2397aa978732e8554a2b303a6b4..70ef2724cdf61e5b2001f0ec6243b7f5e9c6bfaa 100644
--- a/arch/riscv/mm/ioremap.c
+++ b/arch/riscv/mm/ioremap.c
@@ -85,7 +85,7 @@ EXPORT_SYMBOL(ioremap);
  *
  * Caller must ensure there is only one unmapping for the same pointer.
  */
-void iounmap(void __iomem *addr)
+void iounmap(volatile void __iomem *addr)
 {
 	vunmap((void *)((unsigned long)addr & PAGE_MASK));
 }
diff --git a/include/lib/libgcc.h b/include/linux/libgcc.h
similarity index 100%
rename from include/lib/libgcc.h
rename to include/linux/libgcc.h
diff --git a/lib/ashldi3.c b/lib/ashldi3.c
index 1b6087db95a54b665262ec8ee142a3a323850578..3ffc46e3bb6c84cee02bcb038b7739a52cbe8761 100644
--- a/lib/ashldi3.c
+++ b/lib/ashldi3.c
@@ -16,7 +16,7 @@
 
 #include <linux/export.h>
 
-#include <lib/libgcc.h>
+#include <linux/libgcc.h>
 
 long long notrace __ashldi3(long long u, word_type b)
 {
diff --git a/lib/ashrdi3.c b/lib/ashrdi3.c
index 2e67c97ac65a98737d054898884a0b944c3cd6de..ea054550f0e800897652b1415d9baa2b356d376d 100644
--- a/lib/ashrdi3.c
+++ b/lib/ashrdi3.c
@@ -16,7 +16,7 @@
 
 #include <linux/export.h>
 
-#include <lib/libgcc.h>
+#include <linux/libgcc.h>
 
 long long notrace __ashrdi3(long long u, word_type b)
 {
diff --git a/lib/cmpdi2.c b/lib/cmpdi2.c
index 6d7ebf6c2b862f32b9dd391c8f456769472ec62d..2250da7e503ebaebbdd86a967eb2b6c36560d3f6 100644
--- a/lib/cmpdi2.c
+++ b/lib/cmpdi2.c
@@ -16,7 +16,7 @@
 
 #include <linux/export.h>
 
-#include <lib/libgcc.h>
+#include <linux/libgcc.h>
 
 word_type notrace __cmpdi2(long long a, long long b)
 {
diff --git a/lib/lshrdi3.c b/lib/lshrdi3.c
index 8e845f4bb65f48eaec6ae720fb2515d1e8de52b8..99cfa5721f2d2e0f042a214ccd40a7d63261d01c 100644
--- a/lib/lshrdi3.c
+++ b/lib/lshrdi3.c
@@ -17,7 +17,7 @@
  */
 
 #include <linux/module.h>
-#include <lib/libgcc.h>
+#include <linux/libgcc.h>
 
 long long notrace __lshrdi3(long long u, word_type b)
 {
diff --git a/lib/muldi3.c b/lib/muldi3.c
index 88938543e10a626f183fcea3e9127af286967daf..54c8b3123376bc0a17c3dec743fd9c42a8231fab 100644
--- a/lib/muldi3.c
+++ b/lib/muldi3.c
@@ -15,7 +15,7 @@
  */
 
 #include <linux/export.h>
-#include <lib/libgcc.h>
+#include <linux/libgcc.h>
 
 #define W_TYPE_SIZE 32
 
diff --git a/lib/ucmpdi2.c b/lib/ucmpdi2.c
index 49a53505c8e3527959f0586de21ea6b774fc7fad..25ca2d4c1e19118b2c34bdee66ab1a64ed54fe3d 100644
--- a/lib/ucmpdi2.c
+++ b/lib/ucmpdi2.c
@@ -15,7 +15,7 @@
  */
 
 #include <linux/module.h>
-#include <lib/libgcc.h>
+#include <linux/libgcc.h>
 
 word_type __ucmpdi2(unsigned long long a, unsigned long long b)
 {