1 files changed, 69 insertions, 0 deletions
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
new file mode 100644
index 000000000..bb4026850
--- /dev/null
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2014 Darius Rad <darius@bluespec.com>
+ * Copyright (C) 2017 SiFive
+ */
+
+#include <linux/syscalls.h>
+#include <asm/unistd.h>
+#include <asm/cacheflush.h>
+#include <asm-generic/mman-common.h>
+
+static long riscv_sys_mmap(unsigned long addr, unsigned long len,
+			   unsigned long prot, unsigned long flags,
+			   unsigned long fd, off_t offset,
+			   unsigned long page_shift_offset)
+{
+	if (unlikely(offset & (~PAGE_MASK >> page_shift_offset)))
+		return -EINVAL;
+
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       offset >> (PAGE_SHIFT - page_shift_offset));
+}
+
+#ifdef CONFIG_64BIT
+SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
+	unsigned long, prot, unsigned long, flags,
+	unsigned long, fd, off_t, offset)
+{
+	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 0);
+}
+#else
+SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
+	unsigned long, prot, unsigned long, flags,
+	unsigned long, fd, off_t, offset)
+{
+	/*
+	 * Note that the shift for mmap2 is constant (12),
+	 * regardless of PAGE_SIZE
+	 */
+	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 12);
+}
+#endif /* !CONFIG_64BIT */
+
+/*
+ * 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)
+{
+	/* Check the reserved flags. */
+	if (unlikely(flags & ~SYS_RISCV_FLUSH_ICACHE_ALL))
+		return -EINVAL;
+
+	flush_icache_mm(current->mm, flags & SYS_RISCV_FLUSH_ICACHE_LOCAL);
+
+	return 0;
+}