1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Copyright (C) 2012 Regents of the University of California
 4 * Copyright (C) 2014 Darius Rad <darius@bluespec.com>
 5 * Copyright (C) 2017 SiFive
 6 */
 7
 8#include <linux/syscalls.h>
 9#include <asm/unistd.h>
10#include <asm/cacheflush.h>
11#include <asm-generic/mman-common.h>
12
13static long riscv_sys_mmap(unsigned long addr, unsigned long len,
14			   unsigned long prot, unsigned long flags,
15			   unsigned long fd, off_t offset,
16			   unsigned long page_shift_offset)
17{
18	if (unlikely(offset & (~PAGE_MASK >> page_shift_offset)))
19		return -EINVAL;
20
21	if ((prot & PROT_WRITE) && (prot & PROT_EXEC))
22		if (unlikely(!(prot & PROT_READ)))
23			return -EINVAL;
24
25	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
26			       offset >> (PAGE_SHIFT - page_shift_offset));
27}
28
29#ifdef CONFIG_64BIT
30SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
31	unsigned long, prot, unsigned long, flags,
32	unsigned long, fd, off_t, offset)
33{
34	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 0);
35}
36#else
37SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
38	unsigned long, prot, unsigned long, flags,
39	unsigned long, fd, off_t, offset)
40{
41	/*
42	 * Note that the shift for mmap2 is constant (12),
43	 * regardless of PAGE_SIZE
44	 */
45	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 12);
46}
47#endif /* !CONFIG_64BIT */
48
49/*
50 * Allows the instruction cache to be flushed from userspace.  Despite RISC-V
51 * having a direct 'fence.i' instruction available to userspace (which we
52 * can't trap!), that's not actually viable when running on Linux because the
53 * kernel might schedule a process on another hart.  There is no way for
54 * userspace to handle this without invoking the kernel (as it doesn't know the
55 * thread->hart mappings), so we've defined a RISC-V specific system call to
56 * flush the instruction cache.
57 *
58 * sys_riscv_flush_icache() is defined to flush the instruction cache over an
59 * address range, with the flush applying to either all threads or just the
60 * caller.  We don't currently do anything with the address range, that's just
61 * in there for forwards compatibility.
62 */
63SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
64	uintptr_t, flags)
65{
66	/* Check the reserved flags. */
67	if (unlikely(flags & ~SYS_RISCV_FLUSH_ICACHE_ALL))
68		return -EINVAL;
69
70	flush_icache_mm(current->mm, flags & SYS_RISCV_FLUSH_ICACHE_LOCAL);
71
72	return 0;
73}