1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Access to PCI I/O memory from user space programs.
4 *
5 * Copyright IBM Corp. 2014
6 * Author(s): Alexey Ishchuk <aishchuk@linux.vnet.ibm.com>
7 */
8 #include <linux/kernel.h>
9 #include <linux/syscalls.h>
10 #include <linux/init.h>
11 #include <linux/mm.h>
12 #include <linux/errno.h>
13 #include <linux/pci.h>
14
get_pfn(unsigned long user_addr,unsigned long access,unsigned long * pfn)15 static long get_pfn(unsigned long user_addr, unsigned long access,
16 unsigned long *pfn)
17 {
18 struct vm_area_struct *vma;
19 long ret;
20
21 down_read(¤t->mm->mmap_sem);
22 ret = -EINVAL;
23 vma = find_vma(current->mm, user_addr);
24 if (!vma)
25 goto out;
26 ret = -EACCES;
27 if (!(vma->vm_flags & access))
28 goto out;
29 ret = follow_pfn(vma, user_addr, pfn);
30 out:
31 up_read(¤t->mm->mmap_sem);
32 return ret;
33 }
34
SYSCALL_DEFINE3(s390_pci_mmio_write,unsigned long,mmio_addr,const void __user *,user_buffer,size_t,length)35 SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
36 const void __user *, user_buffer, size_t, length)
37 {
38 u8 local_buf[64];
39 void __iomem *io_addr;
40 void *buf;
41 unsigned long pfn;
42 long ret;
43
44 if (!zpci_is_enabled())
45 return -ENODEV;
46
47 if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
48 return -EINVAL;
49 if (length > 64) {
50 buf = kmalloc(length, GFP_KERNEL);
51 if (!buf)
52 return -ENOMEM;
53 } else
54 buf = local_buf;
55
56 ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
57 if (ret)
58 goto out;
59 io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
60
61 ret = -EFAULT;
62 if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
63 goto out;
64
65 if (copy_from_user(buf, user_buffer, length))
66 goto out;
67
68 ret = zpci_memcpy_toio(io_addr, buf, length);
69 out:
70 if (buf != local_buf)
71 kfree(buf);
72 return ret;
73 }
74
SYSCALL_DEFINE3(s390_pci_mmio_read,unsigned long,mmio_addr,void __user *,user_buffer,size_t,length)75 SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
76 void __user *, user_buffer, size_t, length)
77 {
78 u8 local_buf[64];
79 void __iomem *io_addr;
80 void *buf;
81 unsigned long pfn;
82 long ret;
83
84 if (!zpci_is_enabled())
85 return -ENODEV;
86
87 if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
88 return -EINVAL;
89 if (length > 64) {
90 buf = kmalloc(length, GFP_KERNEL);
91 if (!buf)
92 return -ENOMEM;
93 } else
94 buf = local_buf;
95
96 ret = get_pfn(mmio_addr, VM_READ, &pfn);
97 if (ret)
98 goto out;
99 io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
100
101 if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) {
102 ret = -EFAULT;
103 goto out;
104 }
105 ret = zpci_memcpy_fromio(buf, io_addr, length);
106 if (ret)
107 goto out;
108 if (copy_to_user(user_buffer, buf, length))
109 ret = -EFAULT;
110
111 out:
112 if (buf != local_buf)
113 kfree(buf);
114 return ret;
115 }
116
