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