diff options
Diffstat (limited to 'arch/s390/pci/pci_mmio.c')
| -rw-r--r-- | arch/s390/pci/pci_mmio.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c new file mode 100644 index 000000000000..62c5ea6d8682 --- /dev/null +++ b/arch/s390/pci/pci_mmio.c @@ -0,0 +1,115 @@ +/* + * Access to PCI I/O memory from user space programs. + * + * Copyright IBM Corp. 2014 + * Author(s): Alexey Ishchuk <aishchuk@linux.vnet.ibm.com> + */ +#include <linux/kernel.h> +#include <linux/syscalls.h> +#include <linux/init.h> +#include <linux/mm.h> +#include <linux/errno.h> +#include <linux/pci.h> + +static long get_pfn(unsigned long user_addr, unsigned long access, + unsigned long *pfn) +{ + struct vm_area_struct *vma; + long ret; + + down_read(¤t->mm->mmap_sem); + ret = -EINVAL; + vma = find_vma(current->mm, user_addr); + if (!vma) + goto out; + ret = -EACCES; + if (!(vma->vm_flags & access)) + goto out; + ret = follow_pfn(vma, user_addr, pfn); +out: + up_read(¤t->mm->mmap_sem); + return ret; +} + +SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr, + const void __user *, user_buffer, size_t, length) +{ + u8 local_buf[64]; + void __iomem *io_addr; + void *buf; + unsigned long pfn; + long ret; + + if (!zpci_is_enabled()) + return -ENODEV; + + if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length) + return -EINVAL; + if (length > 64) { + buf = kmalloc(length, GFP_KERNEL); + if (!buf) + return -ENOMEM; + } else + buf = local_buf; + + ret = get_pfn(mmio_addr, VM_WRITE, &pfn); + if (ret) + goto out; + io_addr = (void *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK)); + + ret = -EFAULT; + if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) + goto out; + + if (copy_from_user(buf, user_buffer, length)) + goto out; + + memcpy_toio(io_addr, buf, length); + ret = 0; +out: + if (buf != local_buf) + kfree(buf); + return ret; +} + +SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr, + void __user *, user_buffer, size_t, length) +{ + u8 local_buf[64]; + void __iomem *io_addr; + void *buf; + unsigned long pfn; + long ret; + + if (!zpci_is_enabled()) + return -ENODEV; + + if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length) + return -EINVAL; + if (length > 64) { + buf = kmalloc(length, GFP_KERNEL); + if (!buf) + return -ENOMEM; + } else + buf = local_buf; + + ret = get_pfn(mmio_addr, VM_READ, &pfn); + if (ret) + goto out; + io_addr = (void *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK)); + + ret = -EFAULT; + if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) + goto out; + + memcpy_fromio(buf, io_addr, length); + + if (copy_to_user(user_buffer, buf, length)) + goto out; + + ret = 0; +out: + if (buf != local_buf) + kfree(buf); + return ret; +} |