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/*
* 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;
}
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