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authorAlexey Ishchuk <aishchuk@linux.vnet.ibm.com>2014-11-14 16:27:58 +0300
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2014-11-19 11:46:43 +0300
commit4eafad7febd482092b331ea72c37274d745956be (patch)
tree81df1dd45ee04b56180da2214fae5a3bfe66ea2a /arch/s390/pci
parent86c558e8d3b774580faf8250092388d52cfde63e (diff)
downloadlinux-4eafad7febd482092b331ea72c37274d745956be.tar.xz
s390/kernel: add system calls for PCI memory access
Add the new __NR_s390_pci_mmio_write and __NR_s390_pci_mmio_read system calls to allow user space applications to access device PCI I/O memory pages on s390x platform. [ Martin Schwidefsky: some code beautification ] Signed-off-by: Alexey Ishchuk <aishchuk@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/pci')
-rw-r--r--arch/s390/pci/Makefile2
-rw-r--r--arch/s390/pci/pci_mmio.c115
2 files changed, 116 insertions, 1 deletions
diff --git a/arch/s390/pci/Makefile b/arch/s390/pci/Makefile
index a9e1dc4ae442..805d8b29193a 100644
--- a/arch/s390/pci/Makefile
+++ b/arch/s390/pci/Makefile
@@ -3,4 +3,4 @@
#
obj-$(CONFIG_PCI) += pci.o pci_dma.o pci_clp.o pci_sysfs.o \
- pci_event.o pci_debug.o pci_insn.o
+ pci_event.o pci_debug.o pci_insn.o pci_mmio.o
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(&current->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(&current->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;
+}