Manpages - s390_pci_mmio_write.2

s390_pci_mmio_write, s390_pci_mmio_read - transfer data to/from PCI MMIO memory page

  #include <sys/syscall.h> /* Definition of SYS_* constants */
  #include <unistd.h>

  int syscall(SYS_s390_pci_mmio_write, unsigned long mmio_addr,
   const void *user_buffer, size_t length);
  int syscall(SYS_s390_pci_mmio_read, unsigned long mmio_addr,
   void *user_buffer, size_t length);

Note: glibc provides no wrappers for these system calls, necessitating the use of *syscall*(2).

The *s390_pci_mmio_write*() system call writes length bytes of data from the user-space buffer user_buffer to the PCI MMIO memory location specified by mmio_addr. The *s390_pci_mmio_read*() system call reads length bytes of data from the PCI MMIO memory location specified by mmio_addr to the user-space buffer user_buffer.

These system calls must be used instead of the simple assignment or data-transfer operations that are used to access the PCI MMIO memory areas mapped to user space on the Linux System z platform. The address specified by mmio_addr must belong to a PCI MMIO memory page mapping in the caller’s address space, and the data being written or read must not cross a page boundary. The length value cannot be greater than the system page size.

On success, *s390_pci_mmio_write*() and *s390_pci_mmio_read*() return 0. On failure, -1 is returned and errno is set to indicate the error.

EFAULT

The address in mmio_addr is invalid.

EFAULT

user_buffer does not point to a valid location in the caller’s address space.

EINVAL

Invalid length argument.

ENODEV

PCI support is not enabled.

ENOMEM

Insufficient memory.

These system calls are available since Linux 3.19.

This Linux-specific system call is available only on the s390 architecture. The required PCI support is available beginning with System z EC12.

*syscall*(2)

This page is part of release 5.13 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.