s390_pci_mmio_write, s390_pci_mmio_read − transfer data to/from PCI MMIO memory page
Standard C library (libc, −lc)
#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[.length],
size_t length);
int syscall(SYS_s390_pci_mmio_read, unsigned long
mmio_addr,
void user_buffer[.length],
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. |
Linux on s390.
Linux 3.19. System z EC12.
syscall(2)