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s390/kernel: add system calls for PCI memory access

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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>
This commit is contained in:
Alexey Ishchuk 2014-11-14 14:27:58 +01:00 committed by Martin Schwidefsky
parent 86c558e8d3
commit 4eafad7feb
7 changed files with 127 additions and 2 deletions
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4
arch/s390/include/uapi/asm/unistd.h
View File

@ -287,7 +287,9 @@
#define __NR_getrandom 349
#define __NR_memfd_create 350
#define __NR_bpf 351
#define NR_syscalls 352
#define __NR_s390_pci_mmio_write 352
#define __NR_s390_pci_mmio_read 353
#define NR_syscalls 354
/*
* There are some system calls that are not present on 64 bit, some

2
arch/s390/kernel/compat_wrapper.c
View File

@ -218,3 +218,5 @@ COMPAT_SYSCALL_WRAP3(seccomp, unsigned int, op, unsigned int, flags, const char
COMPAT_SYSCALL_WRAP3(getrandom, char __user *, buf, size_t, count, unsigned int, flags)
COMPAT_SYSCALL_WRAP2(memfd_create, const char __user *, uname, unsigned int, flags)
COMPAT_SYSCALL_WRAP3(bpf, int, cmd, union bpf_attr *, attr, unsigned int, size);
COMPAT_SYSCALL_WRAP3(s390_pci_mmio_write, const unsigned long, mmio_addr, const void __user *, user_buffer, const size_t, length);
COMPAT_SYSCALL_WRAP3(s390_pci_mmio_read, const unsigned long, mmio_addr, void __user *, user_buffer, const size_t, length);

2
arch/s390/kernel/entry.h
View File

@ -74,4 +74,6 @@ struct old_sigaction;
long sys_s390_personality(unsigned int personality);
long sys_s390_runtime_instr(int command, int signum);
long sys_s390_pci_mmio_write(unsigned long, const void __user *, size_t);
long sys_s390_pci_mmio_read(unsigned long, void __user *, size_t);
#endif /* _ENTRY_H */

2
arch/s390/kernel/syscalls.S
View File

@ -360,3 +360,5 @@ SYSCALL(sys_seccomp,sys_seccomp,compat_sys_seccomp)
SYSCALL(sys_getrandom,sys_getrandom,compat_sys_getrandom)
SYSCALL(sys_memfd_create,sys_memfd_create,compat_sys_memfd_create) /* 350 */
SYSCALL(sys_bpf,sys_bpf,compat_sys_bpf)
SYSCALL(sys_ni_syscall,sys_s390_pci_mmio_write,compat_sys_s390_pci_mmio_write)
SYSCALL(sys_ni_syscall,sys_s390_pci_mmio_read,compat_sys_s390_pci_mmio_read)

2
arch/s390/pci/Makefile
View File

@ -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

115
arch/s390/pci/pci_mmio.c Normal file
View File

@ -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;
}

2
kernel/sys_ni.c
View File

@ -169,6 +169,8 @@ cond_syscall(ppc_rtas);
cond_syscall(sys_spu_run);
cond_syscall(sys_spu_create);
cond_syscall(sys_subpage_prot);
cond_syscall(sys_s390_pci_mmio_read);
cond_syscall(sys_s390_pci_mmio_write);
/* mmu depending weak syscall entries */
cond_syscall(sys_mprotect);