cregit-Linux how code gets into the kernel

Release 4.14 arch/s390/pci/pci_mmio.c

Directory: arch/s390/pci
// SPDX-License-Identifier: GPL-2.0
/*
 * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Alexey Ishchuk106100.00%1100.00%
Total106100.00%1100.00%

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 __iomem *)((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; ret = zpci_memcpy_toio(io_addr, buf, length); 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 __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK)); if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) { ret = -EFAULT; goto out; } ret = zpci_memcpy_fromio(buf, io_addr, length); if (ret) goto out; if (copy_to_user(user_buffer, buf, length)) ret = -EFAULT; out: if (buf != local_buf) kfree(buf); return ret; }

Overall Contributors

PersonTokensPropCommitsCommitProp
Alexey Ishchuk51695.38%125.00%
Sebastian Ott224.07%125.00%
Heiko Carstens20.37%125.00%
Greg Kroah-Hartman10.18%125.00%
Total541100.00%4100.00%
Directory: arch/s390/pci
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