// SPDX-License-Identifier: GPL-2.0 /* * Access to PCI I/O memory from user space programs. * * Copyright IBM Corp. 2014 * Author(s): Alexey Ishchuk */ #include #include #include #include #include #include #include #include static inline void zpci_err_mmio(u8 cc, u8 status, u64 offset) { struct { u64 offset; u8 cc; u8 status; } data = {offset, cc, status}; zpci_err_hex(&data, sizeof(data)); } static inline int __pcistb_mio_inuser( void __iomem *ioaddr, const void __user *src, u64 len, u8 *status) { int cc = -ENXIO; asm volatile ( " sacf 256\n" "0: .insn rsy,0xeb00000000d4,%[len],%[ioaddr],%[src]\n" "1: ipm %[cc]\n" " srl %[cc],28\n" "2: sacf 768\n" EX_TABLE(0b, 2b) EX_TABLE(1b, 2b) : [cc] "+d" (cc), [len] "+d" (len) : [ioaddr] "a" (ioaddr), [src] "Q" (*((u8 __force *)src)) : "cc", "memory"); *status = len >> 24 & 0xff; return cc; } static inline int __pcistg_mio_inuser( void __iomem *ioaddr, const void __user *src, u64 ulen, u8 *status) { register u64 addr asm("2") = (u64 __force) ioaddr; register u64 len asm("3") = ulen; int cc = -ENXIO; u64 val = 0; u64 cnt = ulen; u8 tmp; /* * copy 0 < @len <= 8 bytes from @src into the right most bytes of * a register, then store it to PCI at @ioaddr while in secondary * address space. pcistg then uses the user mappings. */ asm volatile ( " sacf 256\n" "0: llgc %[tmp],0(%[src])\n" " sllg %[val],%[val],8\n" " aghi %[src],1\n" " ogr %[val],%[tmp]\n" " brctg %[cnt],0b\n" "1: .insn rre,0xb9d40000,%[val],%[ioaddr]\n" "2: ipm %[cc]\n" " srl %[cc],28\n" "3: sacf 768\n" EX_TABLE(0b, 3b) EX_TABLE(1b, 3b) EX_TABLE(2b, 3b) : [src] "+a" (src), [cnt] "+d" (cnt), [val] "+d" (val), [tmp] "=d" (tmp), [len] "+d" (len), [cc] "+d" (cc), [ioaddr] "+a" (addr) :: "cc", "memory"); *status = len >> 24 & 0xff; /* did we read everything from user memory? */ if (!cc && cnt != 0) cc = -EFAULT; return cc; } static inline int __memcpy_toio_inuser(void __iomem *dst, const void __user *src, size_t n) { int size, rc = 0; u8 status = 0; mm_segment_t old_fs; if (!src) return -EINVAL; old_fs = enable_sacf_uaccess(); while (n > 0) { size = zpci_get_max_write_size((u64 __force) dst, (u64 __force) src, n, ZPCI_MAX_WRITE_SIZE); if (size > 8) /* main path */ rc = __pcistb_mio_inuser(dst, src, size, &status); else rc = __pcistg_mio_inuser(dst, src, size, &status); if (rc) break; src += size; dst += size; n -= size; } disable_sacf_uaccess(old_fs); if (rc) zpci_err_mmio(rc, status, (__force u64) dst); return rc; } static long get_pfn(unsigned long user_addr, unsigned long access, unsigned long *pfn) { struct vm_area_struct *vma; long ret; down_read(¤t->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(¤t->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; /* * Only support read access to MIO capable devices on a MIO enabled * system. Otherwise we would have to check for every address if it is * a special ZPCI_ADDR and we would have to do a get_pfn() which we * don't need for MIO capable devices. */ if (static_branch_likely(&have_mio)) { ret = __memcpy_toio_inuser((void __iomem *) mmio_addr, user_buffer, length); return ret; } 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; } static inline int __pcilg_mio_inuser( void __user *dst, const void __iomem *ioaddr, u64 ulen, u8 *status) { register u64 addr asm("2") = (u64 __force) ioaddr; register u64 len asm("3") = ulen; u64 cnt = ulen; int shift = ulen * 8; int cc = -ENXIO; u64 val, tmp; /* * read 0 < @len <= 8 bytes from the PCI memory mapped at @ioaddr (in * user space) into a register using pcilg then store these bytes at * user address @dst */ asm volatile ( " sacf 256\n" "0: .insn rre,0xb9d60000,%[val],%[ioaddr]\n" "1: ipm %[cc]\n" " srl %[cc],28\n" " ltr %[cc],%[cc]\n" " jne 4f\n" "2: ahi %[shift],-8\n" " srlg %[tmp],%[val],0(%[shift])\n" "3: stc %[tmp],0(%[dst])\n" " aghi %[dst],1\n" " brctg %[cnt],2b\n" "4: sacf 768\n" EX_TABLE(0b, 4b) EX_TABLE(1b, 4b) EX_TABLE(3b, 4b) : [cc] "+d" (cc), [val] "=d" (val), [len] "+d" (len), [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp), [shift] "+d" (shift) : [ioaddr] "a" (addr) : "cc", "memory"); /* did we write everything to the user space buffer? */ if (!cc && cnt != 0) cc = -EFAULT; *status = len >> 24 & 0xff; return cc; } static inline int __memcpy_fromio_inuser(void __user *dst, const void __iomem *src, unsigned long n) { int size, rc = 0; u8 status; mm_segment_t old_fs; old_fs = enable_sacf_uaccess(); while (n > 0) { size = zpci_get_max_write_size((u64 __force) src, (u64 __force) dst, n, ZPCI_MAX_READ_SIZE); rc = __pcilg_mio_inuser(dst, src, size, &status); if (rc) break; src += size; dst += size; n -= size; } disable_sacf_uaccess(old_fs); if (rc) zpci_err_mmio(rc, status, (__force u64) dst); return rc; } 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; /* * Only support write access to MIO capable devices on a MIO enabled * system. Otherwise we would have to check for every address if it is * a special ZPCI_ADDR and we would have to do a get_pfn() which we * don't need for MIO capable devices. */ if (static_branch_likely(&have_mio)) { ret = __memcpy_fromio_inuser( user_buffer, (const void __iomem *)mmio_addr, length); return ret; } 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; }