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-rw-r--r--arch/s390/pci/pci_mmio.c335
1 files changed, 335 insertions, 0 deletions
diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c
new file mode 100644
index 000000000..a90499c08
--- /dev/null
+++ b/arch/s390/pci/pci_mmio.c
@@ -0,0 +1,335 @@
+// 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>
+#include <asm/asm-extable.h>
+#include <asm/pci_io.h>
+#include <asm/pci_debug.h>
+
+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)
+{
+ union register_pair ioaddr_len = {.even = (u64 __force)ioaddr, .odd = 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"
+ "4: sllg %[val],%[val],8\n"
+ " aghi %[src],1\n"
+ " ogr %[val],%[tmp]\n"
+ " brctg %[cnt],0b\n"
+ "1: .insn rre,0xb9d40000,%[val],%[ioaddr_len]\n"
+ "2: ipm %[cc]\n"
+ " srl %[cc],28\n"
+ "3: sacf 768\n"
+ EX_TABLE(0b, 3b) EX_TABLE(4b, 3b) EX_TABLE(1b, 3b) EX_TABLE(2b, 3b)
+ :
+ [src] "+a" (src), [cnt] "+d" (cnt),
+ [val] "+d" (val), [tmp] "=d" (tmp),
+ [cc] "+d" (cc), [ioaddr_len] "+&d" (ioaddr_len.pair)
+ :: "cc", "memory");
+ *status = ioaddr_len.odd >> 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;
+
+ if (!src)
+ return -EINVAL;
+
+ while (n > 0) {
+ size = zpci_get_max_io_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;
+ }
+ if (rc)
+ zpci_err_mmio(rc, status, (__force u64) dst);
+ return rc;
+}
+
+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;
+ struct vm_area_struct *vma;
+ pte_t *ptep;
+ spinlock_t *ptl;
+ long ret;
+
+ if (!zpci_is_enabled())
+ return -ENODEV;
+
+ if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
+ return -EINVAL;
+
+ /*
+ * We only support write access to MIO capable devices if we are on
+ * a MIO enabled system. Otherwise we would have to check for every
+ * address if it is a special ZPCI_ADDR and would have to do
+ * a pfn lookup which we don't need for MIO capable devices. Currently
+ * ISM devices are the only devices without MIO support and there is no
+ * known need for accessing these from userspace.
+ */
+ 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 = -EFAULT;
+ if (copy_from_user(buf, user_buffer, length))
+ goto out_free;
+
+ mmap_read_lock(current->mm);
+ ret = -EINVAL;
+ vma = vma_lookup(current->mm, mmio_addr);
+ if (!vma)
+ goto out_unlock_mmap;
+ if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+ goto out_unlock_mmap;
+ ret = -EACCES;
+ if (!(vma->vm_flags & VM_WRITE))
+ goto out_unlock_mmap;
+
+ ret = follow_pte(vma->vm_mm, mmio_addr, &ptep, &ptl);
+ if (ret)
+ goto out_unlock_mmap;
+
+ io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) |
+ (mmio_addr & ~PAGE_MASK));
+
+ if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
+ goto out_unlock_pt;
+
+ ret = zpci_memcpy_toio(io_addr, buf, length);
+out_unlock_pt:
+ pte_unmap_unlock(ptep, ptl);
+out_unlock_mmap:
+ mmap_read_unlock(current->mm);
+out_free:
+ 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)
+{
+ union register_pair ioaddr_len = {.even = (u64 __force)ioaddr, .odd = 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_len]\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"
+ "5: aghi %[dst],1\n"
+ " brctg %[cnt],2b\n"
+ "4: sacf 768\n"
+ EX_TABLE(0b, 4b) EX_TABLE(1b, 4b) EX_TABLE(3b, 4b) EX_TABLE(5b, 4b)
+ :
+ [ioaddr_len] "+&d" (ioaddr_len.pair),
+ [cc] "+d" (cc), [val] "=d" (val),
+ [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp),
+ [shift] "+d" (shift)
+ :: "cc", "memory");
+
+ /* did we write everything to the user space buffer? */
+ if (!cc && cnt != 0)
+ cc = -EFAULT;
+
+ *status = ioaddr_len.odd >> 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;
+
+ while (n > 0) {
+ size = zpci_get_max_io_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;
+ }
+ 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;
+ struct vm_area_struct *vma;
+ pte_t *ptep;
+ spinlock_t *ptl;
+ long ret;
+
+ if (!zpci_is_enabled())
+ return -ENODEV;
+
+ if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
+ return -EINVAL;
+
+ /*
+ * We only support read access to MIO capable devices if we are on
+ * a MIO enabled system. Otherwise we would have to check for every
+ * address if it is a special ZPCI_ADDR and would have to do
+ * a pfn lookup which we don't need for MIO capable devices. Currently
+ * ISM devices are the only devices without MIO support and there is no
+ * known need for accessing these from userspace.
+ */
+ 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;
+ }
+
+ mmap_read_lock(current->mm);
+ ret = -EINVAL;
+ vma = vma_lookup(current->mm, mmio_addr);
+ if (!vma)
+ goto out_unlock_mmap;
+ if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+ goto out_unlock_mmap;
+ ret = -EACCES;
+ if (!(vma->vm_flags & VM_WRITE))
+ goto out_unlock_mmap;
+
+ ret = follow_pte(vma->vm_mm, mmio_addr, &ptep, &ptl);
+ if (ret)
+ goto out_unlock_mmap;
+
+ io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) |
+ (mmio_addr & ~PAGE_MASK));
+
+ if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) {
+ ret = -EFAULT;
+ goto out_unlock_pt;
+ }
+ ret = zpci_memcpy_fromio(buf, io_addr, length);
+
+out_unlock_pt:
+ pte_unmap_unlock(ptep, ptl);
+out_unlock_mmap:
+ mmap_read_unlock(current->mm);
+
+ if (!ret && copy_to_user(user_buffer, buf, length))
+ ret = -EFAULT;
+
+ if (buf != local_buf)
+ kfree(buf);
+ return ret;
+}
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