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-rw-r--r--arch/s390/lib/uaccess_pt.c320
1 files changed, 319 insertions, 1 deletions
diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index 24ead559c7b..637192fa7c9 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -1,7 +1,8 @@
/*
* arch/s390/lib/uaccess_pt.c
*
- * User access functions based on page table walks.
+ * User access functions based on page table walks for enhanced
+ * system layout without hardware support.
*
* Copyright IBM Corp. 2006
* Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
@@ -134,6 +135,49 @@ fault:
goto retry;
}
+/*
+ * Do DAT for user address by page table walk, return kernel address.
+ * This function needs to be called with current->mm->page_table_lock held.
+ */
+static inline unsigned long __dat_user_addr(unsigned long uaddr)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long pfn, ret;
+ pgd_t *pgd;
+ pmd_t *pmd;
+ pte_t *pte;
+ int rc;
+
+ ret = 0;
+retry:
+ pgd = pgd_offset(mm, uaddr);
+ if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
+ goto fault;
+
+ pmd = pmd_offset(pgd, uaddr);
+ if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
+ goto fault;
+
+ pte = pte_offset_map(pmd, uaddr);
+ if (!pte || !pte_present(*pte))
+ goto fault;
+
+ pfn = pte_pfn(*pte);
+ if (!pfn_valid(pfn))
+ goto out;
+
+ ret = (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1));
+out:
+ return ret;
+fault:
+ spin_unlock(&mm->page_table_lock);
+ rc = __handle_fault(mm, uaddr, 0);
+ spin_lock(&mm->page_table_lock);
+ if (rc)
+ goto out;
+ goto retry;
+}
+
size_t copy_from_user_pt(size_t n, const void __user *from, void *to)
{
size_t rc;
@@ -156,3 +200,277 @@ size_t copy_to_user_pt(size_t n, void __user *to, const void *from)
}
return __user_copy_pt((unsigned long) to, (void *) from, n, 1);
}
+
+static size_t clear_user_pt(size_t n, void __user *to)
+{
+ long done, size, ret;
+
+ if (segment_eq(get_fs(), KERNEL_DS)) {
+ memset((void __kernel __force *) to, 0, n);
+ return 0;
+ }
+ done = 0;
+ do {
+ if (n - done > PAGE_SIZE)
+ size = PAGE_SIZE;
+ else
+ size = n - done;
+ ret = __user_copy_pt((unsigned long) to + done,
+ &empty_zero_page, size, 1);
+ done += size;
+ if (ret)
+ return ret + n - done;
+ } while (done < n);
+ return 0;
+}
+
+static size_t strnlen_user_pt(size_t count, const char __user *src)
+{
+ char *addr;
+ unsigned long uaddr = (unsigned long) src;
+ struct mm_struct *mm = current->mm;
+ unsigned long offset, pfn, done, len;
+ pgd_t *pgd;
+ pmd_t *pmd;
+ pte_t *pte;
+ size_t len_str;
+
+ if (segment_eq(get_fs(), KERNEL_DS))
+ return strnlen((const char __kernel __force *) src, count) + 1;
+ done = 0;
+retry:
+ spin_lock(&mm->page_table_lock);
+ do {
+ pgd = pgd_offset(mm, uaddr);
+ if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
+ goto fault;
+
+ pmd = pmd_offset(pgd, uaddr);
+ if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
+ goto fault;
+
+ pte = pte_offset_map(pmd, uaddr);
+ if (!pte || !pte_present(*pte))
+ goto fault;
+
+ pfn = pte_pfn(*pte);
+ if (!pfn_valid(pfn)) {
+ done = -1;
+ goto out;
+ }
+
+ offset = uaddr & (PAGE_SIZE-1);
+ addr = (char *)(pfn << PAGE_SHIFT) + offset;
+ len = min(count - done, PAGE_SIZE - offset);
+ len_str = strnlen(addr, len);
+ done += len_str;
+ uaddr += len_str;
+ } while ((len_str == len) && (done < count));
+out:
+ spin_unlock(&mm->page_table_lock);
+ return done + 1;
+fault:
+ spin_unlock(&mm->page_table_lock);
+ if (__handle_fault(mm, uaddr, 0)) {
+ return 0;
+ }
+ goto retry;
+}
+
+static size_t strncpy_from_user_pt(size_t count, const char __user *src,
+ char *dst)
+{
+ size_t n = strnlen_user_pt(count, src);
+
+ if (!n)
+ return -EFAULT;
+ if (n > count)
+ n = count;
+ if (segment_eq(get_fs(), KERNEL_DS)) {
+ memcpy(dst, (const char __kernel __force *) src, n);
+ if (dst[n-1] == '\0')
+ return n-1;
+ else
+ return n;
+ }
+ if (__user_copy_pt((unsigned long) src, dst, n, 0))
+ return -EFAULT;
+ if (dst[n-1] == '\0')
+ return n-1;
+ else
+ return n;
+}
+
+static size_t copy_in_user_pt(size_t n, void __user *to,
+ const void __user *from)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long offset_from, offset_to, offset_max, pfn_from, pfn_to,
+ uaddr, done, size;
+ unsigned long uaddr_from = (unsigned long) from;
+ unsigned long uaddr_to = (unsigned long) to;
+ pgd_t *pgd_from, *pgd_to;
+ pmd_t *pmd_from, *pmd_to;
+ pte_t *pte_from, *pte_to;
+ int write_user;
+
+ done = 0;
+retry:
+ spin_lock(&mm->page_table_lock);
+ do {
+ pgd_from = pgd_offset(mm, uaddr_from);
+ if (pgd_none(*pgd_from) || unlikely(pgd_bad(*pgd_from))) {
+ uaddr = uaddr_from;
+ write_user = 0;
+ goto fault;
+ }
+ pgd_to = pgd_offset(mm, uaddr_to);
+ if (pgd_none(*pgd_to) || unlikely(pgd_bad(*pgd_to))) {
+ uaddr = uaddr_to;
+ write_user = 1;
+ goto fault;
+ }
+
+ pmd_from = pmd_offset(pgd_from, uaddr_from);
+ if (pmd_none(*pmd_from) || unlikely(pmd_bad(*pmd_from))) {
+ uaddr = uaddr_from;
+ write_user = 0;
+ goto fault;
+ }
+ pmd_to = pmd_offset(pgd_to, uaddr_to);
+ if (pmd_none(*pmd_to) || unlikely(pmd_bad(*pmd_to))) {
+ uaddr = uaddr_to;
+ write_user = 1;
+ goto fault;
+ }
+
+ pte_from = pte_offset_map(pmd_from, uaddr_from);
+ if (!pte_from || !pte_present(*pte_from)) {
+ uaddr = uaddr_from;
+ write_user = 0;
+ goto fault;
+ }
+ pte_to = pte_offset_map(pmd_to, uaddr_to);
+ if (!pte_to || !pte_present(*pte_to) || !pte_write(*pte_to)) {
+ uaddr = uaddr_to;
+ write_user = 1;
+ goto fault;
+ }
+
+ pfn_from = pte_pfn(*pte_from);
+ if (!pfn_valid(pfn_from))
+ goto out;
+ pfn_to = pte_pfn(*pte_to);
+ if (!pfn_valid(pfn_to))
+ goto out;
+
+ offset_from = uaddr_from & (PAGE_SIZE-1);
+ offset_to = uaddr_from & (PAGE_SIZE-1);
+ offset_max = max(offset_from, offset_to);
+ size = min(n - done, PAGE_SIZE - offset_max);
+
+ memcpy((void *)(pfn_to << PAGE_SHIFT) + offset_to,
+ (void *)(pfn_from << PAGE_SHIFT) + offset_from, size);
+ done += size;
+ uaddr_from += size;
+ uaddr_to += size;
+ } while (done < n);
+out:
+ spin_unlock(&mm->page_table_lock);
+ return n - done;
+fault:
+ spin_unlock(&mm->page_table_lock);
+ if (__handle_fault(mm, uaddr, write_user))
+ return n - done;
+ goto retry;
+}
+
+#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg) \
+ asm volatile("0: l %1,0(%6)\n" \
+ "1: " insn \
+ "2: cs %1,%2,0(%6)\n" \
+ "3: jl 1b\n" \
+ " lhi %0,0\n" \
+ "4:\n" \
+ EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b) \
+ : "=d" (ret), "=&d" (oldval), "=&d" (newval), \
+ "=m" (*uaddr) \
+ : "0" (-EFAULT), "d" (oparg), "a" (uaddr), \
+ "m" (*uaddr) : "cc" );
+
+int futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
+{
+ int oldval = 0, newval, ret;
+
+ spin_lock(&current->mm->page_table_lock);
+ uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
+ if (!uaddr) {
+ spin_unlock(&current->mm->page_table_lock);
+ return -EFAULT;
+ }
+ get_page(virt_to_page(uaddr));
+ spin_unlock(&current->mm->page_table_lock);
+ switch (op) {
+ case FUTEX_OP_SET:
+ __futex_atomic_op("lr %2,%5\n",
+ ret, oldval, newval, uaddr, oparg);
+ break;
+ case FUTEX_OP_ADD:
+ __futex_atomic_op("lr %2,%1\nar %2,%5\n",
+ ret, oldval, newval, uaddr, oparg);
+ break;
+ case FUTEX_OP_OR:
+ __futex_atomic_op("lr %2,%1\nor %2,%5\n",
+ ret, oldval, newval, uaddr, oparg);
+ break;
+ case FUTEX_OP_ANDN:
+ __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
+ ret, oldval, newval, uaddr, oparg);
+ break;
+ case FUTEX_OP_XOR:
+ __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
+ ret, oldval, newval, uaddr, oparg);
+ break;
+ default:
+ ret = -ENOSYS;
+ }
+ put_page(virt_to_page(uaddr));
+ *old = oldval;
+ return ret;
+}
+
+int futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval)
+{
+ int ret;
+
+ spin_lock(&current->mm->page_table_lock);
+ uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
+ if (!uaddr) {
+ spin_unlock(&current->mm->page_table_lock);
+ return -EFAULT;
+ }
+ get_page(virt_to_page(uaddr));
+ spin_unlock(&current->mm->page_table_lock);
+ asm volatile(" cs %1,%4,0(%5)\n"
+ "0: lr %0,%1\n"
+ "1:\n"
+ EX_TABLE(0b,1b)
+ : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
+ : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
+ : "cc", "memory" );
+ put_page(virt_to_page(uaddr));
+ return ret;
+}
+
+struct uaccess_ops uaccess_pt = {
+ .copy_from_user = copy_from_user_pt,
+ .copy_from_user_small = copy_from_user_pt,
+ .copy_to_user = copy_to_user_pt,
+ .copy_to_user_small = copy_to_user_pt,
+ .copy_in_user = copy_in_user_pt,
+ .clear_user = clear_user_pt,
+ .strnlen_user = strnlen_user_pt,
+ .strncpy_from_user = strncpy_from_user_pt,
+ .futex_atomic_op = futex_atomic_op_pt,
+ .futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
+};
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-11 12:52:41 +0000