Initial file dump from open source releaseHEADmaster

1 files changed, 476 insertions, 0 deletions

diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
new file mode 100644
index 00000000..1bf40ef5
--- /dev/null
+++ b/arch/s390/lib/uaccess_pt.c
@@ -0,0 +1,476 @@
+/*
+ *  User access functions based on page table walks for enhanced
+ *  system layout without hardware support.
+ *
+ *    Copyright IBM Corp. 2006, 2012
+ *    Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
+ */
+
+#include <linux/errno.h>
+#include <linux/hardirq.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <asm/uaccess.h>
+#include <asm/futex.h>
+#include "uaccess.h"
+
+#ifndef CONFIG_64BIT
+#define AHI	"ahi"
+#define SLR	"slr"
+#else
+#define AHI	"aghi"
+#define SLR	"slgr"
+#endif
+
+static size_t strnlen_kernel(size_t count, const char __user *src)
+{
+	register unsigned long reg0 asm("0") = 0UL;
+	unsigned long tmp1, tmp2;
+
+	asm volatile(
+		"   la	  %2,0(%1)\n"
+		"   la	  %3,0(%0,%1)\n"
+		"  "SLR"  %0,%0\n"
+		"0: srst  %3,%2\n"
+		"   jo	  0b\n"
+		"   la	  %0,1(%3)\n"	/* strnlen_kernel results includes \0 */
+		"  "SLR"  %0,%1\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "+a" (count), "+a" (src), "=a" (tmp1), "=a" (tmp2)
+		: "d" (reg0) : "cc", "memory");
+	return count;
+}
+
+static size_t copy_in_kernel(size_t count, void __user *to,
+			     const void __user *from)
+{
+	unsigned long tmp1;
+
+	asm volatile(
+		"  "AHI"  %0,-1\n"
+		"   jo	  5f\n"
+		"   bras  %3,3f\n"
+		"0:"AHI"  %0,257\n"
+		"1: mvc	  0(1,%1),0(%2)\n"
+		"   la	  %1,1(%1)\n"
+		"   la	  %2,1(%2)\n"
+		"  "AHI"  %0,-1\n"
+		"   jnz	  1b\n"
+		"   j	  5f\n"
+		"2: mvc	  0(256,%1),0(%2)\n"
+		"   la	  %1,256(%1)\n"
+		"   la	  %2,256(%2)\n"
+		"3:"AHI"  %0,-256\n"
+		"   jnm	  2b\n"
+		"4: ex	  %0,1b-0b(%3)\n"
+		"5:"SLR"  %0,%0\n"
+		"6:\n"
+		EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
+		: "+a" (count), "+a" (to), "+a" (from), "=a" (tmp1)
+		: : "cc", "memory");
+	return count;
+}
+
+/*
+ * Returns kernel address for user virtual address. If the returned address is
+ * >= -4095 (IS_ERR_VALUE(x) returns true), a fault has occured and the address
+ * contains the (negative) exception code.
+ */
+#ifdef CONFIG_64BIT
+
+static unsigned long follow_table(struct mm_struct *mm,
+				  unsigned long address, int write)
+{
+	unsigned long *table = (unsigned long *)__pa(mm->pgd);
+
+	if (unlikely(address > mm->context.asce_limit - 1))
+		return -0x38UL;
+	switch (mm->context.asce_bits & _ASCE_TYPE_MASK) {
+	case _ASCE_TYPE_REGION1:
+		table = table + ((address >> 53) & 0x7ff);
+		if (unlikely(*table & _REGION_ENTRY_INV))
+			return -0x39UL;
+		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
+		/* fallthrough */
+	case _ASCE_TYPE_REGION2:
+		table = table + ((address >> 42) & 0x7ff);
+		if (unlikely(*table & _REGION_ENTRY_INV))
+			return -0x3aUL;
+		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
+		/* fallthrough */
+	case _ASCE_TYPE_REGION3:
+		table = table + ((address >> 31) & 0x7ff);
+		if (unlikely(*table & _REGION_ENTRY_INV))
+			return -0x3bUL;
+		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
+		/* fallthrough */
+	case _ASCE_TYPE_SEGMENT:
+		table = table + ((address >> 20) & 0x7ff);
+		if (unlikely(*table & _SEGMENT_ENTRY_INV))
+			return -0x10UL;
+		if (unlikely(*table & _SEGMENT_ENTRY_LARGE)) {
+			if (write && (*table & _SEGMENT_ENTRY_RO))
+				return -0x04UL;
+			return (*table & _SEGMENT_ENTRY_ORIGIN_LARGE) +
+				(address & ~_SEGMENT_ENTRY_ORIGIN_LARGE);
+		}
+		table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);
+	}
+	table = table + ((address >> 12) & 0xff);
+	if (unlikely(*table & _PAGE_INVALID))
+		return -0x11UL;
+	if (write && (*table & _PAGE_RO))
+		return -0x04UL;
+	return (*table & PAGE_MASK) + (address & ~PAGE_MASK);
+}
+
+#else /* CONFIG_64BIT */
+
+static unsigned long follow_table(struct mm_struct *mm,
+				  unsigned long address, int write)
+{
+	unsigned long *table = (unsigned long *)__pa(mm->pgd);
+
+	table = table + ((address >> 20) & 0x7ff);
+	if (unlikely(*table & _SEGMENT_ENTRY_INV))
+		return -0x10UL;
+	table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);
+	table = table + ((address >> 12) & 0xff);
+	if (unlikely(*table & _PAGE_INVALID))
+		return -0x11UL;
+	if (write && (*table & _PAGE_RO))
+		return -0x04UL;
+	return (*table & PAGE_MASK) + (address & ~PAGE_MASK);
+}
+
+#endif /* CONFIG_64BIT */
+
+static __always_inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
+					     size_t n, int write_user)
+{
+	struct mm_struct *mm = current->mm;
+	unsigned long offset, done, size, kaddr;
+	void *from, *to;
+
+	done = 0;
+retry:
+	spin_lock(&mm->page_table_lock);
+	do {
+		kaddr = follow_table(mm, uaddr, write_user);
+		if (IS_ERR_VALUE(kaddr))
+			goto fault;
+
+		offset = uaddr & ~PAGE_MASK;
+		size = min(n - done, PAGE_SIZE - offset);
+		if (write_user) {
+			to = (void *) kaddr;
+			from = kptr + done;
+		} else {
+			from = (void *) kaddr;
+			to = kptr + done;
+		}
+		memcpy(to, from, size);
+		done += size;
+		uaddr += size;
+	} while (done < n);
+	spin_unlock(&mm->page_table_lock);
+	return n - done;
+fault:
+	spin_unlock(&mm->page_table_lock);
+	if (__handle_fault(uaddr, -kaddr, write_user))
+		return n - done;
+	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 __always_inline unsigned long __dat_user_addr(unsigned long uaddr,
+						     int write)
+{
+	struct mm_struct *mm = current->mm;
+	unsigned long kaddr;
+	int rc;
+
+retry:
+	kaddr = follow_table(mm, uaddr, write);
+	if (IS_ERR_VALUE(kaddr))
+		goto fault;
+
+	return kaddr;
+fault:
+	spin_unlock(&mm->page_table_lock);
+	rc = __handle_fault(uaddr, -kaddr, write);
+	spin_lock(&mm->page_table_lock);
+	if (!rc)
+		goto retry;
+	return 0;
+}
+
+size_t copy_from_user_pt(size_t n, const void __user *from, void *to)
+{
+	size_t rc;
+
+	if (segment_eq(get_fs(), KERNEL_DS))
+		return copy_in_kernel(n, (void __user *) to, from);
+	rc = __user_copy_pt((unsigned long) from, to, n, 0);
+	if (unlikely(rc))
+		memset(to + n - rc, 0, rc);
+	return rc;
+}
+
+size_t copy_to_user_pt(size_t n, void __user *to, const void *from)
+{
+	if (segment_eq(get_fs(), KERNEL_DS))
+		return copy_in_kernel(n, to, (void __user *) from);
+	return __user_copy_pt((unsigned long) to, (void *) from, n, 1);
+}
+
+static size_t clear_user_pt(size_t n, void __user *to)
+{
+	void *zpage = (void *) empty_zero_page;
+	long done, size, ret;
+
+	done = 0;
+	do {
+		if (n - done > PAGE_SIZE)
+			size = PAGE_SIZE;
+		else
+			size = n - done;
+		if (segment_eq(get_fs(), KERNEL_DS))
+			ret = copy_in_kernel(n, to, (void __user *) zpage);
+		else
+			ret = __user_copy_pt((unsigned long) to, zpage, size, 1);
+		done += size;
+		to += 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)
+{
+	unsigned long uaddr = (unsigned long) src;
+	struct mm_struct *mm = current->mm;
+	unsigned long offset, done, len, kaddr;
+	size_t len_str;
+
+	if (unlikely(!count))
+		return 0;
+	if (segment_eq(get_fs(), KERNEL_DS))
+		return strnlen_kernel(count, src);
+	done = 0;
+retry:
+	spin_lock(&mm->page_table_lock);
+	do {
+		kaddr = follow_table(mm, uaddr, 0);
+		if (IS_ERR_VALUE(kaddr))
+			goto fault;
+
+		offset = uaddr & ~PAGE_MASK;
+		len = min(count - done, PAGE_SIZE - offset);
+		len_str = strnlen((char *) kaddr, len);
+		done += len_str;
+		uaddr += len_str;
+	} while ((len_str == len) && (done < count));
+	spin_unlock(&mm->page_table_lock);
+	return done + 1;
+fault:
+	spin_unlock(&mm->page_table_lock);
+	if (__handle_fault(uaddr, -kaddr, 0))
+		return 0;
+	goto retry;
+}
+
+static size_t strncpy_from_user_pt(size_t count, const char __user *src,
+				   char *dst)
+{
+	size_t done, len, offset, len_str;
+
+	if (unlikely(!count))
+		return 0;
+	done = 0;
+	do {
+		offset = (size_t)src & ~PAGE_MASK;
+		len = min(count - done, PAGE_SIZE - offset);
+		if (segment_eq(get_fs(), KERNEL_DS)) {
+			if (copy_in_kernel(len, (void __user *) dst, src))
+				return -EFAULT;
+		} else {
+			if (__user_copy_pt((unsigned long) src, dst, len, 0))
+				return -EFAULT;
+		}
+		len_str = strnlen(dst, len);
+		done += len_str;
+		src += len_str;
+		dst += len_str;
+	} while ((len_str == len) && (done < count));
+	return done;
+}
+
+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_max, uaddr, done, size, error_code;
+	unsigned long uaddr_from = (unsigned long) from;
+	unsigned long uaddr_to = (unsigned long) to;
+	unsigned long kaddr_to, kaddr_from;
+	int write_user;
+
+	if (segment_eq(get_fs(), KERNEL_DS))
+		return copy_in_kernel(n, to, from);
+	done = 0;
+retry:
+	spin_lock(&mm->page_table_lock);
+	do {
+		write_user = 0;
+		uaddr = uaddr_from;
+		kaddr_from = follow_table(mm, uaddr_from, 0);
+		error_code = kaddr_from;
+		if (IS_ERR_VALUE(error_code))
+			goto fault;
+
+		write_user = 1;
+		uaddr = uaddr_to;
+		kaddr_to = follow_table(mm, uaddr_to, 1);
+		error_code = (unsigned long) kaddr_to;
+		if (IS_ERR_VALUE(error_code))
+			goto fault;
+
+		offset_max = max(uaddr_from & ~PAGE_MASK,
+				 uaddr_to & ~PAGE_MASK);
+		size = min(n - done, PAGE_SIZE - offset_max);
+
+		memcpy((void *) kaddr_to, (void *) kaddr_from, size);
+		done += size;
+		uaddr_from += size;
+		uaddr_to += size;
+	} while (done < n);
+	spin_unlock(&mm->page_table_lock);
+	return n - done;
+fault:
+	spin_unlock(&mm->page_table_lock);
+	if (__handle_fault(uaddr, -error_code, 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" );
+
+static int __futex_atomic_op_pt(int op, u32 __user *uaddr, int oparg, int *old)
+{
+	int oldval = 0, newval, ret;
+
+	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;
+	}
+	if (ret == 0)
+		*old = oldval;
+	return ret;
+}
+
+int futex_atomic_op_pt(int op, u32 __user *uaddr, int oparg, int *old)
+{
+	int ret;
+
+	if (segment_eq(get_fs(), KERNEL_DS))
+		return __futex_atomic_op_pt(op, uaddr, oparg, old);
+	spin_lock(&current->mm->page_table_lock);
+	uaddr = (u32 __force __user *)
+		__dat_user_addr((__force unsigned long) uaddr, 1);
+	if (!uaddr) {
+		spin_unlock(&current->mm->page_table_lock);
+		return -EFAULT;
+	}
+	get_page(virt_to_page(uaddr));
+	spin_unlock(&current->mm->page_table_lock);
+	ret = __futex_atomic_op_pt(op, uaddr, oparg, old);
+	put_page(virt_to_page(uaddr));
+	return ret;
+}
+
+static int __futex_atomic_cmpxchg_pt(u32 *uval, u32 __user *uaddr,
+				     u32 oldval, u32 newval)
+{
+	int ret;
+
+	asm volatile("0: cs   %1,%4,0(%5)\n"
+		     "1: la   %0,0\n"
+		     "2:\n"
+		     EX_TABLE(0b,2b) EX_TABLE(1b,2b)
+		     : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
+		     : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
+		     : "cc", "memory" );
+	*uval = oldval;
+	return ret;
+}
+
+int futex_atomic_cmpxchg_pt(u32 *uval, u32 __user *uaddr,
+			    u32 oldval, u32 newval)
+{
+	int ret;
+
+	if (segment_eq(get_fs(), KERNEL_DS))
+		return __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
+	spin_lock(&current->mm->page_table_lock);
+	uaddr = (u32 __force __user *)
+		__dat_user_addr((__force unsigned long) uaddr, 1);
+	if (!uaddr) {
+		spin_unlock(&current->mm->page_table_lock);
+		return -EFAULT;
+	}
+	get_page(virt_to_page(uaddr));
+	spin_unlock(&current->mm->page_table_lock);
+	ret = __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
+	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,
+};