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Diffstat (limited to 'arch/x86/include/asm/futex.h')
-rw-r--r--arch/x86/include/asm/futex.h99
1 files changed, 63 insertions, 36 deletions
diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h
index 13c83fe97988..f9c00110a69a 100644
--- a/arch/x86/include/asm/futex.h
+++ b/arch/x86/include/asm/futex.h
@@ -12,76 +12,103 @@
#include <asm/processor.h>
#include <asm/smap.h>
-#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
- asm volatile("\t" ASM_STAC "\n" \
- "1:\t" insn "\n" \
- "2:\t" ASM_CLAC "\n" \
+#define unsafe_atomic_op1(insn, oval, uaddr, oparg, label) \
+do { \
+ int oldval = 0, ret; \
+ asm volatile("1:\t" insn "\n" \
+ "2:\n" \
"\t.section .fixup,\"ax\"\n" \
"3:\tmov\t%3, %1\n" \
"\tjmp\t2b\n" \
"\t.previous\n" \
_ASM_EXTABLE_UA(1b, 3b) \
: "=r" (oldval), "=r" (ret), "+m" (*uaddr) \
- : "i" (-EFAULT), "0" (oparg), "1" (0))
+ : "i" (-EFAULT), "0" (oparg), "1" (0)); \
+ if (ret) \
+ goto label; \
+ *oval = oldval; \
+} while(0)
-#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
- asm volatile("\t" ASM_STAC "\n" \
- "1:\tmovl %2, %0\n" \
- "\tmovl\t%0, %3\n" \
+
+#define unsafe_atomic_op2(insn, oval, uaddr, oparg, label) \
+do { \
+ int oldval = 0, ret, tem; \
+ asm volatile("1:\tmovl %2, %0\n" \
+ "2:\tmovl\t%0, %3\n" \
"\t" insn "\n" \
- "2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \
- "\tjnz\t1b\n" \
- "3:\t" ASM_CLAC "\n" \
+ "3:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \
+ "\tjnz\t2b\n" \
+ "4:\n" \
"\t.section .fixup,\"ax\"\n" \
- "4:\tmov\t%5, %1\n" \
- "\tjmp\t3b\n" \
+ "5:\tmov\t%5, %1\n" \
+ "\tjmp\t4b\n" \
"\t.previous\n" \
- _ASM_EXTABLE_UA(1b, 4b) \
- _ASM_EXTABLE_UA(2b, 4b) \
+ _ASM_EXTABLE_UA(1b, 5b) \
+ _ASM_EXTABLE_UA(3b, 5b) \
: "=&a" (oldval), "=&r" (ret), \
"+m" (*uaddr), "=&r" (tem) \
- : "r" (oparg), "i" (-EFAULT), "1" (0))
+ : "r" (oparg), "i" (-EFAULT), "1" (0)); \
+ if (ret) \
+ goto label; \
+ *oval = oldval; \
+} while(0)
-static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
+static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
u32 __user *uaddr)
{
- int oldval = 0, ret, tem;
-
- pagefault_disable();
+ if (!user_access_begin(uaddr, sizeof(u32)))
+ return -EFAULT;
switch (op) {
case FUTEX_OP_SET:
- __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
+ unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault);
break;
case FUTEX_OP_ADD:
- __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
- uaddr, oparg);
+ unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval,
+ uaddr, oparg, Efault);
break;
case FUTEX_OP_OR:
- __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr, oparg);
+ unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault);
break;
case FUTEX_OP_ANDN:
- __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr, ~oparg);
+ unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault);
break;
case FUTEX_OP_XOR:
- __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr, oparg);
+ unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault);
break;
default:
- ret = -ENOSYS;
+ user_access_end();
+ return -ENOSYS;
}
-
- pagefault_enable();
-
- if (!ret)
- *oval = oldval;
-
- return ret;
+ user_access_end();
+ return 0;
+Efault:
+ user_access_end();
+ return -EFAULT;
}
static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
- return user_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval);
+ int ret = 0;
+
+ if (!user_access_begin(uaddr, sizeof(u32)))
+ return -EFAULT;
+ asm volatile("\n"
+ "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"
+ "2:\n"
+ "\t.section .fixup, \"ax\"\n"
+ "3:\tmov %3, %0\n"
+ "\tjmp 2b\n"
+ "\t.previous\n"
+ _ASM_EXTABLE_UA(1b, 3b)
+ : "+r" (ret), "=a" (oldval), "+m" (*uaddr)
+ : "i" (-EFAULT), "r" (newval), "1" (oldval)
+ : "memory"
+ );
+ user_access_end();
+ *uval = oldval;
+ return ret;
}
#endif