Commit 4c132d1d authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

x86/futex: Remove .fixup usage 



Use the new EX_TYPE_IMM_REG to store -EFAULT into the designated 'ret'
register, this removes the need for anonymous .fixup code.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20211110101325.426016322@infradead.org
parent d52a7344

arch/x86/include/asm/extable_fixup_types.h

+2 −0
Original line number Diff line number Diff line
@@ -42,6 +42,8 @@ 
#define	EX_TYPE_DEFAULT_MCE_SAFE	14

#define	EX_TYPE_FAULT_MCE_SAFE		15

#define	EX_TYPE_POP_ZERO		16



#define	EX_TYPE_IMM_REG			17 /* reg := (long)imm */

#define	EX_TYPE_EFAULT_REG		(EX_TYPE_IMM_REG | EX_DATA_IMM(-EFAULT))



#endif

arch/x86/include/asm/futex.h

+8 −20
Original line number Diff line number Diff line
@@ -17,13 +17,9 @@ 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)			\

		     _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %1) \

		     : "=r" (oldval), "=r" (ret), "+m" (*uaddr)	\

		     : "i" (-EFAULT), "0" (oparg), "1" (0));	\

		     : "0" (oparg), "1" (0));	\

	if (ret)						\

		goto label;					\

	*oval = oldval;						\
@@ -39,15 +35,11 @@ do { \ 
		     "3:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"	\

		     "\tjnz\t2b\n"				\

		     "4:\n"					\

		     "\t.section .fixup,\"ax\"\n"		\

		     "5:\tmov\t%5, %1\n"			\

		     "\tjmp\t4b\n"				\

		     "\t.previous\n"				\

		     _ASM_EXTABLE_UA(1b, 5b)			\

		     _ASM_EXTABLE_UA(3b, 5b)			\

		     _ASM_EXTABLE_TYPE_REG(1b, 4b, EX_TYPE_EFAULT_REG, %1) \

		     _ASM_EXTABLE_TYPE_REG(3b, 4b, EX_TYPE_EFAULT_REG, %1) \

		     : "=&a" (oldval), "=&r" (ret),		\

		       "+m" (*uaddr), "=&r" (tem)		\

		     : "r" (oparg), "i" (-EFAULT), "1" (0));	\

		     : "r" (oparg), "1" (0));			\

	if (ret)						\

		goto label;					\

	*oval = oldval;						\
@@ -95,15 +87,11 @@ static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 
	if (!user_access_begin(uaddr, sizeof(u32)))

		return -EFAULT;

	asm volatile("\n"

		"1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"

		"1:\t" LOCK_PREFIX "cmpxchgl %3, %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)

		_ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0) \

		: "+r" (ret), "=a" (oldval), "+m" (*uaddr)

		: "i" (-EFAULT), "r" (newval), "1" (oldval)

		: "r" (newval), "1" (oldval)

		: "memory"

	);

	user_access_end();