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x86/futex: Remove .fixup usage

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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: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20211110101325.426016322@infradead.org
This commit is contained in:
Peter Zijlstra 2021-11-10 11:01:11 +01:00
parent d52a7344bd
commit 4c132d1d84
2 changed files with 10 additions and 20 deletions
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2
arch/x86/include/asm/extable_fixup_types.h
View File

@ -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

28
arch/x86/include/asm/futex.h
View File

@ -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();