diff options
author | Will Deacon <will.deacon@arm.com> | 2019-05-01 15:34:17 +0100 |
---|---|---|
committer | Will Deacon <will.deacon@arm.com> | 2019-05-01 15:34:17 +0100 |
commit | 9431ac2bf6b742d87cdac051adc1976308070110 (patch) | |
tree | 653c740b32bd411c2b79f81ecd6841f46814c87b /arch/arm64/include/asm | |
parent | 61cf61d81e326163ce1557ceccfca76e11d0e57c (diff) | |
parent | 427503519739e779c0db8afe876c1b33f3ac60ae (diff) | |
download | linux-9431ac2bf6b742d87cdac051adc1976308070110.tar.bz2 |
Merge branch 'for-next/futex' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into for-next/core
Diffstat (limited to 'arch/arm64/include/asm')
-rw-r--r-- | arch/arm64/include/asm/futex.h | 63 |
1 files changed, 39 insertions, 24 deletions
diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h index cccb83ad7fa8..bdb3c05070a2 100644 --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -23,26 +23,34 @@ #include <asm/errno.h> +#define FUTEX_MAX_LOOPS 128 /* What's the largest number you can think of? */ + #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \ do { \ + unsigned int loops = FUTEX_MAX_LOOPS; \ + \ uaccess_enable(); \ asm volatile( \ " prfm pstl1strm, %2\n" \ "1: ldxr %w1, %2\n" \ insn "\n" \ -"2: stlxr %w3, %w0, %2\n" \ -" cbnz %w3, 1b\n" \ -" dmb ish\n" \ +"2: stlxr %w0, %w3, %2\n" \ +" cbz %w0, 3f\n" \ +" sub %w4, %w4, %w0\n" \ +" cbnz %w4, 1b\n" \ +" mov %w0, %w7\n" \ "3:\n" \ +" dmb ish\n" \ " .pushsection .fixup,\"ax\"\n" \ " .align 2\n" \ -"4: mov %w0, %w5\n" \ +"4: mov %w0, %w6\n" \ " b 3b\n" \ " .popsection\n" \ _ASM_EXTABLE(1b, 4b) \ _ASM_EXTABLE(2b, 4b) \ - : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp) \ - : "r" (oparg), "Ir" (-EFAULT) \ + : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp), \ + "+r" (loops) \ + : "r" (oparg), "Ir" (-EFAULT), "Ir" (-EAGAIN) \ : "memory"); \ uaccess_disable(); \ } while (0) @@ -50,30 +58,30 @@ do { \ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr) { - int oldval = 0, ret, tmp; + int oldval, ret, tmp; u32 __user *uaddr = __uaccess_mask_ptr(_uaddr); pagefault_disable(); switch (op) { case FUTEX_OP_SET: - __futex_atomic_op("mov %w0, %w4", + __futex_atomic_op("mov %w3, %w5", ret, oldval, uaddr, tmp, oparg); break; case FUTEX_OP_ADD: - __futex_atomic_op("add %w0, %w1, %w4", + __futex_atomic_op("add %w3, %w1, %w5", ret, oldval, uaddr, tmp, oparg); break; case FUTEX_OP_OR: - __futex_atomic_op("orr %w0, %w1, %w4", + __futex_atomic_op("orr %w3, %w1, %w5", ret, oldval, uaddr, tmp, oparg); break; case FUTEX_OP_ANDN: - __futex_atomic_op("and %w0, %w1, %w4", + __futex_atomic_op("and %w3, %w1, %w5", ret, oldval, uaddr, tmp, ~oparg); break; case FUTEX_OP_XOR: - __futex_atomic_op("eor %w0, %w1, %w4", + __futex_atomic_op("eor %w3, %w1, %w5", ret, oldval, uaddr, tmp, oparg); break; default: @@ -93,6 +101,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr, u32 oldval, u32 newval) { int ret = 0; + unsigned int loops = FUTEX_MAX_LOOPS; u32 val, tmp; u32 __user *uaddr; @@ -104,24 +113,30 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr, asm volatile("// futex_atomic_cmpxchg_inatomic\n" " prfm pstl1strm, %2\n" "1: ldxr %w1, %2\n" -" sub %w3, %w1, %w4\n" -" cbnz %w3, 3f\n" -"2: stlxr %w3, %w5, %2\n" -" cbnz %w3, 1b\n" -" dmb ish\n" +" sub %w3, %w1, %w5\n" +" cbnz %w3, 4f\n" +"2: stlxr %w3, %w6, %2\n" +" cbz %w3, 3f\n" +" sub %w4, %w4, %w3\n" +" cbnz %w4, 1b\n" +" mov %w0, %w8\n" "3:\n" +" dmb ish\n" +"4:\n" " .pushsection .fixup,\"ax\"\n" -"4: mov %w0, %w6\n" -" b 3b\n" +"5: mov %w0, %w7\n" +" b 4b\n" " .popsection\n" - _ASM_EXTABLE(1b, 4b) - _ASM_EXTABLE(2b, 4b) - : "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp) - : "r" (oldval), "r" (newval), "Ir" (-EFAULT) + _ASM_EXTABLE(1b, 5b) + _ASM_EXTABLE(2b, 5b) + : "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp), "+r" (loops) + : "r" (oldval), "r" (newval), "Ir" (-EFAULT), "Ir" (-EAGAIN) : "memory"); uaccess_disable(); - *uval = val; + if (!ret) + *uval = val; + return ret; } |