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1 | /* SPDX-License-Identifier: GPL-2.0 */ |
---|---|
2 | #ifndef __ASM_QSPINLOCK_PARAVIRT_H |
3 | #define __ASM_QSPINLOCK_PARAVIRT_H |
4 | |
5 | #include <asm/ibt.h> |
6 | |
7 | void __lockfunc __pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked); |
8 | |
9 | /* |
10 | * For x86-64, PV_CALLEE_SAVE_REGS_THUNK() saves and restores 8 64-bit |
11 | * registers. For i386, however, only 1 32-bit register needs to be saved |
12 | * and restored. So an optimized version of __pv_queued_spin_unlock() is |
13 | * hand-coded for 64-bit, but it isn't worthwhile to do it for 32-bit. |
14 | */ |
15 | #ifdef CONFIG_64BIT |
16 | |
17 | __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text"); |
18 | #define __pv_queued_spin_unlock __pv_queued_spin_unlock |
19 | |
20 | /* |
21 | * Optimized assembly version of __raw_callee_save___pv_queued_spin_unlock |
22 | * which combines the registers saving trunk and the body of the following |
23 | * C code. Note that it puts the code in the .spinlock.text section which |
24 | * is equivalent to adding __lockfunc in the C code: |
25 | * |
26 | * void __lockfunc __pv_queued_spin_unlock(struct qspinlock *lock) |
27 | * { |
28 | * u8 lockval = cmpxchg(&lock->locked, _Q_LOCKED_VAL, 0); |
29 | * |
30 | * if (likely(lockval == _Q_LOCKED_VAL)) |
31 | * return; |
32 | * pv_queued_spin_unlock_slowpath(lock, lockval); |
33 | * } |
34 | * |
35 | * For x86-64, |
36 | * rdi = lock (first argument) |
37 | * rsi = lockval (second argument) |
38 | * rdx = internal variable (set to 0) |
39 | */ |
40 | #define PV_UNLOCK_ASM \ |
41 | FRAME_BEGIN \ |
42 | "push %rdx\n\t" \ |
43 | "mov $0x1,%eax\n\t" \ |
44 | "xor %edx,%edx\n\t" \ |
45 | LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t" \ |
46 | "cmp $0x1,%al\n\t" \ |
47 | "jne .slowpath\n\t" \ |
48 | "pop %rdx\n\t" \ |
49 | FRAME_END \ |
50 | ASM_RET \ |
51 | ".slowpath:\n\t" \ |
52 | "push %rsi\n\t" \ |
53 | "movzbl %al,%esi\n\t" \ |
54 | "call __raw_callee_save___pv_queued_spin_unlock_slowpath\n\t" \ |
55 | "pop %rsi\n\t" \ |
56 | "pop %rdx\n\t" \ |
57 | FRAME_END |
58 | |
59 | DEFINE_PARAVIRT_ASM(__raw_callee_save___pv_queued_spin_unlock, |
60 | PV_UNLOCK_ASM, .spinlock.text); |
61 | |
62 | #else /* CONFIG_64BIT */ |
63 | |
64 | extern void __lockfunc __pv_queued_spin_unlock(struct qspinlock *lock); |
65 | __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock, ".spinlock.text"); |
66 | |
67 | #endif /* CONFIG_64BIT */ |
68 | #endif |
69 |
Warning: This file is not a C or C++ file. It does not have highlighting.