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