Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *    Out of line spinlock code.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *    Copyright IBM Corp. 2004, 2006
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/spinlock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/jiffies.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/smp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/percpu.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <asm/alternative.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <asm/io.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) int spin_retry = -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) static int __init spin_retry_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) 	if (spin_retry < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 		spin_retry = 1000;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) early_initcall(spin_retry_init);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30)  * spin_retry= parameter
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) static int __init spin_retry_setup(char *str)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	spin_retry = simple_strtoul(str, &str, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 	return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) __setup("spin_retry=", spin_retry_setup);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) struct spin_wait {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	struct spin_wait *next, *prev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	int node_id;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) } __aligned(32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) static DEFINE_PER_CPU_ALIGNED(struct spin_wait, spin_wait[4]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) #define _Q_LOCK_CPU_OFFSET	0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) #define _Q_LOCK_STEAL_OFFSET	16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) #define _Q_TAIL_IDX_OFFSET	18
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) #define _Q_TAIL_CPU_OFFSET	20
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) #define _Q_LOCK_CPU_MASK	0x0000ffff
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) #define _Q_LOCK_STEAL_ADD	0x00010000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) #define _Q_LOCK_STEAL_MASK	0x00030000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) #define _Q_TAIL_IDX_MASK	0x000c0000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) #define _Q_TAIL_CPU_MASK	0xfff00000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) #define _Q_LOCK_MASK		(_Q_LOCK_CPU_MASK | _Q_LOCK_STEAL_MASK)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) #define _Q_TAIL_MASK		(_Q_TAIL_IDX_MASK | _Q_TAIL_CPU_MASK)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) void arch_spin_lock_setup(int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	struct spin_wait *node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	int ix;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	node = per_cpu_ptr(&spin_wait[0], cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	for (ix = 0; ix < 4; ix++, node++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 		memset(node, 0, sizeof(*node));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 		node->node_id = ((cpu + 1) << _Q_TAIL_CPU_OFFSET) +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 			(ix << _Q_TAIL_IDX_OFFSET);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) static inline int arch_load_niai4(int *lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	int owner;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	asm_inline volatile(
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 		ALTERNATIVE("", ".long 0xb2fa0040", 49)	/* NIAI 4 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 		"	l	%0,%1\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 		: "=d" (owner) : "Q" (*lock) : "memory");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	return owner;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) static inline int arch_cmpxchg_niai8(int *lock, int old, int new)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 	int expected = old;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	asm_inline volatile(
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 		ALTERNATIVE("", ".long 0xb2fa0080", 49)	/* NIAI 8 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 		"	cs	%0,%3,%1\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 		: "=d" (old), "=Q" (*lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 		: "0" (old), "d" (new), "Q" (*lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 		: "cc", "memory");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	return expected == old;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) static inline struct spin_wait *arch_spin_decode_tail(int lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	int ix, cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	ix = (lock & _Q_TAIL_IDX_MASK) >> _Q_TAIL_IDX_OFFSET;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	cpu = (lock & _Q_TAIL_CPU_MASK) >> _Q_TAIL_CPU_OFFSET;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 	return per_cpu_ptr(&spin_wait[ix], cpu - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) static inline int arch_spin_yield_target(int lock, struct spin_wait *node)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	if (lock & _Q_LOCK_CPU_MASK)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 		return lock & _Q_LOCK_CPU_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	if (node == NULL || node->prev == NULL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 		return 0;	/* 0 -> no target cpu */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	while (node->prev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 		node = node->prev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	return node->node_id >> _Q_TAIL_CPU_OFFSET;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) static inline void arch_spin_lock_queued(arch_spinlock_t *lp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	struct spin_wait *node, *next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	int lockval, ix, node_id, tail_id, old, new, owner, count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	ix = S390_lowcore.spinlock_index++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	barrier();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	lockval = SPINLOCK_LOCKVAL;	/* cpu + 1 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	node = this_cpu_ptr(&spin_wait[ix]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	node->prev = node->next = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	node_id = node->node_id;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	/* Enqueue the node for this CPU in the spinlock wait queue */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	while (1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 		old = READ_ONCE(lp->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		if ((old & _Q_LOCK_CPU_MASK) == 0 &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 		    (old & _Q_LOCK_STEAL_MASK) != _Q_LOCK_STEAL_MASK) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 			/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 			 * The lock is free but there may be waiters.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 			 * With no waiters simply take the lock, if there
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 			 * are waiters try to steal the lock. The lock may
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 			 * be stolen three times before the next queued
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 			 * waiter will get the lock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 			 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 			new = (old ? (old + _Q_LOCK_STEAL_ADD) : 0) | lockval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 			if (__atomic_cmpxchg_bool(&lp->lock, old, new))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 				/* Got the lock */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 				goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 			/* lock passing in progress */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 		/* Make the node of this CPU the new tail. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 		new = node_id | (old & _Q_LOCK_MASK);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 		if (__atomic_cmpxchg_bool(&lp->lock, old, new))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	/* Set the 'next' pointer of the tail node in the queue */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	tail_id = old & _Q_TAIL_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	if (tail_id != 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		node->prev = arch_spin_decode_tail(tail_id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 		WRITE_ONCE(node->prev->next, node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	/* Pass the virtual CPU to the lock holder if it is not running */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	owner = arch_spin_yield_target(old, node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	if (owner && arch_vcpu_is_preempted(owner - 1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 		smp_yield_cpu(owner - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	/* Spin on the CPU local node->prev pointer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	if (tail_id != 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 		count = spin_retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 		while (READ_ONCE(node->prev) != NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 			if (count-- >= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 				continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 			count = spin_retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 			/* Query running state of lock holder again. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 			owner = arch_spin_yield_target(old, node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 			if (owner && arch_vcpu_is_preempted(owner - 1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 				smp_yield_cpu(owner - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	/* Spin on the lock value in the spinlock_t */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	count = spin_retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	while (1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 		old = READ_ONCE(lp->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 		owner = old & _Q_LOCK_CPU_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 		if (!owner) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 			tail_id = old & _Q_TAIL_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 			new = ((tail_id != node_id) ? tail_id : 0) | lockval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 			if (__atomic_cmpxchg_bool(&lp->lock, old, new))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 				/* Got the lock */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 				break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 		if (count-- >= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 		count = spin_retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 		if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(owner - 1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 			smp_yield_cpu(owner - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 	/* Pass lock_spin job to next CPU in the queue */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	if (node_id && tail_id != node_id) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 		/* Wait until the next CPU has set up the 'next' pointer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 		while ((next = READ_ONCE(node->next)) == NULL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 			;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 		next->prev = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207)  out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	S390_lowcore.spinlock_index--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) static inline void arch_spin_lock_classic(arch_spinlock_t *lp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	int lockval, old, new, owner, count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	lockval = SPINLOCK_LOCKVAL;	/* cpu + 1 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	/* Pass the virtual CPU to the lock holder if it is not running */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	owner = arch_spin_yield_target(READ_ONCE(lp->lock), NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	if (owner && arch_vcpu_is_preempted(owner - 1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 		smp_yield_cpu(owner - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	count = spin_retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	while (1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 		old = arch_load_niai4(&lp->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 		owner = old & _Q_LOCK_CPU_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 		/* Try to get the lock if it is free. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 		if (!owner) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 			new = (old & _Q_TAIL_MASK) | lockval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 			if (arch_cmpxchg_niai8(&lp->lock, old, new)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 				/* Got the lock */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 				return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 		if (count-- >= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 		count = spin_retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 		if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(owner - 1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 			smp_yield_cpu(owner - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) void arch_spin_lock_wait(arch_spinlock_t *lp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	if (test_cpu_flag(CIF_DEDICATED_CPU))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 		arch_spin_lock_queued(lp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 		arch_spin_lock_classic(lp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) EXPORT_SYMBOL(arch_spin_lock_wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) int arch_spin_trylock_retry(arch_spinlock_t *lp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	int cpu = SPINLOCK_LOCKVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	int owner, count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	for (count = spin_retry; count > 0; count--) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 		owner = READ_ONCE(lp->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 		/* Try to get the lock if it is free. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 		if (!owner) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 			if (__atomic_cmpxchg_bool(&lp->lock, 0, cpu))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 				return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) EXPORT_SYMBOL(arch_spin_trylock_retry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) void arch_read_lock_wait(arch_rwlock_t *rw)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 	if (unlikely(in_interrupt())) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 		while (READ_ONCE(rw->cnts) & 0x10000)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 			barrier();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 	/* Remove this reader again to allow recursive read locking */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	__atomic_add_const(-1, &rw->cnts);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	/* Put the reader into the wait queue */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 	arch_spin_lock(&rw->wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 	/* Now add this reader to the count value again */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 	__atomic_add_const(1, &rw->cnts);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 	/* Loop until the writer is done */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	while (READ_ONCE(rw->cnts) & 0x10000)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 		barrier();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 	arch_spin_unlock(&rw->wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) EXPORT_SYMBOL(arch_read_lock_wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) void arch_write_lock_wait(arch_rwlock_t *rw)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 	int old;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 	/* Add this CPU to the write waiters */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	__atomic_add(0x20000, &rw->cnts);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 	/* Put the writer into the wait queue */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 	arch_spin_lock(&rw->wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 	while (1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 		old = READ_ONCE(rw->cnts);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 		if ((old & 0x1ffff) == 0 &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 		    __atomic_cmpxchg_bool(&rw->cnts, old, old | 0x10000))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 			/* Got the lock */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 		barrier();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 	arch_spin_unlock(&rw->wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) EXPORT_SYMBOL(arch_write_lock_wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) void arch_spin_relax(arch_spinlock_t *lp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 	int cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	cpu = READ_ONCE(lp->lock) & _Q_LOCK_CPU_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 	if (!cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 	if (MACHINE_IS_LPAR && !arch_vcpu_is_preempted(cpu - 1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 	smp_yield_cpu(cpu - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) EXPORT_SYMBOL(arch_spin_relax);