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/usr/src/linux-headers-5.15.0-190/arch/arc/include/asm/

/usr/src/linux-headers-5.15.0-190/arch/arc/include/asm

Name	Size	Mode	Actions
arcregs.h	9477	0644	edit dl rm
asm-offsets.h	165	0644	edit dl rm
asserts.h	958	0644	edit dl rm
atomic-llsc.h	2864	0644	edit dl rm
atomic-spinlock.h	2569	0644	edit dl rm
atomic.h	1153	0644	edit dl rm
atomic64-arcv2.h	6095	0644	edit dl rm
barrier.h	1376	0644	edit dl rm
bitops.h	3885	0644	edit dl rm
bug.h	819	0644	edit dl rm
cache.h	3604	0644	edit dl rm
cacheflush.h	3824	0644	edit dl rm
checksum.h	2371	0644	edit dl rm
cmpxchg.h	3188	0644	edit dl rm
current.h	549	0644	edit dl rm
delay.h	1896	0644	edit dl rm
disasm.h	3813	0644	edit dl rm
dma.h	313	0644	edit dl rm
dsp-impl.h	3860	0644	edit dl rm
dsp.h	796	0644	edit dl rm
dwarf.h	746	0644	edit dl rm
elf.h	1935	0644	edit dl rm
entry-arcv2.h	7419	0644	edit dl rm
entry-compact.h	8810	0644	edit dl rm
entry.h	6687	0644	edit dl rm
exec.h	264	0644	edit dl rm
fb.h	411	0644	edit dl rm
fpu.h	1125	0644	edit dl rm
futex.h	3611	0644	edit dl rm
highmem.h	1422	0644	edit dl rm
hugepage.h	2071	0644	edit dl rm
io.h	6291	0644	edit dl rm
irq.h	679	0644	edit dl rm
irqflags-arcv2.h	3491	0644	edit dl rm
irqflags-compact.h	4293	0644	edit dl rm
irqflags.h	363	0644	edit dl rm
jump_label.h	1976	0644	edit dl rm
Kbuild	153	0644	edit dl rm
kdebug.h	254	0644	edit dl rm
kgdb.h	1239	0644	edit dl rm
kprobes.h	1186	0644	edit dl rm
linkage.h	1484	0644	edit dl rm
mach_desc.h	1943	0644	edit dl rm
mmu-arcv2.h	2494	0644	edit dl rm
mmu.h	387	0644	edit dl rm
mmu_context.h	5568	0644	edit dl rm
module.h	428	0644	edit dl rm
page.h	3313	0644	edit dl rm
pci.h	360	0644	edit dl rm
perf_event.h	6879	0644	edit dl rm
pgalloc.h	2888	0644	edit dl rm
pgtable-bits-arcv2.h	4896	0644	edit dl rm
pgtable-levels.h	5626	0644	edit dl rm
pgtable.h	780	0644	edit dl rm
processor.h	3253	0644	edit dl rm
ptrace.h	3759	0644	edit dl rm
sections.h	261	0644	edit dl rm
segment.h	476	0644	edit dl rm
serial.h	498	0644	edit dl rm
setup.h	1274	0644	edit dl rm
shmparam.h	296	0644	edit dl rm
smp.h	3823	0644	edit dl rm
spinlock.h	8580	0644	edit dl rm
spinlock_types.h	905	0644	edit dl rm
stacktrace.h	1178	0644	edit dl rm
string.h	1036	0644	edit dl rm
switch_to.h	553	0644	edit dl rm
syscall.h	1738	0644	edit dl rm
syscalls.h	547	0644	edit dl rm
thread_info.h	3339	0644	edit dl rm
timex.h	362	0644	edit dl rm
tlb.h	262	0644	edit dl rm
tlbflush.h	1654	0644	edit dl rm
uaccess.h	17019	0644	edit dl rm
unaligned.h	625	0644	edit dl rm
unwind.h	3446	0644	edit dl rm
vermagic.h	157	0644	edit dl rm
vmalloc.h	87	0644	edit dl rm

Edit: /usr/src/linux-headers-5.15.0-190/arch/arc/include/asm/spinlock.h (8580B)

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 */

#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H

#include <asm/spinlock_types.h>
#include <asm/processor.h>
#include <asm/barrier.h>

#define arch_spin_is_locked(x)	((x)->slock != __ARCH_SPIN_LOCK_UNLOCKED__)

#ifdef CONFIG_ARC_HAS_LLSC

static inline void arch_spin_lock(arch_spinlock_t *lock)
{
	unsigned int val;

__asm__ __volatile__(
	"1:	llock	%[val], [%[slock]]	\n"
	"	breq	%[val], %[LOCKED], 1b	\n"	/* spin while LOCKED */
	"	scond	%[LOCKED], [%[slock]]	\n"	/* acquire */
	"	bnz	1b			\n"
	"					\n"
	: [val]		"=&r"	(val)
	: [slock]	"r"	(&(lock->slock)),
	  [LOCKED]	"r"	(__ARCH_SPIN_LOCK_LOCKED__)
	: "memory", "cc");

/*
	 * ACQUIRE barrier to ensure load/store after taking the lock
	 * don't "bleed-up" out of the critical section (leak-in is allowed)
	 * http://www.spinics.net/lists/kernel/msg2010409.html
	 *
	 * ARCv2 only has load-load, store-store and all-all barrier
	 * thus need the full all-all barrier
	 */
	smp_mb();
}

/* 1 - lock taken successfully */
static inline int arch_spin_trylock(arch_spinlock_t *lock)
{
	unsigned int val, got_it = 0;

__asm__ __volatile__(
	"1:	llock	%[val], [%[slock]]	\n"
	"	breq	%[val], %[LOCKED], 4f	\n"	/* already LOCKED, just bail */
	"	scond	%[LOCKED], [%[slock]]	\n"	/* acquire */
	"	bnz	1b			\n"
	"	mov	%[got_it], 1		\n"
	"4:					\n"
	"					\n"
	: [val]		"=&r"	(val),
	  [got_it]	"+&r"	(got_it)
	: [slock]	"r"	(&(lock->slock)),
	  [LOCKED]	"r"	(__ARCH_SPIN_LOCK_LOCKED__)
	: "memory", "cc");

smp_mb();

return got_it;
}

static inline void arch_spin_unlock(arch_spinlock_t *lock)
{
	smp_mb();

WRITE_ONCE(lock->slock, __ARCH_SPIN_LOCK_UNLOCKED__);
}

/*
 * Read-write spinlocks, allowing multiple readers but only one writer.
 * Unfair locking as Writers could be starved indefinitely by Reader(s)
 */

static inline void arch_read_lock(arch_rwlock_t *rw)
{
	unsigned int val;

/*
	 * zero means writer holds the lock exclusively, deny Reader.
	 * Otherwise grant lock to first/subseq reader
	 *
	 * 	if (rw->counter > 0) {
	 *		rw->counter--;
	 *		ret = 1;
	 *	}
	 */

__asm__ __volatile__(
	"1:	llock	%[val], [%[rwlock]]	\n"
	"	brls	%[val], %[WR_LOCKED], 1b\n"	/* <= 0: spin while write locked */
	"	sub	%[val], %[val], 1	\n"	/* reader lock */
	"	scond	%[val], [%[rwlock]]	\n"
	"	bnz	1b			\n"
	"					\n"
	: [val]		"=&r"	(val)
	: [rwlock]	"r"	(&(rw->counter)),
	  [WR_LOCKED]	"ir"	(0)
	: "memory", "cc");

smp_mb();
}

/* 1 - lock taken successfully */
static inline int arch_read_trylock(arch_rwlock_t *rw)
{
	unsigned int val, got_it = 0;

__asm__ __volatile__(
	"1:	llock	%[val], [%[rwlock]]	\n"
	"	brls	%[val], %[WR_LOCKED], 4f\n"	/* <= 0: already write locked, bail */
	"	sub	%[val], %[val], 1	\n"	/* counter-- */
	"	scond	%[val], [%[rwlock]]	\n"
	"	bnz	1b			\n"	/* retry if collided with someone */
	"	mov	%[got_it], 1		\n"
	"					\n"
	"4: ; --- done ---			\n"

: [val]		"=&r"	(val),
	  [got_it]	"+&r"	(got_it)
	: [rwlock]	"r"	(&(rw->counter)),
	  [WR_LOCKED]	"ir"	(0)
	: "memory", "cc");

smp_mb();

return got_it;
}

static inline void arch_write_lock(arch_rwlock_t *rw)
{
	unsigned int val;

/*
	 * If reader(s) hold lock (lock < __ARCH_RW_LOCK_UNLOCKED__),
	 * deny writer. Otherwise if unlocked grant to writer
	 * Hence the claim that Linux rwlocks are unfair to writers.
	 * (can be starved for an indefinite time by readers).
	 *
	 *	if (rw->counter == __ARCH_RW_LOCK_UNLOCKED__) {
	 *		rw->counter = 0;
	 *		ret = 1;
	 *	}
	 */

__asm__ __volatile__(
	"1:	llock	%[val], [%[rwlock]]	\n"
	"	brne	%[val], %[UNLOCKED], 1b	\n"	/* while !UNLOCKED spin */
	"	mov	%[val], %[WR_LOCKED]	\n"
	"	scond	%[val], [%[rwlock]]	\n"
	"	bnz	1b			\n"
	"					\n"
	: [val]		"=&r"	(val)
	: [rwlock]	"r"	(&(rw->counter)),
	  [UNLOCKED]	"ir"	(__ARCH_RW_LOCK_UNLOCKED__),
	  [WR_LOCKED]	"ir"	(0)
	: "memory", "cc");

smp_mb();
}

/* 1 - lock taken successfully */
static inline int arch_write_trylock(arch_rwlock_t *rw)
{
	unsigned int val, got_it = 0;

__asm__ __volatile__(
	"1:	llock	%[val], [%[rwlock]]	\n"
	"	brne	%[val], %[UNLOCKED], 4f	\n"	/* !UNLOCKED, bail */
	"	mov	%[val], %[WR_LOCKED]	\n"
	"	scond	%[val], [%[rwlock]]	\n"
	"	bnz	1b			\n"	/* retry if collided with someone */
	"	mov	%[got_it], 1		\n"
	"					\n"
	"4: ; --- done ---			\n"

: [val]		"=&r"	(val),
	  [got_it]	"+&r"	(got_it)
	: [rwlock]	"r"	(&(rw->counter)),
	  [UNLOCKED]	"ir"	(__ARCH_RW_LOCK_UNLOCKED__),
	  [WR_LOCKED]	"ir"	(0)
	: "memory", "cc");

smp_mb();

return got_it;
}

static inline void arch_read_unlock(arch_rwlock_t *rw)
{
	unsigned int val;

smp_mb();

/*
	 * rw->counter++;
	 */
	__asm__ __volatile__(
	"1:	llock	%[val], [%[rwlock]]	\n"
	"	add	%[val], %[val], 1	\n"
	"	scond	%[val], [%[rwlock]]	\n"
	"	bnz	1b			\n"
	"					\n"
	: [val]		"=&r"	(val)
	: [rwlock]	"r"	(&(rw->counter))
	: "memory", "cc");
}

static inline void arch_write_unlock(arch_rwlock_t *rw)
{
	smp_mb();

WRITE_ONCE(rw->counter, __ARCH_RW_LOCK_UNLOCKED__);
}

#else	/* !CONFIG_ARC_HAS_LLSC */

static inline void arch_spin_lock(arch_spinlock_t *lock)
{
	unsigned int val = __ARCH_SPIN_LOCK_LOCKED__;

/*
	 * Per lkmm, smp_mb() is only required after _lock (and before_unlock)
	 * for ACQ and REL semantics respectively. However EX based spinlocks
	 * need the extra smp_mb to workaround a hardware quirk.
	 */
	smp_mb();

__asm__ __volatile__(
	"1:	ex  %0, [%1]		\n"
	"	breq  %0, %2, 1b	\n"
	: "+&r" (val)
	: "r"(&(lock->slock)), "ir"(__ARCH_SPIN_LOCK_LOCKED__)
	: "memory");

smp_mb();
}

/* 1 - lock taken successfully */
static inline int arch_spin_trylock(arch_spinlock_t *lock)
{
	unsigned int val = __ARCH_SPIN_LOCK_LOCKED__;

smp_mb();

__asm__ __volatile__(
	"1:	ex  %0, [%1]		\n"
	: "+r" (val)
	: "r"(&(lock->slock))
	: "memory");

smp_mb();

return (val == __ARCH_SPIN_LOCK_UNLOCKED__);
}

static inline void arch_spin_unlock(arch_spinlock_t *lock)
{
	unsigned int val = __ARCH_SPIN_LOCK_UNLOCKED__;

/*
	 * RELEASE barrier: given the instructions avail on ARCv2, full barrier
	 * is the only option
	 */
	smp_mb();

/*
	 * EX is not really required here, a simple STore of 0 suffices.
	 * However this causes tasklist livelocks in SystemC based SMP virtual
	 * platforms where the systemc core scheduler uses EX as a cue for
	 * moving to next core. Do a git log of this file for details
	 */
	__asm__ __volatile__(
	"	ex  %0, [%1]		\n"
	: "+r" (val)
	: "r"(&(lock->slock))
	: "memory");

/*
	 * see pairing version/comment in arch_spin_lock above
	 */
	smp_mb();
}

/*
 * Read-write spinlocks, allowing multiple readers but only one writer.
 * Unfair locking as Writers could be starved indefinitely by Reader(s)
 *
 * The spinlock itself is contained in @counter and access to it is
 * serialized with @lock_mutex.
 */

/* 1 - lock taken successfully */
static inline int arch_read_trylock(arch_rwlock_t *rw)
{
	int ret = 0;
	unsigned long flags;

local_irq_save(flags);
	arch_spin_lock(&(rw->lock_mutex));

/*
	 * zero means writer holds the lock exclusively, deny Reader.
	 * Otherwise grant lock to first/subseq reader
	 */
	if (rw->counter > 0) {
		rw->counter--;
		ret = 1;
	}

arch_spin_unlock(&(rw->lock_mutex));
	local_irq_restore(flags);

return ret;
}

/* 1 - lock taken successfully */
static inline int arch_write_trylock(arch_rwlock_t *rw)
{
	int ret = 0;
	unsigned long flags;

local_irq_save(flags);
	arch_spin_lock(&(rw->lock_mutex));

/*
	 * If reader(s) hold lock (lock < __ARCH_RW_LOCK_UNLOCKED__),
	 * deny writer. Otherwise if unlocked grant to writer
	 * Hence the claim that Linux rwlocks are unfair to writers.
	 * (can be starved for an indefinite time by readers).
	 */
	if (rw->counter == __ARCH_RW_LOCK_UNLOCKED__) {
		rw->counter = 0;
		ret = 1;
	}
	arch_spin_unlock(&(rw->lock_mutex));
	local_irq_restore(flags);

return ret;
}

static inline void arch_read_lock(arch_rwlock_t *rw)
{
	while (!arch_read_trylock(rw))
		cpu_relax();
}

static inline void arch_write_lock(arch_rwlock_t *rw)
{
	while (!arch_write_trylock(rw))
		cpu_relax();
}

static inline void arch_read_unlock(arch_rwlock_t *rw)
{
	unsigned long flags;

local_irq_save(flags);
	arch_spin_lock(&(rw->lock_mutex));
	rw->counter++;
	arch_spin_unlock(&(rw->lock_mutex));
	local_irq_restore(flags);
}

static inline void arch_write_unlock(arch_rwlock_t *rw)
{
	unsigned long flags;

local_irq_save(flags);
	arch_spin_lock(&(rw->lock_mutex));
	rw->counter = __ARCH_RW_LOCK_UNLOCKED__;
	arch_spin_unlock(&(rw->lock_mutex));
	local_irq_restore(flags);
}

#endif

#endif /* __ASM_SPINLOCK_H */

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