__ __ __ __ _____ _ _ _____ _ _ _ | \/ | \ \ / / | __ \ (_) | | / ____| | | | | | \ / |_ __\ V / | |__) | __ ___ ____ _| |_ ___ | (___ | |__ ___| | | | |\/| | '__|> < | ___/ '__| \ \ / / _` | __/ _ \ \___ \| '_ \ / _ \ | | | | | | |_ / . \ | | | | | |\ V / (_| | || __/ ____) | | | | __/ | | |_| |_|_(_)_/ \_\ |_| |_| |_| \_/ \__,_|\__\___| |_____/|_| |_|\___V 2.1 if you need WebShell for Seo everyday contact me on Telegram Telegram Address : @jackleetFor_More_Tools:
#ifndef _TOOLS_LINUX_RING_BUFFER_H_
#define _TOOLS_LINUX_RING_BUFFER_H_
#include <asm/barrier.h>
#include <linux/perf_event.h>
/*
* Contract with kernel for walking the perf ring buffer from
* user space requires the following barrier pairing (quote
* from kernel/events/ring_buffer.c):
*
* Since the mmap() consumer (userspace) can run on a
* different CPU:
*
* kernel user
*
* if (LOAD ->data_tail) { LOAD ->data_head
* (A) smp_rmb() (C)
* STORE $data LOAD $data
* smp_wmb() (B) smp_mb() (D)
* STORE ->data_head STORE ->data_tail
* }
*
* Where A pairs with D, and B pairs with C.
*
* In our case A is a control dependency that separates the
* load of the ->data_tail and the stores of $data. In case
* ->data_tail indicates there is no room in the buffer to
* store $data we do not.
*
* D needs to be a full barrier since it separates the data
* READ from the tail WRITE.
*
* For B a WMB is sufficient since it separates two WRITEs,
* and for C an RMB is sufficient since it separates two READs.
*
* Note, instead of B, C, D we could also use smp_store_release()
* in B and D as well as smp_load_acquire() in C.
*
* However, this optimization does not make sense for all kernel
* supported architectures since for a fair number it would
* resolve into READ_ONCE() + smp_mb() pair for smp_load_acquire(),
* and smp_mb() + WRITE_ONCE() pair for smp_store_release().
*
* Thus for those smp_wmb() in B and smp_rmb() in C would still
* be less expensive. For the case of D this has either the same
* cost or is less expensive, for example, due to TSO x86 can
* avoid the CPU barrier entirely.
*/
static inline u64 ring_buffer_read_head(struct perf_event_mmap_page *base)
{
/*
* Architectures where smp_load_acquire() does not fallback to
* READ_ONCE() + smp_mb() pair.
*/
#if defined(__x86_64__) || defined(__aarch64__) || defined(__powerpc64__) || \
defined(__ia64__) || defined(__sparc__) && defined(__arch64__)
return smp_load_acquire(&base->data_head);
#else
u64 head = READ_ONCE(base->data_head);
smp_rmb();
return head;
#endif
}
static inline void ring_buffer_write_tail(struct perf_event_mmap_page *base,
u64 tail)
{
smp_store_release(&base->data_tail, tail);
}
#endif /* _TOOLS_LINUX_RING_BUFFER_H_ */
| Name | Type | Size | Permission | Actions |
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| sched | Folder | 0755 |
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| unaligned | Folder | 0755 |
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| align.h | File | 339 B | 0644 |
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| arm-smccc.h | File | 5.63 KB | 0644 |
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| atomic.h | File | 363 B | 0644 |
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| compiler-gcc.h | File | 1.24 KB | 0644 |
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| compiler_types.h | File | 1.09 KB | 0644 |
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| const.h | File | 421 B | 0644 |
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| coresight-pmu.h | File | 2.32 KB | 0644 |
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| ctype.h | File | 1.9 KB | 0644 |
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| debug_locks.h | File | 288 B | 0644 |
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| delay.h | File | 117 B | 0644 |
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| err.h | File | 1.99 KB | 0644 |
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| export.h | File | 129 B | 0644 |
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| filter.h | File | 9.59 KB | 0644 |
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| find.h | File | 5.77 KB | 0644 |
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| ftrace.h | File | 120 B | 0644 |
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| gfp.h | File | 322 B | 0644 |
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| gfp_types.h | File | 46 B | 0644 |
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| hashtable.h | File | 4.44 KB | 0644 |
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| interrupt.h | File | 129 B | 0644 |
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| interval_tree_generic.h | File | 6.7 KB | 0644 |
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| irqflags.h | File | 1.37 KB | 0644 |
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| jhash.h | File | 4.46 KB | 0644 |
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| kallsyms.h | File | 646 B | 0644 |
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| kconfig.h | File | 2.39 KB | 0644 |
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| kern_levels.h | File | 954 B | 0644 |
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| kernel.h | File | 2.64 KB | 0644 |
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| linkage.h | File | 123 B | 0644 |
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| list.h | File | 22.48 KB | 0644 |
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| list_sort.h | File | 374 B | 0644 |
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| lockdep.h | File | 1.43 KB | 0644 |
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| log2.h | File | 4.46 KB | 0644 |
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| math.h | File | 764 B | 0644 |
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| math64.h | File | 1.22 KB | 0644 |
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| module.h | File | 270 B | 0644 |
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| mutex.h | File | 117 B | 0644 |
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| nmi.h | File | 0 B | 0644 |
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| numa.h | File | 292 B | 0644 |
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| objtool_types.h | File | 1.8 KB | 0644 |
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| overflow.h | File | 4.11 KB | 0644 |
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| poison.h | File | 2.5 KB | 0644 |
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| proc_fs.h | File | 123 B | 0644 |
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| rbtree.h | File | 9.32 KB | 0644 |
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| rbtree_augmented.h | File | 9.34 KB | 0644 |
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| rcu.h | File | 437 B | 0644 |
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| refcount.h | File | 4.11 KB | 0644 |
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| ring_buffer.h | File | 2.4 KB | 0644 |
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| rwsem.h | File | 920 B | 0644 |
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| seq_file.h | File | 126 B | 0644 |
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| sizes.h | File | 1.12 KB | 0644 |
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| slab.h | File | 1.17 KB | 0644 |
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| spinlock.h | File | 1.24 KB | 0644 |
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| stacktrace.h | File | 678 B | 0644 |
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| static_call_types.h | File | 2.74 KB | 0644 |
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| string.h | File | 1.4 KB | 0644 |
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| stringify.h | File | 380 B | 0644 |
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| time64.h | File | 347 B | 0644 |
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| types.h | File | 1.72 KB | 0644 |
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| zalloc.h | File | 252 B | 0644 |
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