// SPDX-License-Identifier: LGPL-2.1
#define _GNU_SOURCE
#include <assert.h>
#include <linux/membarrier.h>
#include <pthread.h>
#include <sched.h>
#include <stdatomic.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <unistd.h>
#include <poll.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
#include <stddef.h>

static inline pid_t rseq_gettid(void)
{
        return syscall(__NR_gettid);
}

#define NR_INJECT       9
static int loop_cnt[NR_INJECT + 1];

static int loop_cnt_1 asm("asm_loop_cnt_1") __attribute__((used));
static int loop_cnt_2 asm("asm_loop_cnt_2") __attribute__((used));
static int loop_cnt_3 asm("asm_loop_cnt_3") __attribute__((used));
static int loop_cnt_4 asm("asm_loop_cnt_4") __attribute__((used));
static int loop_cnt_5 asm("asm_loop_cnt_5") __attribute__((used));
static int loop_cnt_6 asm("asm_loop_cnt_6") __attribute__((used));

static int opt_modulo, verbose;

static int opt_yield, opt_signal, opt_sleep,
                opt_disable_rseq, opt_threads = 200,
                opt_disable_mod = 0, opt_test = 's', opt_mb = 0;

#ifndef RSEQ_SKIP_FASTPATH
static long long opt_reps = 5000;
#else
static long long opt_reps = 100;
#endif

static __thread __attribute__((tls_model("initial-exec")))
unsigned int signals_delivered;

#ifndef BENCHMARK

static __thread __attribute__((tls_model("initial-exec"), unused))
unsigned int yield_mod_cnt, nr_abort;

#define printf_verbose(fmt, ...)                        \
        do {                                            \
                if (verbose)                            \
                        printf(fmt, ## __VA_ARGS__);    \
        } while (0)

#ifdef __i386__

#define INJECT_ASM_REG  "eax"

#define RSEQ_INJECT_CLOBBER \
        , INJECT_ASM_REG

#define RSEQ_INJECT_ASM(n) \
        "mov asm_loop_cnt_" #n ", %%" INJECT_ASM_REG "\n\t" \
        "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \
        "jz 333f\n\t" \
        "222:\n\t" \
        "dec %%" INJECT_ASM_REG "\n\t" \
        "jnz 222b\n\t" \
        "333:\n\t"

#elif defined(__x86_64__)

#define INJECT_ASM_REG_P        "rax"
#define INJECT_ASM_REG          "eax"

#define RSEQ_INJECT_CLOBBER \
        , INJECT_ASM_REG_P \
        , INJECT_ASM_REG

#define RSEQ_INJECT_ASM(n) \
        "lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG_P "\n\t" \
        "mov (%%" INJECT_ASM_REG_P "), %%" INJECT_ASM_REG "\n\t" \
        "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \
        "jz 333f\n\t" \
        "222:\n\t" \
        "dec %%" INJECT_ASM_REG "\n\t" \
        "jnz 222b\n\t" \
        "333:\n\t"

#elif defined(__s390__)

#define RSEQ_INJECT_INPUT \
        , [loop_cnt_1]"m"(loop_cnt[1]) \
        , [loop_cnt_2]"m"(loop_cnt[2]) \
        , [loop_cnt_3]"m"(loop_cnt[3]) \
        , [loop_cnt_4]"m"(loop_cnt[4]) \
        , [loop_cnt_5]"m"(loop_cnt[5]) \
        , [loop_cnt_6]"m"(loop_cnt[6])

#define INJECT_ASM_REG  "r12"

#define RSEQ_INJECT_CLOBBER \
        , INJECT_ASM_REG

#define RSEQ_INJECT_ASM(n) \
        "l %%" INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
        "ltr %%" INJECT_ASM_REG ", %%" INJECT_ASM_REG "\n\t" \
        "je 333f\n\t" \
        "222:\n\t" \
        "ahi %%" INJECT_ASM_REG ", -1\n\t" \
        "jnz 222b\n\t" \
        "333:\n\t"

#elif defined(__ARMEL__)

#define RSEQ_INJECT_INPUT \
        , [loop_cnt_1]"m"(loop_cnt[1]) \
        , [loop_cnt_2]"m"(loop_cnt[2]) \
        , [loop_cnt_3]"m"(loop_cnt[3]) \
        , [loop_cnt_4]"m"(loop_cnt[4]) \
        , [loop_cnt_5]"m"(loop_cnt[5]) \
        , [loop_cnt_6]"m"(loop_cnt[6])

#define INJECT_ASM_REG  "r4"

#define RSEQ_INJECT_CLOBBER \
        , INJECT_ASM_REG

#define RSEQ_INJECT_ASM(n) \
        "ldr " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
        "cmp " INJECT_ASM_REG ", #0\n\t" \
        "beq 333f\n\t" \
        "222:\n\t" \
        "subs " INJECT_ASM_REG ", #1\n\t" \
        "bne 222b\n\t" \
        "333:\n\t"

#elif defined(__AARCH64EL__)

#define RSEQ_INJECT_INPUT \
        , [loop_cnt_1] "Qo" (loop_cnt[1]) \
        , [loop_cnt_2] "Qo" (loop_cnt[2]) \
        , [loop_cnt_3] "Qo" (loop_cnt[3]) \
        , [loop_cnt_4] "Qo" (loop_cnt[4]) \
        , [loop_cnt_5] "Qo" (loop_cnt[5]) \
        , [loop_cnt_6] "Qo" (loop_cnt[6])

#define INJECT_ASM_REG  RSEQ_ASM_TMP_REG32

#define RSEQ_INJECT_ASM(n) \
        "       ldr     " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n"       \
        "       cbz     " INJECT_ASM_REG ", 333f\n"                     \
        "222:\n"                                                        \
        "       sub     " INJECT_ASM_REG ", " INJECT_ASM_REG ", #1\n"   \
        "       cbnz    " INJECT_ASM_REG ", 222b\n"                     \
        "333:\n"

#elif __PPC__

#define RSEQ_INJECT_INPUT \
        , [loop_cnt_1]"m"(loop_cnt[1]) \
        , [loop_cnt_2]"m"(loop_cnt[2]) \
        , [loop_cnt_3]"m"(loop_cnt[3]) \
        , [loop_cnt_4]"m"(loop_cnt[4]) \
        , [loop_cnt_5]"m"(loop_cnt[5]) \
        , [loop_cnt_6]"m"(loop_cnt[6])

#define INJECT_ASM_REG  "r18"

#define RSEQ_INJECT_CLOBBER \
        , INJECT_ASM_REG

#define RSEQ_INJECT_ASM(n) \
        "lwz %%" INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
        "cmpwi %%" INJECT_ASM_REG ", 0\n\t" \
        "beq 333f\n\t" \
        "222:\n\t" \
        "subic. %%" INJECT_ASM_REG ", %%" INJECT_ASM_REG ", 1\n\t" \
        "bne 222b\n\t" \
        "333:\n\t"

#elif defined(__mips__)

#define RSEQ_INJECT_INPUT \
        , [loop_cnt_1]"m"(loop_cnt[1]) \
        , [loop_cnt_2]"m"(loop_cnt[2]) \
        , [loop_cnt_3]"m"(loop_cnt[3]) \
        , [loop_cnt_4]"m"(loop_cnt[4]) \
        , [loop_cnt_5]"m"(loop_cnt[5]) \
        , [loop_cnt_6]"m"(loop_cnt[6])

#define INJECT_ASM_REG  "$5"

#define RSEQ_INJECT_CLOBBER \
        , INJECT_ASM_REG

#define RSEQ_INJECT_ASM(n) \
        "lw " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
        "beqz " INJECT_ASM_REG ", 333f\n\t" \
        "222:\n\t" \
        "addiu " INJECT_ASM_REG ", -1\n\t" \
        "bnez " INJECT_ASM_REG ", 222b\n\t" \
        "333:\n\t"

#else
#error unsupported target
#endif

#define RSEQ_INJECT_FAILED \
        nr_abort++;

#define RSEQ_INJECT_C(n) \
{ \
        int loc_i, loc_nr_loops = loop_cnt[n]; \
        \
        for (loc_i = 0; loc_i < loc_nr_loops; loc_i++) { \
                rseq_barrier(); \
        } \
        if (loc_nr_loops == -1 && opt_modulo) { \
                if (yield_mod_cnt == opt_modulo - 1) { \
                        if (opt_sleep > 0) \
                                poll(NULL, 0, opt_sleep); \
                        if (opt_yield) \
                                sched_yield(); \
                        if (opt_signal) \
                                raise(SIGUSR1); \
                        yield_mod_cnt = 0; \
                } else { \
                        yield_mod_cnt++; \
                } \
        } \
}

#else

#define printf_verbose(fmt, ...)

#endif /* BENCHMARK */

#include "rseq.h"

struct percpu_lock_entry {
        intptr_t v;
} __attribute__((aligned(128)));

struct percpu_lock {
        struct percpu_lock_entry c[CPU_SETSIZE];
};

struct test_data_entry {
        intptr_t count;
} __attribute__((aligned(128)));

struct spinlock_test_data {
        struct percpu_lock lock;
        struct test_data_entry c[CPU_SETSIZE];
};

struct spinlock_thread_test_data {
        struct spinlock_test_data *data;
        long long reps;
        int reg;
};

struct inc_test_data {
        struct test_data_entry c[CPU_SETSIZE];
};

struct inc_thread_test_data {
        struct inc_test_data *data;
        long long reps;
        int reg;
};

struct percpu_list_node {
        intptr_t data;
        struct percpu_list_node *next;
};

struct percpu_list_entry {
        struct percpu_list_node *head;
} __attribute__((aligned(128)));

struct percpu_list {
        struct percpu_list_entry c[CPU_SETSIZE];
};

#define BUFFER_ITEM_PER_CPU     100

struct percpu_buffer_node {
        intptr_t data;
};

struct percpu_buffer_entry {
        intptr_t offset;
        intptr_t buflen;
        struct percpu_buffer_node **array;
} __attribute__((aligned(128)));

struct percpu_buffer {
        struct percpu_buffer_entry c[CPU_SETSIZE];
};

#define MEMCPY_BUFFER_ITEM_PER_CPU      100

struct percpu_memcpy_buffer_node {
        intptr_t data1;
        uint64_t data2;
};

struct percpu_memcpy_buffer_entry {
        intptr_t offset;
        intptr_t buflen;
        struct percpu_memcpy_buffer_node *array;
} __attribute__((aligned(128)));

struct percpu_memcpy_buffer {
        struct percpu_memcpy_buffer_entry c[CPU_SETSIZE];
};

/* A simple percpu spinlock. Grabs lock on current cpu. */
static int rseq_this_cpu_lock(struct percpu_lock *lock)
{
        int cpu;

        for (;;) {
                int ret;

                cpu = rseq_cpu_start();
                ret = rseq_cmpeqv_storev(&lock->c[cpu].v,
                                         0, 1, cpu);
                if (rseq_likely(!ret))
                        break;
                /* Retry if comparison fails or rseq aborts. */
        }
        /*
         * Acquire semantic when taking lock after control dependency.
         * Matches rseq_smp_store_release().
         */
        rseq_smp_acquire__after_ctrl_dep();
        return cpu;
}

static void rseq_percpu_unlock(struct percpu_lock *lock, int cpu)
{
        assert(lock->c[cpu].v == 1);
        /*
         * Release lock, with release semantic. Matches
         * rseq_smp_acquire__after_ctrl_dep().
         */
        rseq_smp_store_release(&lock->c[cpu].v, 0);
}

void *test_percpu_spinlock_thread(void *arg)
{
        struct spinlock_thread_test_data *thread_data = arg;
        struct spinlock_test_data *data = thread_data->data;
        long long i, reps;

        if (!opt_disable_rseq && thread_data->reg &&
            rseq_register_current_thread())
                abort();
        reps = thread_data->reps;
        for (i = 0; i < reps; i++) {
                int cpu = rseq_cpu_start();

                cpu = rseq_this_cpu_lock(&data->lock);
                data->c[cpu].count++;
                rseq_percpu_unlock(&data->lock, cpu);
#ifndef BENCHMARK
                if (i != 0 && !(i % (reps / 10)))
                        printf_verbose("tid %d: count %lld\n",
                                       (int) rseq_gettid(), i);
#endif
        }
        printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
                       (int) rseq_gettid(), nr_abort, signals_delivered);
        if (!opt_disable_rseq && thread_data->reg &&
            rseq_unregister_current_thread())
                abort();
        return NULL;
}

/*
 * A simple test which implements a sharded counter using a per-cpu
 * lock.  Obviously real applications might prefer to simply use a
 * per-cpu increment; however, this is reasonable for a test and the
 * lock can be extended to synchronize more complicated operations.
 */
void test_percpu_spinlock(void)
{
        const int num_threads = opt_threads;
        int i, ret;
        uint64_t sum;
        pthread_t test_threads[num_threads];
        struct spinlock_test_data data;
        struct spinlock_thread_test_data thread_data[num_threads];

        memset(&data, 0, sizeof(data));
        for (i = 0; i < num_threads; i++) {
                thread_data[i].reps = opt_reps;
                if (opt_disable_mod <= 0 || (i % opt_disable_mod))
                        thread_data[i].reg = 1;
                else
                        thread_data[i].reg = 0;
                thread_data[i].data = &data;
                ret = pthread_create(&test_threads[i], NULL,
                                     test_percpu_spinlock_thread,
                                     &thread_data[i]);
                if (ret) {
                        errno = ret;
                        perror("pthread_create");
                        abort();
                }
        }

        for (i = 0; i < num_threads; i++) {
                ret = pthread_join(test_threads[i], NULL);
                if (ret) {
                        errno = ret;
                        perror("pthread_join");
                        abort();
                }
        }

        sum = 0;
        for (i = 0; i < CPU_SETSIZE; i++)
                sum += data.c[i].count;

        assert(sum == (uint64_t)opt_reps * num_threads);
}

void *test_percpu_inc_thread(void *arg)
{
        struct inc_thread_test_data *thread_data = arg;
        struct inc_test_data *data = thread_data->data;
        long long i, reps;

        if (!opt_disable_rseq && thread_data->reg &&
            rseq_register_current_thread())
                abort();
        reps = thread_data->reps;
        for (i = 0; i < reps; i++) {
                int ret;

                do {
                        int cpu;

                        cpu = rseq_cpu_start();
                        ret = rseq_addv(&data->c[cpu].count, 1, cpu);
                } while (rseq_unlikely(ret));
#ifndef BENCHMARK
                if (i != 0 && !(i % (reps / 10)))
                        printf_verbose("tid %d: count %lld\n",
                                       (int) rseq_gettid(), i);
#endif
        }
        printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
                       (int) rseq_gettid(), nr_abort, signals_delivered);
        if (!opt_disable_rseq && thread_data->reg &&
            rseq_unregister_current_thread())
                abort();
        return NULL;
}

void test_percpu_inc(void)
{
        const int num_threads = opt_threads;
        int i, ret;
        uint64_t sum;
        pthread_t test_threads[num_threads];
        struct inc_test_data data;
        struct inc_thread_test_data thread_data[num_threads];

        memset(&data, 0, sizeof(data));
        for (i = 0; i < num_threads; i++) {
                thread_data[i].reps = opt_reps;
                if (opt_disable_mod <= 0 || (i % opt_disable_mod))
                        thread_data[i].reg = 1;
                else
                        thread_data[i].reg = 0;
                thread_data[i].data = &data;
                ret = pthread_create(&test_threads[i], NULL,
                                     test_percpu_inc_thread,
                                     &thread_data[i]);
                if (ret) {
                        errno = ret;
                        perror("pthread_create");
                        abort();
                }
        }

        for (i = 0; i < num_threads; i++) {
                ret = pthread_join(test_threads[i], NULL);
                if (ret) {
                        errno = ret;
                        perror("pthread_join");
                        abort();
                }
        }

        sum = 0;
        for (i = 0; i < CPU_SETSIZE; i++)
                sum += data.c[i].count;

        assert(sum == (uint64_t)opt_reps * num_threads);
}

void this_cpu_list_push(struct percpu_list *list,
                        struct percpu_list_node *node,
                        int *_cpu)
{
        int cpu;

        for (;;) {
                intptr_t *targetptr, newval, expect;
                int ret;

                cpu = rseq_cpu_start();
                /* Load list->c[cpu].head with single-copy atomicity. */
                expect = (intptr_t)RSEQ_READ_ONCE(list->c[cpu].head);
                newval = (intptr_t)node;
                targetptr = (intptr_t *)&list->c[cpu].head;
                node->next = (struct percpu_list_node *)expect;
                ret = rseq_cmpeqv_storev(targetptr, expect, newval, cpu);
                if (rseq_likely(!ret))
                        break;
                /* Retry if comparison fails or rseq aborts. */
        }
        if (_cpu)
                *_cpu = cpu;
}

/*
 * Unlike a traditional lock-less linked list; the availability of a
 * rseq primitive allows us to implement pop without concerns over
 * ABA-type races.
 */
struct percpu_list_node *this_cpu_list_pop(struct percpu_list *list,
                                           int *_cpu)
{
        struct percpu_list_node *node = NULL;
        int cpu;

        for (;;) {
                struct percpu_list_node *head;
                intptr_t *targetptr, expectnot, *load;
                off_t offset;
                int ret;

                cpu = rseq_cpu_start();
                targetptr = (intptr_t *)&list->c[cpu].head;
                expectnot = (intptr_t)NULL;
                offset = offsetof(struct percpu_list_node, next);
                load = (intptr_t *)&head;
                ret = rseq_cmpnev_storeoffp_load(targetptr, expectnot,
                                                   offset, load, cpu);
                if (rseq_likely(!ret)) {
                        node = head;
                        break;
                }
                if (ret > 0)
                        break;
                /* Retry if rseq aborts. */
        }
        if (_cpu)
                *_cpu = cpu;
        return node;
}

/*
 * __percpu_list_pop is not safe against concurrent accesses. Should
 * only be used on lists that are not concurrently modified.
 */
struct percpu_list_node *__percpu_list_pop(struct percpu_list *list, int cpu)
{
        struct percpu_list_node *node;

        node = list->c[cpu].head;
        if (!node)
                return NULL;
        list->c[cpu].head = node->next;
        return node;
}

void *test_percpu_list_thread(void *arg)
{
        long long i, reps;
        struct percpu_list *list = (struct percpu_list *)arg;

        if (!opt_disable_rseq && rseq_register_current_thread())
                abort();

        reps = opt_reps;
        for (i = 0; i < reps; i++) {
                struct percpu_list_node *node;

                node = this_cpu_list_pop(list, NULL);
                if (opt_yield)
                        sched_yield();  /* encourage shuffling */
                if (node)
                        this_cpu_list_push(list, node, NULL);
        }

        printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
                       (int) rseq_gettid(), nr_abort, signals_delivered);
        if (!opt_disable_rseq && rseq_unregister_current_thread())
                abort();

        return NULL;
}

/* Simultaneous modification to a per-cpu linked list from many threads.  */
void test_percpu_list(void)
{
        const int num_threads = opt_threads;
        int i, j, ret;
        uint64_t sum = 0, expected_sum = 0;
        struct percpu_list list;
        pthread_t test_threads[num_threads];
        cpu_set_t allowed_cpus;

        memset(&list, 0, sizeof(list));

        /* Generate list entries for every usable cpu. */
        sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
        for (i = 0; i < CPU_SETSIZE; i++) {
                if (!CPU_ISSET(i, &allowed_cpus))
                        continue;
                for (j = 1; j <= 100; j++) {
                        struct percpu_list_node *node;

                        expected_sum += j;

                        node = malloc(sizeof(*node));
                        assert(node);
                        node->data = j;
                        node->next = list.c[i].head;
                        list.c[i].head = node;
                }
        }

        for (i = 0; i < num_threads; i++) {
                ret = pthread_create(&test_threads[i], NULL,
                                     test_percpu_list_thread, &list);
                if (ret) {
                        errno = ret;
                        perror("pthread_create");
                        abort();
                }
        }

        for (i = 0; i < num_threads; i++) {
                ret = pthread_join(test_threads[i], NULL);
                if (ret) {
                        errno = ret;
                        perror("pthread_join");
                        abort();
                }
        }

        for (i = 0; i < CPU_SETSIZE; i++) {
                struct percpu_list_node *node;

                if (!CPU_ISSET(i, &allowed_cpus))
                        continue;

                while ((node = __percpu_list_pop(&list, i))) {
                        sum += node->data;
                        free(node);
                }
        }

        /*
         * All entries should now be accounted for (unless some external
         * actor is interfering with our allowed affinity while this
         * test is running).
         */
        assert(sum == expected_sum);
}

bool this_cpu_buffer_push(struct percpu_buffer *buffer,
                          struct percpu_buffer_node *node,
                          int *_cpu)
{
        bool result = false;
        int cpu;

        for (;;) {
                intptr_t *targetptr_spec, newval_spec;
                intptr_t *targetptr_final, newval_final;
                intptr_t offset;
                int ret;

                cpu = rseq_cpu_start();
                offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
                if (offset == buffer->c[cpu].buflen)
                        break;
                newval_spec = (intptr_t)node;
                targetptr_spec = (intptr_t *)&buffer->c[cpu].array[offset];
                newval_final = offset + 1;
                targetptr_final = &buffer->c[cpu].offset;
                if (opt_mb)
                        ret = rseq_cmpeqv_trystorev_storev_release(
                                targetptr_final, offset, targetptr_spec,
                                newval_spec, newval_final, cpu);
                else
                        ret = rseq_cmpeqv_trystorev_storev(targetptr_final,
                                offset, targetptr_spec, newval_spec,
                                newval_final, cpu);
                if (rseq_likely(!ret)) {
                        result = true;
                        break;
                }
                /* Retry if comparison fails or rseq aborts. */
        }
        if (_cpu)
                *_cpu = cpu;
        return result;
}

struct percpu_buffer_node *this_cpu_buffer_pop(struct percpu_buffer *buffer,
                                               int *_cpu)
{
        struct percpu_buffer_node *head;
        int cpu;

        for (;;) {
                intptr_t *targetptr, newval;
                intptr_t offset;
                int ret;

                cpu = rseq_cpu_start();
                /* Load offset with single-copy atomicity. */
                offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
                if (offset == 0) {
                        head = NULL;
                        break;
                }
                head = RSEQ_READ_ONCE(buffer->c[cpu].array[offset - 1]);
                newval = offset - 1;
                targetptr = (intptr_t *)&buffer->c[cpu].offset;
                ret = rseq_cmpeqv_cmpeqv_storev(targetptr, offset,
                        (intptr_t *)&buffer->c[cpu].array[offset - 1],
                        (intptr_t)head, newval, cpu);
                if (rseq_likely(!ret))
                        break;
                /* Retry if comparison fails or rseq aborts. */
        }
        if (_cpu)
                *_cpu = cpu;
        return head;
}

/*
 * __percpu_buffer_pop is not safe against concurrent accesses. Should
 * only be used on buffers that are not concurrently modified.
 */
struct percpu_buffer_node *__percpu_buffer_pop(struct percpu_buffer *buffer,
                                               int cpu)
{
        struct percpu_buffer_node *head;
        intptr_t offset;

        offset = buffer->c[cpu].offset;
        if (offset == 0)
                return NULL;
        head = buffer->c[cpu].array[offset - 1];
        buffer->c[cpu].offset = offset - 1;
        return head;
}

void *test_percpu_buffer_thread(void *arg)
{
        long long i, reps;
        struct percpu_buffer *buffer = (struct percpu_buffer *)arg;

        if (!opt_disable_rseq && rseq_register_current_thread())
                abort();

        reps = opt_reps;
        for (i = 0; i < reps; i++) {
                struct percpu_buffer_node *node;

                node = this_cpu_buffer_pop(buffer, NULL);
                if (opt_yield)
                        sched_yield();  /* encourage shuffling */
                if (node) {
                        if (!this_cpu_buffer_push(buffer, node, NULL)) {
                                /* Should increase buffer size. */
                                abort();
                        }
                }
        }

        printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
                       (int) rseq_gettid(), nr_abort, signals_delivered);
        if (!opt_disable_rseq && rseq_unregister_current_thread())
                abort();

        return NULL;
}

/* Simultaneous modification to a per-cpu buffer from many threads.  */
void test_percpu_buffer(void)
{
        const int num_threads = opt_threads;
        int i, j, ret;
        uint64_t sum = 0, expected_sum = 0;
        struct percpu_buffer buffer;
        pthread_t test_threads[num_threads];
        cpu_set_t allowed_cpus;

        memset(&buffer, 0, sizeof(buffer));

        /* Generate list entries for every usable cpu. */
        sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
        for (i = 0; i < CPU_SETSIZE; i++) {
                if (!CPU_ISSET(i, &allowed_cpus))
                        continue;
                /* Worse-case is every item in same CPU. */
                buffer.c[i].array =
                        malloc(sizeof(*buffer.c[i].array) * CPU_SETSIZE *
                               BUFFER_ITEM_PER_CPU);
                assert(buffer.c[i].array);
                buffer.c[i].buflen = CPU_SETSIZE * BUFFER_ITEM_PER_CPU;
                for (j = 1; j <= BUFFER_ITEM_PER_CPU; j++) {
                        struct percpu_buffer_node *node;

                        expected_sum += j;

                        /*
                         * We could theoretically put the word-sized
                         * "data" directly in the buffer. However, we
                         * want to model objects that would not fit
                         * within a single word, so allocate an object
                         * for each node.
                         */
                        node = malloc(sizeof(*node));
                        assert(node);
                        node->data = j;
                        buffer.c[i].array[j - 1] = node;
                        buffer.c[i].offset++;
                }
        }

        for (i = 0; i < num_threads; i++) {
                ret = pthread_create(&test_threads[i], NULL,
                                     test_percpu_buffer_thread, &buffer);
                if (ret) {
                        errno = ret;
                        perror("pthread_create");
                        abort();
                }
        }

        for (i = 0; i < num_threads; i++) {
                ret = pthread_join(test_threads[i], NULL);
                if (ret) {
                        errno = ret;
                        perror("pthread_join");
                        abort();
                }
        }

        for (i = 0; i < CPU_SETSIZE; i++) {
                struct percpu_buffer_node *node;

                if (!CPU_ISSET(i, &allowed_cpus))
                        continue;

                while ((node = __percpu_buffer_pop(&buffer, i))) {
                        sum += node->data;
                        free(node);
                }
                free(buffer.c[i].array);
        }

        /*
         * All entries should now be accounted for (unless some external
         * actor is interfering with our allowed affinity while this
         * test is running).
         */
        assert(sum == expected_sum);
}

bool this_cpu_memcpy_buffer_push(struct percpu_memcpy_buffer *buffer,
                                 struct percpu_memcpy_buffer_node item,
                                 int *_cpu)
{
        bool result = false;
        int cpu;

        for (;;) {
                intptr_t *targetptr_final, newval_final, offset;
                char *destptr, *srcptr;
                size_t copylen;
                int ret;

                cpu = rseq_cpu_start();
                /* Load offset with single-copy atomicity. */
                offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
                if (offset == buffer->c[cpu].buflen)
                        break;
                destptr = (char *)&buffer->c[cpu].array[offset];
                srcptr = (char *)&item;
                /* copylen must be <= 4kB. */
                copylen = sizeof(item);
                newval_final = offset + 1;
                targetptr_final = &buffer->c[cpu].offset;
                if (opt_mb)
                        ret = rseq_cmpeqv_trymemcpy_storev_release(
                                targetptr_final, offset,
                                destptr, srcptr, copylen,
                                newval_final, cpu);
                else
                        ret = rseq_cmpeqv_trymemcpy_storev(targetptr_final,
                                offset, destptr, srcptr, copylen,
                                newval_final, cpu);
                if (rseq_likely(!ret)) {
                        result = true;
                        break;
                }
                /* Retry if comparison fails or rseq aborts. */
        }
        if (_cpu)
                *_cpu = cpu;
        return result;
}

bool this_cpu_memcpy_buffer_pop(struct percpu_memcpy_buffer *buffer,
                                struct percpu_memcpy_buffer_node *item,
                                int *_cpu)
{
        bool result = false;
        int cpu;

        for (;;) {
                intptr_t *targetptr_final, newval_final, offset;
                char *destptr, *srcptr;
                size_t copylen;
                int ret;

                cpu = rseq_cpu_start();
                /* Load offset with single-copy atomicity. */
                offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
                if (offset == 0)
                        break;
                destptr = (char *)item;
                srcptr = (char *)&buffer->c[cpu].array[offset - 1];
                /* copylen must be <= 4kB. */
                copylen = sizeof(*item);
                newval_final = offset - 1;
                targetptr_final = &buffer->c[cpu].offset;
                ret = rseq_cmpeqv_trymemcpy_storev(targetptr_final,
                        offset, destptr, srcptr, copylen,
                        newval_final, cpu);
                if (rseq_likely(!ret)) {
                        result = true;
                        break;
                }
                /* Retry if comparison fails or rseq aborts. */
        }
        if (_cpu)
                *_cpu = cpu;
        return result;
}

/*
 * __percpu_memcpy_buffer_pop is not safe against concurrent accesses. Should
 * only be used on buffers that are not concurrently modified.
 */
bool __percpu_memcpy_buffer_pop(struct percpu_memcpy_buffer *buffer,
                                struct percpu_memcpy_buffer_node *item,
                                int cpu)
{
        intptr_t offset;

        offset = buffer->c[cpu].offset;
        if (offset == 0)
                return false;
        memcpy(item, &buffer->c[cpu].array[offset - 1], sizeof(*item));
        buffer->c[cpu].offset = offset - 1;
        return true;
}

void *test_percpu_memcpy_buffer_thread(void *arg)
{
        long long i, reps;
        struct percpu_memcpy_buffer *buffer = (struct percpu_memcpy_buffer *)arg;

        if (!opt_disable_rseq && rseq_register_current_thread())
                abort();

        reps = opt_reps;
        for (i = 0; i < reps; i++) {
                struct percpu_memcpy_buffer_node item;
                bool result;

                result = this_cpu_memcpy_buffer_pop(buffer, &item, NULL);
                if (opt_yield)
                        sched_yield();  /* encourage shuffling */
                if (result) {
                        if (!this_cpu_memcpy_buffer_push(buffer, item, NULL)) {
                                /* Should increase buffer size. */
                                abort();
                        }
                }
        }

        printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
                       (int) rseq_gettid(), nr_abort, signals_delivered);
        if (!opt_disable_rseq && rseq_unregister_current_thread())
                abort();

        return NULL;
}

/* Simultaneous modification to a per-cpu buffer from many threads.  */
void test_percpu_memcpy_buffer(void)
{
        const int num_threads = opt_threads;
        int i, j, ret;
        uint64_t sum = 0, expected_sum = 0;
        struct percpu_memcpy_buffer buffer;
        pthread_t test_threads[num_threads];
        cpu_set_t allowed_cpus;

        memset(&buffer, 0, sizeof(buffer));

        /* Generate list entries for every usable cpu. */
        sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
        for (i = 0; i < CPU_SETSIZE; i++) {
                if (!CPU_ISSET(i, &allowed_cpus))
                        continue;
                /* Worse-case is every item in same CPU. */
                buffer.c[i].array =
                        malloc(sizeof(*buffer.c[i].array) * CPU_SETSIZE *
                               MEMCPY_BUFFER_ITEM_PER_CPU);
                assert(buffer.c[i].array);
                buffer.c[i].buflen = CPU_SETSIZE * MEMCPY_BUFFER_ITEM_PER_CPU;
                for (j = 1; j <= MEMCPY_BUFFER_ITEM_PER_CPU; j++) {
                        expected_sum += 2 * j + 1;

                        /*
                         * We could theoretically put the word-sized
                         * "data" directly in the buffer. However, we
                         * want to model objects that would not fit
                         * within a single word, so allocate an object
                         * for each node.
                         */
                        buffer.c[i].array[j - 1].data1 = j;
                        buffer.c[i].array[j - 1].data2 = j + 1;
                        buffer.c[i].offset++;
                }
        }

        for (i = 0; i < num_threads; i++) {
                ret = pthread_create(&test_threads[i], NULL,
                                     test_percpu_memcpy_buffer_thread,
                                     &buffer);
                if (ret) {
                        errno = ret;
                        perror("pthread_create");
                        abort();
                }
        }

        for (i = 0; i < num_threads; i++) {
                ret = pthread_join(test_threads[i], NULL);
                if (ret) {
                        errno = ret;
                        perror("pthread_join");
                        abort();
                }
        }

        for (i = 0; i < CPU_SETSIZE; i++) {
                struct percpu_memcpy_buffer_node item;

                if (!CPU_ISSET(i, &allowed_cpus))
                        continue;

                while (__percpu_memcpy_buffer_pop(&buffer, &item, i)) {
                        sum += item.data1;
                        sum += item.data2;
                }
                free(buffer.c[i].array);
        }

        /*
         * All entries should now be accounted for (unless some external
         * actor is interfering with our allowed affinity while this
         * test is running).
         */
        assert(sum == expected_sum);
}

static void test_signal_interrupt_handler(int signo)
{
        signals_delivered++;
}

static int set_signal_handler(void)
{
        int ret = 0;
        struct sigaction sa;
        sigset_t sigset;

        ret = sigemptyset(&sigset);
        if (ret < 0) {
                perror("sigemptyset");
                return ret;
        }

        sa.sa_handler = test_signal_interrupt_handler;
        sa.sa_mask = sigset;
        sa.sa_flags = 0;
        ret = sigaction(SIGUSR1, &sa, NULL);
        if (ret < 0) {
                perror("sigaction");
                return ret;
        }

        printf_verbose("Signal handler set for SIGUSR1\n");

        return ret;
}

/* Test MEMBARRIER_CMD_PRIVATE_RESTART_RSEQ_ON_CPU membarrier command. */
#ifdef RSEQ_ARCH_HAS_OFFSET_DEREF_ADDV
struct test_membarrier_thread_args {
        int stop;
        intptr_t percpu_list_ptr;
};

/* Worker threads modify data in their "active" percpu lists. */
void *test_membarrier_worker_thread(void *arg)
{
        struct test_membarrier_thread_args *args =
                (struct test_membarrier_thread_args *)arg;
        const int iters = opt_reps;
        int i;

        if (rseq_register_current_thread()) {
                fprintf(stderr, "Error: rseq_register_current_thread(...) failed(%d): %s\n",
                        errno, strerror(errno));
                abort();
        }

        /* Wait for initialization. */
        while (!atomic_load(&args->percpu_list_ptr)) {}

        for (i = 0; i < iters; ++i) {
                int ret;

                do {
                        int cpu = rseq_cpu_start();

                        ret = rseq_offset_deref_addv(&args->percpu_list_ptr,
                                sizeof(struct percpu_list_entry) * cpu, 1, cpu);
                } while (rseq_unlikely(ret));
        }

        if (rseq_unregister_current_thread()) {
                fprintf(stderr, "Error: rseq_unregister_current_thread(...) failed(%d): %s\n",
                        errno, strerror(errno));
                abort();
        }
        return NULL;
}

void test_membarrier_init_percpu_list(struct percpu_list *list)
{
        int i;

        memset(list, 0, sizeof(*list));
        for (i = 0; i < CPU_SETSIZE; i++) {
                struct percpu_list_node *node;

                node = malloc(sizeof(*node));
                assert(node);
                node->data = 0;
                node->next = NULL;
                list->c[i].head = node;
        }
}

void test_membarrier_free_percpu_list(struct percpu_list *list)
{
        int i;

        for (i = 0; i < CPU_SETSIZE; i++)
                free(list->c[i].head);
}

static int sys_membarrier(int cmd, int flags, int cpu_id)
{
        return syscall(__NR_membarrier, cmd, flags, cpu_id);
}

/*
 * The manager thread swaps per-cpu lists that worker threads see,
 * and validates that there are no unexpected modifications.
 */
void *test_membarrier_manager_thread(void *arg)
{
        struct test_membarrier_thread_args *args =
                (struct test_membarrier_thread_args *)arg;
        struct percpu_list list_a, list_b;
        intptr_t expect_a = 0, expect_b = 0;
        int cpu_a = 0, cpu_b = 0;

        if (rseq_register_current_thread()) {
                fprintf(stderr, "Error: rseq_register_current_thread(...) failed(%d): %s\n",
                        errno, strerror(errno));
                abort();
        }

        /* Init lists. */
        test_membarrier_init_percpu_list(&list_a);
        test_membarrier_init_percpu_list(&list_b);

        atomic_store(&args->percpu_list_ptr, (intptr_t)&list_a);

        while (!atomic_load(&args->stop)) {
                /* list_a is "active". */
                cpu_a = rand() % CPU_SETSIZE;
                /*
                 * As list_b is "inactive", we should never see changes
                 * to list_b.
                 */
                if (expect_b != atomic_load(&list_b.c[cpu_b].head->data)) {
                        fprintf(stderr, "Membarrier test failed\n");
                        abort();
                }

                /* Make list_b "active". */
                atomic_store(&args->percpu_list_ptr, (intptr_t)&list_b);
                if (sys_membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ,
                                        MEMBARRIER_CMD_FLAG_CPU, cpu_a) &&
                                errno != ENXIO /* missing CPU */) {
                        perror("sys_membarrier");
                        abort();
                }
                /*
                 * Cpu A should now only modify list_b, so the values
                 * in list_a should be stable.
                 */
                expect_a = atomic_load(&list_a.c[cpu_a].head->data);

                cpu_b = rand() % CPU_SETSIZE;
                /*
                 * As list_a is "inactive", we should never see changes
                 * to list_a.
                 */
                if (expect_a != atomic_load(&list_a.c[cpu_a].head->data)) {
                        fprintf(stderr, "Membarrier test failed\n");
                        abort();
                }

                /* Make list_a "active". */
                atomic_store(&args->percpu_list_ptr, (intptr_t)&list_a);
                if (sys_membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ,
                                        MEMBARRIER_CMD_FLAG_CPU, cpu_b) &&
                                errno != ENXIO /* missing CPU*/) {
                        perror("sys_membarrier");
                        abort();
                }
                /* Remember a value from list_b. */
                expect_b = atomic_load(&list_b.c[cpu_b].head->data);
        }

        test_membarrier_free_percpu_list(&list_a);
        test_membarrier_free_percpu_list(&list_b);

        if (rseq_unregister_current_thread()) {
                fprintf(stderr, "Error: rseq_unregister_current_thread(...) failed(%d): %s\n",
                        errno, strerror(errno));
                abort();
        }
        return NULL;
}

void test_membarrier(void)
{
        const int num_threads = opt_threads;
        struct test_membarrier_thread_args thread_args;
        pthread_t worker_threads[num_threads];
        pthread_t manager_thread;
        int i, ret;

        if (sys_membarrier(MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ, 0, 0)) {
                perror("sys_membarrier");
                abort();
        }

        thread_args.stop = 0;
        thread_args.percpu_list_ptr = 0;
        ret = pthread_create(&manager_thread, NULL,
                        test_membarrier_manager_thread, &thread_args);
        if (ret) {
                errno = ret;
                perror("pthread_create");
                abort();
        }

        for (i = 0; i < num_threads; i++) {
                ret = pthread_create(&worker_threads[i], NULL,
                                test_membarrier_worker_thread, &thread_args);
                if (ret) {
                        errno = ret;
                        perror("pthread_create");
                        abort();
                }
        }


        for (i = 0; i < num_threads; i++) {
                ret = pthread_join(worker_threads[i], NULL);
                if (ret) {
                        errno = ret;
                        perror("pthread_join");
                        abort();
                }
        }

        atomic_store(&thread_args.stop, 1);
        ret = pthread_join(manager_thread, NULL);
        if (ret) {
                errno = ret;
                perror("pthread_join");
                abort();
        }
}
#else /* RSEQ_ARCH_HAS_OFFSET_DEREF_ADDV */
void test_membarrier(void)
{
        fprintf(stderr, "rseq_offset_deref_addv is not implemented on this architecture. "
                        "Skipping membarrier test.\n");
}
#endif

static void show_usage(int argc, char **argv)
{
        printf("Usage : %s <OPTIONS>\n",
                argv[0]);
        printf("OPTIONS:\n");
        printf("        [-1 loops] Number of loops for delay injection 1\n");
        printf("        [-2 loops] Number of loops for delay injection 2\n");
        printf("        [-3 loops] Number of loops for delay injection 3\n");
        printf("        [-4 loops] Number of loops for delay injection 4\n");
        printf("        [-5 loops] Number of loops for delay injection 5\n");
        printf("        [-6 loops] Number of loops for delay injection 6\n");
        printf("        [-7 loops] Number of loops for delay injection 7 (-1 to enable -m)\n");
        printf("        [-8 loops] Number of loops for delay injection 8 (-1 to enable -m)\n");
        printf("        [-9 loops] Number of loops for delay injection 9 (-1 to enable -m)\n");
        printf("        [-m N] Yield/sleep/kill every modulo N (default 0: disabled) (>= 0)\n");
        printf("        [-y] Yield\n");
        printf("        [-k] Kill thread with signal\n");
        printf("        [-s S] S: =0: disabled (default), >0: sleep time (ms)\n");
        printf("        [-t N] Number of threads (default 200)\n");
        printf("        [-r N] Number of repetitions per thread (default 5000)\n");
        printf("        [-d] Disable rseq system call (no initialization)\n");
        printf("        [-D M] Disable rseq for each M threads\n");
        printf("        [-T test] Choose test: (s)pinlock, (l)ist, (b)uffer, (m)emcpy, (i)ncrement, membarrie(r)\n");
        printf("        [-M] Push into buffer and memcpy buffer with memory barriers.\n");
        printf("        [-v] Verbose output.\n");
        printf("        [-h] Show this help.\n");
        printf("\n");
}

int main(int argc, char **argv)
{
        int i;

        for (i = 1; i < argc; i++) {
                if (argv[i][0] != '-')
                        continue;
                switch (argv[i][1]) {
                case '1':
                case '2':
                case '3':
                case '4':
                case '5':
                case '6':
                case '7':
                case '8':
                case '9':
                        if (argc < i + 2) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        loop_cnt[argv[i][1] - '0'] = atol(argv[i + 1]);
                        i++;
                        break;
                case 'm':
                        if (argc < i + 2) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        opt_modulo = atol(argv[i + 1]);
                        if (opt_modulo < 0) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        i++;
                        break;
                case 's':
                        if (argc < i + 2) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        opt_sleep = atol(argv[i + 1]);
                        if (opt_sleep < 0) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        i++;
                        break;
                case 'y':
                        opt_yield = 1;
                        break;
                case 'k':
                        opt_signal = 1;
                        break;
                case 'd':
                        opt_disable_rseq = 1;
                        break;
                case 'D':
                        if (argc < i + 2) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        opt_disable_mod = atol(argv[i + 1]);
                        if (opt_disable_mod < 0) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        i++;
                        break;
                case 't':
                        if (argc < i + 2) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        opt_threads = atol(argv[i + 1]);
                        if (opt_threads < 0) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        i++;
                        break;
                case 'r':
                        if (argc < i + 2) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        opt_reps = atoll(argv[i + 1]);
                        if (opt_reps < 0) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        i++;
                        break;
                case 'h':
                        show_usage(argc, argv);
                        goto end;
                case 'T':
                        if (argc < i + 2) {
                                show_usage(argc, argv);
                                goto error;
                        }
                        opt_test = *argv[i + 1];
                        switch (opt_test) {
                        case 's':
                        case 'l':
                        case 'i':
                        case 'b':
                        case 'm':
                        case 'r':
                                break;
                        default:
                                show_usage(argc, argv);
                                goto error;
                        }
                        i++;
                        break;
                case 'v':
                        verbose = 1;
                        break;
                case 'M':
                        opt_mb = 1;
                        break;
                default:
                        show_usage(argc, argv);
                        goto error;
                }
        }

        loop_cnt_1 = loop_cnt[1];
        loop_cnt_2 = loop_cnt[2];
        loop_cnt_3 = loop_cnt[3];
        loop_cnt_4 = loop_cnt[4];
        loop_cnt_5 = loop_cnt[5];
        loop_cnt_6 = loop_cnt[6];

        if (set_signal_handler())
                goto error;

        if (!opt_disable_rseq && rseq_register_current_thread())
                goto error;
        switch (opt_test) {
        case 's':
                printf_verbose("spinlock\n");
                test_percpu_spinlock();
                break;
        case 'l':
                printf_verbose("linked list\n");
                test_percpu_list();
                break;
        case 'b':
                printf_verbose("buffer\n");
                test_percpu_buffer();
                break;
        case 'm':
                printf_verbose("memcpy buffer\n");
                test_percpu_memcpy_buffer();
                break;
        case 'i':
                printf_verbose("counter increment\n");
                test_percpu_inc();
                break;
        case 'r':
                printf_verbose("membarrier\n");
                test_membarrier();
                break;
        }
        if (!opt_disable_rseq && rseq_unregister_current_thread())
                abort();
end:
        return 0;

error:
        return -1;
}