mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
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119 lines
3.0 KiB
C
119 lines
3.0 KiB
C
// https://cirosantilli.com/linux-kernel-module-cheat#atomic-c */
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#if __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_THREADS__)
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#include <assert.h>
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#include <stdatomic.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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#include <threads.h>
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#if LKMC_USERLAND_ATOMIC_STD_ATOMIC
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atomic_uint global = 0;
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#else
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uint64_t global = 0;
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#endif
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int my_thread_main(void *thr_data) {
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size_t niters = *(size_t *)thr_data;
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for (size_t i = 0; i < niters; ++i) {
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#if LKMC_USERLAND_ATOMIC_X86_64_INC
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__asm__ __volatile__ (
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"incq %0;"
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: "+g" (global),
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"+g" (i)
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:
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:
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);
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#elif LKMC_USERLAND_ATOMIC_X86_64_LOCK_INC
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__asm__ __volatile__ (
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"lock incq %0;"
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: "+m" (global),
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"+g" (i)
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:
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:
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);
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#elif LKMC_USERLAND_ATOMIC_AARCH64_ADD
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__asm__ __volatile__ (
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"add %0, %0, 1;"
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: "+r" (global),
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"+g" (i)
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:
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:
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);
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#elif LKMC_USERLAND_ATOMIC_LDAXR_STLXR
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uint64_t scratch64;
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uint64_t scratch32;
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__asm__ __volatile__ (
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"1:"
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"ldaxr %[scratch64], [%[addr]];"
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"add %[scratch64], %[scratch64], 1;"
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"stlxr %w[scratch32], %[scratch64], [%[addr]];"
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"cbnz %w[scratch32], 1b;"
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: "=m" (global),
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"+g" (i),
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[scratch64] "=&r" (scratch64),
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[scratch32] "=&r" (scratch32)
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: [addr] "r" (&global)
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:
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);
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#elif LKMC_USERLAND_ATOMIC_AARCH64_LDADD
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__asm__ __volatile__ (
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"ldadd %[inc], xzr, [%[addr]];"
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: "=m" (global),
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"+g" (i)
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: [inc] "r" (1),
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[addr] "r" (&global)
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:
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);
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#else
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__asm__ __volatile__ (
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""
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: "+g" (i)
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: "g" (global)
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:
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);
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global++;
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#endif
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}
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return 0;
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}
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#endif
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int main(int argc, char **argv) {
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#if __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_THREADS__)
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size_t niters, nthreads;
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thrd_t *threads;
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if (argc > 1) {
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nthreads = strtoull(argv[1], NULL, 0);
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} else {
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nthreads = 2;
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}
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if (argc > 2) {
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niters = strtoull(argv[2], NULL, 0);
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} else {
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niters = 10;
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}
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threads = malloc(sizeof(thrd_t) * nthreads);
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for(size_t i = 0; i < nthreads; ++i)
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assert(thrd_create(threads + i, my_thread_main, &niters) == thrd_success);
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for(size_t i = 0; i < nthreads; ++i)
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assert(thrd_join(threads[i], NULL) == thrd_success);
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free(threads);
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uint64_t expect = nthreads * niters;
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#if LKMC_USERLAND_ATOMIC_FAIL || \
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LKMC_USERLAND_ATOMIC_X86_64_INC || \
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LKMC_USERLAND_ATOMIC_AARCH64_ADD
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printf("expect %ju\n", (uintmax_t)expect);
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printf("global %ju\n", (uintmax_t)global);
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#else
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assert(global == expect);
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#endif
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#else
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(void)argc;
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(void)argv;
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#endif
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}
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