cregit-Linux how code gets into the kernel

Release 4.10 tools/perf/arch/x86/tests/rdpmc.c

#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <linux/types.h>
#include "perf.h"
#include "debug.h"
#include "tests/tests.h"
#include "cloexec.h"
#include "util.h"
#include "arch-tests.h"


static u64 rdpmc(unsigned int counter) { unsigned int low, high; asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter)); return low | ((u64)high) << 32; }

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static u64 rdtsc(void) { unsigned int low, high; asm volatile("rdtsc" : "=a" (low), "=d" (high)); return low | ((u64)high) << 32; }

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static u64 mmap_read_self(void *addr) { struct perf_event_mmap_page *pc = addr; u32 seq, idx, time_mult = 0, time_shift = 0; u64 count, cyc = 0, time_offset = 0, enabled, running, delta; do { seq = pc->lock; barrier(); enabled = pc->time_enabled; running = pc->time_running; if (enabled != running) { cyc = rdtsc(); time_mult = pc->time_mult; time_shift = pc->time_shift; time_offset = pc->time_offset; } idx = pc->index; count = pc->offset; if (idx) count += rdpmc(idx - 1); barrier(); } while (pc->lock != seq); if (enabled != running) { u64 quot, rem; quot = (cyc >> time_shift); rem = cyc & (((u64)1 << time_shift) - 1); delta = time_offset + quot * time_mult + ((rem * time_mult) >> time_shift); enabled += delta; if (idx) running += delta; quot = count / running; rem = count % running; count = quot * enabled + (rem * enabled) / running; } return count; }

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jiri olsajiri olsa23398.73%150.00%
adrian hunteradrian hunter31.27%150.00%
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/* * If the RDPMC instruction faults then signal this back to the test parent task: */
static void segfault_handler(int sig __maybe_unused, siginfo_t *info __maybe_unused, void *uc __maybe_unused) { exit(-1); }

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static int __test__rdpmc(void) { volatile int tmp = 0; u64 i, loops = 1000; int n; int fd; void *addr; struct perf_event_attr attr = { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_INSTRUCTIONS, .exclude_kernel = 1, }; u64 delta_sum = 0; struct sigaction sa; char sbuf[STRERR_BUFSIZE]; sigfillset(&sa.sa_mask); sa.sa_sigaction = segfault_handler; sa.sa_flags = 0; sigaction(SIGSEGV, &sa, NULL); fd = sys_perf_event_open(&attr, 0, -1, -1, perf_event_open_cloexec_flag()); if (fd < 0) { pr_err("Error: sys_perf_event_open() syscall returned " "with %d (%s)\n", fd, str_error_r(errno, sbuf, sizeof(sbuf))); return -1; } addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0); if (addr == (void *)(-1)) { pr_err("Error: mmap() syscall returned with (%s)\n", str_error_r(errno, sbuf, sizeof(sbuf))); goto out_close; } for (n = 0; n < 6; n++) { u64 stamp, now, delta; stamp = mmap_read_self(addr); for (i = 0; i < loops; i++) tmp++; now = mmap_read_self(addr); loops *= 10; delta = now - stamp; pr_debug("%14d: %14Lu\n", n, (long long)delta); delta_sum += delta; } munmap(addr, page_size); pr_debug(" "); out_close: close(fd); if (!delta_sum) return -1; return 0; }

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jiri olsajiri olsa28090.32%120.00%
masami hiramatsumasami hiramatsu206.45%120.00%
colin kingcolin king61.94%120.00%
yann droneaudyann droneaud20.65%120.00%
arnaldo carvalho de meloarnaldo carvalho de melo20.65%120.00%
Total310100.00%5100.00%


int test__rdpmc(int subtest __maybe_unused) { int status = 0; int wret = 0; int ret; int pid; pid = fork(); if (pid < 0) return -1; if (!pid) { ret = __test__rdpmc(); exit(ret); } wret = waitpid(pid, &status, 0); if (wret < 0 || status) return -1; return 0; }

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jiri olsajiri olsa8196.43%150.00%
arnaldo carvalho de meloarnaldo carvalho de melo33.57%150.00%
Total84100.00%2100.00%


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jiri olsajiri olsa70392.62%110.00%
masami hiramatsumasami hiramatsu202.64%110.00%
arnaldo carvalho de meloarnaldo carvalho de melo172.24%330.00%
colin kingcolin king60.79%110.00%
yann droneaudyann droneaud50.66%110.00%
matt flemingmatt fleming40.53%110.00%
adrian hunteradrian hunter30.40%110.00%
borislav petkovborislav petkov10.13%110.00%
Total759100.00%10100.00%
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