mirror of https://gitee.com/openkylin/linux.git
111 lines
2.6 KiB
C
111 lines
2.6 KiB
C
/*
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* Adapted from Anton Blanchard's context switch microbenchmark.
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*
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* Copyright 2009, Anton Blanchard, IBM Corporation.
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* Copyright 2016, Mikey Neuling, Chris Smart, IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* This program tests the copy paste abort functionality of a P9
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* (or later) by setting up two processes on the same CPU, one
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* which executes the copy instruction and the other which
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* executes paste.
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*
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* The paste instruction should never succeed, as the cp_abort
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* instruction is called by the kernel during a context switch.
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*
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include "utils.h"
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#include <sched.h>
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#define READ_FD 0
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#define WRITE_FD 1
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#define NUM_LOOPS 1000
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/* This defines the "paste" instruction from Power ISA 3.0 Book II, section 4.4. */
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#define PASTE(RA, RB, L, RC) \
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.long (0x7c00070c | (RA) << (31-15) | (RB) << (31-20) | (L) << (31-10) | (RC) << (31-31))
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int paste(void *i)
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{
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int cr;
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asm volatile(str(PASTE(0, %1, 1, 1))";"
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"mfcr %0;"
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: "=r" (cr)
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: "b" (i)
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: "memory"
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);
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return cr;
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}
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/* This defines the "copy" instruction from Power ISA 3.0 Book II, section 4.4. */
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#define COPY(RA, RB, L) \
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.long (0x7c00060c | (RA) << (31-15) | (RB) << (31-20) | (L) << (31-10))
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void copy(void *i)
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{
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asm volatile(str(COPY(0, %0, 1))";"
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:
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: "b" (i)
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: "memory"
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);
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}
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int test_cp_abort(void)
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{
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/* 128 bytes for a full cache line */
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char buf[128] __cacheline_aligned;
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cpu_set_t cpuset;
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int fd1[2], fd2[2], pid;
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char c;
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/* only run this test on a P9 or later */
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SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_3_00));
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/*
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* Run both processes on the same CPU, so that copy is more likely
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* to leak into a paste.
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*/
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CPU_ZERO(&cpuset);
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CPU_SET(pick_online_cpu(), &cpuset);
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FAIL_IF(sched_setaffinity(0, sizeof(cpuset), &cpuset));
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FAIL_IF(pipe(fd1) || pipe(fd2));
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pid = fork();
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FAIL_IF(pid < 0);
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if (!pid) {
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for (int i = 0; i < NUM_LOOPS; i++) {
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FAIL_IF((write(fd1[WRITE_FD], &c, 1)) != 1);
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FAIL_IF((read(fd2[READ_FD], &c, 1)) != 1);
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/* A paste succeeds if CR0 EQ bit is set */
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FAIL_IF(paste(buf) & 0x20000000);
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}
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} else {
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for (int i = 0; i < NUM_LOOPS; i++) {
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FAIL_IF((read(fd1[READ_FD], &c, 1)) != 1);
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copy(buf);
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FAIL_IF((write(fd2[WRITE_FD], &c, 1) != 1));
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}
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}
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return 0;
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}
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int main(int argc, char *argv[])
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{
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return test_harness(test_cp_abort, "cp_abort");
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}
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