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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2018 IBM Corporation.
*/
#define __SANE_USERSPACE_TYPES__
#include <sys/types.h>
#include <stdint.h>
#include <malloc.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "utils.h"
#define CACHELINE_SIZE 128
struct perf_event_read {
__u64 nr;
__u64 l1d_misses;
};
static inline __u64 load(void *addr)
{
__u64 tmp;
asm volatile("ld %0,0(%1)" : "=r"(tmp) : "b"(addr));
return tmp;
}
static void syscall_loop(char *p, unsigned long iterations,
unsigned long zero_size)
{
for (unsigned long i = 0; i < iterations; i++) {
for (unsigned long j = 0; j < zero_size; j += CACHELINE_SIZE)
load(p + j);
getppid();
}
}
static void sigill_handler(int signr, siginfo_t *info, void *unused)
{
static int warned = 0;
ucontext_t *ctx = (ucontext_t *)unused;
unsigned long *pc = &UCONTEXT_NIA(ctx);
/* mtspr 3,RS to check for move to DSCR below */
if ((*((unsigned int *)*pc) & 0xfc1fffff) == 0x7c0303a6) {
if (!warned++)
printf("WARNING: Skipping over dscr setup. Consider running 'ppc64_cpu --dscr=1' manually.\n");
*pc += 4;
} else {
printf("SIGILL at %p\n", pc);
abort();
}
}
static void set_dscr(unsigned long val)
{
static int init = 0;
struct sigaction sa;
if (!init) {
memset(&sa, 0, sizeof(sa));
sa.sa_sigaction = sigill_handler;
sa.sa_flags = SA_SIGINFO;
if (sigaction(SIGILL, &sa, NULL))
perror("sigill_handler");
init = 1;
}
asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));
}
int rfi_flush_test(void)
{
char *p;
int repetitions = 10;
int fd, passes = 0, iter, rc = 0;
struct perf_event_read v;
__u64 l1d_misses_total = 0;
unsigned long iterations = 100000, zero_size = 24 * 1024;
unsigned long l1d_misses_expected;
int rfi_flush_orig, rfi_flush;
int have_entry_flush, entry_flush_orig;
SKIP_IF(geteuid() != 0);
// The PMU event we use only works on Power7 or later
SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_orig) < 0) {
perror("Unable to read powerpc/rfi_flush debugfs file");
SKIP_IF(1);
}
if (read_debugfs_file("powerpc/entry_flush", &entry_flush_orig) < 0) {
have_entry_flush = 0;
} else {
have_entry_flush = 1;
if (entry_flush_orig != 0) {
if (write_debugfs_file("powerpc/entry_flush", 0) < 0) {
perror("error writing to powerpc/entry_flush debugfs file");
return 1;
}
}
}
rfi_flush = rfi_flush_orig;
fd = perf_event_open_counter(PERF_TYPE_RAW, /* L1d miss */ 0x400f0, -1);
FAIL_IF(fd < 0);
p = (char *)memalign(zero_size, CACHELINE_SIZE);
FAIL_IF(perf_event_enable(fd));
// disable L1 prefetching
set_dscr(1);
iter = repetitions;
/*
* We expect to see l1d miss for each cacheline access when rfi_flush
* is set. Allow a small variation on this.
*/
l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);
again:
FAIL_IF(perf_event_reset(fd));
syscall_loop(p, iterations, zero_size);
FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));
if (rfi_flush && v.l1d_misses >= l1d_misses_expected)
passes++;
else if (!rfi_flush && v.l1d_misses < (l1d_misses_expected / 2))
passes++;
l1d_misses_total += v.l1d_misses;
while (--iter)
goto again;
if (passes < repetitions) {
printf("FAIL (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d failures]\n",
rfi_flush, l1d_misses_total, rfi_flush ? '<' : '>',
rfi_flush ? repetitions * l1d_misses_expected :
repetitions * l1d_misses_expected / 2,
repetitions - passes, repetitions);
rc = 1;
} else
printf("PASS (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d pass]\n",
rfi_flush, l1d_misses_total, rfi_flush ? '>' : '<',
rfi_flush ? repetitions * l1d_misses_expected :
repetitions * l1d_misses_expected / 2,
passes, repetitions);
if (rfi_flush == rfi_flush_orig) {
rfi_flush = !rfi_flush_orig;
if (write_debugfs_file("powerpc/rfi_flush", rfi_flush) < 0) {
perror("error writing to powerpc/rfi_flush debugfs file");
return 1;
}
iter = repetitions;
l1d_misses_total = 0;
passes = 0;
goto again;
}
perf_event_disable(fd);
close(fd);
set_dscr(0);
if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_orig) < 0) {
perror("unable to restore original value of powerpc/rfi_flush debugfs file");
return 1;
}
if (have_entry_flush) {
if (write_debugfs_file("powerpc/entry_flush", entry_flush_orig) < 0) {
perror("unable to restore original value of powerpc/entry_flush "
"debugfs file");
return 1;
}
}
return rc;
}
int main(int argc, char *argv[])
{
return test_harness(rfi_flush_test, "rfi_flush_test");
}
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