/* -*- mode: C; c-basic-offset: 3; -*- */
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <ctype.h> // isspace
#include <fcntl.h> // open
#include <unistd.h> // lseek
#include <sys/stat.h> // S_IRUSR
// This file determines s390x features a processor supports.
//
// We return:
// - 0 if the machine provides the asked-for feature and the cpu
// model, if specified, matches the machine
// - 1 the machine does not provide the asked-for feature or the
// cpu model, if specified, does not match the machine
// - 1 for an unknown cpu model in /proc/cpu_info
// - 2 if the asked-for feature isn't recognised (this will be the case for
// any feature if run on a non-s390x machine).
// - 3 if there was a usage error (it also prints an error message).
//
// USAGE:
//
// s390x_features <feature> [<machine-model>]
//
// The machine_model is optional and it can be something like:
//
// z9 -- Host needs to be a z9 (and nothing else)
// z9: -- Host needs to be a z9 or any later model
// :z9 -- Host needs to be a model up to and including z9
// z900:z9 -- Host needs to be at least a z900 and at most a z9.
// Any model in between is OK, too.
jmp_buf env;
#if defined(VGA_s390x)
void handle_sigill(int signum)
{
longjmp(env, 1);
}
unsigned long long stfle(void)
{
unsigned long long ret;
signal(SIGILL, handle_sigill);
if (setjmp(env)) {
/* stfle not available: assume no facilities */
return 0;
} else {
asm volatile("lghi 0, 0\n"
".insn s,0xb2b00000,%0\n" /* stfle */
: "=Q" (ret)::"0", "cc");
return ret;
}
}
/* Read /proc/cpuinfo. Look for lines like these
processor 0: version = FF, identification = 0117C9, machine = 2064
and return the machine model or NULL on error.
Adapted from function VG_(get_machine_model) in coregrind/m_machine.c */
typedef struct {
const char *cpuinfo_name;
const char *real_name;
} model_info;
/* Array needs to be sorted chronologically. Oldest to newest */
model_info models[] = {
{ "2064", "z900" },
{ "2066", "z800" },
{ "2084", "z990" },
{ "2086", "z890" },
{ "2094", "z9-EC" },
{ "2096", "z9-BC" },
{ "2097", "z10-EC" },
{ "2098", "z10-BC" },
{ "2817", "z196" },
{ "2818", "z114" },
{ "2827", "zEC12" },
{ "2828", "zBC12" },
};
/* Locate a machine model by name. Name can be either the cpuinfo
name or the external name. */
static model_info *locate_model(const char *name)
{
model_info *p;
/* Try cpuinfo name first */
for (p = models; p != models + sizeof models / sizeof models[0]; ++p) {
if (strcmp(p->cpuinfo_name, name) == 0) return p; // found it
}
/* Now try external name */
for (p = models; p != models + sizeof models / sizeof models[0]; ++p) {
if (strcmp(p->real_name, name) == 0) return p; // found it
}
return NULL;
}
static model_info *get_host(void)
{
int n, fh;
size_t num_bytes, file_buf_size;
char *p, *m, *model_name, *file_buf;
model_info *model;
/* Slurp contents of /proc/cpuinfo into FILE_BUF */
fh = open("/proc/cpuinfo", O_RDONLY, S_IRUSR);
if (fh < 0) return NULL;
/* Determine the size of /proc/cpuinfo.
Work around broken-ness in /proc file system implementation.
fstat returns a zero size for /proc/cpuinfo although it is
claimed to be a regular file. */
num_bytes = 0;
file_buf_size = 1000;
file_buf = malloc(file_buf_size + 1);
while (42) {
n = read(fh, file_buf, file_buf_size);
if (n < 0) break;
num_bytes += n;
if (n < file_buf_size) break; /* reached EOF */
}
if (n < 0) num_bytes = 0; /* read error; ignore contents */
if (num_bytes > file_buf_size) {
free(file_buf);
lseek(fh, 0, SEEK_SET);
file_buf = malloc(num_bytes + 1);
n = read(fh, file_buf, num_bytes);
if (n < 0) num_bytes = 0;
}
file_buf[num_bytes] = '\0';
close(fh);
/* Parse file */
model = models + sizeof models / sizeof models[0];
for (p = file_buf; *p; ++p) {
/* Beginning of line */
if (strncmp(p, "processor", sizeof "processor" - 1 ) != 0) continue;
m = strstr(p, "machine");
if (m == NULL) continue;
p = m + sizeof "machine" - 1;
while (isspace(*p) || *p == '=') {
if (*p == '\n') goto next_line;
++p;
}
model_name = p;
for (n = 0; n < sizeof models / sizeof models[0]; ++n) {
model_info *mm = models + n;
size_t len = strlen(mm->cpuinfo_name);
if (strncmp(mm->cpuinfo_name, model_name, len) == 0 &&
isspace(model_name[len])) {
/* In case there are different CPUs in this cluster return the
one with the dewest capabilities ("oldest" model). */
if (mm < model) model = mm;
p = model_name + len;
break;
}
}
/* Skip until end-of-line */
while (*p != '\n')
++p;
next_line: ;
}
free(file_buf);
if (model == models + sizeof models / sizeof models[0]) return NULL;
return model;
}
/* Convenience macro that maps the facility bit number as given in the
Principles of Ops "facility indications" section to a bit mask */
#define FAC_BIT(x) (1ULL << (63 - (x)))
static int go(char *feature, char *cpu)
{
unsigned long long facilities;
unsigned long long match;
model_info *host, *from, *to, *p;
char *colon;
facilities = stfle();
if (strcmp(feature, "s390x-zarch") == 0 ) {
match = (facilities & FAC_BIT(1)) && (facilities & FAC_BIT(2));
} else if (strcmp(feature, "s390x-n3") == 0 ) {
match = facilities & FAC_BIT(0);
} else if (strcmp(feature, "s390x-stfle") == 0 ) {
match = facilities & FAC_BIT(7);
} else if (strcmp(feature, "s390x-ldisp") == 0 ) {
match = (facilities & FAC_BIT(18)) && (facilities & FAC_BIT(19));
} else if (strcmp(feature, "s390x-eimm") == 0 ) {
match = facilities & FAC_BIT(21);
} else if (strcmp(feature, "s390x-stckf") == 0 ) {
match = facilities & FAC_BIT(25);
} else if (strcmp(feature, "s390x-genins") == 0 ) {
match = facilities & FAC_BIT(34);
} else if (strcmp(feature, "s390x-exrl") == 0 ) {
match = facilities & FAC_BIT(35);
} else if (strcmp(feature, "s390x-etf3") == 0 ) {
match = facilities & FAC_BIT(30);
} else if (strcmp(feature, "s390x-fpext") == 0 ) {
match = facilities & FAC_BIT(37);
} else if (strcmp(feature, "s390x-dfp") == 0 ) {
match = facilities & FAC_BIT(42);
} else if (strcmp(feature, "s390x-pfpo") == 0 ) {
match = facilities & FAC_BIT(44);
} else {
return 2; // Unrecognised feature.
}
if (match == 0) return 1; // facility not provided
/* Host provides facility. If no CPU was specified, we're done. */
if (cpu == NULL) return 0;
host = get_host();
if (host == NULL) return 1; // unknown model
// printf("host = %s (%s)\n", host->cpuinfo_name, host->real_name);
/* Determine interval of models in which to search for HOST. */
from = to = NULL;
colon = strchr(cpu, ':');
if (colon == NULL) {
// match exact
from = to = locate_model(cpu);
} else if (colon == cpu) {
// :NAME match machines up to and including CPU
from = models;
to = locate_model(cpu + 1);
} else if (colon[1] == '\0') {
// NAME: match machines beginning with CPU or later
*colon = '\0';
from = locate_model(cpu);
to = models + sizeof models / sizeof models[0] - 1;
*colon = ':';
} else {
// NAME:NAME match machines in interval
*colon = '\0';
from = locate_model(cpu);
to = locate_model(colon + 1);
*colon = ':';
}
if (from == NULL || to == NULL || from > to) {
fprintf(stderr, "invalid cpu specification '%s'\n", cpu);
return 3;
}
#if 0
printf("from %s (%s) to %s (%s)\n", from->cpuinfo_name, from->real_name,
to->cpuinfo_name, to->real_name);
#endif
/* Search for HOST. */
for (p = from; p <= to; ++p) {
if (p == host) return 0;
}
return 1; // host does not match CPU specification
}
#else
static int go(char *feature, char *cpu)
{
return 2; // Feature not recognised (non-s390x machine!)
}
#endif
//---------------------------------------------------------------------------
// main
//---------------------------------------------------------------------------
int main(int argc, char **argv)
{
int rc, inverted = 0;
if (argc < 2 || argc > 3) {
fprintf( stderr, "usage: s390x_features <feature> [<machine-model>]\n" );
exit(3); // Usage error.
}
if (argv[1][0] == '!') {
assert(argv[2] == NULL); // not allowed
inverted = 1;
++argv[1];
}
rc = go(argv[1], argv[2]);
if (inverted) {
switch (rc) {
case 0: rc = 1; break;
case 1: rc = 0; break;
case 2: rc = 2; break;
}
}
// printf("rc = %d\n", rc);
return rc;
}