blob: 6b1ceeb6e9bcc0fa1bfc886de3c9be736d9d8b71 [file] [log] [blame]
/*
* Transactional Memory Unit Tests
*
* Copyright 2016 Suraj Jitindar Singh, IBM.
*
* This work is licensed under the terms of the GNU LGPL, version 2.
*/
#include <libcflat.h>
#include <asm/hcall.h>
#include <asm/processor.h>
#include <asm/time.h>
#include <asm/handlers.h>
#include <asm/smp.h>
#include <asm/setup.h>
#include <devicetree.h>
/* Check "ibm,pa-features" property of a CPU node for the TM flag */
static void cpu_has_tm(int fdtnode, u64 regval __unused, void *ptr)
{
const struct fdt_property *prop;
int plen;
prop = fdt_get_property(dt_fdt(), fdtnode, "ibm,pa-features", &plen);
if (!prop) /* No features means TM is also not available */
return;
/* Sanity check for the property layout (first two bytes are header) */
assert(plen >= 8 && prop->data[1] == 0 && prop->data[0] <= plen - 2);
/*
* The "Transactional Memory Category Support" flags are at byte
* offset 22 and 23 of the attribute type 0, so when adding the
* two bytes for the header, we've got to look at offset 24 for
* the TM support bit.
*/
if (prop->data[0] >= 24 && (prop->data[24] & 0x80) != 0)
*(int *)ptr += 1;
}
/* Check amount of CPUs nodes that have the TM flag */
static int count_cpus_with_tm(void)
{
int ret;
int available = 0;
ret = dt_for_each_cpu_node(cpu_has_tm, &available);
if (ret < 0)
return ret;
return available;
}
/*
* Enable transactional memory
* Returns: FALSE - Failure
* TRUE - Success
*/
static bool enable_tm(void)
{
uint64_t msr = 0;
asm volatile ("mfmsr %[msr]" : [msr] "=r" (msr));
msr |= (((uint64_t) 1) << 32);
asm volatile ("mtmsrd %[msr]\n\t"
"mfmsr %[msr]" : [msr] "+r" (msr));
return !!(msr & (((uint64_t) 1) << 32));
}
/*
* Test H_CEDE call while transactional memory transaction is suspended
*
* WARNING: This tests for a known vulnerability in which the host may go down.
* Probably best not to run this if your host going down is going to cause
* problems.
*
* If the test passes then your kernel probably has the necessary patch.
* If the test fails then the H_CEDE call was unsuccessful and the
* vulnerability wasn't tested.
* If the test hits the vulnerability then it will never complete or report and
* the qemu process will block indefinitely. RCU stalls will be detected on the
* cpu and any process scheduled on the lost cpu will also block indefinitely.
*/
static void test_h_cede_tm(int argc, char **argv)
{
int i;
if (argc > 2)
report_abort("Unsupported argument: '%s'", argv[2]);
if (!start_all_cpus(halt, 0))
report_abort("Failed to start secondary cpus");
if (!enable_tm())
report_abort("Failed to enable tm");
/*
* Begin a transaction and guarantee we are in the suspend state
* before continuing
*/
asm volatile ("1: .long 0x7c00051d\n\t" /* tbegin. */
"beq 2f\n\t"
".long 0x7c0005dd\n\t" /* tsuspend. */
"2: .long 0x7c00059c\n\t" /* tcheck cr0 */
"bf 2,1b" : : : "cr0");
for (i = 0; i < 500; i++) {
msleep(10);
mdelay(5);
}
report(i == 500, "H_CEDE TM");
}
struct {
const char *name;
void (*func)(int argc, char **argv);
} hctests[] = {
{ "h_cede_tm", test_h_cede_tm },
{ NULL, NULL }
};
int main(int argc, char **argv)
{
bool all;
int i, cpus_with_tm;
report_prefix_push("tm");
cpus_with_tm = count_cpus_with_tm();
if (cpus_with_tm == 0) {
report_skip("TM is not available");
goto done;
}
report(cpus_with_tm == nr_cpus,
"TM available in all 'ibm,pa-features' properties");
all = argc == 1 || !strcmp(argv[1], "all");
for (i = 0; hctests[i].name != NULL; i++) {
if (all || strcmp(argv[1], hctests[i].name) == 0) {
report_prefix_push(hctests[i].name);
hctests[i].func(argc, argv);
report_prefix_pop();
}
}
done:
report_prefix_pop();
return report_summary();
}