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selftests/powerpc: Test preservation of FPU and VMX regs across preemption

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Loop in assembly checking the registers with many threads.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Cyril Bur 2016-02-29 17:53:44 +11:00 committed by Michael Ellerman
parent 01127f1ead
commit e5ab8be68e
6 changed files with 310 additions and 3 deletions
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2
tools/testing/selftests/powerpc/math/.gitignore vendored
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@ -1,2 +1,4 @@
fpu_syscall
vmx_syscall
fpu_preempt
vmx_preempt

5
tools/testing/selftests/powerpc/math/Makefile
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@ -1,4 +1,4 @@
TEST_PROGS := fpu_syscall vmx_syscall
TEST_PROGS := fpu_syscall fpu_preempt vmx_syscall vmx_preempt
all: $(TEST_PROGS)
@ -6,7 +6,10 @@ $(TEST_PROGS): ../harness.c
$(TEST_PROGS): CFLAGS += -O2 -g -pthread -m64 -maltivec
fpu_syscall: fpu_asm.S
fpu_preempt: fpu_asm.S
vmx_syscall: vmx_asm.S
vmx_preempt: vmx_asm.S
include ../../lib.mk

37
tools/testing/selftests/powerpc/math/fpu_asm.S
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@ -159,3 +159,40 @@ FUNC_START(test_fpu)
POP_BASIC_STACK(256)
blr
FUNC_END(test_fpu)
# int preempt_fpu(double *darray, int *threads_running, int *running)
# On starting will (atomically) decrement not_ready as a signal that the FPU
# has been loaded with darray. Will proceed to check the validity of the FPU
# registers while running is not zero.
FUNC_START(preempt_fpu)
PUSH_BASIC_STACK(256)
std r3,STACK_FRAME_PARAM(0)(sp) # double *darray
std r4,STACK_FRAME_PARAM(1)(sp) # int *threads_starting
std r5,STACK_FRAME_PARAM(2)(sp) # int *running
PUSH_FPU(STACK_FRAME_LOCAL(3,0))
bl load_fpu
nop
sync
# Atomic DEC
ld r3,STACK_FRAME_PARAM(1)(sp)
1: lwarx r4,0,r3
addi r4,r4,-1
stwcx. r4,0,r3
bne- 1b
2: ld r3,STACK_FRAME_PARAM(0)(sp)
bl check_fpu
nop
cmpdi r3,0
bne 3f
ld r4,STACK_FRAME_PARAM(2)(sp)
ld r5,0(r4)
cmpwi r5,0
bne 2b
3: POP_FPU(STACK_FRAME_LOCAL(3,0))
POP_BASIC_STACK(256)
blr
FUNC_END(preempt_fpu)

113
tools/testing/selftests/powerpc/math/fpu_preempt.c Normal file
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@ -0,0 +1,113 @@
/*
* Copyright 2015, Cyril Bur, IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* This test attempts to see if the FPU registers change across preemption.
* Two things should be noted here a) The check_fpu function in asm only checks
* the non volatile registers as it is reused from the syscall test b) There is
* no way to be sure preemption happened so this test just uses many threads
* and a long wait. As such, a successful test doesn't mean much but a failure
* is bad.
*/
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <pthread.h>
#include "utils.h"
/* Time to wait for workers to get preempted (seconds) */
#define PREEMPT_TIME 20
/*
* Factor by which to multiply number of online CPUs for total number of
* worker threads
*/
#define THREAD_FACTOR 8
__thread double darray[] = {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,
2.1};
int threads_starting;
int running;
extern void preempt_fpu(double *darray, int *threads_starting, int *running);
void *preempt_fpu_c(void *p)
{
int i;
srand(pthread_self());
for (i = 0; i < 21; i++)
darray[i] = rand();
/* Test failed if it ever returns */
preempt_fpu(darray, &threads_starting, &running);
return p;
}
int test_preempt_fpu(void)
{
int i, rc, threads;
pthread_t *tids;
threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
tids = malloc((threads) * sizeof(pthread_t));
FAIL_IF(!tids);
running = true;
threads_starting = threads;
for (i = 0; i < threads; i++) {
rc = pthread_create(&tids[i], NULL, preempt_fpu_c, NULL);
FAIL_IF(rc);
}
setbuf(stdout, NULL);
/* Not really necessary but nice to wait for every thread to start */
printf("\tWaiting for all workers to start...");
while(threads_starting)
asm volatile("": : :"memory");
printf("done\n");
printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
sleep(PREEMPT_TIME);
printf("done\n");
printf("\tStopping workers...");
/*
* Working are checking this value every loop. In preempt_fpu 'cmpwi r5,0; bne 2b'.
* r5 will have loaded the value of running.
*/
running = 0;
for (i = 0; i < threads; i++) {
void *rc_p;
pthread_join(tids[i], &rc_p);
/*
* Harness will say the fail was here, look at why preempt_fpu
* returned
*/
if ((long) rc_p)
printf("oops\n");
FAIL_IF((long) rc_p);
}
printf("done\n");
free(tids);
return 0;
}
int main(int argc, char *argv[])
{
return test_harness(test_preempt_fpu, "fpu_preempt");
}

44
tools/testing/selftests/powerpc/math/vmx_asm.S
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@ -9,6 +9,7 @@
#include "../basic_asm.h"
# POS MUST BE 16 ALIGNED!
#define PUSH_VMX(pos,reg) \
li reg,pos; \
stvx v20,reg,sp; \
@ -35,6 +36,7 @@
addi reg,reg,16; \
stvx v31,reg,sp;
# POS MUST BE 16 ALIGNED!
#define POP_VMX(pos,reg) \
li reg,pos; \
lvx v20,reg,sp; \
@ -93,7 +95,7 @@ FUNC_END(load_vmx)
# Should be safe from C, only touches r4, r5 and v0,v1,v2
FUNC_START(check_vmx)
PUSH_BASIC_STACK(16)
PUSH_BASIC_STACK(32)
mr r4,r3
li r3,1 # assume a bad result
li r5,0
@ -162,7 +164,7 @@ FUNC_START(check_vmx)
cmpdi r0,0xffffffffffffffff
bne 1f
li r3,0
1: POP_BASIC_STACK(16)
1: POP_BASIC_STACK(32)
blr
FUNC_END(check_vmx)
@ -193,3 +195,41 @@ FUNC_START(test_vmx)
POP_BASIC_STACK(512)
blr
FUNC_END(test_vmx)
# int preempt_vmx(vector int *varray, int *threads_starting, int *running)
# On starting will (atomically) decrement threads_starting as a signal that
# the VMX have been loaded with varray. Will proceed to check the validity of
# the VMX registers while running is not zero.
FUNC_START(preempt_vmx)
PUSH_BASIC_STACK(512)
std r3,STACK_FRAME_PARAM(0)(sp) # vector int *varray
std r4,STACK_FRAME_PARAM(1)(sp) # int *threads_starting
std r5,STACK_FRAME_PARAM(2)(sp) # int *running
# VMX need to write to 16 byte aligned addresses, skip STACK_FRAME_LOCAL(3,0)
PUSH_VMX(STACK_FRAME_LOCAL(4,0),r4)
bl load_vmx
nop
sync
# Atomic DEC
ld r3,STACK_FRAME_PARAM(1)(sp)
1: lwarx r4,0,r3
addi r4,r4,-1
stwcx. r4,0,r3
bne- 1b
2: ld r3,STACK_FRAME_PARAM(0)(sp)
bl check_vmx
nop
cmpdi r3,0
bne 3f
ld r4,STACK_FRAME_PARAM(2)(sp)
ld r5,0(r4)
cmpwi r5,0
bne 2b
3: POP_VMX(STACK_FRAME_LOCAL(4,0),r4)
POP_BASIC_STACK(512)
blr
FUNC_END(preempt_vmx)

112
tools/testing/selftests/powerpc/math/vmx_preempt.c Normal file
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@ -0,0 +1,112 @@
/*
* Copyright 2015, Cyril Bur, IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* This test attempts to see if the VMX registers change across preemption.
* Two things should be noted here a) The check_vmx function in asm only checks
* the non volatile registers as it is reused from the syscall test b) There is
* no way to be sure preemption happened so this test just uses many threads
* and a long wait. As such, a successful test doesn't mean much but a failure
* is bad.
*/
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <pthread.h>
#include "utils.h"
/* Time to wait for workers to get preempted (seconds) */
#define PREEMPT_TIME 20
/*
* Factor by which to multiply number of online CPUs for total number of
* worker threads
*/
#define THREAD_FACTOR 8
__thread vector int varray[] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10,11,12},
{13,14,15,16},{17,18,19,20},{21,22,23,24},
{25,26,27,28},{29,30,31,32},{33,34,35,36},
{37,38,39,40},{41,42,43,44},{45,46,47,48}};
int threads_starting;
int running;
extern void preempt_vmx(vector int *varray, int *threads_starting, int *running);
void *preempt_vmx_c(void *p)
{
int i, j;
srand(pthread_self());
for (i = 0; i < 12; i++)
for (j = 0; j < 4; j++)
varray[i][j] = rand();
/* Test fails if it ever returns */
preempt_vmx(varray, &threads_starting, &running);
return p;
}
int test_preempt_vmx(void)
{
int i, rc, threads;
pthread_t *tids;
threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
tids = malloc(threads * sizeof(pthread_t));
FAIL_IF(!tids);
running = true;
threads_starting = threads;
for (i = 0; i < threads; i++) {
rc = pthread_create(&tids[i], NULL, preempt_vmx_c, NULL);
FAIL_IF(rc);
}
setbuf(stdout, NULL);
/* Not really nessesary but nice to wait for every thread to start */
printf("\tWaiting for all workers to start...");
while(threads_starting)
asm volatile("": : :"memory");
printf("done\n");
printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
sleep(PREEMPT_TIME);
printf("done\n");
printf("\tStopping workers...");
/*
* Working are checking this value every loop. In preempt_vmx 'cmpwi r5,0; bne 2b'.
* r5 will have loaded the value of running.
*/
running = 0;
for (i = 0; i < threads; i++) {
void *rc_p;
pthread_join(tids[i], &rc_p);
/*
* Harness will say the fail was here, look at why preempt_vmx
* returned
*/
if ((long) rc_p)
printf("oops\n");
FAIL_IF((long) rc_p);
}
printf("done\n");
return 0;
}
int main(int argc, char *argv[])
{
return test_harness(test_preempt_vmx, "vmx_preempt");
}