[PATCH v4 2/9] selftests/powerpc: Test preservation of FPU and VMX regs across preemption
Cyril Bur
cyrilbur at gmail.com
Mon Feb 15 16:07:23 AEDT 2016
Loop in assembly checking the registers with many threads.
Signed-off-by: Cyril Bur <cyrilbur at gmail.com>
---
tools/testing/selftests/powerpc/math/.gitignore | 2 +
tools/testing/selftests/powerpc/math/Makefile | 5 +-
tools/testing/selftests/powerpc/math/fpu_asm.S | 34 +++++++
tools/testing/selftests/powerpc/math/fpu_preempt.c | 113 +++++++++++++++++++++
tools/testing/selftests/powerpc/math/vmx_asm.S | 44 +++++++-
tools/testing/selftests/powerpc/math/vmx_preempt.c | 113 +++++++++++++++++++++
6 files changed, 306 insertions(+), 5 deletions(-)
create mode 100644 tools/testing/selftests/powerpc/math/fpu_preempt.c
create mode 100644 tools/testing/selftests/powerpc/math/vmx_preempt.c
diff --git a/tools/testing/selftests/powerpc/math/.gitignore b/tools/testing/selftests/powerpc/math/.gitignore
index b19b269..1a6f09e 100644
--- a/tools/testing/selftests/powerpc/math/.gitignore
+++ b/tools/testing/selftests/powerpc/math/.gitignore
@@ -1,2 +1,4 @@
fpu_syscall
vmx_syscall
+fpu_preempt
+vmx_preempt
diff --git a/tools/testing/selftests/powerpc/math/Makefile b/tools/testing/selftests/powerpc/math/Makefile
index 418bef1..b6f4158 100644
--- a/tools/testing/selftests/powerpc/math/Makefile
+++ b/tools/testing/selftests/powerpc/math/Makefile
@@ -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
diff --git a/tools/testing/selftests/powerpc/math/fpu_asm.S b/tools/testing/selftests/powerpc/math/fpu_asm.S
index 8733874..46bbe99 100644
--- a/tools/testing/selftests/powerpc/math/fpu_asm.S
+++ b/tools/testing/selftests/powerpc/math/fpu_asm.S
@@ -159,3 +159,37 @@ 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 r3,32(sp) #double *darray
+ std r4,40(sp) #volatile int *not_ready
+ std r5,48(sp) #int *running
+ PUSH_FPU(56)
+
+ bl load_fpu
+
+ #Atomic DEC
+ ld r3,40(sp)
+1: lwarx r4,0,r3
+ addi r4,r4,-1
+ stwcx. r4,0,r3
+ bne- 1b
+
+2: ld r3, 32(sp)
+ bl check_fpu
+ cmpdi r3,0
+ bne 3f
+ ld r4, 48(sp)
+ ld r5, 0(r4)
+ cmpwi r5,0
+ bne 2b
+
+3: POP_FPU(56)
+ POP_BASIC_STACK(256)
+ blr
+FUNC_END(preempt_fpu)
diff --git a/tools/testing/selftests/powerpc/math/fpu_preempt.c b/tools/testing/selftests/powerpc/math/fpu_preempt.c
new file mode 100644
index 0000000..0f85b79
--- /dev/null
+++ b/tools/testing/selftests/powerpc/math/fpu_preempt.c
@@ -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");
+}
diff --git a/tools/testing/selftests/powerpc/math/vmx_asm.S b/tools/testing/selftests/powerpc/math/vmx_asm.S
index 9ed32e7..416b5b0 100644
--- a/tools/testing/selftests/powerpc/math/vmx_asm.S
+++ b/tools/testing/selftests/powerpc/math/vmx_asm.S
@@ -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 r0,0xffffffff
bne 1f
li r3,0
-1: POP_BASIC_STACK(16)
+1: POP_BASIC_STACK(32)
blr
FUNC_END(check_vmx)
@@ -174,7 +176,7 @@ FUNC_START(test_vmx)
PUSH_BASIC_STACK(512)
std r3,40(sp) #Address of varray
std r4,48(sp) #address of pid
- PUSH_VMX(56, r4)
+ PUSH_VMX(64, r4)
bl load_vmx
@@ -187,7 +189,41 @@ FUNC_START(test_vmx)
ld r3,40(sp)
bl check_vmx
- POP_VMX(56,r4)
+ POP_VMX(64,r4)
POP_BASIC_STACK(512)
blr
FUNC_END(test_vmx)
+
+#int preempt_vmx(v4si *varray, int *threads_starting, int *running)
+#On starting will (atomically) decrement not_ready as a signal that the FPU
+#has been loaded with varray. Will proceed to check the validity of the FPU
+#registers while running is not zero.
+FUNC_START(preempt_vmx)
+ PUSH_BASIC_STACK(512)
+ std r3,32(sp) #v4si *varray
+ std r4,40(sp) #volatile int *not_ready
+ std r5,48(sp) #int *running
+ PUSH_VMX(64,r4)
+
+ bl load_vmx
+
+ #Atomic DEC
+ ld r3,40(sp)
+1: lwarx r4,0,r3
+ addi r4,r4,-1
+ stwcx. r4,0,r3
+ bne- 1b
+
+2: ld r3,32(sp)
+ bl check_vmx
+ cmpdi r3,0
+ bne 3f
+ ld r4,48(sp)
+ ld r5,0(r4)
+ cmpwi r5,0
+ bne 2b
+
+3: POP_VMX(64,r4)
+ POP_BASIC_STACK(512)
+ blr
+FUNC_END(preempt_vmx)
diff --git a/tools/testing/selftests/powerpc/math/vmx_preempt.c b/tools/testing/selftests/powerpc/math/vmx_preempt.c
new file mode 100644
index 0000000..9474e78
--- /dev/null
+++ b/tools/testing/selftests/powerpc/math/vmx_preempt.c
@@ -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 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
+
+typedef int v4si __attribute__ ((vector_size (16)));
+__thread v4si 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(v4si *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");
+}
--
2.7.1
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