On 01/13/2015 03:22 AM, Anshuman Khandual wrote:
> This patch adds a test case for the system wide DSCR default
> value, which when changed through it's sysfs interface must
> be visible to all threads reading DSCR either through the
> privilege state SPR or the problem state SPR. The DSCR value
> change should be immediate as well.
> 
> Signed-off-by: Anshuman Khandual <khand...@linux.vnet.ibm.com>
> ---
>  tools/testing/selftests/powerpc/Makefile           |   2 +-
>  tools/testing/selftests/powerpc/dscr/Makefile      |  17 +++
>  tools/testing/selftests/powerpc/dscr/dscr.h        | 120 ++++++++++++++++++++
>  .../selftests/powerpc/dscr/dscr_default_test.c     | 121 
> +++++++++++++++++++++
>  4 files changed, 259 insertions(+), 1 deletion(-)
>  create mode 100644 tools/testing/selftests/powerpc/dscr/Makefile
>  create mode 100644 tools/testing/selftests/powerpc/dscr/dscr.h
>  create mode 100644 tools/testing/selftests/powerpc/dscr/dscr_default_test.c
> 
> diff --git a/tools/testing/selftests/powerpc/Makefile 
> b/tools/testing/selftests/powerpc/Makefile
> index f6ff90a..1318883 100644
> --- a/tools/testing/selftests/powerpc/Makefile
> +++ b/tools/testing/selftests/powerpc/Makefile
> @@ -13,7 +13,7 @@ CFLAGS := -Wall -O2 -flto -Wall -Werror 
> -DGIT_VERSION='"$(GIT_VERSION)"' -I$(CUR
>  
>  export CC CFLAGS
>  
> -TARGETS = pmu copyloops mm tm primitives
> +TARGETS = pmu copyloops mm tm primitives dscr
>  
>  endif
>  
> diff --git a/tools/testing/selftests/powerpc/dscr/Makefile 
> b/tools/testing/selftests/powerpc/dscr/Makefile
> new file mode 100644
> index 0000000..0aa90ab
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/dscr/Makefile
> @@ -0,0 +1,17 @@
> +PROGS := dscr_default_test
> +
> +CFLAGS := $(CFLAGS) -lpthread
> +
> +all: $(PROGS)
> +
> +$(PROGS): ../harness.c
> +
> +run_tests: all
> +     @-for PROG in $(PROGS); do \
> +             ./$$PROG; \
> +     done;
> +
> +clean:
> +     rm -f $(PROGS) *.o
> +
> +.PHONY: all run_tests clean
> diff --git a/tools/testing/selftests/powerpc/dscr/dscr.h 
> b/tools/testing/selftests/powerpc/dscr/dscr.h
> new file mode 100644
> index 0000000..2e6535b
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/dscr/dscr.h
> @@ -0,0 +1,120 @@
> +/*
> + * POWER Data Stream Control Register (DSCR)
> + *
> + * This header file contains helper functions and macros
> + * required for all the DSCR related test cases.
> + *
> + * Copyright (C) 2012 Anton Blanchard <an...@au.ibm.com>, IBM
> + * Copyright (C) 2015 Anshuman Khandual <khand...@linux.vnet.ibm.com>, IBM
> + *
> + * 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.
> + */
> +#ifndef _SELFTESTS_POWERPC_DSCR_DSCR_H
> +#define _SELFTESTS_POWERPC_DSCR_DSCR_H
> +
> +#include <unistd.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <fcntl.h>
> +#include <dirent.h>
> +#include <pthread.h>
> +#include <sched.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <sys/wait.h>
> +
> +#include "utils.h"
> +
> +#define SPRN_DSCR    0x11    /* Privilege state SPR */
> +#define SPRN_DSCR_USR        0x03    /* Problem state SPR */
> +#define THREADS              100     /* Max threads */
> +#define COUNT                100     /* Max iterations */
> +#define DSCR_MAX     16      /* Max DSCR value */
> +#define LEN_MAX              100     /* Max name length */
> +
> +#define DSCR_DEFAULT "/sys/devices/system/cpu/dscr_default"
> +#define CPU_PATH     "/sys/devices/system/cpu/"
> +
> +#define rmb()  asm volatile("lwsync":::"memory")
> +#define wmb()  asm volatile("lwsync":::"memory")
> +
> +#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
> +
> +/* Prilvilege state DSCR access */
> +inline unsigned long get_dscr(void)
> +{
> +     unsigned long ret;
> +
> +     asm volatile("mfspr %0,%1" : "=r" (ret): "i" (SPRN_DSCR));
> +
> +     return ret;
> +}
> +
> +inline void set_dscr(unsigned long val)
> +{
> +     asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));
> +}
> +
> +/* Problem state DSCR access */
> +inline unsigned long get_dscr_usr(void)
> +{
> +     unsigned long ret;
> +
> +     asm volatile("mfspr %0,%1" : "=r" (ret): "i" (SPRN_DSCR_USR));
> +
> +     return ret;
> +}
> +
> +inline void set_dscr_usr(unsigned long val)
> +{
> +     asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR_USR));
> +}
> +
> +/* Default DSCR access */
> +unsigned long get_default_dscr(void)
> +{
> +     int fd = -1;
> +     char buf[16];
> +     unsigned long val;
> +
> +     if (fd == -1) {
> +             fd = open(DSCR_DEFAULT, O_RDONLY);
> +             if (fd == -1) {
> +                     perror("open() failed\n");
> +                     exit(1);
> +             }
> +     }
> +     memset(buf, 0, sizeof(buf));
> +     lseek(fd, 0, SEEK_SET);
> +     read(fd, buf, sizeof(buf));
> +     sscanf(buf, "%lx", &val);
> +     close(fd);
> +     return val;
> +}
> +
> +void set_default_dscr(unsigned long val)
> +{
> +     int fd = -1;
> +     char buf[16];
> +
> +     if (fd == -1) {
> +             fd = open(DSCR_DEFAULT, O_RDWR);
> +             if (fd == -1) {
> +                     perror("open() failed\n");
> +                     exit(1);
> +             }
> +     }
> +     sprintf(buf, "%lx\n", val);
> +     write(fd, buf, strlen(buf));
> +     close(fd);
> +}
> +
> +double uniform_deviate(int seed)
> +{
> +     return seed * (1.0 / (RAND_MAX + 1.0));
> +}
> +#endif       /* _SELFTESTS_POWERPC_DSCR_DSCR_H */
> diff --git a/tools/testing/selftests/powerpc/dscr/dscr_default_test.c 
> b/tools/testing/selftests/powerpc/dscr/dscr_default_test.c
> new file mode 100644
> index 0000000..fd8b7b9
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/dscr/dscr_default_test.c
> @@ -0,0 +1,121 @@
> +/*
> + * POWER Data Stream Control Register (DSCR) default test
> + *
> + * This test modifies the system wide default DSCR through
> + * it's sysfs interface and then verifies that all threads
> + * see the correct changed DSCR value immediately.
> + *
> + * Copyright (C) 2012 Anton Blanchard <an...@au.ibm.com>, IBM
> + * Copyright (C) 2015 Anshuman Khandual <khand...@linux.vnet.ibm.com>, IBM
> + *
> + * 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.
> + */
> +#include "dscr.h"
> +
> +static unsigned long dscr;           /* System DSCR default */
> +static unsigned long sequence;
> +static unsigned long result[THREADS];
> +
> +static void *do_test(void *in)
> +{
> +     unsigned long thread = (unsigned long)in;
> +     unsigned long i;
> +
> +     for (i = 0; i < COUNT; i++) {
> +             unsigned long d, cur_dscr, cur_dscr_usr;
> +             unsigned long s1, s2;
> +
> +             s1 = ACCESS_ONCE(sequence);
> +             if (s1 & 1)
> +                     continue;
> +             rmb();
> +
> +             d = dscr;
> +             cur_dscr = get_dscr();
> +             cur_dscr_usr = get_dscr_usr();
> +
> +             rmb();
> +             s2 = sequence;
> +
> +             if (s1 != s2)
> +                     continue;
> +
> +             if (cur_dscr != d) {
> +                     fprintf(stderr, "thread %ld kernel DSCR should be %ld "
> +                             "but is %ld\n", thread, d, cur_dscr);
> +                     result[thread] = 1;
> +                     pthread_exit(&result[thread]);
> +             }
> +
> +             if (cur_dscr_usr != d) {
> +                     fprintf(stderr, "thread %ld user DSCR should be %ld "
> +                             "but is %ld\n", thread, d, cur_dscr_usr);
> +                     result[thread] = 1;
> +                     pthread_exit(&result[thread]);
> +             }
> +     }
> +     result[thread] = 0;
> +     pthread_exit(&result[thread]);
> +}
> +
> +int test_body(void)
> +{
> +     pthread_t threads[THREADS];
> +     unsigned long i, *status[THREADS];
> +
> +     /* Initial DSCR default */
> +     dscr = 1;
> +     set_default_dscr(dscr);
> +
> +     /* Spawn all testing threads */
> +     for (i = 0; i < THREADS; i++) {
> +             if (pthread_create(&threads[i], NULL, do_test, (void *)i)) {
> +                     perror("pthread_create() failed\n");
> +                     exit(1);
> +             }
> +     }
> +
> +     srand(getpid());
> +
> +     /* Keep changing the DSCR default */
> +     for (i = 0; i < COUNT; i++) {
> +             double ret = uniform_deviate(rand());
> +
> +             if (ret < 0.0001) {
> +                     sequence++;
> +                     wmb();
> +
> +                     dscr++;
> +                     if (dscr > DSCR_MAX)
> +                             dscr = 0;
> +
> +                     set_default_dscr(dscr);
> +
> +                     wmb();
> +                     sequence++;
> +             }
> +     }
> +
> +     /* Individual testing thread exit status */
> +     for (i = 0; i < THREADS; i++) {
> +             if (pthread_join(threads[i], (void **)&(status[i]))) {
> +                     perror("pthread_join() failed\n");
> +                     exit(1);
> +             }
> +
> +             if (*status[i]) {
> +                     printf("%ldth thread failed to join with %ld status\n",
> +                                                             i, *status[i]);
> +                     return 1;
> +             }
> +     }
> +     return 0;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +     return test_harness(test_body, "dscr_default_test");
> +}
> 

Could you please add a .gitignore for powerpc targets as we
discussed earlier. It can be separate patch.

Also, I would like to see the test results reports using
kselftest.h - it can be separate patch in the interest of
getting tests in.

Acked-by: Shuah Khan <shua...@osg.samsung.com>

Please take this through powerpc maintainer git.

thanks,
-- Shuah

-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shua...@osg.samsung.com | (970) 217-8978
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