[V2,3/5] syscalls: semctl: Add new test to verify the _time_high fields

The _time_high fields must be reset by the kernel, add a test to verify
that.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V2: Remove stale file.

 configure.ac                                  |   1 +
 include/sembuf.h                              | 234 ++++++++++++++++++
 runtest/syscalls                              |   1 +
 runtest/syscalls-ipc                          |   1 +
 .../kernel/syscalls/ipc/semctl/.gitignore     |   1 +
 testcases/kernel/syscalls/ipc/semctl/Makefile |   5 +-
 .../kernel/syscalls/ipc/semctl/semctl08.c     |  52 ++++
 7 files changed, 294 insertions(+), 1 deletion(-)
 create mode 100644 include/sembuf.h
 create mode 100644 testcases/kernel/syscalls/ipc/semctl/semctl08.c

Hi!
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> V2: Remove stale file.
> 
>  configure.ac                                  |   1 +
>  include/sembuf.h                              | 234 ++++++++++++++++++
>  runtest/syscalls                              |   1 +
>  runtest/syscalls-ipc                          |   1 +
>  .../kernel/syscalls/ipc/semctl/.gitignore     |   1 +
>  testcases/kernel/syscalls/ipc/semctl/Makefile |   5 +-
>  .../kernel/syscalls/ipc/semctl/semctl08.c     |  52 ++++
>  7 files changed, 294 insertions(+), 1 deletion(-)
>  create mode 100644 include/sembuf.h
>  create mode 100644 testcases/kernel/syscalls/ipc/semctl/semctl08.c
> 
> diff --git a/configure.ac b/configure.ac
> index eaf33dd60350..c513fdf440c2 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -151,6 +151,7 @@ AC_CHECK_TYPES([struct fs_quota_statv],,,[#include <xfs/xqm.h>])
>  AC_CHECK_TYPES([struct if_nextdqblk],,,[#include <linux/quota.h>])
>  AC_CHECK_TYPES([struct iovec],,,[#include <sys/uio.h>])
>  AC_CHECK_TYPES([struct ipc64_perm],,,[#include <sys/ipcbuf.h>])
> +AC_CHECK_TYPES([struct semid64_ds],,,[#include <sys/sem.h>])
>  
>  AC_CHECK_TYPES([struct mmsghdr],,,[
>  #define _GNU_SOURCE
> diff --git a/include/sembuf.h b/include/sembuf.h
> new file mode 100644
> index 000000000000..00263abca995
> --- /dev/null
> +++ b/include/sembuf.h
> @@ -0,0 +1,234 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2020 Linaro Limited. All rights reserved.
> + * Author: Viresh Kumar <viresh.kumar@linaro.org>
> + */
> +
> +#ifndef IPC_SEMBUF_H
> +#define IPC_SEMBUF_H
> +
> +#include <linux/posix_types.h>
> +#include <sys/sem.h>
> +#include "tst_timer.h"
> +#include "ipcbuf.h"
> +
> +#ifndef HAVE_SEMID64_DS
> +
> +#if defined(__mips__)
> +#define HAVE_SEMID64_DS
> +/*
> + * The semid64_ds structure for the MIPS architecture.
> + * Note extra padding because this structure is passed back and forth
> + * between kernel and user space.
> + *
> + * Pad space is left for 2 miscellaneous 64-bit values on mips64,
> + * but used for the upper 32 bit of the time values on mips32.
> + */
> +#if defined(__arch64__)
> +struct semid64_ds {
> +	struct ipc64_perm sem_perm;		/* permissions .. see ipc.h */
> +	long		 sem_otime;		/* last semop time */
> +	long		 sem_ctime;		/* last change time */
> +	unsigned long	sem_nsems;		/* no. of semaphores in array */
> +	unsigned long	__unused1;
> +	unsigned long	__unused2;
> +};
> +#else
> +#define HAVE_SEMID64_DS_TIME_HIGH
> +struct semid64_ds {
> +	struct ipc64_perm sem_perm;		/* permissions .. see ipc.h */
> +	unsigned long   sem_otime;		/* last semop time */
> +	unsigned long   sem_ctime;		/* last change time */
> +	unsigned long	sem_nsems;		/* no. of semaphores in array */
> +	unsigned long	sem_otime_high;
> +	unsigned long	sem_ctime_high;
> +};
> +#endif
> +#endif /* __mips__ */
> +
> +#if defined(__hppa__)
> +#define HAVE_SEMID64_DS
> +/*
> + * The semid64_ds structure for parisc architecture.
> + * Note extra padding because this structure is passed back and forth
> + * between kernel and user space.
> + *
> + * Pad space is left for:
> + * - 2 miscellaneous 32-bit values
> + */
> +struct semid64_ds {
> +	struct ipc64_perm sem_perm;		/* permissions .. see ipc.h */
> +#if __BITS_PER_LONG == 64
> +	long		sem_otime;		/* last semop time */
> +	long		sem_ctime;		/* last change time */
> +#else
> +#define HAVE_SEMID64_DS_TIME_HIGH
> +	unsigned long	sem_otime_high;
> +	unsigned long	sem_otime;		/* last semop time */
> +	unsigned long	sem_ctime_high;
> +	unsigned long	sem_ctime;		/* last change time */
> +#endif
> +	unsigned long	sem_nsems;		/* no. of semaphores in array */
> +	unsigned long	__unused1;
> +	unsigned long	__unused2;
> +};
> +#endif /* __hppa__ */
> +
> +#if defined(__powerpc__) || defined(__powerpc64__)
> +#define HAVE_SEMID64_DS
> +/*
> + * The semid64_ds structure for PPC architecture.
> + * Note extra padding because this structure is passed back and forth
> + * between kernel and user space.
> + *
> + * Pad space is left for:
> + * - 2 miscellaneous 32/64-bit values
> + */
> +
> +struct semid64_ds {
> +	struct ipc64_perm sem_perm;	/* permissions .. see ipc.h */
> +#ifndef __powerpc64__
> +#define HAVE_SEMID64_DS_TIME_HIGH
> +	unsigned long	sem_otime_high;
> +	unsigned long	sem_otime;	/* last semop time */
> +	unsigned long	sem_ctime_high;
> +	unsigned long	sem_ctime;	/* last change time */
> +#else
> +	long		sem_otime;	/* last semop time */
> +	long		sem_ctime;	/* last change time */
> +#endif
> +	unsigned long	sem_nsems;	/* no. of semaphores in array */
> +	unsigned long	__unused3;
> +	unsigned long	__unused4;
> +};
> +#endif /* defined(__powerpc__) || defined(__powerpc64__) */
> +
> +#if defined(__sparc__)
> +#define HAVE_SEMID64_DS
> +/*
> + * The semid64_ds structure for sparc architecture.
> + * Note extra padding because this structure is passed back and forth
> + * between kernel and user space.
> + *
> + * Pad space is left for:
> + * - 2 miscellaneous 32-bit values
> + */
> +
> +struct semid64_ds {
> +	struct ipc64_perm sem_perm;		/* permissions .. see ipc.h */
> +#if defined(__arch64__)
> +	long		sem_otime;		/* last semop time */
> +	long		sem_ctime;		/* last change time */
> +#else
> +#define HAVE_SEMID64_DS_TIME_HIGH
> +	unsigned long	sem_otime_high;
> +	unsigned long	sem_otime;		/* last semop time */
> +	unsigned long	sem_ctime_high;
> +	unsigned long	sem_ctime;		/* last change time */
> +#endif
> +	unsigned long	sem_nsems;		/* no. of semaphores in array */
> +	unsigned long	__unused1;
> +	unsigned long	__unused2;
> +};
> +#endif /* __sparc__ */
> +
> +#if defined(__x86_64__)
> +#define HAVE_SEMID64_DS
> +/*
> + * The semid64_ds structure for x86 architecture.
> + * Note extra padding because this structure is passed back and forth
> + * between kernel and user space.
> + *
> + * Pad space is left for:
> + * - 2 miscellaneous 32-bit values
> + *
> + * x86_64 and x32 incorrectly added padding here, so the structures
> + * are still incompatible with the padding on x86.
> + */
> +struct semid64_ds {
> +	struct ipc64_perm sem_perm;	/* permissions .. see ipc.h */
> +#ifdef __i386__
> +#define HAVE_SEMID64_DS_TIME_HIGH
> +	unsigned long	sem_otime;	/* last semop time */
> +	unsigned long	sem_otime_high;
> +	unsigned long	sem_ctime;	/* last change time */
> +	unsigned long	sem_ctime_high;
> +#else
> +	__kernel_long_t sem_otime;	/* last semop time */
> +	__kernel_ulong_t __unused1;
> +	__kernel_long_t sem_ctime;	/* last change time */
> +	__kernel_ulong_t __unused2;
> +#endif
> +	__kernel_ulong_t sem_nsems;	/* no. of semaphores in array */
> +	__kernel_ulong_t __unused3;
> +	__kernel_ulong_t __unused4;
> +};
> +#endif /* defined(__x86_64__) */
> +
> +#if defined(__xtensa__)
> +#define HAVE_SEMID64_DS
> +#define HAVE_SEMID64_DS_TIME_HIGH
> +
> +struct semid64_ds {
> +	struct ipc64_perm sem_perm;		/* permissions .. see ipc.h */
> +#ifdef __XTENSA_EL__
> +	unsigned long	sem_otime;		/* last semop time */
> +	unsigned long	sem_otime_high;
> +	unsigned long	sem_ctime;		/* last change time */
> +	unsigned long	sem_ctime_high;
> +#else
> +	unsigned long	sem_otime_high;
> +	unsigned long	sem_otime;		/* last semop time */
> +	unsigned long	sem_ctime_high;
> +	unsigned long	sem_ctime;		/* last change time */
> +#endif
> +	unsigned long	sem_nsems;		/* no. of semaphores in array */
> +	unsigned long	__unused3;
> +	unsigned long	__unused4;
> +};
> +
> +#endif /* __xtensa__ */
> +
> +#ifndef HAVE_SEMID64_DS
> +/*
> + * The semid64_ds structure for most architectures (though it came
> + * from x86_32 originally). Note extra padding because this structure
> + * is passed back and forth between kernel and user space.
> + *
> + * semid64_ds was originally meant to be architecture specific, but
> + * everyone just ended up making identical copies without specific
> + * optimizations, so we may just as well all use the same one.
> + *
> + * 64 bit architectures use a 64-bit long time field here, while
> + * 32 bit architectures have a pair of unsigned long values.
> + *
> + * On big-endian systems, the padding is in the wrong place for
> + * historic reasons, so user space has to reconstruct a time_t
> + * value using
> + *
> + * user_semid_ds.sem_otime = kernel_semid64_ds.sem_otime +
> + *		((long long)kernel_semid64_ds.sem_otime_high << 32)
> + *
> + * Pad space is left for 2 miscellaneous 32-bit values
> + */
> +struct semid64_ds {
> +	struct ipc64_perm sem_perm;	/* permissions .. see ipc.h */
> +#if __BITS_PER_LONG == 64
> +	long		sem_otime;	/* last semop time */
> +	long		sem_ctime;	/* last change time */
> +#else
> +#define HAVE_SEMID64_DS_TIME_HIGH
> +	unsigned long	sem_otime;	/* last semop time */
> +	unsigned long	sem_otime_high;
> +	unsigned long	sem_ctime;	/* last change time */
> +	unsigned long	sem_ctime_high;
> +#endif
> +	unsigned long	sem_nsems;	/* no. of semaphores in array */
> +	unsigned long	__unused3;
> +	unsigned long	__unused4;
> +};
> +#endif /* semid64_ds */
> +
> +#endif /* HAVE_SEMID64_DS */
> +
> +#endif /* IPC_SEMBUF_H */

Can we please put the header into the lapi/ and also split this patch
so that we have one for the the fallback definition and one for the
actuall test?

> diff --git a/runtest/syscalls b/runtest/syscalls
> index edd3e8de7861..db14ba4baf9e 100644
> --- a/runtest/syscalls
> +++ b/runtest/syscalls
> @@ -1156,6 +1156,7 @@ semctl04 semctl04
>  semctl05 semctl05
>  semctl06 semctl06
>  semctl07 semctl07
> +semctl08 semctl08
>  
>  semget01 semget01
>  semget02 semget02
> diff --git a/runtest/syscalls-ipc b/runtest/syscalls-ipc
> index 54d8622d4223..f912cb067f74 100644
> --- a/runtest/syscalls-ipc
> +++ b/runtest/syscalls-ipc
> @@ -33,6 +33,7 @@ semctl04 semctl04
>  semctl05 semctl05
>  semctl06 semctl06
>  semctl07 semctl07
> +semctl08 semctl08
>  
>  semget01 semget01
>  semget02 semget02
> diff --git a/testcases/kernel/syscalls/ipc/semctl/.gitignore b/testcases/kernel/syscalls/ipc/semctl/.gitignore
> index b6899acf5da6..6189a04cc3c6 100644
> --- a/testcases/kernel/syscalls/ipc/semctl/.gitignore
> +++ b/testcases/kernel/syscalls/ipc/semctl/.gitignore
> @@ -5,3 +5,4 @@
>  /semctl05
>  /semctl06
>  /semctl07
> +/semctl08
> diff --git a/testcases/kernel/syscalls/ipc/semctl/Makefile b/testcases/kernel/syscalls/ipc/semctl/Makefile
> index aa211d37f8ee..150f581825c5 100644
> --- a/testcases/kernel/syscalls/ipc/semctl/Makefile
> +++ b/testcases/kernel/syscalls/ipc/semctl/Makefile
> @@ -5,7 +5,10 @@ top_srcdir              ?= ../../../../..
>  
>  include $(top_srcdir)/include/mk/testcases.mk
>  
> -LDLIBS  += -lltpipc
> +semctl01 semctl02 semctl03 semctl04 semctl05 semctl06 semctl07: LDLIBS += -lltpipc
> +semctl08: LDLIBS += -lltpnewipc
> +
>  LDFLAGS += -L$(top_builddir)/libs/libltpipc
> +LDFLAGS += -L$(top_builddir)/libs/libltpnewipc

This does not apply anymore after my fix. This should be:

LTPLIBS = ltpipc ltpnewipc

Which would add a dependency on these libraries in the build system and
also append the LDFLAGS, then all we need to do is to add the LDLIBS.

>  include $(top_srcdir)/include/mk/generic_leaf_target.mk
> diff --git a/testcases/kernel/syscalls/ipc/semctl/semctl08.c b/testcases/kernel/syscalls/ipc/semctl/semctl08.c
> new file mode 100644
> index 000000000000..90a88989f2d3
> --- /dev/null
> +++ b/testcases/kernel/syscalls/ipc/semctl/semctl08.c
> @@ -0,0 +1,52 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2020 Viresh Kumar <viresh.kumar@linaro.org>
> + *
> + * Description:
> + * Cross verify the _high fields being set to 0 by the kernel.
> + */
> +#include "lapi/semun.h"
> +#include "tst_test.h"
> +#include "libnewipc.h"
> +#include "sembuf.h"
> +
> +#ifdef HAVE_SEMID64_DS_TIME_HIGH
> +
> +static void run(void)
> +{
> +	struct semid64_ds buf_ds = {
> +		.sem_otime_high = 0x0A0A,
> +		.sem_ctime_high = 0x0A0A,
> +	};
> +	int semid;
> +	union semun arg;
> +	key_t key;
> +
> +	/* get an IPC resource key */
> +	key = GETIPCKEY();
> +
> +	semid = semget(key, 1, SEM_RA | IPC_CREAT);
> +	if (semid == -1)
> +		tst_brk(TBROK | TERRNO, "couldn't create semaphore");
> +
> +	arg.buf = (struct semid_ds *)&buf_ds;
> +	TEST(semctl(semid, 0, IPC_STAT, arg));
> +	if (TST_RET == -1)
> +		tst_brk(TFAIL | TTERRNO, "semctl() failed");
> +
> +	if (buf_ds.sem_otime_high || buf_ds.sem_ctime_high)
> +		tst_res(TFAIL, "time_high fields aren't cleared by the kernel");
> +	else
> +		tst_res(TPASS, "time_high fields cleared by the kernel");
> +
> +	if (semctl(semid, 0, IPC_RMID, arg) == -1)
> +		tst_res(TINFO, "WARNING: semaphore deletion failed.");
> +}
> +
> +static struct tst_test test = {
> +	.test_all = run,
> +	.needs_tmpdir = 1,
> +};
> +#else
> +TST_TEST_TCONF("test requires struct semid64_ds to have the time_high fields");
> +#endif

Other than that the patch looks good.

On 15-06-20, 15:31, Cyril Hrubis wrote:
> > diff --git a/testcases/kernel/syscalls/ipc/semctl/Makefile b/testcases/kernel/syscalls/ipc/semctl/Makefile
> > index aa211d37f8ee..150f581825c5 100644
> > --- a/testcases/kernel/syscalls/ipc/semctl/Makefile
> > +++ b/testcases/kernel/syscalls/ipc/semctl/Makefile
> > @@ -5,7 +5,10 @@ top_srcdir              ?= ../../../../..
> >  
> >  include $(top_srcdir)/include/mk/testcases.mk
> >  
> > -LDLIBS  += -lltpipc
> > +semctl01 semctl02 semctl03 semctl04 semctl05 semctl06 semctl07: LDLIBS += -lltpipc
> > +semctl08: LDLIBS += -lltpnewipc
> > +
> >  LDFLAGS += -L$(top_builddir)/libs/libltpipc
> > +LDFLAGS += -L$(top_builddir)/libs/libltpnewipc
> 
> This does not apply anymore after my fix. This should be:
> 
> LTPLIBS = ltpipc ltpnewipc
> 
> Which would add a dependency on these libraries in the build system and
> also append the LDFLAGS, then all we need to do is to add the LDLIBS.

diff --git a/testcases/kernel/syscalls/ipc/semctl/Makefile b/testcases/kernel/syscalls/ipc/semctl/Makefile
index 6895fb1967a1..d7002872ab42 100644
--- a/testcases/kernel/syscalls/ipc/semctl/Makefile
+++ b/testcases/kernel/syscalls/ipc/semctl/Makefile
@@ -3,7 +3,7 @@
 
 top_srcdir              ?= ../../../../..
 
-LTPLIBS = ltpipc
+LTPLIBS = ltpipc ltpnewipc
 
 include $(top_srcdir)/include/mk/testcases.mk
 
@@ -11,4 +11,4 @@ semctl01 semctl02 semctl03 semctl04 semctl05 semctl06 semctl07: LDLIBS += -lltpi
 semctl08: LDLIBS += -lltpnewipc
 
 include $(top_srcdir)/include/mk/generic_leaf_target.mk
-LDFLAGS += -L$(top_builddir)/libs/libltpnewipc

This doesn't build for some reason.

make -C "/mnt/ssd/all/work/repos/tools/ltp/libs/libltpipc /mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc" -f "/mnt/ssd/all/work/repos/tools/ltp/libs/libltpipc /mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc/Makefile" all
make[1]: *** /mnt/ssd/all/work/repos/tools/ltp/libs/libltpipc /mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc: No such file or directory.  Stop.
../../../../../include/mk/testcases.mk:52: recipe for target '/mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc/libltpnewipc.a' failed
make: *** [/mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc/libltpnewipc.a] Error 2

Hi!
> diff --git a/testcases/kernel/syscalls/ipc/semctl/Makefile b/testcases/kernel/syscalls/ipc/semctl/Makefile
> index 6895fb1967a1..d7002872ab42 100644
> --- a/testcases/kernel/syscalls/ipc/semctl/Makefile
> +++ b/testcases/kernel/syscalls/ipc/semctl/Makefile
> @@ -3,7 +3,7 @@
>  
>  top_srcdir              ?= ../../../../..
>  
> -LTPLIBS = ltpipc
> +LTPLIBS = ltpipc ltpnewipc
>  
>  include $(top_srcdir)/include/mk/testcases.mk
>  
> @@ -11,4 +11,4 @@ semctl01 semctl02 semctl03 semctl04 semctl05 semctl06 semctl07: LDLIBS += -lltpi
>  semctl08: LDLIBS += -lltpnewipc
>  
>  include $(top_srcdir)/include/mk/generic_leaf_target.mk
> -LDFLAGS += -L$(top_builddir)/libs/libltpnewipc
> 
> This doesn't build for some reason.
> 
> make -C "/mnt/ssd/all/work/repos/tools/ltp/libs/libltpipc /mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc" -f "/mnt/ssd/all/work/repos/tools/ltp/libs/libltpipc /mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc/Makefile" all
> make[1]: *** /mnt/ssd/all/work/repos/tools/ltp/libs/libltpipc /mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc: No such file or directory.  Stop.
> ../../../../../include/mk/testcases.mk:52: recipe for target '/mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc/libltpnewipc.a' failed
> make: *** [/mnt/ssd/all/work/repos/tools/ltp/libs/libltpnewipc/libltpnewipc.a] Error 2

Ah, right, the rule that rebuilds the libraries does not work correctly
for more than one library because I do pass "$^" there which is the list
of directories and not a single directory.

As a quick hack this should fix it:

diff --git a/include/mk/testcases.mk b/include/mk/testcases.mk
index 684655fbf..7e0ec13f9 100644
--- a/include/mk/testcases.mk
+++ b/include/mk/testcases.mk
@@ -49,7 +49,9 @@ LTPLIBS_FILES = $(addsuffix .a, $(addprefix $(abs_top_builddir)/libs/, $(foreach
 MAKE_DEPS += $(LTPLIBS_FILES)
 
 $(LTPLIBS_FILES): $(LTPLIBS_DIRS)
-       $(MAKE) -C "$^" -f "$(subst $(abs_top_builddir),$(abs_top_srcdir),$^)/Makefile" all
+       for dir in $^; do \
+               $(MAKE) -C "$$dir" -f "$(subst $(abs_top_builddir),$(abs_top_srcdir),$$dir)/Makefile" all; \
+       done
 
 LDFLAGS += $(addprefix -L$(top_builddir)/libs/lib, $(LTPLIBS))


This does not parallelize the build but I guess that it would be fine since
when we rebuild LTP from top directory the libraries are build first anyways
and this is no-op.

On 16-06-20, 11:52, Cyril Hrubis wrote:
> Ah, right, the rule that rebuilds the libraries does not work correctly
> for more than one library because I do pass "$^" there which is the list
> of directories and not a single directory.
> 
> As a quick hack this should fix it:
> 
> diff --git a/include/mk/testcases.mk b/include/mk/testcases.mk
> index 684655fbf..7e0ec13f9 100644
> --- a/include/mk/testcases.mk
> +++ b/include/mk/testcases.mk
> @@ -49,7 +49,9 @@ LTPLIBS_FILES = $(addsuffix .a, $(addprefix $(abs_top_builddir)/libs/, $(foreach
>  MAKE_DEPS += $(LTPLIBS_FILES)
>  
>  $(LTPLIBS_FILES): $(LTPLIBS_DIRS)
> -       $(MAKE) -C "$^" -f "$(subst $(abs_top_builddir),$(abs_top_srcdir),$^)/Makefile" all
> +       for dir in $^; do \
> +               $(MAKE) -C "$$dir" -f "$(subst $(abs_top_builddir),$(abs_top_srcdir),$$dir)/Makefile" all; \
> +       done
>  
>  LDFLAGS += $(addprefix -L$(top_builddir)/libs/lib, $(LTPLIBS))
> 
> 
> This does not parallelize the build but I guess that it would be fine since
> when we rebuild LTP from top directory the libraries are build first anyways
> and this is no-op.

Tested-by: Viresh Kumar <viresh.kumar@linaro.org>

Please merge it, I am sending my patches again based on this.

Hi!
> Please merge it, I am sending my patches again based on this.

I've just pushed a proper fix with a pattern rule instead.