svn commit: r211738 - head/sys/cddl/contrib/opensolaris/uts/common/dtrace

[Rui Paulo]

On 24 Aug 2010, at 12:48, Kostik Belousov wrote:

> On Tue, Aug 24, 2010 at 11:11:58AM +0000, Rui Paulo wrote:
>> Author: rpaulo
>> Date: Tue Aug 24 11:11:58 2010
>> New Revision: 211738
>> URL: http://svn.freebsd.org/changeset/base/211738
>> 
>> Log:
>>  Port the fasttrap provider to FreeBSD. This provider is responsible for
>>  injecting debugging probes in the userland programs and is the basis for
>>  the pid provider and the usdt provider.
>> 
>>  Sponsored by:	The FreeBSD Foundation
>> 
>> Modified:
>>  head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
>> 
>> Modified: head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
>> ==============================================================================
>> --- head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c	Tue Aug 24 09:57:06 2010	(r211737)
>> +++ head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c	Tue Aug 24 11:11:58 2010	(r211738)
>> @@ -17,6 +17,10 @@
>>  * information: Portions Copyright [yyyy] [name of copyright owner]
>>  *
>>  * CDDL HEADER END
>> + *
>> + * Portions Copyright 2010 The FreeBSD Foundation
>> + *
>> + * $FreeBSD$
>>  */
>> 
>> /*
>> @@ -24,7 +28,9 @@
>>  * Use is subject to license terms.
>>  */
>> 
>> +#if defined(sun)
>> #pragma ident	"%Z%%M%	%I%	%E% SMI"
>> +#endif
>> 
>> #include <sys/atomic.h>
>> #include <sys/errno.h>
>> @@ -32,11 +38,15 @@
>> #include <sys/modctl.h>
>> #include <sys/conf.h>
>> #include <sys/systm.h>
>> +#if defined(sun)
>> #include <sys/ddi.h>
>> +#endif
>> #include <sys/sunddi.h>
>> #include <sys/cpuvar.h>
>> #include <sys/kmem.h>
>> +#if defined(sun)
>> #include <sys/strsubr.h>
>> +#endif
>> #include <sys/fasttrap.h>
>> #include <sys/fasttrap_impl.h>
>> #include <sys/fasttrap_isa.h>
>> @@ -44,9 +54,17 @@
>> #include <sys/dtrace_impl.h>
>> #include <sys/sysmacros.h>
>> #include <sys/proc.h>
>> -#include <sys/priv.h>
>> #include <sys/policy.h>
>> +#if defined(sun)
>> #include <util/qsort.h>
>> +#endif
>> +#include <sys/mutex.h>
>> +#include <sys/kernel.h>
>> +#if !defined(sun)
>> +#include <sys/user.h>
>> +#include <sys/dtrace_bsd.h>
>> +#include <cddl/dev/dtrace/dtrace_cddl.h>
>> +#endif
>> 
>> /*
>>  * User-Land Trap-Based Tracing
>> @@ -125,11 +143,20 @@
>>  *	never hold the provider lock and creation lock simultaneously
>>  */
>> 
>> -static dev_info_t *fasttrap_devi;
>> +static d_open_t fasttrap_open;
>> +static d_ioctl_t fasttrap_ioctl;
>> +
>> +static struct cdevsw fasttrap_cdevsw = {
>> +	.d_version	= D_VERSION,
>> +	.d_open		= fasttrap_open,
>> +	.d_ioctl	= fasttrap_ioctl,
>> +	.d_name		= "fasttrap",
>> +};
>> +static struct cdev *fasttrap_cdev;
>> static dtrace_meta_provider_id_t fasttrap_meta_id;
>> 
>> -static timeout_id_t fasttrap_timeout;
>> -static kmutex_t fasttrap_cleanup_mtx;
>> +static struct callout fasttrap_timeout;
>> +static struct mtx fasttrap_cleanup_mtx;
>> static uint_t fasttrap_cleanup_work;
>> 
>> /*
>> @@ -229,6 +256,7 @@ fasttrap_hash_str(const char *p)
>> void
>> fasttrap_sigtrap(proc_t *p, kthread_t *t, uintptr_t pc)
>> {
>> +#if defined(sun)
>> 	sigqueue_t *sqp = kmem_zalloc(sizeof (sigqueue_t), KM_SLEEP);
>> 
>> 	sqp->sq_info.si_signo = SIGTRAP;
>> @@ -241,6 +269,17 @@ fasttrap_sigtrap(proc_t *p, kthread_t *t
>> 
>> 	if (t != NULL)
>> 		aston(t);
>> +#else
>> +	ksiginfo_t *ksi = kmem_zalloc(sizeof (ksiginfo_t), KM_SLEEP);
>> +
>> +	ksiginfo_init(ksi);
>> +	ksi->ksi_signo = SIGTRAP;
>> +	ksi->ksi_code = TRAP_DTRACE;
>> +	ksi->ksi_addr = (caddr_t)pc;
>> +	PROC_LOCK(p);
>> +	(void) pksignal(p, SIGTRAP, ksi);
>> +	PROC_UNLOCK(p);
>> +#endif
> From the quick look at the solaris part of the code, I think that the
> signal should be posted to the specific thread, and not to the process.
> 

I'll use tdsignal, thanks.

>> }
>> 
>> /*
>> @@ -250,17 +289,24 @@ fasttrap_sigtrap(proc_t *p, kthread_t *t
>> static void
>> fasttrap_mod_barrier(uint64_t gen)
>> {
>> +#if defined(sun)
>> 	int i;
>> +#endif
>> 
>> 	if (gen < fasttrap_mod_gen)
>> 		return;
>> 
>> 	fasttrap_mod_gen++;
>> 
>> +#if defined(sun)
>> 	for (i = 0; i < NCPU; i++) {
>> 		mutex_enter(&cpu_core[i].cpuc_pid_lock);
>> 		mutex_exit(&cpu_core[i].cpuc_pid_lock);
>> 	}
>> +#else
>> +	/* XXX */
>> +	__asm __volatile("": : :"memory");
> Indeed XXX. Semantic of acquiring/releasing a mutex, even on Solaris,
> is much stricter then performing compiler-level memory barrier.

I don't know what kind of mutexes we have in FreeBSD to mimc this behavior.

Regards,
--
Rui Paulo