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

[Kostik Belousov]

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.

>  }
>  
>  /*
> @@ -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.
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