Date: Sat, 2 Feb 2008 22:24:09 GMT From: John Birrell <jb@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 134676 for review Message-ID: <200802022224.m12MO9VT082054@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=134676 Change 134676 by jb@jb_freebsd1 on 2008/02/02 22:24:04 IFdtrace Affected files ... .. //depot/projects/dtrace7/src/sys/i386/i386/trap.c#3 edit Differences ... ==== //depot/projects/dtrace7/src/sys/i386/i386/trap.c#3 (text+ko) ==== @@ -49,6 +49,7 @@ #include "opt_hwpmc_hooks.h" #include "opt_isa.h" #include "opt_kdb.h" +#include "opt_kdtrace.h" #include "opt_ktrace.h" #include "opt_npx.h" #include "opt_trap.h" @@ -102,6 +103,24 @@ #include <machine/clock.h> #endif +#ifdef KDTRACE_HOOKS +#include <sys/dtrace_bsd.h> + +/* + * This is a hook which is initialised by the dtrace module + * to handle traps which might occur during DTrace probe + * execution. + */ +dtrace_trap_func_t dtrace_trap_func; + +/* + * This is a hook which is initialised by the systrace module + * when it is loaded. This keeps the DTrace syscall provider + * implementation opaque. + */ +systrace_probe_func_t systrace_probe_func; +#endif + extern void trap(struct trapframe *frame); extern void syscall(struct trapframe *frame); @@ -219,6 +238,24 @@ goto out; #endif +#ifdef KDTRACE_HOOKS + /* + * A trap can occur while DTrace executes a probe. Before + * executing the probe, DTrace blocks re-scheduling and sets + * a flag in it's per-cpu flags to indicate that it doesn't + * want to fault. On returning from the the probe, the no-fault + * flag is cleared and finally re-scheduling is enabled. + * + * If the DTrace kernel module has registered a trap handler, + * call it and if it returns non-zero, assume that it has + * handled the trap and modified the trap frame so that this + * function can return normally. + */ + if (dtrace_trap_func != NULL) + if ((*dtrace_trap_func)(frame, type)) + goto out; +#endif + if ((frame->tf_eflags & PSL_I) == 0) { /* * Buggy application or kernel code has disabled @@ -1031,9 +1068,34 @@ PTRACESTOP_SC(p, td, S_PT_SCE); +#ifdef KDTRACE_HOOKS + /* + * If the systrace module has registered it's probe + * callback and if there is a probe active for the + * syscall 'entry', process the probe. + */ + if (systrace_probe_func != NULL && callp->sy_entry != 0) + (*systrace_probe_func)(callp->sy_entry, code, callp, + args); +#endif + AUDIT_SYSCALL_ENTER(code, td); error = (*callp->sy_call)(td, args); AUDIT_SYSCALL_EXIT(error, td); + + /* Save the latest error return value. */ + td->td_errno = error; + +#ifdef KDTRACE_HOOKS + /* + * If the systrace module has registered it's probe + * callback and if there is a probe active for the + * syscall 'return', process the probe. + */ + if (systrace_probe_func != NULL && callp->sy_return != 0) + (*systrace_probe_func)(callp->sy_return, code, callp, + args); +#endif } switch (error) {
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