Date: Mon, 9 Jun 2008 03:11:32 GMT From: John Birrell <jb@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 143158 for review Message-ID: <200806090311.m593BWaf051487@repoman.freebsd.org>
next in thread | raw e-mail | index | archive | help
http://perforce.freebsd.org/chv.cgi?CH=143158 Change 143158 by jb@freebsd3 on 2008/06/09 03:10:30 Add the hooks for the syscall (systrace) provider. Note that this requires an ABI change, so a separate kernel option is required to make it work. BREAK_SYSENT_ABI should be obvious. Affected files ... .. //depot/projects/dtrace6/src/sys/i386/i386/trap.c#2 edit Differences ... ==== //depot/projects/dtrace6/src/sys/i386/i386/trap.c#2 (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" @@ -109,6 +110,26 @@ static void trap_fatal(struct trapframe *, vm_offset_t); void dblfault_handler(void); +#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; + +dtrace_doubletrap_func_t dtrace_doubletrap_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 inthand_t IDTVEC(lcall_syscall); #define MAX_TRAP_MSG 30 @@ -215,6 +236,25 @@ 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 ((type == T_PROTFLT || type == T_PAGEFLT) && + 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 @@ -855,6 +895,10 @@ void dblfault_handler() { +#ifdef KDTRACE_HOOKS + if (dtrace_doubletrap_func != NULL) + (*dtrace_doubletrap_func)(); +#endif printf("\nFatal double fault:\n"); printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); @@ -980,9 +1024,34 @@ PTRACESTOP_SC(p, td, S_PT_SCE); +#if defined(KDTRACE_HOOKS) && defined(BREAK_SYSENT_ABI) + /* + * 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; + +#if defined(KDTRACE_HOOKS) && defined(BREAK_SYSENT_ABI) + /* + * 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) {
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200806090311.m593BWaf051487>