Custom DTrace kernel module files plus FreeBSD-specific DTrace providers.

1 files changed, 503 insertions, 0 deletions

diff --git a/sys/cddl/dev/dtrace/i386/dtrace_subr.c b/sys/cddl/dev/dtrace/i386/dtrace_subr.c
new file mode 100644
index 0000000..50515b6
--- /dev/null
+++ b/sys/cddl/dev/dtrace/i386/dtrace_subr.c
@@ -0,0 +1,503 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ *
+ * $FreeBSD$
+ *
+ */
+/*
+ * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/types.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/kmem.h>
+#include <sys/smp.h>
+#include <sys/dtrace_impl.h>
+#include <sys/dtrace_bsd.h>
+#include <machine/clock.h>
+#include <machine/frame.h>
+#include <vm/pmap.h>
+
+extern uintptr_t 	kernelbase;
+extern uintptr_t 	dtrace_in_probe_addr;
+extern int		dtrace_in_probe;
+
+int dtrace_invop(uintptr_t, uintptr_t *, uintptr_t);
+
+typedef struct dtrace_invop_hdlr {
+	int (*dtih_func)(uintptr_t, uintptr_t *, uintptr_t);
+	struct dtrace_invop_hdlr *dtih_next;
+} dtrace_invop_hdlr_t;
+
+dtrace_invop_hdlr_t *dtrace_invop_hdlr;
+
+int
+dtrace_invop(uintptr_t addr, uintptr_t *stack, uintptr_t eax)
+{
+	dtrace_invop_hdlr_t *hdlr;
+	int rval;
+
+	for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next)
+		if ((rval = hdlr->dtih_func(addr, stack, eax)) != 0)
+			return (rval);
+
+	return (0);
+}
+
+void
+dtrace_invop_add(int (*func)(uintptr_t, uintptr_t *, uintptr_t))
+{
+	dtrace_invop_hdlr_t *hdlr;
+
+	hdlr = kmem_alloc(sizeof (dtrace_invop_hdlr_t), KM_SLEEP);
+	hdlr->dtih_func = func;
+	hdlr->dtih_next = dtrace_invop_hdlr;
+	dtrace_invop_hdlr = hdlr;
+}
+
+void
+dtrace_invop_remove(int (*func)(uintptr_t, uintptr_t *, uintptr_t))
+{
+	dtrace_invop_hdlr_t *hdlr = dtrace_invop_hdlr, *prev = NULL;
+
+	for (;;) {
+		if (hdlr == NULL)
+			panic("attempt to remove non-existent invop handler");
+
+		if (hdlr->dtih_func == func)
+			break;
+
+		prev = hdlr;
+		hdlr = hdlr->dtih_next;
+	}
+
+	if (prev == NULL) {
+		ASSERT(dtrace_invop_hdlr == hdlr);
+		dtrace_invop_hdlr = hdlr->dtih_next;
+	} else {
+		ASSERT(dtrace_invop_hdlr != hdlr);
+		prev->dtih_next = hdlr->dtih_next;
+	}
+
+	kmem_free(hdlr, 0);
+}
+
+void
+dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
+{
+	(*func)(0, kernelbase);
+}
+
+void
+dtrace_xcall(processorid_t cpu, dtrace_xcall_t func, void *arg)
+{
+	cpumask_t cpus;
+
+	critical_enter();
+
+	if (cpu == DTRACE_CPUALL)
+		cpus = all_cpus;
+	else
+		cpus = (cpumask_t) (1 << cpu);
+
+	/* If the current CPU is in the set, call the function directly: */
+	if ((cpus & (1 << curcpu)) != 0) {
+		(*func)(arg);
+
+		/* Mask the current CPU from the set */
+		cpus &= ~(1 << curcpu);
+	}
+
+	/* If there are any CPUs in the set, cross-call to those CPUs */
+	if (cpus != 0)
+		smp_rendezvous_cpus(cpus, NULL, func, smp_no_rendevous_barrier, arg);
+
+	critical_exit();
+}
+
+static void
+dtrace_sync_func(void)
+{
+}
+
+void
+dtrace_sync(void)
+{
+        dtrace_xcall(DTRACE_CPUALL, (dtrace_xcall_t)dtrace_sync_func, NULL);
+}
+
+#ifdef notyet
+int (*dtrace_fasttrap_probe_ptr)(struct regs *);
+int (*dtrace_pid_probe_ptr)(struct regs *);
+int (*dtrace_return_probe_ptr)(struct regs *);
+
+void
+dtrace_user_probe(struct regs *rp, caddr_t addr, processorid_t cpuid)
+{
+	krwlock_t *rwp;
+	proc_t *p = curproc;
+	extern void trap(struct regs *, caddr_t, processorid_t);
+
+	if (USERMODE(rp->r_cs) || (rp->r_ps & PS_VM)) {
+		if (curthread->t_cred != p->p_cred) {
+			cred_t *oldcred = curthread->t_cred;
+			/*
+			 * DTrace accesses t_cred in probe context.  t_cred
+			 * must always be either NULL, or point to a valid,
+			 * allocated cred structure.
+			 */
+			curthread->t_cred = crgetcred();
+			crfree(oldcred);
+		}
+	}
+
+	if (rp->r_trapno == T_DTRACE_RET) {
+		uint8_t step = curthread->t_dtrace_step;
+		uint8_t ret = curthread->t_dtrace_ret;
+		uintptr_t npc = curthread->t_dtrace_npc;
+
+		if (curthread->t_dtrace_ast) {
+			aston(curthread);
+			curthread->t_sig_check = 1;
+		}
+
+		/*
+		 * Clear all user tracing flags.
+		 */
+		curthread->t_dtrace_ft = 0;
+
+		/*
+		 * If we weren't expecting to take a return probe trap, kill
+		 * the process as though it had just executed an unassigned
+		 * trap instruction.
+		 */
+		if (step == 0) {
+			tsignal(curthread, SIGILL);
+			return;
+		}
+
+		/*
+		 * If we hit this trap unrelated to a return probe, we're
+		 * just here to reset the AST flag since we deferred a signal
+		 * until after we logically single-stepped the instruction we
+		 * copied out.
+		 */
+		if (ret == 0) {
+			rp->r_pc = npc;
+			return;
+		}
+
+		/*
+		 * We need to wait until after we've called the
+		 * dtrace_return_probe_ptr function pointer to set %pc.
+		 */
+		rwp = &CPU->cpu_ft_lock;
+		rw_enter(rwp, RW_READER);
+		if (dtrace_return_probe_ptr != NULL)
+			(void) (*dtrace_return_probe_ptr)(rp);
+		rw_exit(rwp);
+		rp->r_pc = npc;
+
+	} else if (rp->r_trapno == T_DTRACE_PROBE) {
+		rwp = &CPU->cpu_ft_lock;
+		rw_enter(rwp, RW_READER);
+		if (dtrace_fasttrap_probe_ptr != NULL)
+			(void) (*dtrace_fasttrap_probe_ptr)(rp);
+		rw_exit(rwp);
+
+	} else if (rp->r_trapno == T_BPTFLT) {
+		uint8_t instr;
+		rwp = &CPU->cpu_ft_lock;
+
+		/*
+		 * The DTrace fasttrap provider uses the breakpoint trap
+		 * (int 3). We let DTrace take the first crack at handling
+		 * this trap; if it's not a probe that DTrace knowns about,
+		 * we call into the trap() routine to handle it like a
+		 * breakpoint placed by a conventional debugger.
+		 */
+		rw_enter(rwp, RW_READER);
+		if (dtrace_pid_probe_ptr != NULL &&
+		    (*dtrace_pid_probe_ptr)(rp) == 0) {
+			rw_exit(rwp);
+			return;
+		}
+		rw_exit(rwp);
+
+		/*
+		 * If the instruction that caused the breakpoint trap doesn't
+		 * look like an int 3 anymore, it may be that this tracepoint
+		 * was removed just after the user thread executed it. In
+		 * that case, return to user land to retry the instuction.
+		 */
+		if (fuword8((void *)(rp->r_pc - 1), &instr) == 0 &&
+		    instr != FASTTRAP_INSTR) {
+			rp->r_pc--;
+			return;
+		}
+
+		trap(rp, addr, cpuid);
+
+	} else {
+		trap(rp, addr, cpuid);
+	}
+}
+
+void
+dtrace_safe_synchronous_signal(void)
+{
+	kthread_t *t = curthread;
+	struct regs *rp = lwptoregs(ttolwp(t));
+	size_t isz = t->t_dtrace_npc - t->t_dtrace_pc;
+
+	ASSERT(t->t_dtrace_on);
+
+	/*
+	 * If we're not in the range of scratch addresses, we're not actually
+	 * tracing user instructions so turn off the flags. If the instruction
+	 * we copied out caused a synchonous trap, reset the pc back to its
+	 * original value and turn off the flags.
+	 */
+	if (rp->r_pc < t->t_dtrace_scrpc ||
+	    rp->r_pc > t->t_dtrace_astpc + isz) {
+		t->t_dtrace_ft = 0;
+	} else if (rp->r_pc == t->t_dtrace_scrpc ||
+	    rp->r_pc == t->t_dtrace_astpc) {
+		rp->r_pc = t->t_dtrace_pc;
+		t->t_dtrace_ft = 0;
+	}
+}
+
+int
+dtrace_safe_defer_signal(void)
+{
+	kthread_t *t = curthread;
+	struct regs *rp = lwptoregs(ttolwp(t));
+	size_t isz = t->t_dtrace_npc - t->t_dtrace_pc;
+
+	ASSERT(t->t_dtrace_on);
+
+	/*
+	 * If we're not in the range of scratch addresses, we're not actually
+	 * tracing user instructions so turn off the flags.
+	 */
+	if (rp->r_pc < t->t_dtrace_scrpc ||
+	    rp->r_pc > t->t_dtrace_astpc + isz) {
+		t->t_dtrace_ft = 0;
+		return (0);
+	}
+
+	/*
+	 * If we've executed the original instruction, but haven't performed
+	 * the jmp back to t->t_dtrace_npc or the clean up of any registers
+	 * used to emulate %rip-relative instructions in 64-bit mode, do that
+	 * here and take the signal right away. We detect this condition by
+	 * seeing if the program counter is the range [scrpc + isz, astpc).
+	 */
+	if (t->t_dtrace_astpc - rp->r_pc <
+	    t->t_dtrace_astpc - t->t_dtrace_scrpc - isz) {
+#ifdef __amd64
+		/*
+		 * If there is a scratch register and we're on the
+		 * instruction immediately after the modified instruction,
+		 * restore the value of that scratch register.
+		 */
+		if (t->t_dtrace_reg != 0 &&
+		    rp->r_pc == t->t_dtrace_scrpc + isz) {
+			switch (t->t_dtrace_reg) {
+			case REG_RAX:
+				rp->r_rax = t->t_dtrace_regv;
+				break;
+			case REG_RCX:
+				rp->r_rcx = t->t_dtrace_regv;
+				break;
+			case REG_R8:
+				rp->r_r8 = t->t_dtrace_regv;
+				break;
+			case REG_R9:
+				rp->r_r9 = t->t_dtrace_regv;
+				break;
+			}
+		}
+#endif
+		rp->r_pc = t->t_dtrace_npc;
+		t->t_dtrace_ft = 0;
+		return (0);
+	}
+
+	/*
+	 * Otherwise, make sure we'll return to the kernel after executing
+	 * the copied out instruction and defer the signal.
+	 */
+	if (!t->t_dtrace_step) {
+		ASSERT(rp->r_pc < t->t_dtrace_astpc);
+		rp->r_pc += t->t_dtrace_astpc - t->t_dtrace_scrpc;
+		t->t_dtrace_step = 1;
+	}
+
+	t->t_dtrace_ast = 1;
+
+	return (1);
+}
+#endif
+
+static int64_t	tgt_cpu_tsc;
+static int64_t	hst_cpu_tsc;
+static int64_t	tsc_skew[MAXCPU];
+
+static void
+dtrace_gethrtime_init_sync(void *arg)
+{
+#ifdef CHECK_SYNC
+	/*
+	 * Delay this function from returning on one
+	 * of the CPUs to check that the synchronisation
+	 * works.
+	 */
+	uintptr_t cpu = (uintptr_t) arg;
+
+	if (cpu == curcpu) {
+		int i;
+		for (i = 0; i < 1000000000; i++)
+			tgt_cpu_tsc = rdtsc();
+		tgt_cpu_tsc = 0;
+	}
+#endif
+}
+
+static void
+dtrace_gethrtime_init_cpu(void *arg)
+{
+	uintptr_t cpu = (uintptr_t) arg;
+
+	if (cpu == curcpu)
+		tgt_cpu_tsc = rdtsc();
+	else
+		hst_cpu_tsc = rdtsc();
+}
+
+static void
+dtrace_gethrtime_init(void *arg)
+{
+	cpumask_t map;
+	int i;
+	struct pcpu *cp;
+
+	/* The current CPU is the reference one. */
+	tsc_skew[curcpu] = 0;
+
+	for (i = 0; i <= mp_maxid; i++) {
+		if (i == curcpu)
+			continue;
+
+		if ((cp = pcpu_find(i)) == NULL)
+			continue;
+
+		map = 0;
+		map |= (1 << curcpu);
+		map |= (1 << i);
+
+		smp_rendezvous_cpus(map, dtrace_gethrtime_init_sync,
+		    dtrace_gethrtime_init_cpu,
+		    smp_no_rendevous_barrier, (void *)(uintptr_t) i);
+
+		tsc_skew[i] = tgt_cpu_tsc - hst_cpu_tsc;
+	}
+}
+
+SYSINIT(dtrace_gethrtime_init, SI_SUB_SMP, SI_ORDER_ANY, dtrace_gethrtime_init, NULL);
+
+/*
+ * DTrace needs a high resolution time function which can
+ * be called from a probe context and guaranteed not to have
+ * instrumented with probes itself.
+ *
+ * Returns nanoseconds since boot.
+ */
+uint64_t
+dtrace_gethrtime()
+{
+	return ((rdtsc() + tsc_skew[curcpu]) * (int64_t) 1000000000 / tsc_freq);
+}
+
+uint64_t
+dtrace_gethrestime(void)
+{
+	printf("%s(%d): XXX\n",__func__,__LINE__);
+	return (0);
+}
+
+/* Function to handle DTrace traps during probes. See i386/i386/trap.c */
+int
+dtrace_trap(struct trapframe *frame, u_int type)
+{
+	/*
+	 * 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.
+	 *
+	 * Check if DTrace has enabled 'no-fault' mode:
+	 *
+	 */
+	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
+		/*
+		 * There are only a couple of trap types that are expected.
+		 * All the rest will be handled in the usual way.
+		 */
+		switch (type) {
+		/* General protection fault. */
+		case T_PROTFLT:
+			/* Flag an illegal operation. */
+			cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_ILLOP;
+
+			/*
+			 * Offset the instruction pointer to the instruction
+			 * following the one causing the fault.
+			 */
+			frame->tf_eip += dtrace_instr_size((u_char *) frame->tf_eip);
+			return (1);
+		/* Page fault. */
+		case T_PAGEFLT:
+			/* Flag a bad address. */
+			cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
+			cpu_core[curcpu].cpuc_dtrace_illval = rcr2();
+
+			/*
+			 * Offset the instruction pointer to the instruction
+			 * following the one causing the fault.
+			 */
+			frame->tf_eip += dtrace_instr_size((u_char *) frame->tf_eip);
+			return (1);
+		default:
+			/* Handle all other traps in the usual way. */
+			break;
+		}
+	}
+
+	/* Handle the trap in the usual way. */
+	return (0);
+}