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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/cddl/dev/dtrace/amd64/dtrace_subr.c |
/*
* 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: release/9.1.0/sys/cddl/dev/dtrace/amd64/dtrace_subr.c 223758 2011-07-04 12:04:52Z attilio $
*
*/
/*
* 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 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);
}
/*ARGSUSED*/
void
dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
{
(*func)(0, (uintptr_t) addr_PTmap);
}
void
dtrace_xcall(processorid_t cpu, dtrace_xcall_t func, void *arg)
{
cpuset_t cpus;
if (cpu == DTRACE_CPUALL)
cpus = all_cpus;
else
CPU_SETOF(cpu, &cpus);
smp_rendezvous_cpus(cpus, smp_no_rendevous_barrier, func,
smp_no_rendevous_barrier, arg);
}
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 uint64_t nsec_scale;
/* See below for the explanation of this macro. */
#define SCALE_SHIFT 28
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)
{
struct pcpu *pc;
uint64_t tsc_f;
cpuset_t map;
int i;
/*
* Get TSC frequency known at this moment.
* This should be constant if TSC is invariant.
* Otherwise tick->time conversion will be inaccurate, but
* will preserve monotonic property of TSC.
*/
tsc_f = atomic_load_acq_64(&tsc_freq);
/*
* The following line checks that nsec_scale calculated below
* doesn't overflow 32-bit unsigned integer, so that it can multiply
* another 32-bit integer without overflowing 64-bit.
* Thus minimum supported TSC frequency is 62.5MHz.
*/
KASSERT(tsc_f > (NANOSEC >> (32 - SCALE_SHIFT)), ("TSC frequency is too low"));
/*
* We scale up NANOSEC/tsc_f ratio to preserve as much precision
* as possible.
* 2^28 factor was chosen quite arbitrarily from practical
* considerations:
* - it supports TSC frequencies as low as 62.5MHz (see above);
* - it provides quite good precision (e < 0.01%) up to THz
* (terahertz) values;
*/
nsec_scale = ((uint64_t)NANOSEC << SCALE_SHIFT) / tsc_f;
/* The current CPU is the reference one. */
sched_pin();
tsc_skew[curcpu] = 0;
CPU_FOREACH(i) {
if (i == curcpu)
continue;
pc = pcpu_find(i);
CPU_SETOF(PCPU_GET(cpuid), &map);
CPU_SET(pc->pc_cpuid, &map);
smp_rendezvous_cpus(map, NULL,
dtrace_gethrtime_init_cpu,
smp_no_rendevous_barrier, (void *)(uintptr_t) i);
tsc_skew[i] = tgt_cpu_tsc - hst_cpu_tsc;
}
sched_unpin();
}
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()
{
uint64_t tsc;
uint32_t lo;
uint32_t hi;
/*
* We split TSC value into lower and higher 32-bit halves and separately
* scale them with nsec_scale, then we scale them down by 2^28
* (see nsec_scale calculations) taking into account 32-bit shift of
* the higher half and finally add.
*/
tsc = rdtsc() + tsc_skew[curcpu];
lo = tsc;
hi = tsc >> 32;
return (((lo * nsec_scale) >> SCALE_SHIFT) +
((hi * nsec_scale) << (32 - SCALE_SHIFT)));
}
uint64_t
dtrace_gethrestime(void)
{
printf("%s(%d): XXX\n",__func__,__LINE__);
return (0);
}
/* Function to handle DTrace traps during probes. See amd64/amd64/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 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) {
/* Privilieged instruction fault. */
case T_PRIVINFLT:
break;
/* 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_rip += dtrace_instr_size((u_char *) frame->tf_rip);
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 = frame->tf_addr;
/*
* Offset the instruction pointer to the instruction
* following the one causing the fault.
*/
frame->tf_rip += dtrace_instr_size((u_char *) frame->tf_rip);
return (1);
default:
/* Handle all other traps in the usual way. */
break;
}
}
/* Handle the trap in the usual way. */
return (0);
}