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dispatch.c
2348 lines (2214 loc) · 103 KB
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dispatch.c
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/* **********************************************************
* Copyright (c) 2011-2022 Google, Inc. All rights reserved.
* Copyright (c) 2000-2010 VMware, Inc. All rights reserved.
* **********************************************************/
/*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of VMware, Inc. nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL VMWARE, INC. OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*/
/* Copyright (c) 2003-2007 Determina Corp. */
/* Copyright (c) 2001-2003 Massachusetts Institute of Technology */
/* Copyright (c) 2000-2001 Hewlett-Packard Company */
/*
* dispatch.c - central dynamo control manager
*/
#include "globals.h"
#include "link.h"
#include "fragment.h"
#include "fcache.h"
#include "monitor.h"
#include "synch.h"
#include "perscache.h"
#include "native_exec.h"
#include "translate.h"
#include "emit.h"
#include "arch.h"
#include "instrument.h"
#ifdef DGC_DIAGNOSTICS
# include "instr.h"
# include "disassemble.h"
#endif
#ifdef RCT_IND_BRANCH
# include "rct.h"
#endif
#ifdef VMX86_SERVER
# include "vmkuw.h"
#endif
/* forward declarations */
static void
dispatch_enter_dynamorio(dcontext_t *dcontext);
static bool
dispatch_enter_fcache(dcontext_t *dcontext, fragment_t *targetf);
static void
dispatch_enter_fcache_stats(dcontext_t *dcontext, fragment_t *targetf);
static void
enter_fcache(dcontext_t *dcontext, fcache_enter_func_t entry, cache_pc pc);
static void
dispatch_enter_native(dcontext_t *dcontext);
static void
dispatch_exit_fcache(dcontext_t *dcontext);
static void
dispatch_exit_fcache_stats(dcontext_t *dcontext);
static void
handle_post_system_call(dcontext_t *dcontext);
static void
handle_special_tag(dcontext_t *dcontext);
#ifdef WINDOWS
static void
handle_callback_return(dcontext_t *dcontext);
#endif
/* PR 356503: detect clients making syscalls via sysenter */
static inline void
found_client_sysenter(void)
{
CLIENT_ASSERT(false,
"Is your client invoking raw system calls via vdso sysenter? "
"While such behavior is not recommended and can create problems, "
"it may work with the -sysenter_is_int80 runtime option.");
}
static bool
exited_due_to_ni_syscall(dcontext_t *dcontext)
{
if (TESTANY(LINK_NI_SYSCALL_ALL, dcontext->last_exit->flags))
return true;
if (TEST(LINK_SPECIAL_EXIT, dcontext->last_exit->flags) &&
(dcontext->upcontext.upcontext.exit_reason == EXIT_REASON_NI_SYSCALL_INT_0x81 ||
dcontext->upcontext.upcontext.exit_reason == EXIT_REASON_NI_SYSCALL_INT_0x82))
return true;
return false;
}
/* This is the central hub of control management in DynamoRIO.
* It is entered with a clean dstack at startup and after every cache
* exit, whether normal or kernel-mediated via a trampoline context switch.
* Having no stack state kept across cache executions avoids
* self-protection issues with the dstack.
*/
void
d_r_dispatch(dcontext_t *dcontext)
{
fragment_t *targetf;
fragment_t coarse_f;
#ifdef HAVE_TLS
# if defined(UNIX) && defined(X86)
/* i#2089: the parent of a new thread has TLS in an unstable state
* and needs to restore it prior to invoking get_thread_private_dcontext().
*/
if (get_at_syscall(dcontext) && was_thread_create_syscall(dcontext))
os_clone_post(dcontext);
# endif
ASSERT(dcontext == get_thread_private_dcontext() ||
/* i#813: the app hit our post-sysenter hook while native */
(dcontext->whereami == DR_WHERE_APP &&
dcontext->last_exit == get_syscall_linkstub()));
#else
# ifdef UNIX
/* CAUTION: for !HAVE_TLS, upon a fork, the child's
* get_thread_private_dcontext() will return NULL because its thread
* id is different and tls_table hasn't been updated yet (will be
* done in post_system_call()). NULL dcontext thus returned causes
* logging/core dumping to malfunction; kstats trigger asserts.
*/
ASSERT(dcontext == get_thread_private_dcontext() || pid_cached != get_process_id());
# endif
#endif
dispatch_enter_dynamorio(dcontext);
LOG(THREAD, LOG_INTERP, 2, "\nd_r_dispatch: target = " PFX "\n", dcontext->next_tag);
/* This is really a 1-iter loop most of the time: we only iterate
* when we obtain a target fragment but then fail to enter the
* cache due to flushing before we get there.
*/
do {
if (is_in_dynamo_dll(dcontext->next_tag) ||
dcontext->next_tag == BACK_TO_NATIVE_AFTER_SYSCALL || dcontext->go_native) {
handle_special_tag(dcontext);
}
/* Neither hotp_only nor thin_client should have any fragment
* fcache related work to do.
*/
ASSERT(!RUNNING_WITHOUT_CODE_CACHE());
targetf = fragment_lookup_fine_and_coarse(dcontext, dcontext->next_tag, &coarse_f,
dcontext->last_exit);
#ifdef UNIX
/* i#1276: dcontext->next_tag could be a special stub pc used by
* DR to maintain control in hybrid execution, in which case the
* target should be replaced with correct app target.
*/
if (targetf == NULL && DYNAMO_OPTION(native_exec) &&
DYNAMO_OPTION(native_exec_opt) && native_exec_replace_next_tag(dcontext))
continue;
#endif
do {
if (targetf != NULL) {
KSTART(monitor_enter);
/* invoke monitor to continue or start a trace
* may result in changing or nullifying targetf
*/
targetf = monitor_cache_enter(dcontext, targetf);
KSTOP_NOT_MATCHING(monitor_enter); /* or monitor_enter_thci */
}
if (targetf != NULL)
break;
/* must call outside of USE_BB_BUILDING_LOCK guard for bb_lock_would_have: */
SHARED_BB_LOCK();
if (USE_BB_BUILDING_LOCK() || targetf == NULL) {
/* must re-lookup while holding lock and keep the lock until we've
* built the bb and added it to the lookup table
* FIXME: optimize away redundant lookup: flags to know why came out?
*/
targetf = fragment_lookup_fine_and_coarse(dcontext, dcontext->next_tag,
&coarse_f, dcontext->last_exit);
}
if (targetf == NULL) {
SELF_PROTECT_LOCAL(dcontext, WRITABLE);
targetf = build_basic_block_fragment(dcontext, dcontext->next_tag, 0,
true /*link*/, true /*visible*/,
false /*!for_trace*/, NULL);
SELF_PROTECT_LOCAL(dcontext, READONLY);
}
if (targetf != NULL && TEST(FRAG_COARSE_GRAIN, targetf->flags)) {
/* targetf is a static temp fragment protected by bb_building_lock,
* so we must make a local copy to use before releasing the lock.
* FIXME: best to pass local wrapper to build_basic_block_fragment
* and all the way through emit and link? Would need linkstubs
* tailing the fragment_t.
*/
ASSERT(USE_BB_BUILDING_LOCK_STEADY_STATE());
fragment_coarse_wrapper(&coarse_f, targetf->tag,
FCACHE_ENTRY_PC(targetf));
targetf = &coarse_f;
}
SHARED_BB_UNLOCK();
if (targetf == NULL)
break;
/* loop around and re-do monitor check */
} while (true);
if (targetf != NULL) {
if (dispatch_enter_fcache(dcontext, targetf)) {
/* won't reach here: will re-enter d_r_dispatch() with a clean stack */
ASSERT_NOT_REACHED();
} else
targetf = NULL; /* targetf was flushed */
}
} while (true);
ASSERT_NOT_REACHED();
}
/* returns true if pc is a point at which DynamoRIO should stop interpreting */
bool
is_stopping_point(dcontext_t *dcontext, app_pc arg_pc)
{
#ifdef DR_APP_EXPORTS
/* TODO i#4720: Find and update other comparisons to function pointers. */
app_pc pc = PC_AS_JMP_TGT(dr_get_isa_mode(dcontext), arg_pc);
#endif
if ((arg_pc /*undecorated*/ == BACK_TO_NATIVE_AFTER_SYSCALL &&
/* case 6253: app may xfer to this "address" in which case pass
* exception to app
*/
dcontext->native_exec_postsyscall != NULL)
#ifdef DR_APP_EXPORTS
|| (!automatic_startup &&
(pc == (app_pc)dynamorio_app_exit ||
/* FIXME: Is this a holdover from long ago? dymamo_thread_exit
* should not be called from the cache.
*/
pc == (app_pc)dynamo_thread_exit || pc == (app_pc)dr_app_stop ||
pc == (app_pc)dr_app_stop_and_cleanup ||
pc == (app_pc)dr_app_stop_and_cleanup_with_stats))
#endif
#ifdef WINDOWS
/* we go all the way to NtTerminateThread/NtTerminateProcess */
#else /* UNIX */
/* we go all the way to SYS_exit or SYS_{,t,tg}kill(SIGABRT) */
#endif
)
return true;
return false;
}
static void
dispatch_enter_fcache_stats(dcontext_t *dcontext, fragment_t *targetf)
{
#ifdef DEBUG
# ifdef DGC_DIAGNOSTICS
if (TEST(FRAG_DYNGEN, targetf->flags) && !is_dyngen_vsyscall(targetf->tag)) {
char buf[MAXIMUM_SYMBOL_LENGTH];
bool stack = is_address_on_stack(dcontext, targetf->tag);
LOG(THREAD, LOG_DISPATCH, 1,
"Entry into dyngen F%d(" PFX "%s%s) via:", targetf->id, targetf->tag,
stack ? " stack" : "",
(targetf->flags & FRAG_DYNGEN_RESTRICTED) != 0 ? " BAD" : "");
if (!LINKSTUB_FAKE(dcontext->last_exit)) {
app_pc translated_pc;
/* can't recreate if fragment is deleted -- but should be fake then */
ASSERT(!TEST(FRAG_WAS_DELETED, dcontext->last_fragment->flags));
translated_pc = recreate_app_pc(
dcontext, EXIT_CTI_PC(dcontext->last_fragment, dcontext->last_exit),
dcontext->last_fragment);
if (translated_pc != NULL) {
disassemble(dcontext, translated_pc, THREAD);
print_symbolic_address(translated_pc, buf, sizeof(buf), false);
LOG(THREAD, LOG_DISPATCH, 1, " %s\n", buf);
}
if (!stack &&
(strstr(buf, "user32.dll") != NULL ||
strstr(buf, "USER32.DLL") != NULL)) {
/* try to find who set up user32 callback */
dump_mcontext_callstack(dcontext);
}
DOLOG(stack ? 1U : 2U, LOG_DISPATCH, {
LOG(THREAD, LOG_DISPATCH, 1, "Originating bb:\n");
disassemble_app_bb(dcontext, dcontext->last_fragment->tag, THREAD);
});
} else {
/* FIXME: print type from last_exit */
LOG(THREAD, LOG_DISPATCH, 1, "\n");
}
if (stack) {
/* try to understand where code is on stack */
LOG(THREAD, LOG_DISPATCH, 1, "cur esp=" PFX " ebp=" PFX "\n",
get_mcontext(dcontext)->xsp, get_mcontext(dcontext)->xbp);
dump_mcontext_callstack(dcontext);
}
}
# endif
if (d_r_stats->loglevel >= 2 && (d_r_stats->logmask & LOG_DISPATCH) != 0) {
/* XXX: should use a different mask - and get printed at level 2 when turned on */
DOLOG(4, LOG_DISPATCH,
{ dump_mcontext(get_mcontext(dcontext), THREAD, DUMP_NOT_XML); });
DOLOG(6, LOG_DISPATCH, { dump_mcontext_callstack(dcontext); });
DOKSTATS({ DOLOG(6, LOG_DISPATCH, { kstats_dump_stack(dcontext); }); });
LOG(THREAD, LOG_DISPATCH, 2, "Entry into F%d(" PFX ")." PFX " %s%s%s",
targetf->id, targetf->tag, FCACHE_ENTRY_PC(targetf),
IF_X86_ELSE(
IF_X64_ELSE(FRAG_IS_32(targetf->flags) ? "(32-bit)" : "", ""),
IF_ARM_ELSE(FRAG_IS_THUMB(targetf->flags) ? "(T32)" : "(A32)", "")),
TEST(FRAG_COARSE_GRAIN, targetf->flags) ? "(coarse)" : "",
((targetf->flags & FRAG_IS_TRACE_HEAD) != 0) ? "(trace head)" : "",
((targetf->flags & FRAG_IS_TRACE) != 0) ? "(trace)" : "");
LOG(THREAD, LOG_DISPATCH, 2, "%s",
TEST(FRAG_SHARED, targetf->flags) ? "(shared)" : "");
# ifdef DGC_DIAGNOSTICS
LOG(THREAD, LOG_DISPATCH, 2, "%s",
TEST(FRAG_DYNGEN, targetf->flags) ? "(dyngen)" : "");
# endif
LOG(THREAD, LOG_DISPATCH, 2, "\n");
DOLOG(3, LOG_SYMBOLS, {
char symbuf[MAXIMUM_SYMBOL_LENGTH];
print_symbolic_address(targetf->tag, symbuf, sizeof(symbuf), true);
LOG(THREAD, LOG_SYMBOLS, 3, "\t%s\n", symbuf);
});
}
#endif /* DEBUG */
}
/* Executes a target fragment in the fragment cache */
static bool
dispatch_enter_fcache(dcontext_t *dcontext, fragment_t *targetf)
{
fcache_enter_func_t fcache_enter;
ASSERT(targetf != NULL);
/* ensure we don't take over when we should be going native */
ASSERT(dcontext->native_exec_postsyscall == NULL);
/* We wait until here, rather than at cache exit time, to do lazy
* linking so we can link to newly created fragments.
*/
if (dcontext->last_exit == get_coarse_exit_linkstub() ||
/* We need to lazy link if either of src or tgt is coarse */
(LINKSTUB_DIRECT(dcontext->last_exit->flags) &&
TEST(FRAG_COARSE_GRAIN, targetf->flags))) {
coarse_lazy_link(dcontext, targetf);
}
if (!enter_nolinking(dcontext, targetf, true)) {
/* not actually entering cache, so back to couldbelinking */
enter_couldbelinking(dcontext, NULL, true);
LOG(THREAD, LOG_DISPATCH, 2, "Just flushed targetf, next_tag is " PFX "\n",
dcontext->next_tag);
STATS_INC(num_entrances_aborted);
/* shared entrance cannot-tell-if-deleted -> invalidate targetf
* but then may double-do the trace!
* FIXME: for now, we abort every time, ok to abort twice (first time
* b/c there was a real flush of targetf), but could be perf hit.
*/
trace_abort(dcontext);
return false;
}
dispatch_enter_fcache_stats(dcontext, targetf);
/* FIXME: for now we do this before the synch point to avoid complexity of
* missing a KSTART(fcache_* for cases like NtSetContextThread where a thread
* appears back at d_r_dispatch() from the synch point w/o ever entering the cache.
* To truly fix we need to have the NtSetContextThread handler determine
* whether its suspended target is at this synch point or in the cache.
*/
DOKSTATS({
/* stopped in dispatch_exit_fcache_stats */
if (TEST(FRAG_IS_TRACE, targetf->flags))
KSTART(fcache_trace_trace);
else
KSTART(fcache_default); /* fcache_bb_bb or fcache_bb_trace */
/* FIXME: overestimates fcache time by counting in
* fcache_enter/fcache_return for it - proper reading of this
* value should discount the minimal cost of
* fcache_enter/fcache_return for actual code cache times
*/
/* FIXME: asynch events currently continue their current kstat
* until they get back to d_r_dispatch, so in-fcache kstats are counting
* the in-DR trampoline execution time!
*/
});
/* synch point for suspend, terminate, and detach */
/* assumes mcontext is valid including errno but not pc (which we fix here)
* assumes that thread is holding no locks
* also assumes past enter_nolinking, so could_be_linking is false
* for safety with respect to flush */
/* a fast check before the heavy lifting */
if (should_wait_at_safe_spot(dcontext)) {
/* FIXME : we could put this synch point in enter_fcache but would need
* to use SYSCALL_PC for syscalls (see issues with that in win32/os.c)
*/
priv_mcontext_t *mcontext = get_mcontext(dcontext);
cache_pc save_pc = mcontext->pc;
/* FIXME : implementation choice, we could do recreate_app_pc
* (fairly expensive but this is rare) instead of using the tag
* which is a little hacky but should always be right */
mcontext->pc = targetf->tag;
/* could be targeting interception code or our dll main, would be
* incorrect for GetContextThread and racy for detach, though we
* would expect it to be very rare */
if (!is_dynamo_address(mcontext->pc)) {
check_wait_at_safe_spot(dcontext, THREAD_SYNCH_VALID_MCONTEXT);
/* If we don't come back here synch-er is responsible for ensuring
* our kstat stack doesn't get off (have to do a KSTART here) -- we
* don't want to do the KSTART of fcache_* before this to avoid
* counting synch time.
*/
} else {
LOG(THREAD, LOG_SYNCH, 1,
"wait_at_safe_spot - unable to wait, targeting dr addr " PFX,
mcontext->pc);
STATS_INC(no_wait_entries);
}
mcontext->pc = save_pc;
}
#ifdef UNIX
/* We store this for purposes like signal unlinking (i#2019) */
dcontext->asynch_target = dcontext->next_tag;
#endif
#if defined(UNIX) && defined(DEBUG)
/* i#238/PR 499179: check that libc errno hasn't changed. It's
* not worth actually saving+restoring since to we'd also need to
* preserve on clean calls, a perf hit. Better to catch all libc
* routines that need it and wrap just those.
*/
ASSERT(
get_libc_errno() == dcontext->libc_errno ||
/* w/ private loader, our errno is disjoint from app's */
INTERNAL_OPTION(private_loader) ||
/* only when pthreads is loaded does libc switch to a per-thread
* errno, so our raw thread tests end up using the same errno
* for each thread!
*/
check_filter("linux.thread;linux.clone", get_short_name(get_application_name())));
#endif
#if defined(UNIX) && !defined(DGC_DIAGNOSTICS) && defined(X86)
/* i#107: handle segment register usage conflicts between app and dr:
* if the target fragment has an instr that updates the segment selector,
* update the corresponding information maintained by DR.
*/
if (INTERNAL_OPTION(mangle_app_seg) && TEST(FRAG_HAS_MOV_SEG, targetf->flags)) {
os_handle_mov_seg(dcontext, targetf->tag);
}
#endif
ASSERT(dr_get_isa_mode(dcontext) ==
FRAG_ISA_MODE(targetf->flags)
IF_X64(||
(dr_get_isa_mode(dcontext) == DR_ISA_IA32 &&
!FRAG_IS_32(targetf->flags) && DYNAMO_OPTION(x86_to_x64))));
if (TEST(FRAG_SHARED, targetf->flags))
fcache_enter = get_fcache_enter_shared_routine(dcontext);
else
fcache_enter = get_fcache_enter_private_routine(dcontext);
enter_fcache(
dcontext,
(fcache_enter_func_t)
/* DEFAULT_ISA_MODE as we want the ISA mode of our gencode */
convert_data_to_function(PC_AS_JMP_TGT(DEFAULT_ISA_MODE, (app_pc)fcache_enter)),
#ifdef AARCH64
/* Entry to fcache requires indirect branch. */
PC_AS_JMP_TGT(FRAG_ISA_MODE(targetf->flags), FCACHE_PREFIX_ENTRY_PC(targetf))
#else
PC_AS_JMP_TGT(FRAG_ISA_MODE(targetf->flags), FCACHE_ENTRY_PC(targetf))
#endif
);
#ifdef UNIX
if (dcontext->signals_pending > 0) {
/* i#2019: the fcache_enter generated code starts with a check for pending
* signals, allowing the signal handling code to simply queue signals that
* arrive in DR code and only attempt to unlink for interruption points known
* to be safe for unlinking.
*/
KSTOP_NOT_MATCHING(fcache_default);
dcontext->whereami = DR_WHERE_DISPATCH;
enter_couldbelinking(dcontext, NULL, true);
dcontext->next_tag = dcontext->asynch_target;
LOG(THREAD, LOG_DISPATCH, 2,
"Signal arrived while in DR: aborting fcache_enter; next_tag is " PFX "\n",
dcontext->next_tag);
STATS_INC(num_entrances_aborted);
trace_abort(dcontext);
receive_pending_signal(dcontext);
return false;
}
#endif
ASSERT_NOT_REACHED();
return false;
}
/* Enters the cache at the specified entrance routine to execute the
* target pc.
* Does not return.
* Caller must do a KSTART to avoid kstats stack mismatches.
* FIXME: only allow access to fcache_enter routine through here?
* Indirect routine needs special treatment for handle_callback_return
*/
static void
enter_fcache(dcontext_t *dcontext, fcache_enter_func_t entry, cache_pc pc)
{
ASSERT(!is_couldbelinking(dcontext));
ASSERT(entry != NULL);
ASSERT(pc != NULL);
ASSERT(check_should_be_protected(DATASEC_RARELY_PROT));
/* CANNOT hold any locks across cache execution, as our thread synch
* assumes none are held
*/
ASSERT_OWN_NO_LOCKS();
ASSERT(dcontext->try_except.try_except_state == NULL);
/* prepare to enter fcache */
LOG(THREAD, LOG_DISPATCH, 4, "fcache_enter = " PFX ", target = " PFX "\n", entry, pc);
set_fcache_target(dcontext, pc);
ASSERT(pc != NULL);
#ifdef PROFILE_RDTSC
if (dynamo_options.profile_times) {
/* prepare to enter fcache */
dcontext->prev_fragment = NULL;
/* top ten cache times */
dcontext->cache_frag_count = (uint64)0;
dcontext->cache_enter_time = get_time();
}
#endif
dcontext->whereami = DR_WHERE_FCACHE;
(*entry)(dcontext);
IF_WINDOWS(ASSERT_NOT_REACHED()); /* returns for signals on unix */
}
/* Handles special tags in DR or elsewhere that do interesting things.
* All PCs checked in here must be in DR or be BACK_TO_NATIVE_AFTER_SYSCALL.
* Does not return if we've hit a stopping point; otherwise returns with an
* updated next_tag for continued dispatch.
*/
static void
handle_special_tag(dcontext_t *dcontext)
{
if (native_exec_is_back_from_native(dcontext->next_tag)) {
/* This can happen if we start interpreting a native module. */
ASSERT(DYNAMO_OPTION(native_exec));
interpret_back_from_native(dcontext); /* updates next_tag */
}
if (is_stopping_point(dcontext, dcontext->next_tag) ||
/* We don't want this to be part of is_stopping_point() b/c we don't
* want bb building for state xl8 to look at it.
*/
dcontext->go_native) {
LOG(THREAD, LOG_INTERP, 1, "\n%s: thread " TIDFMT " returning to app @" PFX "\n",
dcontext->go_native ? "Requested to go native"
: "Found DynamoRIO stopping point",
d_r_get_thread_id(), dcontext->next_tag);
#ifdef DR_APP_EXPORTS
if (dcontext->next_tag == (app_pc)dr_app_stop)
send_all_other_threads_native();
#endif
dispatch_enter_native(dcontext);
ASSERT_NOT_REACHED(); /* noreturn */
}
}
#if defined(DR_APP_EXPORTS) || defined(UNIX)
static void
dispatch_at_stopping_point(dcontext_t *dcontext)
{
/* start/stop interface */
KSTOP_NOT_MATCHING(dispatch_num_exits);
/* if we stop in middle of tracing, thread-shared state may be messed
* up (e.g., monitor grabs fragment lock for unlinking),
* so abort the trace
*/
if (is_building_trace(dcontext)) {
LOG(THREAD, LOG_INTERP, 1, "squashing trace-in-progress\n");
trace_abort(dcontext);
}
LOG(THREAD, LOG_INTERP, 1, "\nappstart_cleanup: found stopping point\n");
# ifdef DEBUG
# ifdef DR_APP_EXPORTS
if (dcontext->next_tag == (app_pc)dynamo_thread_exit)
LOG(THREAD, LOG_INTERP, 1, "\t==dynamo_thread_exit\n");
else if (dcontext->next_tag == (app_pc)dynamorio_app_exit)
LOG(THREAD, LOG_INTERP, 1, "\t==dynamorio_app_exit\n");
else if (dcontext->next_tag == (app_pc)dr_app_stop)
LOG(THREAD, LOG_INTERP, 1, "\t==dr_app_stop\n");
else if (dcontext->next_tag == (app_pc)dr_app_stop_and_cleanup)
LOG(THREAD, LOG_INTERP, 1, "\t==dr_app_stop_and_cleanup\n");
else if (dcontext->next_tag == (app_pc)dr_app_stop_and_cleanup_with_stats)
LOG(THREAD, LOG_INTERP, 1, "\t==dr_app_stop_and_cleanup_with_stats\n");
# endif
# endif
/* XXX i#95: should we add an instrument_thread_detach_event()? */
# ifdef DR_APP_EXPORTS
/* not_under will be called by dynamo_shared_exit so skip it here. */
if (dcontext->next_tag != (app_pc)dr_app_stop_and_cleanup &&
dcontext->next_tag != (app_pc)dr_app_stop_and_cleanup_with_stats)
# endif
dynamo_thread_not_under_dynamo(dcontext);
dcontext->go_native = false;
}
#endif
/* Called when we reach an interpretation stopping point either for
* start/stop control of DR or for native_exec. In both cases we give up
* control and "go native", but we do not clean up the current thread,
* assuming we will either take control back, or the app will explicitly
* request we clean up.
*/
static void
dispatch_enter_native(dcontext_t *dcontext)
{
/* The new fcache_enter's clean dstack design makes it usable for
* entering native execution as well as the fcache.
*/
fcache_enter_func_t go_native =
(fcache_enter_func_t)convert_data_to_function(PC_AS_JMP_TGT(
DEFAULT_ISA_MODE, (app_pc)get_fcache_enter_gonative_routine(dcontext)));
set_last_exit(dcontext, (linkstub_t *)get_native_exec_linkstub());
ASSERT_OWN_NO_LOCKS();
if (dcontext->next_tag == BACK_TO_NATIVE_AFTER_SYSCALL) {
/* we're simply going native again after an intercepted syscall,
* not finalizing this thread or anything
*/
IF_WINDOWS(DEBUG_DECLARE(extern dcontext_t * early_inject_load_helper_dcontext;))
ASSERT(DYNAMO_OPTION(native_exec_syscalls)); /* else wouldn't have intercepted */
/* Assert here we have a reason for going back to native (-native_exec and
* non-empty native_exec_areas, RUNNING_WITHOUT_CODE_CACHE, hotp nudge thread
* pretending to be native while loading a dll, or on win2k
* early_inject_init() pretending to be native to find the inject address). */
ASSERT((DYNAMO_OPTION(native_exec) && native_exec_areas != NULL &&
!vmvector_empty(native_exec_areas)) ||
IF_WINDOWS((DYNAMO_OPTION(early_inject) &&
early_inject_load_helper_dcontext ==
get_thread_private_dcontext()) ||)
IF_HOTP(dcontext->nudge_thread ||)
/* clients requesting native execution come here */
dr_bb_hook_exists() ||
dcontext->currently_stopped || RUNNING_WITHOUT_CODE_CACHE());
ASSERT(dcontext->native_exec_postsyscall != NULL);
LOG(THREAD, LOG_ASYNCH, 1, "Returning to native " PFX " after a syscall\n",
dcontext->native_exec_postsyscall);
dcontext->next_tag =
PC_AS_JMP_TGT(dr_get_isa_mode(dcontext), dcontext->native_exec_postsyscall);
if (!dcontext->currently_stopped)
dynamo_thread_not_under_dynamo(dcontext);
dcontext->native_exec_postsyscall = NULL;
LOG(THREAD, LOG_DISPATCH, 2,
"Entry into native_exec after intercepted syscall\n");
/* restore state as though never came out for syscall */
KSTOP_NOT_MATCHING_DC(dcontext, dispatch_num_exits);
#ifdef KSTATS
if (!dcontext->currently_stopped)
KSTART_DC(dcontext, fcache_default);
#endif
enter_nolinking(dcontext, NULL, true);
} else {
#if defined(DR_APP_EXPORTS) || defined(UNIX)
dcontext->next_tag = PC_AS_JMP_TGT(dr_get_isa_mode(dcontext), dcontext->next_tag);
dispatch_at_stopping_point(dcontext);
enter_nolinking(dcontext, NULL, false);
#else
ASSERT_NOT_REACHED();
#endif
}
set_fcache_target(dcontext, dcontext->next_tag);
dcontext->whereami = DR_WHERE_APP;
#ifdef UNIX
do {
(*go_native)(dcontext);
/* If fcache_enter returns, there's a pending signal. It must
* be an alarm signal so we drop it as the simplest solution.
*/
ASSERT(dcontext->signals_pending > 0);
dcontext->signals_pending = 0;
} while (true);
#else
(*go_native)(dcontext);
#endif
ASSERT_NOT_REACHED();
}
static void
set_next_tag_to_prior_syscall(dcontext_t *dcontext)
{
/* We need to remember both the post-syscall resumption point and
* the fact that we need to execute a syscall, but we only have
* a single PC field to place it into inside our sigreturn frame
* and other places. Our solution is to point back at the
* syscall instruction itself. The walk-backward scheme here is a
* little hacky perhaps. We'll make a bb just for this syscall, which
* will not know the syscall number: but any re-execution in a loop
* will go back to the main bb.
*/
dcontext->next_tag -= syscall_instr_length(
dcontext->last_fragment == NULL ? DEFAULT_ISA_MODE
: FRAG_ISA_MODE(dcontext->last_fragment->flags));
ASSERT(is_syscall_at_pc(dcontext, dcontext->next_tag));
}
static void
dispatch_enter_dynamorio(dcontext_t *dcontext)
{
/* We're transitioning to DynamoRIO from somewhere: either the fcache,
* the kernel (DR_WHERE_TRAMPOLINE), or the app itself via our start/stop API.
* N.B.: set whereami to DR_WHERE_APP iff this is the first d_r_dispatch() entry
* for this thread!
*/
dr_where_am_i_t wherewasi = dcontext->whereami;
#if defined(UNIX) && !defined(X64)
if (!(wherewasi == DR_WHERE_FCACHE || wherewasi == DR_WHERE_TRAMPOLINE ||
wherewasi == DR_WHERE_APP) &&
get_syscall_method() == SYSCALL_METHOD_SYSENTER) {
/* This is probably our own syscalls hitting our own sysenter
* hook (PR 212570), since we're not completely user library
* independent (PR 206369).
* The primary calls I'm worried about are dl{open,close}.
* Note that we can't go jump to vsyscall_syscall_end_pc here b/c
* fcache_return cleared the dstack, so we can't really recover.
* We could put in a custom exit stub and return routine and recover,
* but we need to get library independent anyway so it's not worth it.
*/
/* PR 356503: clients using libraries that make syscalls can end up here */
found_client_sysenter();
ASSERT_BUG_NUM(
206369, false && "DR's own syscall (via user library) hit the sysenter hook");
}
#endif
ASSERT(wherewasi == DR_WHERE_FCACHE || wherewasi == DR_WHERE_TRAMPOLINE ||
wherewasi == DR_WHERE_APP ||
/* If the thread was waiting at check_wait_at_safe_point when getting
* suspended, we were in dispatch (ref i#3427). We will be here after the
* thread's context is being reset proactively (due to some -reset_at_*
* option) or before sending it native.
*/
((dcontext->go_native || dcontext->last_exit == get_reset_linkstub()) &&
wherewasi == DR_WHERE_DISPATCH));
dcontext->whereami = DR_WHERE_DISPATCH;
ASSERT_LOCAL_HEAP_UNPROTECTED(dcontext);
ASSERT(check_should_be_protected(DATASEC_RARELY_PROT));
/* CANNOT hold any locks across cache execution, as our thread synch
* assumes none are held
*/
ASSERT_OWN_NO_LOCKS();
#if defined(UNIX) && defined(DEBUG)
/* i#238/PR 499179: check that libc errno hasn't changed */
/* w/ private loader, our errno is disjoint from app's */
if (!INTERNAL_OPTION(private_loader))
dcontext->libc_errno = get_libc_errno();
os_enter_dynamorio();
#endif
DOLOG(2, LOG_INTERP, {
if (wherewasi == DR_WHERE_APP) {
LOG(THREAD, LOG_INTERP, 2, "\ninitial d_r_dispatch: target = " PFX "\n",
dcontext->next_tag);
dump_mcontext_callstack(dcontext);
dump_mcontext(get_mcontext(dcontext), THREAD, DUMP_NOT_XML);
}
});
/* We have to perform some tasks with last_exit early, before we
* become couldbelinking -- the rest are done in dispatch_exit_fcache().
* It's ok to de-reference last_exit since even though deleter may assume
* no one has ptrs to it, cannot delete until we're officially out of the
* cache, which doesn't happen until enter_couldbelinking -- still kind of
* messy that we're violating assumption of no ptrs...
*/
if (wherewasi == DR_WHERE_APP) { /* first entrance */
if (dcontext->last_exit == get_syscall_linkstub()) {
/* i#813: the app hit our post-sysenter hook while native.
* XXX: should we try to process ni syscalls here? But we're only
* seeing post- and not pre-.
*/
LOG(THREAD, LOG_INTERP, 2, "hit post-sysenter hook while native\n");
ASSERT(dcontext->currently_stopped || IS_CLIENT_THREAD(dcontext));
dcontext->next_tag = BACK_TO_NATIVE_AFTER_SYSCALL;
dcontext->native_exec_postsyscall =
IF_UNIX_ELSE(vsyscall_sysenter_displaced_pc, vsyscall_syscall_end_pc);
} else {
ASSERT(dcontext->last_exit == get_starting_linkstub() ||
/* The start/stop API will set this linkstub. */
IF_APP_EXPORTS(dcontext->last_exit == get_native_exec_linkstub() ||)
/* new thread */
IF_WINDOWS_ELSE_0(dcontext->last_exit == get_asynch_linkstub()));
}
} else {
/* MUST be set, if only to a fake linkstub_t */
ASSERT(dcontext->last_exit != NULL);
/* cache last_exit's fragment */
dcontext->last_fragment = linkstub_fragment(dcontext, dcontext->last_exit);
/* If we exited from an indirect branch then dcontext->next_tag
* already has the next tag value; otherwise we must set it here,
* before we might dive back into the cache for a system call.
*/
if (LINKSTUB_DIRECT(dcontext->last_exit->flags)) {
if (INTERNAL_OPTION(cbr_single_stub)) {
linkstub_t *nxt = linkstub_shares_next_stub(
dcontext, dcontext->last_fragment, dcontext->last_exit);
if (nxt != NULL) {
/* must distinguish the two based on eflags */
dcontext->last_exit = linkstub_cbr_disambiguate(
dcontext, dcontext->last_fragment, dcontext->last_exit, nxt);
ASSERT(dcontext->last_fragment ==
linkstub_fragment(dcontext, dcontext->last_exit));
STATS_INC(cbr_disambiguations);
}
}
dcontext->next_tag =
EXIT_TARGET_TAG(dcontext, dcontext->last_fragment, dcontext->last_exit);
} else {
/* get src info from coarse ibl exit into the right place */
if (DYNAMO_OPTION(coarse_units)) {
if (is_ibl_sourceless_linkstub((const linkstub_t *)dcontext->last_exit))
set_coarse_ibl_exit(dcontext);
else if (DYNAMO_OPTION(use_persisted) &&
dcontext->last_exit == get_coarse_exit_linkstub()) {
/* i#670: for frozen unit, shift from persist-time mod base
* to use-time mod base
*/
coarse_info_t *info = dcontext->coarse_exit.dir_exit;
ASSERT(info != NULL);
if (info->mod_shift != 0 &&
dcontext->next_tag >= info->base_pc + info->mod_shift &&
dcontext->next_tag < info->end_pc + info->mod_shift) {
dcontext->next_tag -= info->mod_shift;
LOG(THREAD, LOG_INTERP, 3, "adjusted shifted-coarse tag to %p\n",
dcontext->next_tag);
}
}
}
}
dispatch_exit_fcache_stats(dcontext);
/* Maybe-permanent native transitions (dr_app_stop()) have to pop kstack,
* and thus so do temporary native_exec transitions. Thus, for neither
* is there anything to pop here.
*/
if (dcontext->last_exit != get_native_exec_linkstub() &&
dcontext->last_exit != get_native_exec_syscall_linkstub())
KSTOP_NOT_MATCHING(dispatch_num_exits);
}
/* KSWITCHed next time around for a better explanation */
KSTART_DC(dcontext, dispatch_num_exits);
if (wherewasi != DR_WHERE_APP) { /* if not first entrance */
if (get_at_syscall(dcontext))
handle_post_system_call(dcontext);
#ifdef X86
/* If the next basic block starts at a debug register value,
* we fire a single step exception before getting to the basic block. */
if (debug_register_fire_on_addr(dcontext->next_tag)) {
LOG(THREAD, LOG_DISPATCH, 2, "Generates single step before " PFX "\n",
dcontext->next_tag);
os_forge_exception(dcontext->next_tag, SINGLE_STEP_EXCEPTION);
ASSERT_NOT_REACHED();
}
#endif
/* A non-ignorable syscall or cb return ending a bb must be acted on
* We do it here to avoid becoming couldbelinking twice.
*
*/
if (exited_due_to_ni_syscall(dcontext) ||
instrument_invoke_another_syscall(dcontext)) {
if (IF_UNIX_ELSE(dcontext->signals_pending > 0, false)) {
/* Avoid running the pre-handler and aborting the fcache_enter w/o
* a good way to undo the pre-handler.
*/
set_next_tag_to_prior_syscall(dcontext);
} else {
handle_system_call(dcontext);
/* We'll return here if decided to skip the syscall; else, back to
* d_r_dispatch.
*/
}
}
#ifdef WINDOWS
else if (TEST(LINK_CALLBACK_RETURN, dcontext->last_exit->flags)) {
handle_callback_return(dcontext);
ASSERT_NOT_REACHED();
}
#endif
#ifdef AARCH64
if (dcontext->last_exit == get_selfmod_linkstub()) {
app_pc begin = (app_pc)dcontext->local_state->spill_space.r2;
app_pc end = (app_pc)dcontext->local_state->spill_space.r3;
dcontext->next_tag = (app_pc)dcontext->local_state->spill_space.r4;
flush_fragments_from_region(dcontext, begin, end - begin, true,
NULL /*flush_completion_callback*/,
NULL /*user_data*/);
}
#endif
if (TEST(LINK_SPECIAL_EXIT, dcontext->last_exit->flags)) {
if (dcontext->upcontext.upcontext.exit_reason == EXIT_REASON_SELFMOD) {
/* Case 8177: If we have a flushed fragment hit a self-write, we
* cannot delete it in our self-write handler (b/c of case 3559's
* incoming links union). But, our self-write handler needs to be
* nolinking and needs to check sandbox2ro_threshold. So, we do our
* self-write check first, but we don't actually delete there for
* FRAG_WAS_DELETED fragments.
*/
SELF_PROTECT_LOCAL(dcontext, WRITABLE);
/* this fragment overwrote its original memory image */
fragment_self_write(dcontext);
/* FIXME: optimize this to stay writable if we're going to
* be exiting d_r_dispatch as well -- no very quick check though
*/
SELF_PROTECT_LOCAL(dcontext, READONLY);
} else if (dcontext->upcontext.upcontext.exit_reason >=
EXIT_REASON_FLOAT_PC_FNSAVE &&
dcontext->upcontext.upcontext.exit_reason <=
EXIT_REASON_FLOAT_PC_XSAVE64) {
float_pc_update(dcontext);
STATS_INC(float_pc_from_dispatch);
/* Restore */
dcontext->upcontext.upcontext.exit_reason = EXIT_REASON_SELFMOD;
} else if (dcontext->upcontext.upcontext.exit_reason ==
EXIT_REASON_SINGLE_STEP) {
/* Delete basic block to generate only one single step exception. */
ASSERT(!TEST(FRAG_SHARED, dcontext->last_fragment->flags));
fragment_delete(dcontext, dcontext->last_fragment, FRAGDEL_ALL);
/* Restore */
dcontext->upcontext.upcontext.exit_reason = EXIT_REASON_SELFMOD;
/* Forge single step exception with right address. */
os_forge_exception(dcontext->next_tag, SINGLE_STEP_EXCEPTION);
ASSERT_NOT_REACHED();
} else if (dcontext->upcontext.upcontext.exit_reason ==
EXIT_REASON_RSEQ_ABORT) {
#ifdef LINUX
rseq_process_native_abort(dcontext);
#else
ASSERT_NOT_REACHED();
#endif
/* Unset the reason. */
dcontext->upcontext.upcontext.exit_reason = EXIT_REASON_SELFMOD;
} else {
/* When adding any new reason, be sure to clear exit_reason,
* as selfmod exits do not bother to set the reason field to
* 0 for performance reasons (they are assumed to be more common
* than any other "special exit").
*/
ASSERT_NOT_REACHED();
}
}
}
/* make sure to tell flushers that we are now going to be mucking
* with link info
*/
if (!enter_couldbelinking(dcontext, dcontext->last_fragment, true)) {