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Invoke the DTrace trap handler before calling trap() on amd64. This matches

Browse Source 
the upstream implementation and helps ensure that a trap induced by tracing
fbt::trap:entry is handled without recursively generating another trap.

This makes it possible to run most (but not all) of the DTrace tests under
common/safety/ without triggering a kernel panic.

Submitted by:	Anton Rang <anton.rang@isilon.com> (original version)
Phabric:	D95
This commit is contained in:
Mark Johnston 2014-07-14 04:38:17 +00:00
parent 1dd381bf67
commit 291624fdf6
10 changed files with 44 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
sys/amd64/amd64/exception.S
View File

@ -228,7 +228,24 @@ alltraps_pushregs_no_rdi:
.type calltrap,@function
calltrap:
movq %rsp,%rdi
#ifdef KDTRACE_HOOKS
/*
* Give DTrace a chance to vet this trap and skip the call to trap() if
* it turns out that it was caused by a DTrace probe.
*/
movq dtrace_trap_func,%rax
testq %rax,%rax
je skiphook
call *%rax
testq %rax,%rax
jne skiptrap
movq %rsp,%rdi
skiphook:
#endif
call trap
#ifdef KDTRACE_HOOKS
skiptrap:
#endif
MEXITCOUNT
jmp doreti /* Handle any pending ASTs */

12
sys/amd64/amd64/trap.c
View File

@ -218,18 +218,6 @@ trap(struct trapframe *frame)
goto out;
}
#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 its 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.
*/
if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
goto out;
#endif
if ((frame->tf_rflags & PSL_I) == 0) {
/*
* Buggy application or kernel code has disabled

14
sys/cddl/dev/dtrace/amd64/dtrace_subr.c
View File

@ -462,29 +462,27 @@ dtrace_gethrestime(void)
return (current_time.tv_sec * 1000000000ULL + current_time.tv_nsec);
}
/* Function to handle DTrace traps during probes. See amd64/amd64/trap.c */
/*
* Function to handle DTrace traps during probes. See amd64/amd64/exception.S.
*/
int
dtrace_trap(struct trapframe *frame, u_int type)
dtrace_trap(struct trapframe *frame)
{
/*
* 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
* a flag in its 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;
switch (frame->tf_trapno) {
/* General protection fault. */
case T_PROTFLT:
/* Flag an illegal operation. */

7
sys/cddl/dev/dtrace/i386/dtrace_subr.c
View File

@ -473,24 +473,23 @@ dtrace_gethrestime(void)
/* Function to handle DTrace traps during probes. See i386/i386/trap.c */
int
dtrace_trap(struct trapframe *frame, u_int type)
dtrace_trap(struct trapframe *frame)
{
/*
* 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
* a flag in its 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) {
switch (frame->tf_trapno) {
/* General protection fault. */
case T_PROTFLT:
/* Flag an illegal operation. */

9
sys/cddl/dev/dtrace/mips/dtrace_subr.c
View File

@ -137,17 +137,20 @@ dtrace_gethrestime(void)
/* Function to handle DTrace traps during probes. See amd64/amd64/trap.c */
int
dtrace_trap(struct trapframe *frame, u_int type)
dtrace_trap(struct trapframe *frame)
{
u_int type;
type = (trapframe->cause & MIPS_CR_EXC_CODE) >> MIPS_CR_EXC_CODE_SHIFT;
/*
* 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
* a flag in its 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) {
/*

7
sys/cddl/dev/dtrace/powerpc/dtrace_subr.c
View File

@ -262,24 +262,23 @@ dtrace_gethrestime(void)
/* Function to handle DTrace traps during probes. See powerpc/powerpc/trap.c */
int
dtrace_trap(struct trapframe *frame, u_int type)
dtrace_trap(struct trapframe *frame)
{
/*
* 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
* a flag in its 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) {
switch (frame->exc) {
/* Page fault. */
case EXC_DSI:
case EXC_DSE:

2
sys/i386/i386/trap.c
View File

@ -246,7 +246,7 @@ trap(struct trapframe *frame)
* flag is cleared and finally re-scheduling is enabled.
*/
if ((type == T_PROTFLT || type == T_PAGEFLT) &&
dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
dtrace_trap_func != NULL && (*dtrace_trap_func)(frame))
goto out;
#endif

4
sys/mips/mips/trap.c
View File

@ -605,7 +605,7 @@ trap(struct trapframe *trapframe)
/*
* 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
* a flag in its 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.
*
@ -618,7 +618,7 @@ trap(struct trapframe *trapframe)
* XXXDTRACE: add pid probe handler here (if ever)
*/
if (!usermode) {
if (dtrace_trap_func != NULL && (*dtrace_trap_func)(trapframe, type))
if (dtrace_trap_func != NULL && (*dtrace_trap_func)(trapframe))
return (trapframe->pc);
}
#endif

4
sys/powerpc/aim/trap.c
View File

@ -167,7 +167,7 @@ trap(struct trapframe *frame)
/*
* 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
* a flag in its 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.
*
@ -176,7 +176,7 @@ trap(struct trapframe *frame)
* handled the trap and modified the trap frame so that this
* function can return normally.
*/
if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame))
return;
#endif

9
sys/sys/dtrace_bsd.h
View File

@ -48,15 +48,14 @@ extern cyclic_clock_func_t cyclic_clock_func;
void clocksource_cyc_set(const struct bintime *t);
int dtrace_trap(struct trapframe *);
/*
* The dtrace module handles traps that occur during a DTrace probe.
* This type definition is used in the trap handler to provide a
* hook for the dtrace module to register it's handler with.
* hook for the dtrace module to register its handler with.
*/
typedef int (*dtrace_trap_func_t)(struct trapframe *, u_int);
int dtrace_trap(struct trapframe *, u_int);
typedef int (*dtrace_trap_func_t)(struct trapframe *);
extern dtrace_trap_func_t dtrace_trap_func;
/*