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Fix some bugs when fetching probe arguments in i386. Firstly ensure that

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the 4 byte-aligned dtrace_invop_callsite can be found and that it
immediately follows the call to dtrace_invop(). Secondly, fix some pointer
arithmetic to account for differences between struct i386_frame and illumos'
struct frame. Finally, ensure that dtrace_getarg() isn't inlined. It works
by following a fixed number of frame pointers to the probe site, so inlining
breaks it.

MFC after:	3 weeks
This commit is contained in:
Mark Johnston 2014-06-23 02:00:14 +00:00
parent 450570a55e
commit efa1aff675
3 changed files with 9 additions and 10 deletions
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4
sys/cddl/contrib/opensolaris/uts/common/sys/dtrace_impl.h
View File

@ -1268,7 +1268,11 @@ typedef struct dtrace_toxrange {
uintptr_t dtt_limit; /* limit of toxic range */
} dtrace_toxrange_t;
#if defined(sun)
extern uint64_t dtrace_getarg(int, int);
#else
extern uint64_t __noinline dtrace_getarg(int, int);
#endif
extern greg_t dtrace_getfp(void);
extern int dtrace_getipl(void);
extern uintptr_t dtrace_caller(int);

8
sys/cddl/dev/dtrace/i386/dtrace_asm.S
View File

@ -49,14 +49,8 @@
* dtrace_invop wants us to do.
*/
call dtrace_invop
/*
* We pushed 3 times for the arguments to dtrace_invop,
* so we need to increment the stack pointer to get rid of
* those values.
*/
addl $12, %esp
ALTENTRY(dtrace_invop_callsite)
addl $12, %esp
cmpl $DTRACE_INVOP_PUSHL_EBP, %eax
je invop_push
cmpl $DTRACE_INVOP_POPL_EBP, %eax

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

@ -413,7 +413,8 @@ dtrace_getarg(int arg, int aframes)
for (i = 1; i <= aframes; i++) {
fp = fp->f_frame;
if (fp->f_retaddr == (long)dtrace_invop_callsite) {
if (P2ROUNDUP(fp->f_retaddr, 4) ==
(long)dtrace_invop_callsite) {
/*
* If we pass through the invalid op handler, we will
* use the pointer that it passed to the stack as the
@ -422,7 +423,7 @@ dtrace_getarg(int arg, int aframes)
* beyond the EIP/RIP that was pushed when the trap was
* taken -- hence the "+ 1" below.
*/
stack = ((uintptr_t **)&fp[1])[1] + 1;
stack = ((uintptr_t **)&fp[1])[0] + 1;
goto load;
}
@ -438,7 +439,7 @@ dtrace_getarg(int arg, int aframes)
*/
arg++;
stack = (uintptr_t *)&fp[1];
stack = (uintptr_t *)fp + 2;
load:
DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);