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Differential D39166 Diff 119080 sys/cddl/dev/kinst/amd64/kinst_isa.c

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sys/cddl/dev/kinst/amd64/kinst_isa.c

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int int
kinst_make_probe(linker_file_t lf, int symindx, linker_symval_t *symval, kinst_make_probe(linker_file_t lf, int symindx, linker_symval_t *symval,
void *opaque) void *opaque)
{ {
struct kinst_probe *kp; struct kinst_probe *kp;
dtrace_kinst_probedesc_t *pd; dtrace_kinst_probedesc_t *pd;
const char *func; const char *func;
int error, instrsize, n, off; uint8_t *instr, *limit, *p;
uint8_t *instr, *limit; int error, instrsize, n, off, found;
pd = opaque; pd = opaque;
func = symval->name; func = symval->name;
if (strcmp(func, pd->kpd_func) != 0 || strcmp(func, "trap_check") == 0) if (strcmp(func, pd->kpd_func) != 0 || strcmp(func, "trap_check") == 0)
return (0); return (0);
instr = (uint8_t *)symval->value; instr = (uint8_t *)symval->value;
limit = (uint8_t *)symval->value + symval->size; limit = (uint8_t *)symval->value + symval->size;
if (instr >= limit) if (instr >= limit)
return (0); return (0);
/* /*
* Ignore functions not beginning with the usual function prologue. * Instead of ignoring functions that do not `push %rbp` in their first
* These might correspond to exception handlers with which we should not * instruction right away, we check if there's a `push %rbp` anywhere
* meddle. This does however exclude functions which can be safely * in the function. Functions that do not push the frame pointer might
* traced, such as cpu_switch(). * correspond to exception handlers with which we should not meddle.
*
* FIXME: This does however exclude functions which can be safely
* traced, such as cpu_switch() and leaf functions compiled without
* `-mno-omit-leaf-frame-pointer`.
*/ */
if (*instr != KINST_PUSHL_RBP) p = instr;
found = 0;
while (p < limit) {
if (*p == KINST_PUSHL_RBP) {
found = 1;
break;
}
p += dtrace_instr_size(p);
}
if (!found)
markjUnsubmitted
Done
Inline Actions

Let's put this in its own function, something like bool kinst_can_trace_func(uint8_t *instr, uint8_t *limit);. kinst_make_probe() has too many local vars otherwise, and we might want to add/change the checks over time, so a separate function is a bit neater.

markj: Let's put this in its own function, something like `bool kinst_can_trace_func(uint8_t *instr…
return (0); return (0);
n = 0; n = 0;
while (instr < limit) { while (instr < limit) {
instrsize = dtrace_instr_size(instr); instrsize = dtrace_instr_size(instr);
off = (int)(instr - (uint8_t *)symval->value); off = (int)(instr - (uint8_t *)symval->value);
if (pd->kpd_off != -1 && off != pd->kpd_off) { if (pd->kpd_off != -1 && off != pd->kpd_off) {
instr += instrsize; instr += instrsize;
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