Author: jhibbits
Date: Fri Oct 24 03:33:01 2014
New Revision: 273570
URL: https://svnweb.freebsd.org/changeset/base/273570
Log:
Three updates to PowerPC FBT:
* Use a constant to define the number of stack frames in a probe exception.
* Only allow function symbols in powerpc64 ('.' prefixed)
* Set the fbtp_roffset for return probes, so the correct dtrace_probe call is
made.
MFC after: 1 week
Modified:
head/sys/cddl/dev/fbt/powerpc/fbt_isa.c
Modified: head/sys/cddl/dev/fbt/powerpc/fbt_isa.c
==============================================================================
--- head/sys/cddl/dev/fbt/powerpc/fbt_isa.c Thu Oct 23 23:20:04 2014
(r273569)
+++ head/sys/cddl/dev/fbt/powerpc/fbt_isa.c Fri Oct 24 03:33:01 2014
(r273570)
@@ -48,6 +48,7 @@
#define FBT_ENTRY "entry"
#define FBT_RETURN "return"
+#define FBT_AFRAMES 7
int
fbt_invop(uintptr_t addr, uintptr_t *stack, uintptr_t rval)
@@ -116,9 +117,17 @@ fbt_provide_module_function(linker_file_
int j;
uint32_t *instr, *limit;
- /* PowerPC64 uses '.' prefixes on symbol names, ignore it. */
+#ifdef __powerpc64__
+ /*
+ * PowerPC64 uses '.' prefixes on symbol names, ignore it, but only
+ * allow symbols with the '.' prefix, so that we don't get the function
+ * descriptor instead.
+ */
if (name[0] == '.')
name++;
+ else
+ return (0);
+#endif
if (strncmp(name, "dtrace_", 7) == 0 &&
strncmp(name, "dtrace_safe_", 12) != 0) {
@@ -147,7 +156,7 @@ fbt_provide_module_function(linker_file_
fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
fbt->fbtp_name = name;
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
- name, FBT_ENTRY, 7, fbt);
+ name, FBT_ENTRY, FBT_AFRAMES, fbt);
fbt->fbtp_patchpoint = instr;
fbt->fbtp_ctl = lf;
fbt->fbtp_loadcnt = lf->loadcnt;
@@ -210,7 +219,7 @@ again:
if (retfbt == NULL) {
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
- name, FBT_RETURN, 7, fbt);
+ name, FBT_RETURN, FBT_AFRAMES, fbt);
} else {
retfbt->fbtp_next = fbt;
fbt->fbtp_id = retfbt->fbtp_id;
@@ -229,6 +238,9 @@ again:
else
fbt->fbtp_rval = DTRACE_INVOP_JUMP;
+ fbt->fbtp_roffset =
+ (uintptr_t)((uint8_t *)instr - (uint8_t *)symval->value);
+
fbt->fbtp_savedval = *instr;
fbt->fbtp_patchval = FBT_PATCHVAL;
fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
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