svn commit: r338359 - in head/sys/cddl/dev/fbt: . aarch64 arm mips powerpc riscv x86
Mark Johnston
markj at FreeBSD.org
Tue Aug 28 20:21:38 UTC 2018
Author: markj
Date: Tue Aug 28 20:21:36 2018
New Revision: 338359
URL: https://svnweb.freebsd.org/changeset/base/338359
Log:
Allow multiple FBT probes to share a tracepoint.
With GNU ifuncs, multiple FBT probes may correspond to the same
instruction. fbt_invop() assumed that this could not happen and
would return after the first probe found in the global FBT hash
table, which might not be the one that's enabled. Fix the problem
on x86 by linking probes that share a tracepoint and having each
linked probe fire when the tracepoint is hit.
PR: 230846
Approved by: re (gjb)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D16921
Modified:
head/sys/cddl/dev/fbt/aarch64/fbt_isa.c
head/sys/cddl/dev/fbt/arm/fbt_isa.c
head/sys/cddl/dev/fbt/fbt.c
head/sys/cddl/dev/fbt/fbt.h
head/sys/cddl/dev/fbt/mips/fbt_isa.c
head/sys/cddl/dev/fbt/powerpc/fbt_isa.c
head/sys/cddl/dev/fbt/riscv/fbt_isa.c
head/sys/cddl/dev/fbt/x86/fbt_isa.c
Modified: head/sys/cddl/dev/fbt/aarch64/fbt_isa.c
==============================================================================
--- head/sys/cddl/dev/fbt/aarch64/fbt_isa.c Tue Aug 28 18:50:34 2018 (r338358)
+++ head/sys/cddl/dev/fbt/aarch64/fbt_isa.c Tue Aug 28 20:21:36 2018 (r338359)
@@ -152,7 +152,7 @@ again:
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
name, FBT_RETURN, 3, fbt);
} else {
- retfbt->fbtp_next = fbt;
+ retfbt->fbtp_probenext = fbt;
fbt->fbtp_id = retfbt->fbtp_id;
}
retfbt = fbt;
Modified: head/sys/cddl/dev/fbt/arm/fbt_isa.c
==============================================================================
--- head/sys/cddl/dev/fbt/arm/fbt_isa.c Tue Aug 28 18:50:34 2018 (r338358)
+++ head/sys/cddl/dev/fbt/arm/fbt_isa.c Tue Aug 28 20:21:36 2018 (r338359)
@@ -165,7 +165,7 @@ again:
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
name, FBT_RETURN, 2, fbt);
} else {
- retfbt->fbtp_next = fbt;
+ retfbt->fbtp_probenext = fbt;
fbt->fbtp_id = retfbt->fbtp_id;
}
retfbt = fbt;
Modified: head/sys/cddl/dev/fbt/fbt.c
==============================================================================
--- head/sys/cddl/dev/fbt/fbt.c Tue Aug 28 18:50:34 2018 (r338358)
+++ head/sys/cddl/dev/fbt/fbt.c Tue Aug 28 20:21:36 2018 (r338359)
@@ -156,7 +156,7 @@ fbt_doubletrap(void)
for (i = 0; i < fbt_probetab_size; i++) {
fbt = fbt_probetab[i];
- for (; fbt != NULL; fbt = fbt->fbtp_next)
+ for (; fbt != NULL; fbt = fbt->fbtp_probenext)
fbt_patch_tracepoint(fbt, fbt->fbtp_savedval);
}
}
@@ -205,39 +205,52 @@ fbt_provide_module(void *arg, modctl_t *lf)
}
static void
+fbt_destroy_one(fbt_probe_t *fbt)
+{
+ fbt_probe_t *hash, *hashprev, *next;
+ int ndx;
+
+ ndx = FBT_ADDR2NDX(fbt->fbtp_patchpoint);
+ for (hash = fbt_probetab[ndx], hashprev = NULL; hash != NULL;
+ hash = hash->fbtp_hashnext, hashprev = hash) {
+ if (hash == fbt) {
+ if ((next = fbt->fbtp_tracenext) != NULL)
+ next->fbtp_hashnext = hash->fbtp_hashnext;
+ else
+ next = hash->fbtp_hashnext;
+ if (hashprev != NULL)
+ hashprev->fbtp_hashnext = next;
+ else
+ fbt_probetab[ndx] = next;
+ goto free;
+ } else if (hash->fbtp_patchpoint == fbt->fbtp_patchpoint) {
+ for (next = hash; next->fbtp_tracenext != NULL;
+ next = next->fbtp_tracenext) {
+ if (fbt == next->fbtp_tracenext) {
+ next->fbtp_tracenext =
+ fbt->fbtp_tracenext;
+ goto free;
+ }
+ }
+ }
+ }
+ panic("probe %p not found in hash table", fbt);
+free:
+ free(fbt, M_FBT);
+}
+
+static void
fbt_destroy(void *arg, dtrace_id_t id, void *parg)
{
- fbt_probe_t *fbt = parg, *next, *hash, *last;
+ fbt_probe_t *fbt = parg, *next;
modctl_t *ctl;
- int ndx;
do {
ctl = fbt->fbtp_ctl;
-
ctl->fbt_nentries--;
- /*
- * Now we need to remove this probe from the fbt_probetab.
- */
- ndx = FBT_ADDR2NDX(fbt->fbtp_patchpoint);
- last = NULL;
- hash = fbt_probetab[ndx];
-
- while (hash != fbt) {
- ASSERT(hash != NULL);
- last = hash;
- hash = hash->fbtp_hashnext;
- }
-
- if (last != NULL) {
- last->fbtp_hashnext = fbt->fbtp_hashnext;
- } else {
- fbt_probetab[ndx] = fbt->fbtp_hashnext;
- }
-
- next = fbt->fbtp_next;
- free(fbt, M_FBT);
-
+ next = fbt->fbtp_probenext;
+ fbt_destroy_one(fbt);
fbt = next;
} while (fbt != NULL);
}
@@ -265,14 +278,16 @@ fbt_enable(void *arg, dtrace_id_t id, void *parg)
return;
}
- for (; fbt != NULL; fbt = fbt->fbtp_next)
+ for (; fbt != NULL; fbt = fbt->fbtp_probenext) {
fbt_patch_tracepoint(fbt, fbt->fbtp_patchval);
+ fbt->fbtp_enabled++;
+ }
}
static void
fbt_disable(void *arg, dtrace_id_t id, void *parg)
{
- fbt_probe_t *fbt = parg;
+ fbt_probe_t *fbt = parg, *hash;
modctl_t *ctl = fbt->fbtp_ctl;
ASSERT(ctl->nenabled > 0);
@@ -281,8 +296,21 @@ fbt_disable(void *arg, dtrace_id_t id, void *parg)
if ((ctl->loadcnt != fbt->fbtp_loadcnt))
return;
- for (; fbt != NULL; fbt = fbt->fbtp_next)
- fbt_patch_tracepoint(fbt, fbt->fbtp_savedval);
+ for (; fbt != NULL; fbt = fbt->fbtp_probenext) {
+ fbt->fbtp_enabled--;
+
+ for (hash = fbt_probetab[FBT_ADDR2NDX(fbt->fbtp_patchpoint)];
+ hash != NULL; hash = hash->fbtp_hashnext) {
+ if (hash->fbtp_patchpoint == fbt->fbtp_patchpoint) {
+ for (; hash != NULL; hash = hash->fbtp_tracenext)
+ if (hash->fbtp_enabled > 0)
+ break;
+ break;
+ }
+ }
+ if (hash == NULL)
+ fbt_patch_tracepoint(fbt, fbt->fbtp_savedval);
+ }
}
static void
@@ -296,7 +324,7 @@ fbt_suspend(void *arg, dtrace_id_t id, void *parg)
if ((ctl->loadcnt != fbt->fbtp_loadcnt))
return;
- for (; fbt != NULL; fbt = fbt->fbtp_next)
+ for (; fbt != NULL; fbt = fbt->fbtp_probenext)
fbt_patch_tracepoint(fbt, fbt->fbtp_savedval);
}
@@ -311,7 +339,7 @@ fbt_resume(void *arg, dtrace_id_t id, void *parg)
if ((ctl->loadcnt != fbt->fbtp_loadcnt))
return;
- for (; fbt != NULL; fbt = fbt->fbtp_next)
+ for (; fbt != NULL; fbt = fbt->fbtp_probenext)
fbt_patch_tracepoint(fbt, fbt->fbtp_patchval);
}
Modified: head/sys/cddl/dev/fbt/fbt.h
==============================================================================
--- head/sys/cddl/dev/fbt/fbt.h Tue Aug 28 18:50:34 2018 (r338358)
+++ head/sys/cddl/dev/fbt/fbt.h Tue Aug 28 20:21:36 2018 (r338359)
@@ -34,9 +34,18 @@
#include "fbt_isa.h"
+/*
+ * fbt_probe is a bit of a misnomer. One of these structures is created for
+ * each trace point of an FBT probe. A probe might have multiple trace points
+ * (e.g., a function with multiple return instructions), and different probes
+ * might have a trace point at the same address (e.g., GNU ifuncs).
+ */
typedef struct fbt_probe {
- struct fbt_probe *fbtp_hashnext;
- fbt_patchval_t *fbtp_patchpoint;
+ struct fbt_probe *fbtp_hashnext; /* global hash table linkage */
+ struct fbt_probe *fbtp_tracenext; /* next probe for tracepoint */
+ struct fbt_probe *fbtp_probenext; /* next tracepoint for probe */
+ int fbtp_enabled;
+ fbt_patchval_t *fbtp_patchpoint;
int8_t fbtp_rval;
fbt_patchval_t fbtp_patchval;
fbt_patchval_t fbtp_savedval;
@@ -46,7 +55,6 @@ typedef struct fbt_probe {
modctl_t *fbtp_ctl;
int fbtp_loadcnt;
int fbtp_symindx;
- struct fbt_probe *fbtp_next;
} fbt_probe_t;
struct linker_file;
Modified: head/sys/cddl/dev/fbt/mips/fbt_isa.c
==============================================================================
--- head/sys/cddl/dev/fbt/mips/fbt_isa.c Tue Aug 28 18:50:34 2018 (r338358)
+++ head/sys/cddl/dev/fbt/mips/fbt_isa.c Tue Aug 28 20:21:36 2018 (r338359)
@@ -142,7 +142,7 @@ again:
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
name, FBT_RETURN, 3, fbt);
} else {
- retfbt->fbtp_next = fbt;
+ retfbt->fbtp_probenext = fbt;
fbt->fbtp_id = retfbt->fbtp_id;
}
retfbt = fbt;
Modified: head/sys/cddl/dev/fbt/powerpc/fbt_isa.c
==============================================================================
--- head/sys/cddl/dev/fbt/powerpc/fbt_isa.c Tue Aug 28 18:50:34 2018 (r338358)
+++ head/sys/cddl/dev/fbt/powerpc/fbt_isa.c Tue Aug 28 20:21:36 2018 (r338359)
@@ -208,7 +208,7 @@ again:
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
name, FBT_RETURN, FBT_AFRAMES, fbt);
} else {
- retfbt->fbtp_next = fbt;
+ retfbt->fbtp_probenext = fbt;
fbt->fbtp_id = retfbt->fbtp_id;
}
Modified: head/sys/cddl/dev/fbt/riscv/fbt_isa.c
==============================================================================
--- head/sys/cddl/dev/fbt/riscv/fbt_isa.c Tue Aug 28 18:50:34 2018 (r338358)
+++ head/sys/cddl/dev/fbt/riscv/fbt_isa.c Tue Aug 28 20:21:36 2018 (r338359)
@@ -141,7 +141,7 @@ again:
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
name, FBT_RETURN, 3, fbt);
} else {
- retfbt->fbtp_next = fbt;
+ retfbt->fbtp_probenext = fbt;
fbt->fbtp_id = retfbt->fbtp_id;
}
retfbt = fbt;
Modified: head/sys/cddl/dev/fbt/x86/fbt_isa.c
==============================================================================
--- head/sys/cddl/dev/fbt/x86/fbt_isa.c Tue Aug 28 18:50:34 2018 (r338358)
+++ head/sys/cddl/dev/fbt/x86/fbt_isa.c Tue Aug 28 20:21:36 2018 (r338359)
@@ -67,6 +67,7 @@ fbt_invop(uintptr_t addr, struct trapframe *frame, uin
uintptr_t *stack;
uintptr_t arg0, arg1, arg2, arg3, arg4;
fbt_probe_t *fbt;
+ int8_t fbtrval;
#ifdef __amd64__
stack = (uintptr_t *)frame->tf_rsp;
@@ -78,7 +79,11 @@ fbt_invop(uintptr_t addr, struct trapframe *frame, uin
cpu = &solaris_cpu[curcpu];
fbt = fbt_probetab[FBT_ADDR2NDX(addr)];
for (; fbt != NULL; fbt = fbt->fbtp_hashnext) {
- if ((uintptr_t)fbt->fbtp_patchpoint == addr) {
+ if ((uintptr_t)fbt->fbtp_patchpoint != addr)
+ continue;
+ fbtrval = fbt->fbtp_rval;
+ for (; fbt != NULL; fbt = fbt->fbtp_tracenext) {
+ ASSERT(fbt->fbtp_rval == fbtrval);
if (fbt->fbtp_roffset == 0) {
#ifdef __amd64__
/* fbt->fbtp_rval == DTRACE_INVOP_PUSHQ_RBP */
@@ -135,9 +140,8 @@ fbt_invop(uintptr_t addr, struct trapframe *frame, uin
rval, 0, 0, 0);
cpu->cpu_dtrace_caller = 0;
}
-
- return (fbt->fbtp_rval);
}
+ return (fbtrval);
}
return (0);
@@ -162,7 +166,7 @@ fbt_provide_module_function(linker_file_t lf, int symi
{
char *modname = opaque;
const char *name = symval->name;
- fbt_probe_t *fbt, *retfbt;
+ fbt_probe_t *fbt, *hash, *retfbt;
int j;
int size;
uint8_t *instr, *limit;
@@ -224,8 +228,18 @@ fbt_provide_module_function(linker_file_t lf, int symi
fbt->fbtp_patchval = FBT_PATCHVAL;
fbt->fbtp_symindx = symindx;
- fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
- fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;
+ for (hash = fbt_probetab[FBT_ADDR2NDX(instr)]; hash != NULL;
+ hash = hash->fbtp_hashnext) {
+ if (hash->fbtp_patchpoint == fbt->fbtp_patchpoint) {
+ fbt->fbtp_tracenext = hash->fbtp_tracenext;
+ hash->fbtp_tracenext = fbt;
+ break;
+ }
+ }
+ if (hash == NULL) {
+ fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
+ fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;
+ }
lf->fbt_nentries++;
@@ -301,7 +315,7 @@ again:
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
name, FBT_RETURN, 3, fbt);
} else {
- retfbt->fbtp_next = fbt;
+ retfbt->fbtp_probenext = fbt;
fbt->fbtp_id = retfbt->fbtp_id;
}
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