3 files changed, 112 insertions, 29 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c1634068adf..948f7d821c6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1350,7 +1350,9 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
         }
         switch (entry->type) {
         case TRACE_FN: {
-                struct ftrace_entry *field = (struct ftrace_entry *)entry;
+                struct ftrace_entry *field;
+
+                trace_assign_type(field, entry);
 
                 seq_print_ip_sym(s, field->ip, sym_flags);
                 trace_seq_puts(s, " (");
@@ -1363,8 +1365,9 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
         }
         case TRACE_CTX:
         case TRACE_WAKE: {
-                struct ctx_switch_entry *field =
-                        (struct ctx_switch_entry *)entry;
+                struct ctx_switch_entry *field;
+
+                trace_assign_type(field, entry);
 
                 T = field->next_state < sizeof(state_to_char) ?
                         state_to_char[field->next_state] : 'X';
@@ -1384,7 +1387,9 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
                 break;
         }
         case TRACE_SPECIAL: {
-                struct special_entry *field = (struct special_entry *)entry;
+                struct special_entry *field;
+
+                trace_assign_type(field, entry);
 
                 trace_seq_printf(s, "# %ld %ld %ld\n",
                                  field->arg1,
@@ -1393,7 +1398,9 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
                 break;
         }
         case TRACE_STACK: {
-                struct stack_entry *field = (struct stack_entry *)entry;
+                struct stack_entry *field;
+
+                trace_assign_type(field, entry);
 
                 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
                         if (i)
@@ -1404,7 +1411,9 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
                 break;
         }
         case TRACE_PRINT: {
-                struct print_entry *field = (struct print_entry *)entry;
+                struct print_entry *field;
+
+                trace_assign_type(field, entry);
 
                 seq_print_ip_sym(s, field->ip, sym_flags);
                 trace_seq_printf(s, ": %s", field->buf);
@@ -1454,7 +1463,9 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
 
         switch (entry->type) {
         case TRACE_FN: {
-                struct ftrace_entry *field = (struct ftrace_entry *)entry;
+                struct ftrace_entry *field;
+
+                trace_assign_type(field, entry);
 
                 ret = seq_print_ip_sym(s, field->ip, sym_flags);
                 if (!ret)
@@ -1480,8 +1491,9 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
         }
         case TRACE_CTX:
         case TRACE_WAKE: {
-                struct ctx_switch_entry *field =
-                        (struct ctx_switch_entry *)entry;
+                struct ctx_switch_entry *field;
+
+                trace_assign_type(field, entry);
 
                 S = field->prev_state < sizeof(state_to_char) ?
                         state_to_char[field->prev_state] : 'X';
@@ -1501,7 +1513,9 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
                 break;
         }
         case TRACE_SPECIAL: {
-                struct special_entry *field = (struct special_entry *)entry;
+                struct special_entry *field;
+
+                trace_assign_type(field, entry);
 
                 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
                                  field->arg1,
@@ -1512,7 +1526,9 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
                 break;
         }
         case TRACE_STACK: {
-                struct stack_entry *field = (struct stack_entry *)entry;
+                struct stack_entry *field;
+
+                trace_assign_type(field, entry);
 
                 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
                         if (i) {
@@ -1531,7 +1547,9 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
                 break;
         }
         case TRACE_PRINT: {
-                struct print_entry *field = (struct print_entry *)entry;
+                struct print_entry *field;
+
+                trace_assign_type(field, entry);
 
                 seq_print_ip_sym(s, field->ip, sym_flags);
                 trace_seq_printf(s, ": %s", field->buf);
@@ -1562,7 +1580,9 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
 
         switch (entry->type) {
         case TRACE_FN: {
-                struct ftrace_entry *field = (struct ftrace_entry *)entry;
+                struct ftrace_entry *field;
+
+                trace_assign_type(field, entry);
 
                 ret = trace_seq_printf(s, "%x %x\n",
                                         field->ip,
@@ -1573,8 +1593,9 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
         }
         case TRACE_CTX:
         case TRACE_WAKE: {
-                struct ctx_switch_entry *field =
-                        (struct ctx_switch_entry *)entry;
+                struct ctx_switch_entry *field;
+
+                trace_assign_type(field, entry);
 
                 S = field->prev_state < sizeof(state_to_char) ?
                         state_to_char[field->prev_state] : 'X';
@@ -1596,7 +1617,9 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
         }
         case TRACE_SPECIAL:
         case TRACE_STACK: {
-                struct special_entry *field = (struct special_entry *)entry;
+                struct special_entry *field;
+
+                trace_assign_type(field, entry);
 
                 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
                                  field->arg1,
@@ -1607,7 +1630,9 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
                 break;
         }
         case TRACE_PRINT: {
-                struct print_entry *field = (struct print_entry *)entry;
+                struct print_entry *field;
+
+                trace_assign_type(field, entry);
 
                 trace_seq_printf(s, "# %lx %s", field->ip, field->buf);
                 if (entry->flags & TRACE_FLAG_CONT)
@@ -1648,7 +1673,9 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
 
         switch (entry->type) {
         case TRACE_FN: {
-                struct ftrace_entry *field = (struct ftrace_entry *)entry;
+                struct ftrace_entry *field;
+
+                trace_assign_type(field, entry);
 
                 SEQ_PUT_HEX_FIELD_RET(s, field->ip);
                 SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
@@ -1656,8 +1683,9 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
         }
         case TRACE_CTX:
         case TRACE_WAKE: {
-                struct ctx_switch_entry *field =
-                        (struct ctx_switch_entry *)entry;
+                struct ctx_switch_entry *field;
+
+                trace_assign_type(field, entry);
 
                 S = field->prev_state < sizeof(state_to_char) ?
                         state_to_char[field->prev_state] : 'X';
@@ -1676,7 +1704,9 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
         }
         case TRACE_SPECIAL:
         case TRACE_STACK: {
-                struct special_entry *field = (struct special_entry *)entry;
+                struct special_entry *field;
+
+                trace_assign_type(field, entry);
 
                 SEQ_PUT_HEX_FIELD_RET(s, field->arg1);
                 SEQ_PUT_HEX_FIELD_RET(s, field->arg2);
@@ -1705,15 +1735,18 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
 
         switch (entry->type) {
         case TRACE_FN: {
-                struct ftrace_entry *field = (struct ftrace_entry *)entry;
+                struct ftrace_entry *field;
+
+                trace_assign_type(field, entry);
 
                 SEQ_PUT_FIELD_RET(s, field->ip);
                 SEQ_PUT_FIELD_RET(s, field->parent_ip);
                 break;
         }
         case TRACE_CTX: {
-                struct ctx_switch_entry *field =
-                        (struct ctx_switch_entry *)entry;
+                struct ctx_switch_entry *field;
+
+                trace_assign_type(field, entry);
 
                 SEQ_PUT_FIELD_RET(s, field->prev_pid);
                 SEQ_PUT_FIELD_RET(s, field->prev_prio);
@@ -1725,7 +1758,9 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
         }
         case TRACE_SPECIAL:
         case TRACE_STACK: {
-                struct special_entry *field = (struct special_entry *)entry;
+                struct special_entry *field;
+
+                trace_assign_type(field, entry);
 
                 SEQ_PUT_FIELD_RET(s, field->arg1);
                 SEQ_PUT_FIELD_RET(s, field->arg2);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index a921ba5d292..f02042d0d82 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -177,6 +177,48 @@ struct trace_array {
         struct trace_array_cpu  *data[NR_CPUS];
 };
 
+#define FTRACE_CMP_TYPE(var, type) \
+        __builtin_types_compatible_p(typeof(var), type *)
+
+#undef IF_ASSIGN
+#define IF_ASSIGN(var, entry, etype, id)                \
+        if (FTRACE_CMP_TYPE(var, etype)) {              \
+                var = (typeof(var))(entry);             \
+                WARN_ON(id && (entry)->type != id);     \
+                break;                                  \
+        }
+
+/* Will cause compile errors if type is not found. */
+extern void __ftrace_bad_type(void);
+
+/*
+ * The trace_assign_type is a verifier that the entry type is
+ * the same as the type being assigned. To add new types simply
+ * add a line with the following format:
+ *
+ * IF_ASSIGN(var, ent, type, id);
+ *
+ *  Where "type" is the trace type that includes the trace_entry
+ *  as the "ent" item. And "id" is the trace identifier that is
+ *  used in the trace_type enum.
+ *
+ *  If the type can have more than one id, then use zero.
+ */
+#define trace_assign_type(var, ent)                                     \
+        do {                                                            \
+                IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);     \
+                IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);        \
+                IF_ASSIGN(var, ent, struct trace_field_cont, TRACE_CONT); \
+                IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
+                IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
+                IF_ASSIGN(var, ent, struct special_entry, 0);           \
+                IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,          \
+                          TRACE_MMIO_RW);                               \
+                IF_ASSIGN(var, ent, struct trace_mmiotrace_map,         \
+                          TRACE_MMIO_MAP);                              \
+                IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT);     \
+                __ftrace_bad_type();                                    \
+        } while (0)
 
 /* Return values for print_line callback */
 enum print_line_t {
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index 1a266aa08e1..0e819f47bb7 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -178,15 +178,17 @@ print_out:
 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 {
         struct trace_entry *entry = iter->ent;
-        struct trace_mmiotrace_rw *field =
-                (struct trace_mmiotrace_rw *)entry;
-        struct mmiotrace_rw *rw = &field->rw;
+        struct trace_mmiotrace_rw *field;
+        struct mmiotrace_rw *rw;
         struct trace_seq *s     = &iter->seq;
         unsigned long long t    = ns2usecs(iter->ts);
         unsigned long usec_rem  = do_div(t, 1000000ULL);
         unsigned secs           = (unsigned long)t;
         int ret = 1;
 
+        trace_assign_type(field, entry);
+        rw = &field->rw;
+
         switch (rw->opcode) {
         case MMIO_READ:
                 ret = trace_seq_printf(s,
@@ -222,13 +224,17 @@ static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 {
         struct trace_entry *entry = iter->ent;
-        struct mmiotrace_map *m = (struct mmiotrace_map *)entry;
+        struct trace_mmiotrace_map *field;
+        struct mmiotrace_map *m;
         struct trace_seq *s     = &iter->seq;
         unsigned long long t    = ns2usecs(iter->ts);
         unsigned long usec_rem  = do_div(t, 1000000ULL);
         unsigned secs           = (unsigned long)t;
         int ret;
 
+        trace_assign_type(field, entry);
+        m = &field->map;
+
         switch (m->opcode) {
         case MMIO_PROBE:
                 ret = trace_seq_printf(s,