*/
#include <linux/module.h>
+#include "../ltt-events.h"
#ifndef SYSCALL_DETAIL
#else /* SYSCALL_DETAIL */
+#include <linux/slab.h>
+#include <asm/ptrace.h>
+#include <asm/syscall.h>
+
+static void syscall_entry_probe(void *__data, struct pt_regs *regs, long id);
+static int lttng_syscalls_register_probe(struct lttng_probe_desc *desc);
+static void lttng_syscalls_unregister_probe(struct lttng_probe_desc *desc);
+
+static struct lttng_probe_desc *syscall_probe_desc;
+
/*
* Create LTTng tracepoint probes.
*/
#define LTTNG_PACKAGE_BUILD
#define CREATE_TRACE_POINTS
-#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
+/* Hijack probe callback for system calls */
+#define TP_PROBE_CB(_template) &syscall_entry_probe
+#define TP_REGISTER_OVERRIDE lttng_syscalls_register_probe
+#define TP_UNREGISTER_OVERRIDE lttng_syscalls_unregister_probe
-#define TRACE_SYSCALL_TABLE(_name, _nr, _nrargs)
+#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
#include "../instrumentation/syscalls/headers/syscalls.h"
+#undef TP_UNREGISTER_OVERRIDE
+#undef TP_REGISTER_OVERRIDE
+#undef TP_PROBE_CB
#undef LTTNG_PACKAGE_BUILD
#undef CREATE_TRACE_POINTS
struct trace_syscall_entry {
void *func;
+ const struct lttng_event_desc *desc; /* Set dynamically */
+ const struct lttng_event_field *fields;
unsigned int nrargs;
};
+static int sc_table_desc_filled;
+
#define CREATE_SYSCALL_TABLE
#undef TRACE_SYSCALL_TABLE
-#define TRACE_SYSCALL_TABLE(_name, _nr, _nrargs) \
- [ _nr ] = { .func = __event_probe__##_name, .nrargs = (_nrargs) },
+#define TRACE_SYSCALL_TABLE(_name, _nr, _nrargs) \
+ [ _nr ] = { \
+ .func = __event_probe__##_name, \
+ .nrargs = (_nrargs), \
+ .fields = __event_fields___##_name, \
+ },
static struct trace_syscall_entry sc_table[] = {
#include "../instrumentation/syscalls/headers/syscalls.h"
};
+
#undef CREATE_SYSCALL_TABLE
+static void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
+{
+ struct trace_syscall_entry *entry;
+ struct ltt_channel *chan = __data;
+ struct ltt_event *event;
+
+ if (unlikely(id >= ARRAY_SIZE(sc_table)))
+ return;
+ entry = &sc_table[id];
+ if (unlikely(!entry->func))
+ return;
+ event = chan->sc_table[id];
+ WARN_ON_ONCE(!event);
+
+ switch (entry->nrargs) {
+ case 0:
+ {
+ void (*fptr)(void *__data) = entry->func;
+
+ fptr(event);
+ break;
+ }
+ case 1:
+ {
+ void (*fptr)(void *__data, unsigned long arg0) = entry->func;
+ unsigned long args[1];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0]);
+ break;
+ }
+ case 2:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1) = entry->func;
+ unsigned long args[2];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1]);
+ break;
+ }
+ case 3:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1,
+ unsigned long arg2) = entry->func;
+ unsigned long args[3];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1], args[2]);
+ break;
+ }
+ case 4:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1,
+ unsigned long arg2,
+ unsigned long arg3) = entry->func;
+ unsigned long args[4];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1], args[2], args[3]);
+ break;
+ }
+ case 5:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1,
+ unsigned long arg2,
+ unsigned long arg3,
+ unsigned long arg4) = entry->func;
+ unsigned long args[5];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1], args[2], args[3], args[4]);
+ break;
+ }
+ case 6:
+ {
+ void (*fptr)(void *__data,
+ unsigned long arg0,
+ unsigned long arg1,
+ unsigned long arg2,
+ unsigned long arg3,
+ unsigned long arg4,
+ unsigned long arg5) = entry->func;
+ unsigned long args[6];
+
+ syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+ fptr(event, args[0], args[1], args[2],
+ args[3], args[4], args[5]);
+ break;
+ }
+ default:
+ break;
+ }
+}
+
+static const struct lttng_event_desc *find_syscall_desc(unsigned int id)
+{
+ unsigned int i;
+
+ for (i = 0; i < syscall_probe_desc->nr_events; i++) {
+ if (syscall_probe_desc->event_desc[i].fields
+ == sc_table[id].fields)
+ return &syscall_probe_desc->event_desc[i];
+ }
+ WARN_ON_ONCE(1);
+ return NULL;
+}
+
+static void fill_sc_table_desc(void)
+{
+ unsigned int i;
+
+ if (sc_table_desc_filled)
+ return;
+ /*
+ * This is O(n^2), but rare. Eventually get the TRACE_EVENT code
+ * to emit per-event symbols to skip this.
+ */
+ for (i = 0; i < ARRAY_SIZE(sc_table); i++) {
+ const struct lttng_event_desc **desc = &sc_table[i].desc;
+
+ if (!sc_table[i].func)
+ continue;
+ (*desc) = find_syscall_desc(i);
+ }
+ sc_table_desc_filled = 1;
+}
+
+
+int lttng_syscalls_register(struct ltt_channel *chan, void *filter)
+{
+ unsigned int i;
+ int ret;
+
+ fill_sc_table_desc();
+
+ if (!chan->sc_table) {
+ /* create syscall table mapping syscall to events */
+ chan->sc_table = kzalloc(sizeof(struct ltt_event *)
+ * ARRAY_SIZE(sc_table), GFP_KERNEL);
+ if (!chan->sc_table)
+ return -ENOMEM;
+ }
+
+ /* Allocate events for each syscall, insert into table */
+ for (i = 0; i < ARRAY_SIZE(sc_table); i++) {
+ struct lttng_kernel_event ev;
+ const struct lttng_event_desc *desc = sc_table[i].desc;
+
+ /*
+ * Skip those already populated by previous failed
+ * register for this channel.
+ */
+ if (chan->sc_table[i])
+ continue;
+ memset(&ev, 0, sizeof(ev));
+ strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
+ ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+ ev.instrumentation = LTTNG_KERNEL_NOOP;
+ chan->sc_table[i] = ltt_event_create(chan, &ev, filter);
+ if (!chan->sc_table[i]) {
+ /*
+ * If something goes wrong in event registration
+ * after the first one, we have no choice but to
+ * leave the previous events in there, until
+ * deleted by session teardown.
+ */
+ return -EINVAL;
+ }
+ }
+ ret = tracepoint_probe_register("syscall_entry",
+ (void *) syscall_entry_probe, chan);
+ return ret;
+}
+
+/*
+ * Only called at session destruction.
+ */
+int lttng_syscalls_unregister(struct ltt_channel *chan)
+{
+ int ret;
+
+ if (!chan->sc_table)
+ return 0;
+ ret = tracepoint_probe_unregister("syscall_entry",
+ (void *) syscall_entry_probe, chan);
+ if (ret)
+ return ret;
+ /* ltt_event destroy will be performed by ltt_session_destroy() */
+ kfree(chan->sc_table);
+ return 0;
+}
+
+static int lttng_syscalls_register_probe(struct lttng_probe_desc *desc)
+{
+ WARN_ON_ONCE(syscall_probe_desc);
+ syscall_probe_desc = desc;
+ return 0;
+}
+
+static void lttng_syscalls_unregister_probe(struct lttng_probe_desc *desc)
+{
+ WARN_ON_ONCE(!syscall_probe_desc);
+ syscall_probe_desc = NULL;
+}
+
#endif /* SYSCALL_DETAIL */
MODULE_LICENSE("GPL and additional rights");
projects / lttng-modules.git / blobdiff