Create override for sys_mmap

[lttng-modules.git] / lttng-syscalls.c

diff --git a/lttng-syscalls.c b/lttng-syscalls.c
index 378d9f1ef64a68344fe0f2b0586b4bcbebdbbb47..b712502b362d6f68942d57cfff5ce9928e344df1 100644 (file)
--- a/lttng-syscalls.c
+++ b/lttng-syscalls.c
@@ -10,11 +10,19 @@
 
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/compat.h>
 #include <asm/ptrace.h>
 #include <asm/syscall.h>
 
 #include "ltt-events.h"
 
+#ifndef CONFIG_COMPAT
+static inline int is_compat_task(void)
+{
+       return 0;
+}
+#endif
+
 static void syscall_entry_probe(void *__data, struct pt_regs *regs, long id);
 
 /*
@@ -69,30 +77,37 @@ static struct trace_syscall_entry sc_table[] = {
 
 #undef CREATE_SYSCALL_TABLE
 
-static void syscall_entry_unknown(struct ltt_channel *chan,
+static void syscall_entry_unknown(struct ltt_event *event,
        struct pt_regs *regs, unsigned int id)
 {
        unsigned long args[UNKNOWN_SYSCALL_NRARGS];
-       struct ltt_event *event;
 
-       event = chan->sc_unknown;
        syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args);
        __event_probe__sys_unknown(event, id, args);
 }
 
+/*
+ * Currently, given that the kernel syscall metadata extraction only
+ * considers native system calls (not 32-bit compability ones), we
+ * fall-back on the "unknown" system call tracing for 32-bit compat.
+ */
 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(is_compat_task())) {
+               syscall_entry_unknown(chan->sc_compat_unknown, regs, id);
+               return;
+       }
        if (unlikely(id >= ARRAY_SIZE(sc_table))) {
-               syscall_entry_unknown(chan, regs, id);
+               syscall_entry_unknown(chan->sc_unknown, regs, id);
                return;
        }
        event = chan->sc_table[id];
        if (unlikely(!event)) {
-               syscall_entry_unknown(chan, regs, id);
+               syscall_entry_unknown(chan->sc_unknown, regs, id);
                return;
        }
        entry = &sc_table[id];
@@ -217,6 +232,22 @@ int lttng_syscalls_register(struct ltt_channel *chan, void *filter)
                }
        }
 
+       if (!chan->sc_compat_unknown) {
+               struct lttng_kernel_event ev;
+               const struct lttng_event_desc *desc =
+                       &__event_desc___compat_sys_unknown;
+
+               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_compat_unknown = ltt_event_create(chan, &ev, filter,
+                                                          desc);
+               if (!chan->sc_compat_unknown) {
+                       return -EINVAL;
+               }
+       }
+
        if (!chan->sc_exit) {
                struct lttng_kernel_event ev;
                const struct lttng_event_desc *desc =