tracing/syscalls: Allow archs to ignore tracing compat syscalls

[karo-tx-linux.git] / kernel / trace / trace_syscalls.c

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 5329e13e74a13816969771b421852916f8bc3a50..7a809e3210583a77f5eb8e8a64ce1cb6552e7f6f 100644 (file)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -1,5 +1,6 @@
 #include <trace/syscall.h>
 #include <trace/events/syscalls.h>
+#include <linux/syscalls.h>
 #include <linux/slab.h>
 #include <linux/kernel.h>
 #include <linux/module.h>      /* for MODULE_NAME_LEN via KSYM_SYMBOL_LEN */
@@ -47,6 +48,38 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name
 }
 #endif
 
+#ifdef ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
+/*
+ * Some architectures that allow for 32bit applications
+ * to run on a 64bit kernel, do not map the syscalls for
+ * the 32bit tasks the same as they do for 64bit tasks.
+ *
+ *     *cough*x86*cough*
+ *
+ * In such a case, instead of reporting the wrong syscalls,
+ * simply ignore them.
+ *
+ * For an arch to ignore the compat syscalls it needs to
+ * define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS as well as
+ * define the function arch_trace_is_compat_syscall() to let
+ * the tracing system know that it should ignore it.
+ */
+static int
+trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
+{
+       if (unlikely(arch_trace_is_compat_syscall(regs)))
+               return -1;
+
+       return syscall_get_nr(task, regs);
+}
+#else
+static inline int
+trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
+{
+       return syscall_get_nr(task, regs);
+}
+#endif /* ARCH_TRACE_IGNORE_COMPAT_SYSCALLS */
+
 static __init struct syscall_metadata *
 find_syscall_meta(unsigned long syscall)
 {
@@ -276,10 +309,10 @@ static void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
        struct syscall_metadata *sys_data;
        struct ring_buffer_event *event;
        struct ring_buffer *buffer;
-       int size;
        int syscall_nr;
+       int size;
 
-       syscall_nr = syscall_get_nr(current, regs);
+       syscall_nr = trace_get_syscall_nr(current, regs);
        if (syscall_nr < 0)
                return;
        if (!test_bit(syscall_nr, enabled_enter_syscalls))
@@ -313,7 +346,7 @@ static void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
        struct ring_buffer *buffer;
        int syscall_nr;
 
-       syscall_nr = syscall_get_nr(current, regs);
+       syscall_nr = trace_get_syscall_nr(current, regs);
        if (syscall_nr < 0)
                return;
        if (!test_bit(syscall_nr, enabled_exit_syscalls))
@@ -502,7 +535,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
        int rctx;
        int size;
 
-       syscall_nr = syscall_get_nr(current, regs);
+       syscall_nr = trace_get_syscall_nr(current, regs);
        if (syscall_nr < 0)
                return;
        if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
@@ -578,7 +611,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
        int rctx;
        int size;
 
-       syscall_nr = syscall_get_nr(current, regs);
+       syscall_nr = trace_get_syscall_nr(current, regs);
        if (syscall_nr < 0)
                return;
        if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))