1 files changed, 47 insertions, 14 deletions

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 7609dd6714c2..7a809e321058 100644
--- 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)
 {
@@ -77,7 +110,7 @@ static struct syscall_metadata *syscall_nr_to_meta(int nr)
         return syscalls_metadata[nr];
 }
 
-enum print_line_t
+static enum print_line_t
 print_syscall_enter(struct trace_iterator *iter, int flags,
                     struct trace_event *event)
 {
@@ -130,7 +163,7 @@ end:
         return TRACE_TYPE_HANDLED;
 }
 
-enum print_line_t
+static enum print_line_t
 print_syscall_exit(struct trace_iterator *iter, int flags,
                    struct trace_event *event)
 {
@@ -270,16 +303,16 @@ static int syscall_exit_define_fields(struct ftrace_event_call *call)
         return ret;
 }
 
-void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
+static void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 {
         struct syscall_trace_enter *entry;
         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))
@@ -305,7 +338,7 @@ void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
                 trace_current_buffer_unlock_commit(buffer, event, 0, 0);
 }
 
-void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
+static void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 {
         struct syscall_trace_exit *entry;
         struct syscall_metadata *sys_data;
@@ -313,7 +346,7 @@ 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))
@@ -337,7 +370,7 @@ void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
                 trace_current_buffer_unlock_commit(buffer, event, 0, 0);
 }
 
-int reg_event_syscall_enter(struct ftrace_event_call *call)
+static int reg_event_syscall_enter(struct ftrace_event_call *call)
 {
         int ret = 0;
         int num;
@@ -356,7 +389,7 @@ int reg_event_syscall_enter(struct ftrace_event_call *call)
         return ret;
 }
 
-void unreg_event_syscall_enter(struct ftrace_event_call *call)
+static void unreg_event_syscall_enter(struct ftrace_event_call *call)
 {
         int num;
 
@@ -371,7 +404,7 @@ void unreg_event_syscall_enter(struct ftrace_event_call *call)
         mutex_unlock(&syscall_trace_lock);
 }
 
-int reg_event_syscall_exit(struct ftrace_event_call *call)
+static int reg_event_syscall_exit(struct ftrace_event_call *call)
 {
         int ret = 0;
         int num;
@@ -390,7 +423,7 @@ int reg_event_syscall_exit(struct ftrace_event_call *call)
         return ret;
 }
 
-void unreg_event_syscall_exit(struct ftrace_event_call *call)
+static void unreg_event_syscall_exit(struct ftrace_event_call *call)
 {
         int num;
 
@@ -459,7 +492,7 @@ unsigned long __init __weak arch_syscall_addr(int nr)
         return (unsigned long)sys_call_table[nr];
 }
 
-int __init init_ftrace_syscalls(void)
+static int __init init_ftrace_syscalls(void)
 {
         struct syscall_metadata *meta;
         unsigned long addr;
@@ -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))