linux-2.6-10000-gcc-4.5.patch

   1 commit 124482935fb7fb9303c8a8ab930149c6a93d9910
   2 Author: Andi Kleen <andi@firstfloor.org>
   3 Date:   Fri Jun 18 23:09:00 2010 +0200
   4
   5     x86: Fix vsyscall on gcc 4.5 with -Os
   6
   7     This fixes the -Os breaks with gcc 4.5 bug.  rdtsc_barrier needs to be
   8     force inlined, otherwise user space will jump into kernel space and
   9     kill init.
  10
  11     This also addresses http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44129
  12     I believe.
  13
  14     Signed-off-by: Andi Kleen <ak@linux.intel.com>
  15     LKML-Reference: <20100618210859.GA10913@basil.fritz.box>
  16     Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
  17     Cc: <stable@kernel.org>
  18
  19 commit 86c38a31aa7f2dd6e74a262710bf8ebf7455acc5
  20 Author: Jeff Mahoney <jeffm@suse.com>
  21 Date:   Wed Feb 24 13:59:23 2010 -0500
  22
  23     tracing: Fix ftrace_event_call alignment for use with gcc 4.5
  24
  25     GCC 4.5 introduces behavior that forces the alignment of structures to
  26     use the largest possible value. The default value is 32 bytes, so if
  27     some structures are defined with a 4-byte alignment and others aren't
  28     declared with an alignment constraint at all - it will align at 32-bytes.
  29
  30     For things like the ftrace events, this results in a non-standard array.
  31     When initializing the ftrace subsystem, we traverse the _ftrace_events
  32     section and call the initialization callback for each event. When the
  33     structures are misaligned, we could be treating another part of the
  34     structure (or the zeroed out space between them) as a function pointer.
  35
  36     This patch forces the alignment for all the ftrace_event_call structures
  37     to 4 bytes.
  38
  39     Without this patch, the kernel fails to boot very early when built with
  40     gcc 4.5.
  41
  42     It's trivial to check the alignment of the members of the array, so it
  43     might be worthwhile to add something to the build system to do that
  44     automatically. Unfortunately, that only covers this case. I've asked one
  45     of the gcc developers about adding a warning when this condition is seen.
  46
  47    Signed-off-by: Jeff Mahoney <jeffm@suse.com>
  48     LKML-Reference: <4B85770B.6010901@suse.com>
  49     Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
  50     Cc: stable@kernel.org
  51
  52 diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
  53 index f08f973..e0fbf29 100644
  54 --- a/arch/x86/include/asm/system.h
  55 +++ b/arch/x86/include/asm/system.h
  56 @@ -449,7 +449,7 @@ void stop_this_cpu(void *dummy);
  57   *
  58   * (Could use an alternative three way for this if there was one.)
  59   */
  60 -static inline void rdtsc_barrier(void)
  61 +static __always_inline void rdtsc_barrier(void)
  62  {
  63         alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
  64         alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);
  65 diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
  66 index 71c9050..3e35002 100644
  67 --- a/include/linux/syscalls.h
  68 +++ b/include/linux/syscalls.h
  69 @@ -154,7 +154,8 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *unused)     \
  70  #define __SC_STR_TDECL6(t, a, ...)     #t, __SC_STR_TDECL5(__VA_ARGS__)
  71
  72  #define SYSCALL_TRACE_ENTER_EVENT(sname)                               \
  73 -       static struct ftrace_event_call event_enter_##sname;            \
  74 +       static struct ftrace_event_call                                 \
  75 +       __attribute__((__aligned__(4))) event_enter_##sname;            \
  76         struct trace_event enter_syscall_print_##sname = {              \
  77                 .trace                  = print_syscall_enter,          \
  78         };                                                              \
  79 @@ -190,7 +191,8 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *unused)     \
  80         }
  81
  82  #define SYSCALL_TRACE_EXIT_EVENT(sname)                                        \
  83 -       static struct ftrace_event_call event_exit_##sname;             \
  84 +       static struct ftrace_event_call                                 \
  85 +       __attribute__((__aligned__(4))) event_exit_##sname;             \
  86         struct trace_event exit_syscall_print_##sname = {               \
  87                 .trace                  = print_syscall_exit,           \
  88         };                                                              \
  89 diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
  90 index bc309b2..f14d954 100644
  91 --- a/include/trace/ftrace.h
  92 +++ b/include/trace/ftrace.h
  93 @@ -65,7 +65,8 @@
  94         };
  95  #undef DEFINE_EVENT
  96  #define DEFINE_EVENT(template, name, proto, args)      \
  97 -       static struct ftrace_event_call event_##name
  98 +       static struct ftrace_event_call                 \
  99 +       __attribute__((__aligned__(4))) event_##name
 100
 101  #undef DEFINE_EVENT_PRINT
 102  #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
 103 diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
 104 index 6167a38..1ad2d01 100644
 105 --- a/kernel/trace/trace.h
 106 +++ b/kernel/trace/trace.h
 107 @@ -760,7 +760,8 @@ extern const char *__stop___trace_bprintk_fmt[];
 108
 109  #undef FTRACE_ENTRY
 110  #define FTRACE_ENTRY(call, struct_name, id, tstruct, print)            \
 111 -       extern struct ftrace_event_call event_##call;
 112 +       extern struct ftrace_event_call                                 \
 113 +       __attribute__((__aligned__(4))) event_##call;
 114  #undef FTRACE_ENTRY_DUP
 115  #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print)                \
 116         FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))