uprobes/core: Make instruction tables volatile

Some versions of gcc spits a warning about the asm operand for
test_bit and also causes the first long of the instruction table
to be output.

Fix is similar to 7115e3fc on arch/x86/kernel/kprobes.c

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Stone <jistone@redhat.com>
Link: http://lkml.kernel.org/r/20120222091535.15880.12502.sendpatchset@srdronam.in.ibm.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 32 insertions, 29 deletions

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index cf2a1849842..13d616d6519 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -53,34 +53,12 @@
           (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf))    \
          << (row % 32))
 
-#ifdef CONFIG_X86_64
-static u32 good_insns_64[256 / 32] = {
-        /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */
-        /*      ----------------------------------------------         */
-        W(0x00, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) | /* 00 */
-        W(0x10, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) , /* 10 */
-        W(0x20, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) | /* 20 */
-        W(0x30, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) , /* 30 */
-        W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */
-        W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 50 */
-        W(0x60, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 60 */
-        W(0x70, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 70 */
-        W(0x80, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */
-        W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */
-        W(0xa0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* a0 */
-        W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* b0 */
-        W(0xc0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0) | /* c0 */
-        W(0xd0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */
-        W(0xe0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* e0 */
-        W(0xf0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1)   /* f0 */
-        /*      ----------------------------------------------         */
-        /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */
-};
-#endif
-
-/* Good-instruction tables for 32-bit apps */
-
-static u32 good_insns_32[256 / 32] = {
+/*
+ * Good-instruction tables for 32-bit apps.  This is non-const and volatile
+ * to keep gcc from statically optimizing it out, as variable_test_bit makes
+ * some versions of gcc to think only *(unsigned long*) is used.
+ */
+static volatile u32 good_insns_32[256 / 32] = {
         /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */
         /*      ----------------------------------------------         */
         W(0x00, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0) | /* 00 */
@@ -104,7 +82,7 @@ static u32 good_insns_32[256 / 32] = {
 };
 
 /* Using this for both 64-bit and 32-bit apps */
-static u32 good_2byte_insns[256 / 32] = {
+static volatile u32 good_2byte_insns[256 / 32] = {
         /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */
         /*      ----------------------------------------------         */
         W(0x00, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1) | /* 00 */
@@ -127,6 +105,31 @@ static u32 good_2byte_insns[256 / 32] = {
         /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */
 };
 
+#ifdef CONFIG_X86_64
+/* Good-instruction tables for 64-bit apps */
+static volatile u32 good_insns_64[256 / 32] = {
+        /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */
+        /*      ----------------------------------------------         */
+        W(0x00, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) | /* 00 */
+        W(0x10, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) , /* 10 */
+        W(0x20, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) | /* 20 */
+        W(0x30, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) , /* 30 */
+        W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */
+        W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 50 */
+        W(0x60, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 60 */
+        W(0x70, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 70 */
+        W(0x80, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */
+        W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */
+        W(0xa0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* a0 */
+        W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* b0 */
+        W(0xc0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0) | /* c0 */
+        W(0xd0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */
+        W(0xe0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* e0 */
+        W(0xf0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1)   /* f0 */
+        /*      ----------------------------------------------         */
+        /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */
+};
+#endif
 #undef W
 
 /*