[PATCH 1/3] uprobes/core: Make instruction tables volatile.

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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Anton Arapov <anton@redhat.com>,
	Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
	Jim Keniston <jkenisto@linux.vnet.ibm.com>,
	Jiri Olsa <jolsa@redhat.com>, Josh Stone <jistone@redhat.com>
Subject: [PATCH 1/3] uprobes/core: Make instruction tables volatile.
Date: Wed, 22 Feb 2012 14:45:35 +0530	[thread overview]
Message-ID: <20120222091535.15880.12502.sendpatchset@srdronam.in.ibm.com> (raw)

From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

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>
---
 arch/x86/kernel/uprobes.c |   61 ++++++++++++++++++++++++---------------------
 1 files changed, 32 insertions(+), 29 deletions(-)

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index cf2a184..13d616d 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
 
 /*

next             reply	other threads:[~2012-02-22  9:16 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-22  9:15 Srikar Dronamraju [this message]
2012-02-22  9:15 ` [PATCH 2/3] uprobes/core: remove uprobe_opcode_sz Srikar Dronamraju
2012-02-22 16:05   ` [tip:perf/uprobes] uprobes/core: Remove uprobe_opcode_sz tip-bot for Srikar Dronamraju
2012-02-22  9:16 ` [PATCH 3/3] uprobes/core: move insn to arch specific structure Srikar Dronamraju
2012-02-22 16:06   ` [tip:perf/uprobes] uprobes/core: Move " tip-bot for Srikar Dronamraju
2012-02-22  9:47 ` [PATCH 1/3] uprobes/core: Make instruction tables volatile Ingo Molnar
2012-02-22 10:04   ` Srikar Dronamraju
2012-02-22 16:04 ` [tip:perf/uprobes] " tip-bot for Srikar Dronamraju

find likely ancestor, descendant, or conflicting patches for this message:
( dfblob:cf2a184 dfblob:13d616d )
 OR (
bs:"[PATCH 1/3] uprobes/core: Make instruction tables volatile." )
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