From ee22477ed5e70fb1aaf12219c312278561c01ca2 Mon Sep 17 00:00:00 2001
From: Jon Medhurst <tixy@yxit.co.uk>
Date: Sat, 26 Mar 2011 19:19:07 +0000
Subject: [PATCH] --- yaml --- r: 258321 b: refs/heads/master c:
 592201a9f154cdd5db59304d1369e94d8b551803 h: refs/heads/master i:   258319:
 f58cadbaa814c1795515237970cedb85b5cf046f v: v3

---
 [refs]                              |  2 +-
 trunk/arch/arm/include/asm/ptrace.h |  8 ++++++++
 trunk/arch/arm/kernel/ptrace.c      | 28 +++-------------------------
 trunk/arch/arm/kernel/traps.c       | 17 ++++++++++++++++-
 4 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/[refs] b/[refs]
index 1b609484308d..b48ef4368a96 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 594810621d9605dd40b6ce42e2e188a7dd6ba27c
+refs/heads/master: 592201a9f154cdd5db59304d1369e94d8b551803
diff --git a/trunk/arch/arm/include/asm/ptrace.h b/trunk/arch/arm/include/asm/ptrace.h
index 312d10877bd7..d484871698da 100644
--- a/trunk/arch/arm/include/asm/ptrace.h
+++ b/trunk/arch/arm/include/asm/ptrace.h
@@ -199,6 +199,14 @@ extern unsigned long profile_pc(struct pt_regs *regs);
 #define predicate(x)		((x) & 0xf0000000)
 #define PREDICATE_ALWAYS	0xe0000000
 
+/*
+ * True if instr is a 32-bit thumb instruction. This works if instr
+ * is the first or only half-word of a thumb instruction. It also works
+ * when instr holds all 32-bits of a wide thumb instruction if stored
+ * in the form (first_half<<16)|(second_half)
+ */
+#define is_wide_instruction(instr)	((unsigned)(instr) >= 0xe800)
+
 /*
  * kprobe-based event tracer support
  */
diff --git a/trunk/arch/arm/kernel/ptrace.c b/trunk/arch/arm/kernel/ptrace.c
index 97260060bf26..897ade059f58 100644
--- a/trunk/arch/arm/kernel/ptrace.c
+++ b/trunk/arch/arm/kernel/ptrace.c
@@ -228,34 +228,12 @@ static struct undef_hook thumb_break_hook = {
 	.fn		= break_trap,
 };
 
-static int thumb2_break_trap(struct pt_regs *regs, unsigned int instr)
-{
-	unsigned int instr2;
-	void __user *pc;
-
-	/* Check the second half of the instruction.  */
-	pc = (void __user *)(instruction_pointer(regs) + 2);
-
-	if (processor_mode(regs) == SVC_MODE) {
-		instr2 = *(u16 *) pc;
-	} else {
-		get_user(instr2, (u16 __user *)pc);
-	}
-
-	if (instr2 == 0xa000) {
-		ptrace_break(current, regs);
-		return 0;
-	} else {
-		return 1;
-	}
-}
-
 static struct undef_hook thumb2_break_hook = {
-	.instr_mask	= 0xffff,
-	.instr_val	= 0xf7f0,
+	.instr_mask	= 0xffffffff,
+	.instr_val	= 0xf7f0a000,
 	.cpsr_mask	= PSR_T_BIT,
 	.cpsr_val	= PSR_T_BIT,
-	.fn		= thumb2_break_trap,
+	.fn		= break_trap,
 };
 
 static int __init ptrace_break_init(void)
diff --git a/trunk/arch/arm/kernel/traps.c b/trunk/arch/arm/kernel/traps.c
index 6807cb1e76dd..2d3436e9f71f 100644
--- a/trunk/arch/arm/kernel/traps.c
+++ b/trunk/arch/arm/kernel/traps.c
@@ -355,9 +355,24 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 	pc = (void __user *)instruction_pointer(regs);
 
 	if (processor_mode(regs) == SVC_MODE) {
-		instr = *(u32 *) pc;
+#ifdef CONFIG_THUMB2_KERNEL
+		if (thumb_mode(regs)) {
+			instr = ((u16 *)pc)[0];
+			if (is_wide_instruction(instr)) {
+				instr <<= 16;
+				instr |= ((u16 *)pc)[1];
+			}
+		} else
+#endif
+			instr = *(u32 *) pc;
 	} else if (thumb_mode(regs)) {
 		get_user(instr, (u16 __user *)pc);
+		if (is_wide_instruction(instr)) {
+			unsigned int instr2;
+			get_user(instr2, (u16 __user *)pc+1);
+			instr <<= 16;
+			instr |= instr2;
+		}
 	} else {
 		get_user(instr, (u32 __user *)pc);
 	}