From 4f7360e66c78d589690cf7e9285cfd4f271a4b81 Mon Sep 17 00:00:00 2001
From: Jon Medhurst <tixy@yxit.co.uk>
Date: Fri, 10 Jun 2011 20:29:04 +0100
Subject: [PATCH] --- yaml --- r: 258354 b: refs/heads/master c:
 263e368a2f1f960db07d7524a4a3e7df951f1f72 h: refs/heads/master v: v3

---
 [refs]                                 |  2 +-
 trunk/arch/arm/kernel/kprobes-common.c | 15 +++++++++++++++
 trunk/arch/arm/kernel/kprobes.h        | 24 ++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 7a97498f16ea..d29d5f54f1f2 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f39ca8b488a6c1e8db47746e1cdb841a6999edd7
+refs/heads/master: 263e368a2f1f960db07d7524a4a3e7df951f1f72
diff --git a/trunk/arch/arm/kernel/kprobes-common.c b/trunk/arch/arm/kernel/kprobes-common.c
index 3a3e765d2090..86fdc4c4c2ce 100644
--- a/trunk/arch/arm/kernel/kprobes-common.c
+++ b/trunk/arch/arm/kernel/kprobes-common.c
@@ -45,9 +45,24 @@ void __init find_str_pc_offset(void)
 #endif /* !find_str_pc_offset */
 
 
+#ifndef test_load_write_pc_interworking
+
+bool load_write_pc_interworks;
+
+void __init test_load_write_pc_interworking(void)
+{
+	int arch = cpu_architecture();
+	BUG_ON(arch == CPU_ARCH_UNKNOWN);
+	load_write_pc_interworks = arch >= CPU_ARCH_ARMv5T;
+}
+
+#endif /* !test_load_write_pc_interworking */
+
+
 void __init arm_kprobe_decode_init(void)
 {
 	find_str_pc_offset();
+	test_load_write_pc_interworking();
 }
 
 
diff --git a/trunk/arch/arm/kernel/kprobes.h b/trunk/arch/arm/kernel/kprobes.h
index 12627a376bf6..5d6bf0d0a18a 100644
--- a/trunk/arch/arm/kernel/kprobes.h
+++ b/trunk/arch/arm/kernel/kprobes.h
@@ -109,6 +109,30 @@ static inline void __kprobes bx_write_pc(long pcv, struct pt_regs *regs)
 	regs->ARM_pc = pcv;
 }
 
+
+#if __LINUX_ARM_ARCH__ >= 6
+
+/* Kernels built for >= ARMv6 should never run on <= ARMv5 hardware, so... */
+#define load_write_pc_interworks true
+#define test_load_write_pc_interworking()
+
+#else /* __LINUX_ARM_ARCH__ < 6 */
+
+/* We need run-time testing to determine if load_write_pc() should interwork. */
+extern bool load_write_pc_interworks;
+void __init test_load_write_pc_interworking(void);
+
+#endif
+
+static inline void __kprobes load_write_pc(long pcv, struct pt_regs *regs)
+{
+	if (load_write_pc_interworks)
+		bx_write_pc(pcv, regs);
+	else
+		regs->ARM_pc = pcv;
+}
+
+
 void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs);
 void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs);