ARM: kprobes: Add load_write_pc()

This writes a value to PC which was obtained as the result of a
LDR or LDM instruction. For ARMv5T and later this must perform
interworking.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/kernel/kprobes-common.c
index 3a3e765d2090..86fdc4c4c2ce 100644
--- a/arch/arm/kernel/kprobes-common.c
+++ b/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();
 }