ARM: 5912/1: Define a 32-bit Thumb-2 breakpoint instruction

Recognize 0xf7f0 0xa000 as a 32-bit breakpoint instruction for
Thumb-2.

Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 31 insertions, 0 deletions

diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index a2ea3854cb3..bd56673c6a6 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -499,10 +499,41 @@ 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,
+        .cpsr_mask      = PSR_T_BIT,
+        .cpsr_val       = PSR_T_BIT,
+        .fn             = thumb2_break_trap,
+};
+
 static int __init ptrace_break_init(void)
 {
         register_undef_hook(&arm_break_hook);
         register_undef_hook(&thumb_break_hook);
+        register_undef_hook(&thumb2_break_hook);
         return 0;
 }