[ARM] 5387/1: Add ptrace VFP support on ARM

This patch adds ptrace support for setting and getting the VFP registers
using PTRACE_SETVFPREGS and PTRACE_GETVFPREGS. The user_vfp structure
defined in asm/user.h contains 32 double registers (to cover VFPv3 and
Neon hardware) and the FPSCR register.

Cc: Paul Brook <paul@codesourcery.com>
Cc: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/ptrace.c

@@ -653,6 +653,54 @@ static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
 }
 #endif
 
+#ifdef CONFIG_VFP
+/*
+ * Get the child VFP state.
+ */
+static int ptrace_getvfpregs(struct task_struct *tsk, void __user *data)
+{
+	struct thread_info *thread = task_thread_info(tsk);
+	union vfp_state *vfp = &thread->vfpstate;
+	struct user_vfp __user *ufp = data;
+
+	vfp_sync_state(thread);
+
+	/* copy the floating point registers */
+	if (copy_to_user(&ufp->fpregs, &vfp->hard.fpregs,
+			 sizeof(vfp->hard.fpregs)))
+		return -EFAULT;
+
+	/* copy the status and control register */
+	if (put_user(vfp->hard.fpscr, &ufp->fpscr))
+		return -EFAULT;
+
+	return 0;
+}
+
+/*
+ * Set the child VFP state.
+ */
+static int ptrace_setvfpregs(struct task_struct *tsk, void __user *data)
+{
+	struct thread_info *thread = task_thread_info(tsk);
+	union vfp_state *vfp = &thread->vfpstate;
+	struct user_vfp __user *ufp = data;
+
+	vfp_sync_state(thread);
+
+	/* copy the floating point registers */
+	if (copy_from_user(&vfp->hard.fpregs, &ufp->fpregs,
+			   sizeof(vfp->hard.fpregs)))
+		return -EFAULT;
+
+	/* copy the status and control register */
+	if (get_user(vfp->hard.fpscr, &ufp->fpscr))
+		return -EFAULT;
+
+	return 0;
+}
+#endif
+
 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 {
 	int ret;
@@ -775,6 +823,16 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 			break;
 #endif
 
+#ifdef CONFIG_VFP
+		case PTRACE_GETVFPREGS:
+			ret = ptrace_getvfpregs(child, (void __user *)data);
+			break;
+
+		case PTRACE_SETVFPREGS:
+			ret = ptrace_setvfpregs(child, (void __user *)data);
+			break;
+#endif
+
 		default:
 			ret = ptrace_request(child, request, addr, data);
 			break;