openrisc: Add floating point regset

Define REGSET_FPU to allow reading and writing the FPCSR fpu state
register.  This will be used primarily by debuggers like GDB.

Signed-off-by: Stafford Horne <shorne@gmail.com>

diff --git a/arch/openrisc/kernel/ptrace.c b/arch/openrisc/kernel/ptrace.c
index 85ace93..0b7d2ca 100644 (file)
--- a/arch/openrisc/kernel/ptrace.c
+++ b/arch/openrisc/kernel/ptrace.c
@@ -85,10 +85,39 @@ static int genregs_set(struct task_struct *target,
 }
 
 /*
+ * As OpenRISC shares GPRs and floating point registers we don't need to export
+ * the floating point registers again.  So here we only export the fpcsr special
+ * purpose register.
+ */
+static int fpregs_get(struct task_struct *target,
+                      const struct user_regset *regset,
+                      struct membuf to)
+{
+       const struct pt_regs *regs = task_pt_regs(target);
+
+       return membuf_store(&to, regs->fpcsr);
+}
+
+static int fpregs_set(struct task_struct *target,
+                      const struct user_regset *regset,
+                      unsigned int pos, unsigned int count,
+                      const void *kbuf, const void __user *ubuf)
+{
+       struct pt_regs *regs = task_pt_regs(target);
+       int ret;
+
+       /* FPCSR */
+       ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+                                &regs->fpcsr, 0, 4);
+       return ret;
+}
+
+/*
  * Define the register sets available on OpenRISC under Linux
  */
 enum or1k_regset {
        REGSET_GENERAL,
+       REGSET_FPU,
 };
 
 static const struct user_regset or1k_regsets[] = {
@@ -100,6 +129,14 @@ static const struct user_regset or1k_regsets[] = {
                            .regset_get = genregs_get,
                            .set = genregs_set,
                            },
+       [REGSET_FPU] = {
+                           .core_note_type = NT_PRFPREG,
+                           .n = sizeof(struct __or1k_fpu_state) / sizeof(long),
+                           .size = sizeof(long),
+                           .align = sizeof(long),
+                           .regset_get = fpregs_get,
+                           .set = fpregs_set,
+                           },
 };
 
 static const struct user_regset_view user_or1k_native_view = {