[POWERPC] Use user_regset accessors for altivec regs

This implements user_regset-style accessors for the powerpc Altivec data,
and rewrites the existing ptrace code in terms of those calls.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index f1ce646..7cdf35a 100644 (file)
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -22,6 +22,7 @@
 #include <linux/errno.h>
 #include <linux/ptrace.h>
 #include <linux/regset.h>
+#include <linux/elf.h>
 #include <linux/user.h>
 #include <linux/security.h>
 #include <linux/signal.h>
@@ -163,30 +164,87 @@ static int set_fpregs(void __user *data, struct task_struct *task,
  * (combined (32- and 64-bit) gdb.
  */
 
+static int vr_active(struct task_struct *target,
+                    const struct user_regset *regset)
+{
+       flush_altivec_to_thread(target);
+       return target->thread.used_vr ? regset->n : 0;
+}
+
+static int vr_get(struct task_struct *target, const struct user_regset *regset,
+                 unsigned int pos, unsigned int count,
+                 void *kbuf, void __user *ubuf)
+{
+       int ret;
+
+       flush_altivec_to_thread(target);
+
+       BUILD_BUG_ON(offsetof(struct thread_struct, vscr) !=
+                    offsetof(struct thread_struct, vr[32]));
+
+       ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+                                 &target->thread.vr, 0,
+                                 33 * sizeof(vector128));
+       if (!ret) {
+               /*
+                * Copy out only the low-order word of vrsave.
+                */
+               union {
+                       elf_vrreg_t reg;
+                       u32 word;
+               } vrsave;
+               memset(&vrsave, 0, sizeof(vrsave));
+               vrsave.word = target->thread.vrsave;
+               ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &vrsave,
+                                         33 * sizeof(vector128), -1);
+       }
+
+       return ret;
+}
+
+static int vr_set(struct task_struct *target, const struct user_regset *regset,
+                 unsigned int pos, unsigned int count,
+                 const void *kbuf, const void __user *ubuf)
+{
+       int ret;
+
+       flush_altivec_to_thread(target);
+
+       BUILD_BUG_ON(offsetof(struct thread_struct, vscr) !=
+                    offsetof(struct thread_struct, vr[32]));
+
+       ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+                                &target->thread.vr, 0, 33 * sizeof(vector128));
+       if (!ret && count > 0) {
+               /*
+                * We use only the first word of vrsave.
+                */
+               union {
+                       elf_vrreg_t reg;
+                       u32 word;
+               } vrsave;
+               memset(&vrsave, 0, sizeof(vrsave));
+               vrsave.word = target->thread.vrsave;
+               ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &vrsave,
+                                        33 * sizeof(vector128), -1);
+               if (!ret)
+                       target->thread.vrsave = vrsave.word;
+       }
+
+       return ret;
+}
+
 /*
  * Get contents of AltiVec register state in task TASK
  */
 static int get_vrregs(unsigned long __user *data, struct task_struct *task)
 {
-       unsigned long regsize;
-
-       /* copy AltiVec registers VR[0] .. VR[31] */
-       regsize = 32 * sizeof(vector128);
-       if (copy_to_user(data, task->thread.vr, regsize))
-               return -EFAULT;
-       data += (regsize / sizeof(unsigned long));
-
-       /* copy VSCR */
-       regsize = 1 * sizeof(vector128);
-       if (copy_to_user(data, &task->thread.vscr, regsize))
+       if (!access_ok(VERIFY_WRITE, data,
+                      33 * sizeof(vector128) + sizeof(u32)))
                return -EFAULT;
-       data += (regsize / sizeof(unsigned long));
 
-       /* copy VRSAVE */
-       if (put_user(task->thread.vrsave, (u32 __user *)data))
-               return -EFAULT;
-
-       return 0;
+       return vr_get(task, NULL, 0, 33 * sizeof(vector128) + sizeof(u32),
+                     NULL, data);
 }
 
 /*
@@ -194,25 +252,11 @@ static int get_vrregs(unsigned long __user *data, struct task_struct *task)
  */
 static int set_vrregs(struct task_struct *task, unsigned long __user *data)
 {
-       unsigned long regsize;
-
-       /* copy AltiVec registers VR[0] .. VR[31] */
-       regsize = 32 * sizeof(vector128);
-       if (copy_from_user(task->thread.vr, data, regsize))
-               return -EFAULT;
-       data += (regsize / sizeof(unsigned long));
-
-       /* copy VSCR */
-       regsize = 1 * sizeof(vector128);
-       if (copy_from_user(&task->thread.vscr, data, regsize))
-               return -EFAULT;
-       data += (regsize / sizeof(unsigned long));
-
-       /* copy VRSAVE */
-       if (get_user(task->thread.vrsave, (u32 __user *)data))
+       if (!access_ok(VERIFY_READ, data, 33 * sizeof(vector128) + sizeof(u32)))
                return -EFAULT;
 
-       return 0;
+       return vr_set(task, NULL, 0, 33 * sizeof(vector128) + sizeof(u32),
+                     NULL, data);
 }
 #endif /* CONFIG_ALTIVEC */