1 files changed, 67 insertions, 4 deletions

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index f2f8540a7f3d..c01a2b846d47 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -164,6 +164,11 @@ int init_fpu(struct task_struct *tsk)
         return 0;
 }
 
+/*
+ * The xstateregs_active() routine is the same as the fpregs_active() routine,
+ * as the "regset->n" for the xstate regset will be updated based on the feature
+ * capabilites supported by the xsave.
+ */
 int fpregs_active(struct task_struct *target, const struct user_regset *regset)
 {
         return tsk_used_math(target) ? regset->n : 0;
@@ -204,8 +209,6 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
         if (ret)
                 return ret;
 
-        set_stopped_child_used_math(target);
-
         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                  &target->thread.xstate->fxsave, 0, -1);
 
@@ -224,6 +227,68 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
         return ret;
 }
 
+int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
+                unsigned int pos, unsigned int count,
+                void *kbuf, void __user *ubuf)
+{
+        int ret;
+
+        if (!cpu_has_xsave)
+                return -ENODEV;
+
+        ret = init_fpu(target);
+        if (ret)
+                return ret;
+
+        /*
+         * Copy the 48bytes defined by the software first into the xstate
+         * memory layout in the thread struct, so that we can copy the entire
+         * xstateregs to the user using one user_regset_copyout().
+         */
+        memcpy(&target->thread.xstate->fxsave.sw_reserved,
+               xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));
+
+        /*
+         * Copy the xstate memory layout.
+         */
+        ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+                                  &target->thread.xstate->xsave, 0, -1);
+        return ret;
+}
+
+int xstateregs_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;
+        struct xsave_hdr_struct *xsave_hdr;
+
+        if (!cpu_has_xsave)
+                return -ENODEV;
+
+        ret = init_fpu(target);
+        if (ret)
+                return ret;
+
+        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+                                 &target->thread.xstate->xsave, 0, -1);
+
+        /*
+         * mxcsr reserved bits must be masked to zero for security reasons.
+         */
+        target->thread.xstate->fxsave.mxcsr &= mxcsr_feature_mask;
+
+        xsave_hdr = &target->thread.xstate->xsave.xsave_hdr;
+
+        xsave_hdr->xstate_bv &= pcntxt_mask;
+        /*
+         * These bits must be zero.
+         */
+        xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0;
+
+        return ret;
+}
+
 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
 
 /*
@@ -404,8 +469,6 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
         if (ret)
                 return ret;
 
-        set_stopped_child_used_math(target);
-
         if (!HAVE_HWFP)
                 return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);