Merge tag 'ktest-for-v3.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/roste...

[cascardo/linux.git] / arch / arm / vfp / vfpmodule.c

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 858748e..bc683b8 100644 (file)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -17,6 +17,8 @@
 #include <linux/sched.h>
 #include <linux/smp.h>
 #include <linux/init.h>
+#include <linux/uaccess.h>
+#include <linux/user.h>
 
 #include <asm/cp15.h>
 #include <asm/cputype.h>
@@ -528,6 +530,103 @@ void vfp_flush_hwstate(struct thread_info *thread)
        put_cpu();
 }
 
+/*
+ * Save the current VFP state into the provided structures and prepare
+ * for entry into a new function (signal handler).
+ */
+int vfp_preserve_user_clear_hwstate(struct user_vfp __user *ufp,
+                                   struct user_vfp_exc __user *ufp_exc)
+{
+       struct thread_info *thread = current_thread_info();
+       struct vfp_hard_struct *hwstate = &thread->vfpstate.hard;
+       int err = 0;
+
+       /* Ensure that the saved hwstate is up-to-date. */
+       vfp_sync_hwstate(thread);
+
+       /*
+        * Copy the floating point registers. There can be unused
+        * registers see asm/hwcap.h for details.
+        */
+       err |= __copy_to_user(&ufp->fpregs, &hwstate->fpregs,
+                             sizeof(hwstate->fpregs));
+       /*
+        * Copy the status and control register.
+        */
+       __put_user_error(hwstate->fpscr, &ufp->fpscr, err);
+
+       /*
+        * Copy the exception registers.
+        */
+       __put_user_error(hwstate->fpexc, &ufp_exc->fpexc, err);
+       __put_user_error(hwstate->fpinst, &ufp_exc->fpinst, err);
+       __put_user_error(hwstate->fpinst2, &ufp_exc->fpinst2, err);
+
+       if (err)
+               return -EFAULT;
+
+       /* Ensure that VFP is disabled. */
+       vfp_flush_hwstate(thread);
+
+       /*
+        * As per the PCS, clear the length and stride bits for function
+        * entry.
+        */
+       hwstate->fpscr &= ~(FPSCR_LENGTH_MASK | FPSCR_STRIDE_MASK);
+
+       /*
+        * Disable VFP in the hwstate so that we can detect if it gets
+        * used.
+        */
+       hwstate->fpexc &= ~FPEXC_EN;
+       return 0;
+}
+
+/* Sanitise and restore the current VFP state from the provided structures. */
+int vfp_restore_user_hwstate(struct user_vfp __user *ufp,
+                            struct user_vfp_exc __user *ufp_exc)
+{
+       struct thread_info *thread = current_thread_info();
+       struct vfp_hard_struct *hwstate = &thread->vfpstate.hard;
+       unsigned long fpexc;
+       int err = 0;
+
+       /*
+        * If VFP has been used, then disable it to avoid corrupting
+        * the new thread state.
+        */
+       if (hwstate->fpexc & FPEXC_EN)
+               vfp_flush_hwstate(thread);
+
+       /*
+        * Copy the floating point registers. There can be unused
+        * registers see asm/hwcap.h for details.
+        */
+       err |= __copy_from_user(&hwstate->fpregs, &ufp->fpregs,
+                               sizeof(hwstate->fpregs));
+       /*
+        * Copy the status and control register.
+        */
+       __get_user_error(hwstate->fpscr, &ufp->fpscr, err);
+
+       /*
+        * Sanitise and restore the exception registers.
+        */
+       __get_user_error(fpexc, &ufp_exc->fpexc, err);
+
+       /* Ensure the VFP is enabled. */
+       fpexc |= FPEXC_EN;
+
+       /* Ensure FPINST2 is invalid and the exception flag is cleared. */
+       fpexc &= ~(FPEXC_EX | FPEXC_FP2V);
+       hwstate->fpexc = fpexc;
+
+       __get_user_error(hwstate->fpinst, &ufp_exc->fpinst, err);
+       __get_user_error(hwstate->fpinst2, &ufp_exc->fpinst2, err);
+
+       return err ? -EFAULT : 0;
+}
+
 /*
  * VFP hardware can lose all context when a CPU goes offline.
  * As we will be running in SMP mode with CPU hotplug, we will save the