ARM: 7400/1: vfp: clear fpscr length and stride bits on entry to sig handler
[linux-flexiantxendom0-3.2.10.git] / arch / arm / vfp / vfpmodule.c
index 0a96f71..bc683b8 100644 (file)
@@ -8,17 +8,21 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
-#include <linux/module.h>
 #include <linux/types.h>
 #include <linux/cpu.h>
+#include <linux/cpu_pm.h>
 #include <linux/kernel.h>
 #include <linux/notifier.h>
 #include <linux/signal.h>
 #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>
+#include <asm/system_info.h>
 #include <asm/thread_notify.h>
 #include <asm/vfp.h>
 
@@ -68,7 +72,7 @@ static bool vfp_state_in_hw(unsigned int cpu, struct thread_info *thread)
 /*
  * Force a reload of the VFP context from the thread structure.  We do
  * this by ensuring that access to the VFP hardware is disabled, and
- * clear last_VFP_context.  Must be called from non-preemptible context.
+ * clear vfp_current_hw_state.  Must be called from non-preemptible context.
  */
 static void vfp_force_reload(unsigned int cpu, struct thread_info *thread)
 {
@@ -436,9 +440,7 @@ static void vfp_enable(void *unused)
        set_copro_access(access | CPACC_FULL(10) | CPACC_FULL(11));
 }
 
-#ifdef CONFIG_PM
-#include <linux/syscore_ops.h>
-
+#ifdef CONFIG_CPU_PM
 static int vfp_pm_suspend(void)
 {
        struct thread_info *ti = current_thread_info();
@@ -468,19 +470,33 @@ static void vfp_pm_resume(void)
        fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
 }
 
-static struct syscore_ops vfp_pm_syscore_ops = {
-       .suspend        = vfp_pm_suspend,
-       .resume         = vfp_pm_resume,
+static int vfp_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd,
+       void *v)
+{
+       switch (cmd) {
+       case CPU_PM_ENTER:
+               vfp_pm_suspend();
+               break;
+       case CPU_PM_ENTER_FAILED:
+       case CPU_PM_EXIT:
+               vfp_pm_resume();
+               break;
+       }
+       return NOTIFY_OK;
+}
+
+static struct notifier_block vfp_cpu_pm_notifier_block = {
+       .notifier_call = vfp_cpu_pm_notifier,
 };
 
 static void vfp_pm_init(void)
 {
-       register_syscore_ops(&vfp_pm_syscore_ops);
+       cpu_pm_register_notifier(&vfp_cpu_pm_notifier_block);
 }
 
 #else
 static inline void vfp_pm_init(void) { }
-#endif /* CONFIG_PM */
+#endif /* CONFIG_CPU_PM */
 
 /*
  * Ensure that the VFP state stored in 'thread->vfpstate' is up to date
@@ -515,6 +531,103 @@ void vfp_flush_hwstate(struct thread_info *thread)
 }
 
 /*
+ * 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
  * hardware state at every thread switch.  We clear our held state when
@@ -597,7 +710,6 @@ static int __init vfp_init(void)
                                elf_hwcap |= HWCAP_VFPv3D16;
                }
 #endif
-#ifdef CONFIG_NEON
                /*
                 * Check for the presence of the Advanced SIMD
                 * load/store instructions, integer and single
@@ -605,10 +717,13 @@ static int __init vfp_init(void)
                 * for NEON if the hardware has the MVFR registers.
                 */
                if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) {
+#ifdef CONFIG_NEON
                        if ((fmrx(MVFR1) & 0x000fff00) == 0x00011100)
                                elf_hwcap |= HWCAP_NEON;
-               }
 #endif
+                       if ((fmrx(MVFR1) & 0xf0000000) == 0x10000000)
+                               elf_hwcap |= HWCAP_VFPv4;
+               }
        }
        return 0;
 }