[PATCH v4 1/2] ARM: vfp: move user vfp state save/restore code out of signal.c
Will Deacon
will.deacon at arm.com
Thu Feb 23 10:07:11 EST 2012
The user VFP state must be preserved (subject to ucontext modifications)
across invocation of a signal handler and this is currently handled by
vfp_{preserve,restore}_context in signal.c
Since this code requires intimate low-level knowledge of the VFP state,
this patch moves it into vfpmodule.c.
Signed-off-by: Will Deacon <will.deacon at arm.com>
---
v4: minor naming changes to appease Dave's dislike of the old ones.
arch/arm/include/asm/thread_info.h | 7 +++
arch/arm/kernel/signal.c | 57 ++-----------------------
arch/arm/vfp/vfpmodule.c | 79 ++++++++++++++++++++++++++++++++++++
3 files changed, 91 insertions(+), 52 deletions(-)
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index d4c24d4..0f04d84 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -118,6 +118,13 @@ extern void iwmmxt_task_switch(struct thread_info *);
extern void vfp_sync_hwstate(struct thread_info *);
extern void vfp_flush_hwstate(struct thread_info *);
+struct user_vfp;
+struct user_vfp_exc;
+
+extern int vfp_preserve_user_clear_hwstate(struct user_vfp __user *,
+ struct user_vfp_exc __user *);
+extern int vfp_restore_user_hwstate(struct user_vfp __user *,
+ struct user_vfp_exc __user *);
#endif
/*
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 9e617bd..b02ce1d 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -179,44 +179,23 @@ static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
static int preserve_vfp_context(struct vfp_sigframe __user *frame)
{
- struct thread_info *thread = current_thread_info();
- struct vfp_hard_struct *h = &thread->vfpstate.hard;
const unsigned long magic = VFP_MAGIC;
const unsigned long size = VFP_STORAGE_SIZE;
int err = 0;
- vfp_sync_hwstate(thread);
__put_user_error(magic, &frame->magic, err);
__put_user_error(size, &frame->size, err);
- /*
- * Copy the floating point registers. There can be unused
- * registers see asm/hwcap.h for details.
- */
- err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs,
- sizeof(h->fpregs));
- /*
- * Copy the status and control register.
- */
- __put_user_error(h->fpscr, &frame->ufp.fpscr, err);
-
- /*
- * Copy the exception registers.
- */
- __put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err);
- __put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
- __put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
+ if (err)
+ return -EFAULT;
- return err ? -EFAULT : 0;
+ return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
}
static int restore_vfp_context(struct vfp_sigframe __user *frame)
{
- struct thread_info *thread = current_thread_info();
- struct vfp_hard_struct *h = &thread->vfpstate.hard;
unsigned long magic;
unsigned long size;
- unsigned long fpexc;
int err = 0;
__get_user_error(magic, &frame->magic, err);
@@ -227,33 +206,7 @@ static int restore_vfp_context(struct vfp_sigframe __user *frame)
if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
return -EINVAL;
- vfp_flush_hwstate(thread);
-
- /*
- * Copy the floating point registers. There can be unused
- * registers see asm/hwcap.h for details.
- */
- err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs,
- sizeof(h->fpregs));
- /*
- * Copy the status and control register.
- */
- __get_user_error(h->fpscr, &frame->ufp.fpscr, err);
-
- /*
- * Sanitise and restore the exception registers.
- */
- __get_user_error(fpexc, &frame->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);
- h->fpexc = fpexc;
-
- __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
- __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
-
- return err ? -EFAULT : 0;
+ return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc);
}
#endif
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 8f3ccdd..1dfe7d8 100644
--- 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/cputype.h>
#include <asm/thread_notify.h>
@@ -527,6 +529,83 @@ 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;
+ 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;
+
+ 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
--
1.7.4.1
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