[PATCH 4.9 02/16] ARM: 8791/1: vfp: use __copy_to_user() when saving VFP state

David Long
2019-02-14T14:49:39Z

From: Julien Thierry <julien.thierry@arm.com>

Commit 3aa2df6ec2ca6bc143a65351cca4266d03a8bc41 upstream.

Use __copy_to_user() rather than __put_user_error() for individual
members when saving VFP state.
This has the benefit of disabling/enabling PAN once per copied struct
intead of once per write.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David A. Long <dave.long@linaro.org>
---
arch/arm/include/asm/thread_info.h | 4 ++--
arch/arm/kernel/signal.c | 13 +++++++------
arch/arm/vfp/vfpmodule.c | 20 ++++++++------------
3 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 57d2ad9c75ca..df8420672c7e 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -124,8 +124,8 @@ 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_preserve_user_clear_hwstate(struct user_vfp *,
+ struct user_vfp_exc *);
extern int vfp_restore_user_hwstate(struct user_vfp *,
struct user_vfp_exc *);
#endif
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index fbb325ff8acc..135b1a8e12eb 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -94,17 +94,18 @@ static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)

static int preserve_vfp_context(struct vfp_sigframe __user *frame)
{
- const unsigned long magic = VFP_MAGIC;
- const unsigned long size = VFP_STORAGE_SIZE;
+ struct vfp_sigframe kframe;
int err = 0;

- __put_user_error(magic, &frame->magic, err);
- __put_user_error(size, &frame->size, err);
+ memset(&kframe, 0, sizeof(kframe));
+ kframe.magic = VFP_MAGIC;
+ kframe.size = VFP_STORAGE_SIZE;

+ err = vfp_preserve_user_clear_hwstate(&kframe.ufp, &kframe.ufp_exc);
if (err)
- return -EFAULT;
+ return err;

- return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
+ return __copy_to_user(frame, &kframe, sizeof(kframe));
}

static int restore_vfp_context(struct vfp_sigframe __user *auxp)
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 8e5e97989fda..df3fa52c0aa3 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -554,12 +554,11 @@ 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)
+int vfp_preserve_user_clear_hwstate(struct user_vfp *ufp,
+ struct user_vfp_exc *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);
@@ -568,22 +567,19 @@ int vfp_preserve_user_clear_hwstate(struct user_vfp __user *ufp,
* 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));
+ memcpy(&ufp->fpregs, &hwstate->fpregs, sizeof(hwstate->fpregs));
+
/*
* Copy the status and control register.
*/
- __put_user_error(hwstate->fpscr, &ufp->fpscr, err);
+ ufp->fpscr = hwstate->fpscr;

/*
* 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;
+ ufp_exc->fpexc = hwstate->fpexc;
+ ufp_exc->fpinst = hwstate->fpinst;
+ ufp_exc->fpinst2 = ufp_exc->fpinst2;

/* Ensure that VFP is disabled. */
vfp_flush_hwstate(thread);
--
2.17.1