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ARM: 7399/1: vfp: move user vfp state save/restore code out of signal.c

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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@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Will Deacon 2012-04-23 15:38:28 +01:00 committed by Russell King
parent ab4d536890
commit 2498814fcb
3 changed files with 90 additions and 51 deletions
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7
arch/arm/include/asm/thread_info.h
View File

@ -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
/*

55
arch/arm/kernel/signal.c
View File

@ -180,44 +180,23 @@ 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);
if (err)
return -EFAULT;
/*
* 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);
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);
@ -228,33 +207,7 @@ 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

79
arch/arm/vfp/vfpmodule.c
View File

@ -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 +530,83 @@ 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;
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