diff options
author | Will Deacon <will.deacon@arm.com> | 2012-04-23 15:38:28 +0100 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-04-23 15:44:41 +0100 |
commit | 2498814fcb3068f19b82b1519b4038721f61af43 (patch) | |
tree | 6a3483bab350438a768b56bb56611d609b2396b4 /arch/arm/vfp/vfpmodule.c | |
parent | ab4d536890853ab6675ede65db40e2c0980cb0ea (diff) | |
download | linux-2498814fcb3068f19b82b1519b4038721f61af43.tar.bz2 |
ARM: 7399/1: vfp: move user vfp state save/restore code out of signal.c
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>
Diffstat (limited to 'arch/arm/vfp/vfpmodule.c')
-rw-r--r-- | arch/arm/vfp/vfpmodule.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index 858748eaa144..05872d92fca2 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/cp15.h> #include <asm/cputype.h> @@ -529,6 +531,83 @@ 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 |