static inline int
restore_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
{
int err;
#ifdef CONFIG_SMP
if (test_tsk_thread_flag(current, TIF_USEDFPU))
regs->psr &= ~PSR_EF;
#else
if (current == last_task_used_math) {
last_task_used_math = NULL;
regs->psr &= ~PSR_EF;
}
#endif
set_used_math();
clear_tsk_thread_flag(current, TIF_USEDFPU);
if (!access_ok(VERIFY_READ, fpu, sizeof(*fpu)))
return -EFAULT;
err = __copy_from_user(¤t->thread.float_regs[0], &fpu->si_float_regs[0],
(sizeof(unsigned long) * 32));
err |= __get_user(current->thread.fsr, &fpu->si_fsr);
err |= __get_user(current->thread.fpqdepth, &fpu->si_fpqdepth);
if (current->thread.fpqdepth != 0)
err |= __copy_from_user(¤t->thread.fpqueue[0],
&fpu->si_fpqueue[0],
((sizeof(unsigned long) +
(sizeof(unsigned long *)))*16));
return err;
}
static inline int restore_sigcontext_fpu(struct pt_regs *regs,
struct sigcontext __user *sc)
{
struct task_struct *tsk = current;
unsigned long used_math_flag;
int ret = 0;
clear_used_math();
__get_user_error(used_math_flag, &sc->used_math_flag, ret);
if (!used_math_flag)
return 0;
set_used_math();
#if IS_ENABLED(CONFIG_LAZY_FPU)
preempt_disable();
if (current == last_task_used_math) {
last_task_used_math = NULL;
disable_ptreg_fpu(regs);
}
preempt_enable();
#else
clear_fpu(regs);
#endif
return __copy_from_user(&tsk->thread.fpu, &sc->fpu,
sizeof(struct fpu_struct));
}
static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
{
struct task_struct *tsk = current;
if (!(boot_cpu_data.flags & CPU_HAS_FPU))
return 0;
set_used_math();
return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0],
sizeof(long)*(16*2+2));
}
int ckpt_restore_fpu(ckpt_desc_t desc)
{
int ret;
int flag;
log_restore_fpu("restoring fpu ...");
if (ckpt_read(desc, &flag, sizeof(int)) != sizeof(int)) {
log_err("failed to get file");
return -EIO;
}
kernel_fpu_begin();
clear_used_math();
if (flag) {
if (!ckpt_get_i387(current)) {
init_fpu(current);
if (!ckpt_get_i387(current)) {
log_err("failed to get i387");
return -EFAULT;
}
}
if (ckpt_read(desc, ckpt_get_i387(current), xstate_size) != xstate_size) {
log_err("failed to get i387");
return -EFAULT;
}
ret = ckpt_check_fpu_state();
if (ret) {
log_err("failed to restore i387");
return ret;
}
set_used_math();
}
kernel_fpu_end();
log_restore_pos(desc);
return 0;
}
int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
{
int ia32_fxstate = (buf != buf_fx);
struct task_struct *tsk = current;
int state_size = xstate_size;
u64 xstate_bv = 0;
int fx_only = 0;
ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
config_enabled(CONFIG_IA32_EMULATION));
if (!buf) {
drop_init_fpu(tsk);
return 0;
}
if (!access_ok(VERIFY_READ, buf, size))
return -EACCES;
if (!used_math() && init_fpu(tsk))
return -1;
if (!static_cpu_has(X86_FEATURE_FPU))
return fpregs_soft_set(current, NULL,
0, sizeof(struct user_i387_ia32_struct),
NULL, buf) != 0;
if (use_xsave()) {
struct _fpx_sw_bytes fx_sw_user;
if (unlikely(check_for_xstate(buf_fx, buf_fx, &fx_sw_user))) {
/*
* Couldn't find the extended state information in the
* memory layout. Restore just the FP/SSE and init all
* the other extended state.
*/
state_size = sizeof(struct i387_fxsave_struct);
fx_only = 1;
} else {
state_size = fx_sw_user.xstate_size;
xstate_bv = fx_sw_user.xstate_bv;
}
}
if (ia32_fxstate) {
/*
* For 32-bit frames with fxstate, copy the user state to the
* thread's fpu state, reconstruct fxstate from the fsave
* header. Sanitize the copied state etc.
*/
struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
struct user_i387_ia32_struct env;
int err = 0;
/*
* Drop the current fpu which clears used_math(). This ensures
* that any context-switch during the copy of the new state,
* avoids the intermediate state from getting restored/saved.
* Thus avoiding the new restored state from getting corrupted.
* We will be ready to restore/save the state only after
* set_used_math() is again set.
*/
drop_fpu(tsk);
if (__copy_from_user(xsave, buf_fx, state_size) ||
__copy_from_user(&env, buf, sizeof(env))) {
err = -1;
} else {
sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);
set_used_math();
}
if (use_eager_fpu())
math_state_restore();
return err;
} else {
/*
* For 64-bit frames and 32-bit fsave frames, restore the user
* state to the registers directly (with exceptions handled).
*/
user_fpu_begin();
if (restore_user_xstate(buf_fx, xstate_bv, fx_only)) {
drop_init_fpu(tsk);
return -1;
}
}
return 0;
}
