void flush_thread(void)
{
struct task_struct *tsk = current;
flush_ptrace_hw_breakpoint(tsk);
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
fpu__clear(&tsk->thread.fpu);
}
static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
{
int ia32_fxstate = (buf != buf_fx);
struct task_struct *tsk = current;
struct fpu *fpu = &tsk->thread.fpu;
int state_size = fpu_kernel_xstate_size;
u64 xfeatures = 0;
int fx_only = 0;
ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) ||
IS_ENABLED(CONFIG_IA32_EMULATION));
if (!buf) {
fpu__clear(fpu);
return 0;
}
if (!access_ok(VERIFY_READ, buf, size))
return -EACCES;
fpu__activate_curr(fpu);
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 fxregs_state);
fx_only = 1;
trace_x86_fpu_xstate_check_failed(fpu);
} else {
state_size = fx_sw_user.xstate_size;
xfeatures = fx_sw_user.xfeatures;
}
}
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 fpu *fpu = &tsk->thread.fpu;
struct user_i387_ia32_struct env;
int err = 0;
/*
* Drop the current fpu which clears fpu->fpstate_active. 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
* fpu->fpstate_active is again set.
*/
fpu__drop(fpu);
if (using_compacted_format()) {
err = copyin_to_xsaves(NULL, buf_fx,
&fpu->state.xsave);
} else {
err = __copy_from_user(&fpu->state.xsave,
buf_fx, state_size);
}
if (err || __copy_from_user(&env, buf, sizeof(env))) {
fpstate_init(&fpu->state);
trace_x86_fpu_init_state(fpu);
err = -1;
} else {
sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
}
fpu->fpstate_active = 1;
if (use_eager_fpu()) {
preempt_disable();
fpu__restore(fpu);
preempt_enable();
}
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 (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) {
fpu__clear(fpu);
return -1;
}
}
return 0;
}