Ejemplo n.º 1
0
/*
 * Restore the extended state if present. Otherwise, restore the FP/SSE
 * state.
 */
static int restore_user_xstate(void __user *buf)
{
	struct _fpx_sw_bytes fx_sw_user;
	u64 mask;
	int err;

	if (((unsigned long)buf % 64) ||
	     check_for_xstate(buf, buf, &fx_sw_user))
		goto fx_only;

	mask = fx_sw_user.xstate_bv;

	/*
	 * restore the state passed by the user.
	 */
	err = xrestore_user(buf, mask);
	if (err)
		return err;

	/*
	 * init the state skipped by the user.
	 */
	mask = pcntxt_mask & ~mask;
	if (unlikely(mask))
		xrstor_state(init_xstate_buf, mask);

	return 0;

fx_only:
	/*
	 * couldn't find the extended state information in the
	 * memory layout. Restore just the FP/SSE and init all
	 * the other extended state.
	 */
	xrstor_state(init_xstate_buf, pcntxt_mask & ~XSTATE_FPSSE);
	return fxrstor_checking((struct i387_fxsave_struct __force_kernel *)buf);
}
Ejemplo n.º 2
0
static int restore_user_xstate(void __user *buf)
{
	struct _fpx_sw_bytes fx_sw_user;
	u64 mask;
	int err;

	if (((unsigned long)buf % 64) ||
	     check_for_xstate(buf, buf, &fx_sw_user))
		goto fx_only;

	mask = fx_sw_user.xstate_bv;

	/*
                                         
  */
	err = xrestore_user(buf, mask);
	if (err)
		return err;

	/*
                                       
  */
	mask = pcntxt_mask & ~mask;
	if (unlikely(mask))
		xrstor_state(init_xstate_buf, mask);

	return 0;

fx_only:
	/*
                                                       
                                                       
                             
  */
	xrstor_state(init_xstate_buf, pcntxt_mask & ~XSTATE_FPSSE);
	return fxrstor_checking((__force struct i387_fxsave_struct *)buf);
}
Ejemplo n.º 3
0
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;
}
Ejemplo n.º 4
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;
}