I use LUKS encryption on my entire drive. Do SSD drives ship with any storage areas which store unencrypted data, even though the data is saved encrypted on user-available SSD storage?
If you use LUKS, the disk doesn't ever see clear text data, and thus can't store it.
LUKS is implemented in the kernel, and encrypts data before sending it to the disk, and decrypting it before handing the blocks to the file system module.
The same goes for any software scheme; the disk will never receive the cleartext. With hardware based encryption, such as Opal this obviously change, as the disk will receive the cleartext in that case.