How can NuttX write log data on a Pixhawk1's SD card?

Hello, My question is a little bit off topic.
I already know PX4 has a log function (i.e. SYS_LOGGER).
But, I would like to know how NuttX can write a log data on a Pixhawk1’s SD card because I want to leave NuttX’s logs on the SD card.
In other words, I don’t figure out that how NuttX codes can access the Pixhawk1’s SD card.
If you have any experience related to my question, Please leave me a reply.