Re: Privilege Levels Below User

On Wed, 12 Jun 2024 09:38:17 -0400, EricP wrote:

https://www.oreilly.com/library/view/understanding-the-linux/0596002130/ch04s08.html

That book is from 2002.

https://coral.googlesource.com/linux-imx/+/refs/heads/release-chef/arch/x86/entry/entry_32.S

That, too, seems a bit old. How about this for a more up-to-date
version:
<https://github.com/torvalds/linux/blob/master/arch/x86/entry/entry_32.S>.
Or try the 64-bit version:
<https://github.com/torvalds/linux/blob/master/arch/x86/entry/entry_64.S>.

The problem I have with this approach is that it deals with all the
race conditions (eg a nested interrupt posts a new softirq between
when you checked for pending softirq's and the IRET) by running with
interrupts disabled for long instruction sequences. I consider that
to be a poor way to do this as that blocks processing all other
interrupts.

But then again, things are complicated enough as it is.