Messages in this thread | | | Date | Fri, 12 Aug 2005 01:25:56 +0200 (CEST) | From | Bodo Eggert <> | Subject | Re: Need help in understanding x86 syscall |
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On Thu, 11 Aug 2005, Steven Rostedt wrote: > On Thu, 2005-08-11 at 15:41 +0200, Bodo Eggert wrote:
> > According to my documentation it isn't. A software interrupt is a far call > > with an extra pushf, and a hardware interrupt is protected against recursion > > by the PIC, not by an interrupt flag. > > I disagree with your definition of a system call. The "int 0x80" > changes from user mode to kernel mode so it is much more powerful than a > "far call".
Far calls and jumps can change to a inner ring. This is done by a special segment selector containing the segment _and_ the offset to jump to (the offset from the call instruction is ignored).
> Also the CPU does protect against recursion and more than > one interrupt coming in at the same time. The PIC also works with the > CPU in this regard, but as I shown in my previous email, the interrupt > flag _does_ protect against it.
Showing == claiming? However, my documentation was wrong.
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