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Merge pull request #15 from tavip/lktp-syscalls-fixes
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Documentation: teaching: syscall lecture: fix slide to fit
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tavip committed Feb 27, 2018
2 parents 1c634de + be0e9d8 commit 11584a0
Showing 1 changed file with 6 additions and 8 deletions.
14 changes: 6 additions & 8 deletions Documentation/teaching/lectures/syscalls.rst
Original file line number Diff line number Diff line change
Expand Up @@ -194,21 +194,19 @@ In summary, this is what happens during a system call:
* The application is setting up the system call number and
parameters and it issues a trap instruction

* The execution mode switches from user to kernel

* During this process, the CPU switches to a kernel stack, while
saving the user stack and return address to userspace
* The execution mode switches from user to kernel; the CPU switches
to a kernel stack; the user stack and the return address to user
space is saved on the kernel stack

* The kernel entry point saves registers on the kernel stack

* The system call dispatcher identifies the system call function
and runs it

* When the system call function returns the userspace registers are
restored and execution is switched back to user mode by executing
an architecture specific instruction (e.g. IRET)
* The userspace registers are restored and execution is switched
back to user (e.g. calling IRET)

* userspace application resumes
* Userspace application resumes


System call table
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