Re: read/write to virtual address
Daniel Krefft <[email protected]>
| Newsgroups | gmane.comp.micro-kernel.l4.devel |
|---|---|
| Message-ID | <[email protected]> |
Hi, we came across two functions (read/write) that are defined in the l4 base API documentation: https://os.inf.tu-dresden.de/L4Re/doc/group__l4__mem__op__api.html 1) What does the description "functionality to access user task memory from the kernel" mean? This could be interpreted as accessing user-space memory from within the kernel?! 2) Are there any equivalent memory read/write functions inside the l4re that also take a virtual address as a parameter? To clarify, all intended operations (read/write) should not modify user-space memory from inside the kernel or vice versa. User-space defined read/write functions should operate in user-space exclusively. Best Daniel On 14.02.2017 23:29, Adam Lackorzynski wrote: > Hi, > > On Tue Feb 14, 2017 at 10:38:26 +0100, Daniel Krefft wrote: >> while working on a checkpoint/restore mechanism for fiasco.oc, we want >> to trace read and write (kernel) calls to (virtual) memory. >> >> 1) Where are these calls defined? We're just able to find ARM specific >> calls inside the kernel, which allow writing and reading to/from a >> virtual address >> >> 2) Are these calls (if existent) platform agnostic (user-space)? Is >> there any kind of interface? > > I do not quite get the question. The kernel (Fiasco) is running in > virtual memory, also when running in the kernel, i.e. any load/store > operation that is in the code is through virtual memory. > Do you want to trace any read/write issued by the kernel to user-level > memory? I'm afraid, the kernel does not do that, i.e. it never touches > user-level memory (except the specially treated UTCB memory). > Could you please describe your question more verbosely? > > > > Adam > > _______________________________________________ > l4-hackers mailing list > [email protected] > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers > -- Daniel Krefft MSc. Wissenschaftlicher Mitarbeiter Technische Universitaet Muenchen Fakultaet fuer Informatik Lehrstuhl fuer Betriebssysteme Arcisstrasse 21 80333 Muenchen Tel. +49 89 289 18791 [email protected] www.os.in.tum.de/personen/krefft