Messages in this thread | | | From | Andy Lutomirski <> | Date | Thu, 31 May 2018 13:14:06 -0700 | Subject | Re: [PATCH V2 01/15] x86/fsgsbase/64: Introduce FS/GS base helper functions |
| |
On Thu, May 31, 2018 at 10:58 AM Chang S. Bae <chang.seok.bae@intel.com> wrote: > > With new helpers, FS/GS base access is centralized. > Eventually, when FSGSBASE instruction enabled, it will > be faster. > > The helpers are used on ptrace APIs (PTRACE_ARCH_PRCTL, > PTRACE_SETREG, PTRACE_GETREG, etc). Idea is to keep > the FS/GS-update mechanism organized. > > Notion of "active" and "inactive" are used to distinguish > GS bases between "kernel" and "user". "inactive" GS base > is the GS base, backed up at kernel entries, of inactive > (user) task's.
I'm fine with the code, but the changelog entry is confusing. A bunch of the active helpers don't contain the term "active".
> +/* > + * Read/write an (inactive) task's fsbase or gsbase. This returns > + * the value that the FS/GS base would have (if the task were to be > + * resumed). The current task is also supported. > + */
Please change to "Read/write a task's fsbase or gsbase. ... These work on current or on a different non-running task."
> + > +unsigned long read_task_fsbase(struct task_struct *task) > +{ > + unsigned long fsbase; > + > + if (task == current) > + fsbase = read_fsbase(); > + else > + /* > + * XXX: This will not behave as expected if called > + * if fsindex != 0 > + */ > + fsbase = task->thread.fsbase; > +
Please put braces around the if and else blocks whenever either of them spans multiple lines. Also, maybe change add a note to the comment and/or the changelog that this is preserving an existing bug and that it's fixed later in the series.
| |