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SubjectRe: [RFC] de-asmify the x86-64 system call slowpath
On 01/27, Al Viro wrote:
>
> BTW, there's an additional pile of obfuscation:
> /* work to do on interrupt/exception return */
> #define _TIF_WORK_MASK \
> (0x0000FFFF & \
> ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT| \
> _TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU))
>
> /* work to do on any return to user space */
> #define _TIF_ALLWORK_MASK \
> ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \
> _TIF_NOHZ)

Heh, yes ;)

> Why is _TIF_UPROBE *not* a part
> of _TIF_DO_NOTIFY_MASK, for example?

Yes, please see another email. That is why uprobe_deny_signal()
sets TIF_NOTIFY_RESUME along with TIF_UPROBE.

Oleg.



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