Re: x86: get rid of the insane TIF_ABI_PENDING bit

From: Roland McGrath
Date: Mon Feb 15 2010 - 16:15:28 EST


> It's entirely possible it is completely superfluous. The patch in
> question only moves the setting. I don't know what gdb or strace use to
> distinguish a 32-bit and a 64-bit process, which is why I thought it
> might have something to do with ptrace.

Well, whatever it that might be, they have no way to know about the
TS_COMPAT setting. TS_COMPAT affects three things: audit_syscall_entry()
parameters, asm/syscall.h stuff, and is_compat_task()--nothing that is
directly visible from userland unless you count /proc/pid/syscall values.
Notably, that includes syscall_get_error() that is used in signal recovery.

AFAICT the only interesting use of is_compat_task() is the drivers/input stuff.


Thanks,
Roland
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