Re: serious performance regression due to NX patch

From: David Mosberger
Date: Mon Jul 12 2004 - 15:36:14 EST


>>>>> On Mon, 12 Jul 2004 13:17:20 -0700 (PDT), Linus Torvalds <torvalds@xxxxxxxx> said:

Linus> No. Make it a CONFIG_DEFAULT_NOEXEC and make the relevant
Linus> architectures do a

Linus> define_bool DEFAULT_NOEXEC y

Linus> in their Kconfig files.

Linus> In general, we should _never_ use an
Linus> architecture-define. They just always end up becoming more
Linus> and more hairy, and less and less obvious what they are all
Linus> about.

Linus> So instead, make a readable and explicit config define, and
Linus> let each architecture just set it (or not) as they wish.

Oops, I responded too fast here. This is still wrong: on ia64 (and
x86-64, I believe), you'll want DEFAULT_NOEXEC for native binaries,
but DEFAULT_EXEC for x86 binaries.

So I think it would be better to have a VM_STACK_EXEC_FLAGS macro in
an asm header file (with suitable default in asm-generic).

--david
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