Dag-Erling Sm鷨grav wrote:
>db <db@traceroute.dk> writes:
>
>
>>Memory on ia32 can be writable and readable. When it is readable it
>>is also executable. On other arch's like AMD64 and IA64, I believe
>>memory can be readable, writable and executable.
>>
>>
>
>Not quite. IA32 can make individual segments readable, writable and /
>or executable, but lacks the ability to do so on a per-page basis.
>Since we have trampoline code at the top of the stack, the entire
>stack segment must be executable. Moving the trampoline off the stack
>would solve the problem on all platforms.
>
>
There has been recent talk of a shared kernel/user memory page..
that could be used for trampoline code.
>W^X across the board is not an option - it would break HotSpot and
>other JIT-based software.
>
>DES
>
>
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