MIPS: non-exec stack & heap when non-exec PT_GNU_STACK is present

The stack and heap have both been executable by default on MIPS until
now. This patch changes the default to be non-executable, but only for
ELF binaries with a non-executable PT_GNU_STACK header present. This
does apply to both the heap & the stack, despite the name PT_GNU_STACK,
and this matches the behaviour of other architectures like ARM & x86.

Current MIPS toolchains do not produce the PT_GNU_STACK header, which
means that we can rely upon this patch not changing the behaviour of
existing binaries. The new default will only take effect for newly
compiled binaries once toolchains are updated to support PT_GNU_STACK,
and since those binaries are newly compiled they can be compiled
expecting the change in default behaviour. Again this matches the way in
which the ARM & x86 architectures handled their implementations of
non-executable memory.

Signed-off-by: Paul Burton <[email protected]>
Cc: Leonid Yegoshin <[email protected]>
Cc: Maciej Rozycki <[email protected]>
Cc: Faraz Shahbazker <[email protected]>
Cc: Raghu Gandham <[email protected]>
Cc: Matthew Fortune <[email protected]>
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/13765/
Signed-off-by: Ralf Baechle <[email protected]>

0 files changed, 0 insertions, 0 deletions