ARM: lib: add call_with_stack function for safely changing stack
authorWill Deacon <will.deacon@arm.com>
Wed, 8 Jun 2011 14:29:00 +0000 (15:29 +0100)
committerWill Deacon <will.deacon@arm.com>
Mon, 12 Dec 2011 16:07:35 +0000 (16:07 +0000)
commit2d81f1fe81b753a5744fd2deceafab3e62ba02d5
treea5660d357bb9920f34751dd3ab39298e3e7cb33e
parentad622671a4da0b6db1c1382e6345e1361c5fbab8
ARM: lib: add call_with_stack function for safely changing stack

When disabling the MMU, it is necessary to take out a 1:1 identity map
of the reset code so that it can safely be executed with and without
the MMU active. To avoid the situation where the physical address of the
reset code aliases with the virtual address of the active stack (which
cannot be included in the 1:1 mapping), it is desirable to change to a
new stack at a location which is less likely to alias.

This code adds a new lib function, call_with_stack:

void call_with_stack(void (*fn)(void *), void *arg, void *sp);

which changes the stack to point at the sp parameter, before invoking
fn(arg) with the new stack selected.

Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arch/arm/lib/Makefile
arch/arm/lib/call_with_stack.S [new file with mode: 0644]