michaelh/zephyr
1
0
Fork 0
Code Releases Activity

arch: arm: introduce macro to describe the privilege stack alignment

Browse source 
We introduce a new define to describe the alignment for a
privilege stack buffer. This macro definition is used by the
privilege stack generation script, to determine the required
alignment of threads' privilege stacks when building with
support for user mode.

We cannot use Z_THREAD_MIN_STACK_ALIGN in this case, because
the privilege stacks do not need to respect the minimum MPU
region alignment requirement, unless, of course, this is
enforced via the MPU Stack Guard feature.

Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit is contained in:
Ioannis Glaropoulos 2019-06-13 13:41:16 +02:00 • committed by Andrew Boie
commit 518bfa39e3
1 changed files with 15 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

15
include/arch/arm/arch.h
View file

@ -155,6 +155,21 @@ extern "C" {
*/
#define STACK_ALIGN MAX(Z_THREAD_MIN_STACK_ALIGN, Z_MPU_GUARD_ALIGN)
/**
* @brief Define alignment of a privilege stack buffer
*
* This is used to determine the required alignment of threads'
* privilege stacks when building with support for user mode.
*
* @note
* The privilege stacks do not need to respect the minimum MPU
* region alignment requirement (unless this is enforced via
* the MPU Stack Guard feature).
*/
#if defined(CONFIG_USERSPACE)
#define Z_PRIVILEGE_STACK_ALIGN MAX(STACK_ALIGN_SIZE, Z_MPU_GUARD_ALIGN)
#endif
/**
* @brief Calculate power of two ceiling for a buffer size input
*