Commit d2c101d4 authored by Alexander Razinkov's avatar Alexander Razinkov Committed by Carles Cufi
Browse files

kernel: init: conditional .bss section zeroing 



Some platforms already have .bss section zeroed-out externally before the
Zephyr initialization and there is no sence to zero it out the second time
from the SW.
Such boot-time optimization could be critical e.g. for RTL Simulation.

Signed-off-by: default avatarAlexander Razinkov <alexander.razinkov@syntacore.com>
parent 8816852c

arch/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -139,6 +139,8 @@ config ARCH_POSIX 
	select NATIVE_BUILD

	select HAS_COVERAGE_SUPPORT

	select BARRIER_OPERATIONS_BUILTIN

	# native_posix gets its memory cleared on entry by the host OS

	select SKIP_BSS_CLEAR

	help

	  POSIX (native) architecture

kernel/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -382,6 +382,16 @@ config INIT_STACKS 
	  water mark can be easily determined. This applies to the stack areas

	  for threads, as well as to the interrupt stack.



config SKIP_BSS_CLEAR

	bool

	help

	  This option disables software .bss section zeroing during Zephyr

	  initialization. Such boot-time optimization could be used for

	  platforms where .bss section is zeroed-out externally.

	  Please pay attention that when this option is enabled

	  the responsibility for .bss zeroing in all possible scenarios

	  (mind e.g. SW reset) is delegated to the external SW or HW.



config BOOT_BANNER

	bool "Boot banner"

	default y

kernel/init.c

+1 −6
Original line number Diff line number Diff line
@@ -165,12 +165,7 @@ void __weak z_early_memcpy(void *dst, const void *src, size_t n) 
__boot_func

void z_bss_zero(void)

{

	if (IS_ENABLED(CONFIG_ARCH_POSIX)) {

		/* native_posix gets its memory cleared on entry by

		 * the host OS, and in any case the host clang/lld

		 * doesn't emit the __bss_end symbol this code expects

		 * to see

		 */

	if (IS_ENABLED(CONFIG_SKIP_BSS_CLEAR)) {

		return;

	}

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