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authorSamuel Holland <samuel@sholland.org>2018-10-17 21:40:18 -0500
committerSamuel Holland <samuel@sholland.org>2019-12-29 12:00:40 -0600
commitf8578e641b38694a6a2dee84ef7a7b3b0b50bd0f (patch)
tree8dba3d725b4d35aac1662ecc1e762834830f8426 /make_helpers
parentcaa0c85d2f8ae61c6ff630ca0cd5ef77ea91f1fc (diff)
downloadtrusted-firmware-a-f8578e641b38694a6a2dee84ef7a7b3b0b50bd0f.tar.gz
bl31: Split into two separate memory regions
Some platforms are extremely memory constrained and must split BL31 between multiple non-contiguous areas in SRAM. Allow the NOBITS sections (.bss, stacks, page tables, and coherent memory) to be placed in a separate region of RAM from the loaded firmware image. Because the NOBITS region may be at a lower address than the rest of BL31, __RW_{START,END}__ and __BL31_{START,END}__ cannot include this region, or el3_entrypoint_common would attempt to invalidate the dcache for the entire address space. New symbols __NOBITS_{START,END}__ are added when SEPARATE_NOBITS_REGION is enabled, and the dcached for the NOBITS region is invalidated separately. Signed-off-by: Samuel Holland <samuel@sholland.org> Change-Id: Idedfec5e4dbee77e94f2fdd356e6ae6f4dc79d37
Diffstat (limited to 'make_helpers')
-rw-r--r--make_helpers/defaults.mk4
1 files changed, 4 insertions, 0 deletions
diff --git a/make_helpers/defaults.mk b/make_helpers/defaults.mk
index a1f9db9d3e..53832c5611 100644
--- a/make_helpers/defaults.mk
+++ b/make_helpers/defaults.mk
@@ -171,6 +171,10 @@ SDEI_SUPPORT := 0
# platform Makefile is free to override this value.
SEPARATE_CODE_AND_RODATA := 0
+# Put NOBITS sections (.bss, stacks, page tables, and coherent memory) in a
+# separate memory region, which may be discontiguous from the rest of BL31.
+SEPARATE_NOBITS_REGION := 0
+
# If the BL31 image initialisation code is recalimed after use for the secondary
# cores stack
RECLAIM_INIT_CODE := 0