fdt: Add Kconfig options to control code size

For better or worse libfdt recent grew a lot of code that checks the
validity of the device tree in great detail. When using unsigned or
unverified data this makes things safer, but it does add to code size.

Add some controls to select the trade-off between safety and code size.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
This commit is contained in:
Simon Glass 2019-10-27 09:47:40 -06:00
parent 8659895350
commit 0d76afc032
2 changed files with 35 additions and 1 deletions

View file

@ -464,6 +464,17 @@ config OF_LIBFDT
particular compatible nodes. The library operates on a flattened
version of the device tree.
config OF_LIBFDT_ASSUME_MASK
hex "Mask of conditions to assume for libfdt"
depends on OF_LIBFDT || FIT
default 0
help
Use this to change the assumptions made by libfdt about the
device tree it is working with. A value of 0 means that no assumptions
are made, and libfdt is able to deal with malicious data. A value of
0xff means all assumptions are made and any invalid data may cause
unsafe execution. See FDT_ASSUME_PERFECT, etc. in libfdt_internal.h
config OF_LIBFDT_OVERLAY
bool "Enable the FDT library overlay support"
depends on OF_LIBFDT
@ -481,6 +492,17 @@ config SPL_OF_LIBFDT
particular compatible nodes. The library operates on a flattened
version of the device tree.
config SPL_OF_LIBFDT_ASSUME_MASK
hex "Mask of conditions to assume for libfdt"
depends on SPL_OF_LIBFDT || FIT
default 0xff
help
Use this to change the assumptions made by libfdt in SPL about the
device tree it is working with. A value of 0 means that no assumptions
are made, and libfdt is able to deal with malicious data. A value of
0xff means all assumptions are made and any invalid data may cause
unsafe execution. See FDT_ASSUME_PERFECT, etc. in libfdt_internal.h
config TPL_OF_LIBFDT
bool "Enable the FDT library for TPL"
default y if TPL_OF_CONTROL
@ -491,6 +513,17 @@ config TPL_OF_LIBFDT
particular compatible nodes. The library operates on a flattened
version of the device tree.
config TPL_OF_LIBFDT_ASSUME_MASK
hex "Mask of conditions to assume for libfdt"
depends on TPL_OF_LIBFDT || FIT
default 0xff
help
Use this to change the assumptions made by libfdt in TPL about the
device tree it is working with. A value of 0 means that no assumptions
are made, and libfdt is able to deal with malicious data. A value of
0xff means all assumptions are made and any invalid data may cause
unsafe execution. See FDT_ASSUME_PERFECT, etc. in libfdt_internal.h
config FDT_FIXUP_PARTITIONS
bool "overwrite MTD partitions in DTS through defined in 'mtdparts'"
depends on OF_LIBFDT

View file

@ -22,4 +22,5 @@ obj-y += fdt_ro.o
# U-Boot own file
obj-y += fdt_region.o
ccflags-y := -I$(srctree)/scripts/dtc/libfdt
ccflags-y := -I$(srctree)/scripts/dtc/libfdt \
-DFDT_ASSUME_MASK=$(CONFIG_$(SPL_TPL_)OF_LIBFDT_ASSUME_MASK)