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Commit 9ec36c01 authored by Raghavendra Rao Ananta's avatar Raghavendra Rao Ananta
Browse files

kbuild: Add support for CONFIG_UNUSED_KSYMS_WHITELIST_ONLY 



CONFIG_UNUSED_KSYMS_WHITELIST_ONLY extends the support for the
existing CONFIG_UNUSED_KSYMS_WHITELIST in a way that, if enabled,
it would allow the kbuild to export ONLY the symbols that are
supplied as a part of whitelist (and of course the ones exported
by modules). That is, the build would break for modules during
modpost with:
ERROR: "<symbol>" [<module>.ko] undefined!

When enabled, the option is quite useful in build integration
systems to detect if the whitelist file needs an update.

Change-Id: Ica0a270214d4d51f6e2269fdc591fb86acbc4f97
Signed-off-by: default avatarRaghavendra Rao Ananta <rananta@codeaurora.org>
parent d476d5ad

Makefile

+2 −0
Original line number Diff line number Diff line
@@ -1362,6 +1362,8 @@ all: modules 


PHONY += modules

modules: $(if $(KBUILD_BUILTIN),vmlinux) modules.order modules.builtin

	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \

	  "$(MAKE) -f $(srctree)/Makefile vmlinux"

	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost

	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/modules-check.sh

init/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -2250,6 +2250,17 @@ config UNUSED_KSYMS_WHITELIST 
	  one per line. The path can be absolute, or relative to the kernel

	  source tree.



config UNUSED_KSYMS_WHITELIST_ONLY

	bool "Export ONLY the symbols that are a part of whitelist"

	depends on UNUSED_KSYMS_WHITELIST != ""

	help

	  Keep ONLY the symbols that are defined in the whitelist. The

	  CONFIG works on top of CONFIG_UNUSED_KSYMS_WHITELIST which takes

	  whitelist file(s) as its settings, and would export only the

	  symbols listed in these file(s).

	  This is mainly used to detect if drivers are using the symbols

	  outside of the whitelist.



endif # MODULES



config MODULES_TREE_LOOKUP

scripts/adjust_autoksyms.sh

+5 −0
Original line number Diff line number Diff line
@@ -40,6 +40,11 @@ esac 
# Generate a new symbol list file

$CONFIG_SHELL $srctree/scripts/gen_autoksyms.sh "$new_ksyms_file"



if [ -n "$CONFIG_UNUSED_KSYMS_WHITELIST_ONLY" ] && [ -f "vmlinux" ] ; then

	info "WARNING" "CONFIG_UNUSED_KSYMS_WHITELIST_ONLY is enabled. "\

"Non-whitelisted symbols will be undefined!"

fi



# Extract changes between old and new list and touch corresponding

# dependency files.

changed=$(

scripts/gen_autoksyms.sh

+38 −8
Original line number Diff line number Diff line
@@ -21,13 +21,18 @@ esac 


ksym_wl=/dev/null

if [ -n "$CONFIG_UNUSED_KSYMS_WHITELIST" ]; then

	# Use 'eval' to expand the whitelist path and check if it is relative

	eval ksym_wl="$CONFIG_UNUSED_KSYMS_WHITELIST"

	[ "${ksym_wl}" != "${ksym_wl#/}" ] || ksym_wl="$abs_srctree/$ksym_wl"

	for UNUSED_KSYMS_WHITELIST_FILE in $CONFIG_UNUSED_KSYMS_WHITELIST; do

		# Use 'eval' to expand the whitelist path and

		# check if it is relative

		eval ksym_wl="$UNUSED_KSYMS_WHITELIST_FILE"

		[ "${ksym_wl}" != "${ksym_wl#/}" ] ||

		ksym_wl="$abs_srctree/$ksym_wl"

		if [ ! -f "$ksym_wl" ]; then

			echo "ERROR: '$ksym_wl' whitelist file not found" >&2

			exit 1

		fi

		ksym_wls="$ksym_wls $ksym_wl"

	done

fi



# Generate a new ksym list file with symbols needed by the current
@@ -42,7 +47,8 @@ EOT 
[ -f modules.order ] && modlist=modules.order || modlist=/dev/null

sed 's/ko$/mod/' $modlist |

xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- |

cat - "$ksym_wl" |

cat - $ksym_wls |

sed 's/^#.*//;s/^ *//;/[[abi_whitelist]]/g' |

sort -u |

sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file"
@@ -50,3 +56,27 @@ sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file" 
if [ -n "$CONFIG_MODVERSIONS" ]; then

	echo "#define __KSYM_module_layout 1" >> "$output_file"

fi



if [ -n "$CONFIG_UNUSED_KSYMS_WHITELIST_ONLY" ] && [ -f "vmlinux" ] ; then

	syms_from_whitelist="$(mktemp)"

	syms_from_vmlinux="$(mktemp)"



	cat $ksym_wls |

	sed 's/^#.*//;s/^ *//;/[[abi_whitelist]]/g' |

	sort -u > "$syms_from_whitelist"



	$NM --defined-only vmlinux |

	grep "__ksymtab_" |

	sed 's/^.*__ksymtab_//' |

	sort -u > "$syms_from_vmlinux"



	# Forcefully unexport the symbols that are not declared in the whitelist

	syms_to_unexport=$(comm -13 "$syms_from_whitelist" "$syms_from_vmlinux")



	for sym_to_unexport in $syms_to_unexport; do

		sed -i "/^#define __KSYM_${sym_to_unexport} 1/d" \

							"$output_file"

	done



	rm -f "$syms_from_whitelist" "$syms_from_vmlinux"

fi