Various subsystems embed non-code build artifacts into the kernel, for example the initramfs, /proc/config.gz, vDSO image, etc. Currently each user has their own implementation for that.
Add a common "blob" framework to provide this functionality. It provides standard kbuild and C APIs to embed and later access non-code build artifacts into the kernel image or modules.
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de
--- This is currently lacking a MAINTAINERS entry. Due to its closeness to kbuild I would tend to add it there. But I can also maintain it on its own. --- include/linux/blob.h | 21 +++++++++++++++++++++ scripts/Makefile.blobs | 19 +++++++++++++++++++ scripts/Makefile.build | 6 ++++++ scripts/Makefile.clean | 2 +- scripts/blob-wrap.c | 27 +++++++++++++++++++++++++++ 5 files changed, 74 insertions(+), 1 deletion(-)
diff --git a/include/linux/blob.h b/include/linux/blob.h new file mode 100644 index 0000000000000000000000000000000000000000..5749c364f7e9c93eb32a6d8870621e3d6df0683c --- /dev/null +++ b/include/linux/blob.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_BLOB_H +#define _LINUX_BLOB_H + +#include <linux/compiler_types.h> +#include <linux/types.h> + +struct blob { + const char *const path; + const u8 *data; + const u8 __private *end; +}; + +#define DECLARE_BLOB(_symbol) extern const struct blob _symbol + +static inline size_t blob_size(const struct blob *blob) +{ + return ACCESS_PRIVATE(blob, end) - blob->data; +} + +#endif /* _LINUX_BLOB_H */ diff --git a/scripts/Makefile.blobs b/scripts/Makefile.blobs new file mode 100644 index 0000000000000000000000000000000000000000..fd20ebb41c1d6509750debf7896a08a143d28759 --- /dev/null +++ b/scripts/Makefile.blobs @@ -0,0 +1,19 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Build linkable blobs +# + +blobs := $(addprefix $(obj)/, $(blobs)) + +blob-stem = $(subst -,_,$(subst .blob,,$(basename $(patsubst $(obj)/%,%,$@)))) +blob-symbol = $(or $($(target-stem)-symbol),$(blob-stem)) + +blob-flags = -DBLOB_SYMBOL="$(blob-symbol)" -DBLOB_INPUT=$< + +quiet_cmd_blob = BLOB $@ + cmd_blob = $(CC) $(c_flags) $(blob-flags) -c -o $@ $(srctree)/scripts/blob-wrap.c + +$(blobs): $(obj)/%.blob.o: $(obj)/% $(srctree)/scripts/blob-wrap.c FORCE + $(call if_changed_dep,blob) + +targets += $(blobs) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 993708d1187459f3678d68ec81ef005e6f51d470..def9791523d718552617ef6ef752c1852d40d996 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -440,6 +440,12 @@ ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(targets) include $(srctree)/scripts/Makefile.dtbs endif
+# $(sort ...) is used here to remove duplicated words and excessive spaces. +blobs := $(sort $(blobs)) +ifneq ($(blobs),) +include $(srctree)/scripts/Makefile.blobs +endif + # Build # ---------------------------------------------------------------------------
diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean index 6ead00ec7313b3e4330a8de5f1342f2da1d6eb84..536972b0a528d117e17296da9936825c3903af6e 100644 --- a/scripts/Makefile.clean +++ b/scripts/Makefile.clean @@ -25,7 +25,7 @@ subdir-ymn := $(addprefix $(obj)/,$(subdir-ymn)) # directory
__clean-files := \ - $(clean-files) $(targets) $(hostprogs) $(userprogs) \ + $(clean-files) $(targets) $(hostprogs) $(userprogs) $(blobs) \ $(extra-y) $(extra-m) $(extra-) \ $(always-y) $(always-m) $(always-) \ $(hostprogs-always-y) $(hostprogs-always-m) $(hostprogs-always-) \ diff --git a/scripts/blob-wrap.c b/scripts/blob-wrap.c new file mode 100644 index 0000000000000000000000000000000000000000..715d6981fa94bee309c693c2b937899c982e27b4 --- /dev/null +++ b/scripts/blob-wrap.c @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include <linux/args.h> +#include <linux/blob.h> +#include <linux/stringify.h> + +#define BLOB_SYMBOL_DATA CONCATENATE(_blob_data_, BLOB_SYMBOL) +#define BLOB_SYMBOL_END CONCATENATE(_blob_end_, BLOB_SYMBOL) + +asm ( +" .pushsection .rodata, "a" \n" +" .global " __stringify(BLOB_SYMBOL_DATA) " \n" + __stringify(BLOB_SYMBOL_DATA) ": \n" +" .incbin "" __stringify(BLOB_INPUT) "" \n" +" .global " __stringify(BLOB_SYMBOL_END) " \n" + __stringify(BLOB_SYMBOL_END) ": \n" +" .popsection \n" +); + +extern const u8 BLOB_SYMBOL_DATA; +extern const u8 BLOB_SYMBOL_END; + +const struct blob BLOB_SYMBOL = { + .path = __stringify(BLOB_INPUT), + .data = &BLOB_SYMBOL_DATA, + .end = &BLOB_SYMBOL_END, +};