linux-kernel - Re: [GIT PULL] Firmware files removal for 4.14-rc1

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Date:   Sat, 16 Sep 2017 08:25:03 +0200
From:   Markus Trippelsdorf <markus@...ppelsdorf.de>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [GIT PULL] Firmware files removal for 4.14-rc1

On 2017.09.16 at 06:51 +0200, Markus Trippelsdorf wrote:
> On 2017.09.15 at 11:56 -0700, Greg KH wrote:
> > The following changes since commit 569dbb88e80deb68974ef6fdd6a13edb9d686261:
> >
> >   Linux 4.13 (2017-09-03 13:56:17 -0700)
> >
> > are available in the git repository at:
> >
> >   git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git/ tags/firmware_removal-4.14-rc1
> >
> > for you to fetch changes up to 5620a0d1aacd554ebebcff373e31107bb1ef7769:
> >
> >   firmware: delete in-kernel firmware (2017-09-14 14:49:41 -0700)
> >
> > ----------------------------------------------------------------
> > Firmware removal patch for 4.14-rc1
> >
> > Many many years ago (at the kernel summit in Boston), we all came to the
> > agreement that the firmware/ tree should be dropped from the kernel, and
> > everyone use the linux-firmware package instead.  For some minor reason,
> > David Woodhouse didn't send the pull request at that point in time, and
> > everyone forgot about this.
> >
> > The topic came up in the hallway track at the Plumbers conference this
> > week, so here's a single patch that drops the whole firmware tree.  The
> > last firmware update was back in 2013, and all distros have been using
> > linux-firmware instead since at least that year, if not before.  The
> > only commits to that directory since 2013 was some kbuild fixups for
> > various build tool issues.
> >
> > So lets finally drop this, we don't need to lug them around in the
> > kernel source tree anymore, especially as no one wants or uses them.
> 
> Well, it is one thing to drop the redundant binary blobs. But is another
> to break perfectly fine setups that worked for years, e.g.:
> 
> CONFIG_FW_LOADER=y
> CONFIG_FIRMWARE_IN_KERNEL=y
> CONFIG_EXTRA_FIRMWARE="amd-ucode/microcode_amd.bin radeon/R600_rlc.bin"
> CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
> 
> Please restore the support for built-in firmware.

The following patch seems to work for me.

 Makefile             |  2 +-
 drivers/base/Kconfig |  5 +----
 firmware/.gitignore  |  6 +++++
 firmware/Makefile    | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 71 insertions(+), 5 deletions(-)
 create mode 100644 firmware/.gitignore
 create mode 100644 firmware/Makefile

diff --git a/Makefile b/Makefile
index 7e2ca4971a39..9f86816c41fd 100644
--- a/Makefile
+++ b/Makefile
@@ -562,7 +562,7 @@ scripts: scripts_basic include/config/auto.conf include/config/tristate.conf \
 
 # Objects we will link into vmlinux / subdirs we need to visit
 init-y		:= init/
-drivers-y	:= drivers/ sound/
+drivers-y	:= drivers/ sound/ firmware/
 net-y		:= net/
 libs-y		:= lib/
 core-y		:= usr/
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index f046d21de57d..1a5f6a157a57 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -140,13 +140,10 @@ config EXTRA_FIRMWARE
 config EXTRA_FIRMWARE_DIR
 	string "Firmware blobs root directory"
 	depends on EXTRA_FIRMWARE != ""
-	default "firmware"
+	default "/lib/firmware"
 	help
 	  This option controls the directory in which the kernel build system
 	  looks for the firmware files listed in the EXTRA_FIRMWARE option.
-	  The default is firmware/ in the kernel source tree, but by changing
-	  this option you can point it elsewhere, such as /lib/firmware/ or
-	  some other directory containing the firmware files.
 
 config FW_LOADER_USER_HELPER
 	bool
diff --git a/firmware/.gitignore b/firmware/.gitignore
new file mode 100644
index 000000000000..d9c69017bc9a
--- /dev/null
+++ b/firmware/.gitignore
@@ -0,0 +1,6 @@
+*.gen.S
+*.fw
+*.bin
+*.csp
+*.dsp
+ihex2fw
diff --git a/firmware/Makefile b/firmware/Makefile
new file mode 100644
index 000000000000..fa0808853883
--- /dev/null
+++ b/firmware/Makefile
@@ -0,0 +1,63 @@
+#
+# kbuild file for firmware/
+#
+
+# Create $(fwabs) from $(CONFIG_EXTRA_FIRMWARE_DIR) -- if it doesn't have a
+# leading /, it's relative to $(srctree).
+fwdir := $(subst $(quote),,$(CONFIG_EXTRA_FIRMWARE_DIR))
+fwabs := $(addprefix $(srctree)/,$(filter-out /%,$(fwdir)))$(filter /%,$(fwdir))
+
+fw-external-y := $(subst $(quote),,$(CONFIG_EXTRA_FIRMWARE))
+
+quiet_cmd_fwbin = MK_FW   $@
+      cmd_fwbin = FWNAME="$(patsubst firmware/%.gen.S,%,$@)";		     \
+		  FWSTR="$(subst /,_,$(subst .,_,$(subst -,_,$(patsubst	     \
+				firmware/%.gen.S,%,$@))))";		     \
+		  ASM_WORD=$(if $(CONFIG_64BIT),.quad,.long);		     \
+		  ASM_ALIGN=$(if $(CONFIG_64BIT),3,2);			     \
+		  PROGBITS=$(if $(CONFIG_ARM),%,@)progbits;		     \
+		  echo "/* Generated by firmware/Makefile */"		> $@;\
+		  echo "    .section .rodata"				>>$@;\
+		  echo "    .p2align $${ASM_ALIGN}"			>>$@;\
+		  echo "_fw_$${FWSTR}_bin:"				>>$@;\
+		  echo "    .incbin \"$(2)\""				>>$@;\
+		  echo "_fw_end:"					>>$@;\
+		  echo "   .section .rodata.str,\"aMS\",$${PROGBITS},1"	>>$@;\
+		  echo "    .p2align $${ASM_ALIGN}"			>>$@;\
+		  echo "_fw_$${FWSTR}_name:"				>>$@;\
+		  echo "    .string \"$$FWNAME\""			>>$@;\
+		  echo "    .section .builtin_fw,\"a\",$${PROGBITS}"	>>$@;\
+		  echo "    .p2align $${ASM_ALIGN}"			>>$@;\
+		  echo "    $${ASM_WORD} _fw_$${FWSTR}_name"		>>$@;\
+		  echo "    $${ASM_WORD} _fw_$${FWSTR}_bin"		>>$@;\
+		  echo "    $${ASM_WORD} _fw_end - _fw_$${FWSTR}_bin"	>>$@;
+
+# One of these files will change, or come into existence, whenever
+# the configuration changes between 32-bit and 64-bit. The .S files
+# need to change when that happens.
+wordsize_deps := $(wildcard include/config/64bit.h include/config/32bit.h \
+		include/config/ppc32.h include/config/ppc64.h \
+		include/config/superh32.h include/config/superh64.h \
+		include/config/x86_32.h include/config/x86_64.h \
+		firmware/Makefile)
+
+$(patsubst %,$(obj)/%.gen.S, $(fw-external-y)): %: $(wordsize_deps) \
+		include/config/extra/firmware/dir.h
+	$(call cmd,fwbin,$(fwabs)/$(patsubst $(obj)/%.gen.S,%,$@))
+
+# The .o files depend on the binaries directly; the .S files don't.
+$(patsubst %,$(obj)/%.gen.o, $(fw-external-y)): $(obj)/%.gen.o: $(fwdir)/%
+
+obj-y				 += $(patsubst %,%.gen.o, $(fw-external-y))
+
+ifeq ($(KBUILD_SRC),)
+# Makefile.build only creates subdirectories for O= builds, but external
+# firmware might live outside the kernel source tree
+_dummy := $(foreach d,$(addprefix $(obj)/,$(dir $(fw-external-y))), $(shell [ -d $(d) ] || mkdir -p $(d)))
+endif
+
+targets := $(patsubst $(obj)/%,%, \
+                                $(shell find $(obj) -name \*.gen.S 2>/dev/null))
+# Without this, built-in.o won't be created when it's empty, and the
+# final vmlinux link will fail.
+obj- := dummy
-- 
Markus