[PATCH 0/2] arm64: Cut rebuild time when changing CONFIG_BLK_DEV_INITRD

[Florian Fainelli]

Hi all,

While investigating why ARM64 required a ton of objects to be rebuilt
when toggling CONFIG_DEV_BLK_INITRD, it became clear that this was
because we define __early_init_dt_declare_initrd() differently and we do
that in arch/arm64/include/asm/memory.h which gets included by a fair
amount of other header files, and translation units as well.

This patch series proposes adding an empty initrd.h to satisfy the need
for drivers/of/fdt.c to unconditionally include that file, and moves the
custom __early_init_dt_declare_initrd() definition away from
asm/memory.h

This cuts the number of objects rebuilds from 1920 down to 26, so a
factor 73 approximately.

Apologies for the long CC list, please let me know how you would go
about merging that and if another approach would be preferable, e.g:
introducing a CONFIG_ARCH_INITRD_BELOW_START_OK Kconfig option or
something like that.

Florian Fainelli (2):
  arch: Add asm-generic/initrd.h and make use of it for most
    architectures
  arm64: Create asm/initrd.h

 arch/alpha/include/asm/Kbuild      |  1 +
 arch/arc/include/asm/Kbuild        |  1 +
 arch/arm/include/asm/Kbuild        |  1 +
 arch/arm64/include/asm/initrd.h    | 13 +++++++++++++
 arch/arm64/include/asm/memory.h    |  8 --------
 arch/c6x/include/asm/Kbuild        |  1 +
 arch/h8300/include/asm/Kbuild      |  1 +
 arch/hexagon/include/asm/Kbuild    |  1 +
 arch/ia64/include/asm/Kbuild       |  1 +
 arch/m68k/include/asm/Kbuild       |  1 +
 arch/microblaze/include/asm/Kbuild |  1 +
 arch/mips/include/asm/Kbuild       |  1 +
 arch/nds32/include/asm/Kbuild      |  1 +
 arch/nios2/include/asm/Kbuild      |  1 +
 arch/openrisc/include/asm/Kbuild   |  1 +
 arch/parisc/include/asm/Kbuild     |  1 +
 arch/powerpc/include/asm/Kbuild    |  1 +
 arch/riscv/include/asm/Kbuild      |  1 +
 arch/s390/include/asm/Kbuild       |  1 +
 arch/sh/include/asm/Kbuild         |  1 +
 arch/sparc/include/asm/Kbuild      |  1 +
 arch/um/include/asm/Kbuild         |  1 +
 arch/unicore32/include/asm/Kbuild  |  1 +
 arch/x86/include/asm/Kbuild        |  1 +
 arch/xtensa/include/asm/Kbuild     |  1 +
 drivers/of/fdt.c                   |  1 +
 include/asm-generic/initrd.h       |  1 +
 27 files changed, 38 insertions(+), 8 deletions(-)
 create mode 100644 arch/arm64/include/asm/initrd.h
 create mode 100644 include/asm-generic/initrd.h

-- 
2.17.1