linux-kernel - [PATCH 0/3] arch/x86: Remove unnecessary dependencies on bootparam.h

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Message-ID: <20231206125433.18420-1-tzimmermann@suse.de>
Date:   Wed,  6 Dec 2023 13:38:36 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     ardb@...nel.org, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org,
        hpa@...or.com, bhelgaas@...gle.com, arnd@...db.de,
        zohar@...ux.ibm.com, dmitry.kasatkin@...il.com,
        paul@...l-moore.com, jmorris@...ei.org, serge@...lyn.com,
        javierm@...hat.com
Cc:     linux-arch@...r.kernel.org, linux-efi@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
        linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        Thomas Zimmermann <tzimmermann@...e.de>
Subject: [PATCH 0/3] arch/x86: Remove unnecessary dependencies on bootparam.h

Reduce built time in some cases by removing unnecessary include statements
for <asm/bootparam.h>. Reorganize some header files accordingly.

While working on the kernel's boot-up graphics, I noticed that touching
include/linux/screen_info.h triggers a complete rebuilt of the kernel
on x86. It turns out that the architecture's PCI and EFI headers include
<asm/bootparam.h>, which depends on <linux/screen_info.h>. But none of
the drivers have any business with boot parameters or the screen_info
state.

The patchset moves a few limes from pci.h and efi.h into separate header
files and then removes the obsolete include statements on x86. I did

  make allmodconfig
  make -j28
  touch include/linus/screen_info.h
  time -j28 make

to measure the time it takes to rebuild. Results without the patchset
are around 20 minutes.

  real    20m46,705s
  user    354m29,166s
  sys     28m27,359s

And with the patchset applied it goes down to about a minute.

  real    0m58,232s
  user    4m37,617s
  sys     0m34,993s

The test system was an Intel i5-13500.

Thomas Zimmermann (3):
  arch/x86: Move struct pci_setup_rom into pci_setup.h
  arch/x86: Add <asm/ima-efi.h> for arch_ima_efi_boot_mode
  arch/x86: Do not include <asm/bootparam.h> in several header files

 arch/x86/include/asm/efi.h              |  3 ---
 arch/x86/include/asm/ima-efi.h          | 12 ++++++++++++
 arch/x86/include/asm/kexec.h            |  1 -
 arch/x86/include/asm/mem_encrypt.h      |  2 +-
 arch/x86/include/asm/pci.h              | 13 -------------
 arch/x86/include/asm/pci_setup.h        | 19 +++++++++++++++++++
 arch/x86/include/asm/sev.h              |  3 ++-
 arch/x86/include/asm/x86_init.h         |  2 --
 arch/x86/pci/common.c                   |  1 +
 drivers/firmware/efi/libstub/x86-stub.c |  1 +
 include/asm-generic/Kbuild              |  1 +
 include/asm-generic/ima-efi.h           | 16 ++++++++++++++++
 security/integrity/ima/ima_efi.c        |  5 +----
 13 files changed, 54 insertions(+), 25 deletions(-)
 create mode 100644 arch/x86/include/asm/ima-efi.h
 create mode 100644 arch/x86/include/asm/pci_setup.h
 create mode 100644 include/asm-generic/ima-efi.h


base-commit: a9d99261a978835b02e248fe18af3026416af3e8
-- 
2.43.0