[PATCH v4 0/4] arch/x86: Remove unnecessary dependencies on bootparam.h

Thomas Zimmermann
2024-01-08T09:59:07Z

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 rebuild 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 code from bootparam.h and efi.h into separate header
files and removes obsolete include statements on x86. I did

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

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 less than one minute.

real 0m56,643s
user 4m0,661s
sys 0m32,956s

The test system is an Intel i5-13500.

v4:
* fix fwd declaration in compressed/misc.h (Ard)
v3:
* keep setup_header in bootparam.h (Ard)
* implement arch_ima_efi_boot_mode() in source file (Ard)
v2:
* only keep struct boot_params in bootparam.h (Ard)
* simplify arch_ima_efi_boot_mode define (Ard)
* updated cover letter

Thomas Zimmermann (4):
arch/x86: Move UAPI setup structures into setup_data.h
arch/x86: Move internal setup_data structures into setup_data.h
arch/x86: Implement arch_ima_efi_boot_mode() in source file
arch/x86: Do not include <asm/bootparam.h> in several files

arch/x86/boot/compressed/acpi.c | 2 +
arch/x86/boot/compressed/cmdline.c | 2 +
arch/x86/boot/compressed/efi.c | 2 +
arch/x86/boot/compressed/efi.h | 9 ---
arch/x86/boot/compressed/misc.h | 3 +-
arch/x86/boot/compressed/pgtable_64.c | 1 +
arch/x86/boot/compressed/sev.c | 1 +
arch/x86/include/asm/efi.h | 14 +----
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/setup_data.h | 32 ++++++++++
arch/x86/include/asm/sev.h | 3 +-
arch/x86/include/asm/x86_init.h | 2 -
arch/x86/include/uapi/asm/bootparam.h | 72 +---------------------
arch/x86/include/uapi/asm/setup_data.h | 83 ++++++++++++++++++++++++++
arch/x86/kernel/crash.c | 1 +
arch/x86/kernel/sev-shared.c | 2 +
arch/x86/platform/efi/efi.c | 5 ++
arch/x86/platform/pvh/enlighten.c | 1 +
arch/x86/xen/enlighten_pvh.c | 1 +
arch/x86/xen/vga.c | 1 -
22 files changed, 142 insertions(+), 111 deletions(-)
create mode 100644 arch/x86/include/asm/setup_data.h
create mode 100644 arch/x86/include/uapi/asm/setup_data.h

--
2.43.0