[alsa-devel] [PATCH 00/12] treewide: break dependencies on x86's RM header

Sean Christopherson
2019-11-20T11:05:43Z

x86's asm/realmode.h, which defines low level structures, variables and
helpers used to bring up APs during SMP boot, ends up getting included in
practically every nook and cranny of the kernel because the address used
by ACPI for resuming from S3 also happens to be stored in the real mode
header, and ACPI bleeds the dependency into its widely included headers.

As a result, modifying realmode.h for even the most trivial change to the
boot code triggers a full kernel rebuild, which is frustrating to say the
least as it some of the most difficult code to get exactly right *and* is
also some of the most functionally isolated code in the kernel.

To break the kernel's widespread dependency on realmode.h, add a wrapper
in the aforementioned ACPI S3 code to access the real mode header instead
of derefencing the header directly in asm/acpi.h and thereby exposing it
to the world via linux/acpi.h.

Build tested on x86 with allyesconfig and allmodconfig, so hopefully there
aren't more build issues lurking, but at this point it wouldn't surprise
me in the least if this somehow manages to break the build.

Based on tip/master, commit ceceaf1f12ba ("Merge branch 'WIP.x86/cleanups'").

Patch Synopsis:
- Patches 01-09 fix a variety of build errors that arise when patch 12
drops realmode.h from asm/acpi.h. Most of the errors are quite absurb
as they have no relation whatsoever to x86's RM boot code, but occur
because realmode.h happens to include asm/io.h.

- Patch 10 removes a spurious include of realmode.h from an ACPI header.

- Patches 11 and 12 implement the wrapper and move it out of acpi.h.

Sean Christopherson (12):
x86/efi: Explicitly include realmode.h to handle RM trampoline quirk
x86/boot: Explicitly include realmode.h to handle RM reservations
x86/ftrace: Explicitly include vmalloc.h for
set_vm_flush_reset_perms()
x86/kprobes: Explicitly include vmalloc.h for
set_vm_flush_reset_perms()
perf/x86/intel: Explicitly include asm/io.h to use virt_to_phys()
efi/capsule-loader: Explicitly include linux/io.h for page_to_phys()
virt: vbox: Explicitly include linux/io.h to pick up various defs
vmw_balloon: Explicitly include linux/io.h for virt_to_phys()
ASoC: Intel: Skylake: Explicitly include linux/io.h for virt_to_phys()
x86/ACPI/sleep: Remove an unnecessary include of asm/realmode.h
ACPI/sleep: Convert acpi_wakeup_address into a function
x86/ACPI/sleep: Move acpi_wakeup_address() definition into sleep.c

arch/ia64/include/asm/acpi.h | 5 ++++-
arch/ia64/kernel/acpi.c | 2 --
arch/x86/events/intel/ds.c | 1 +
arch/x86/include/asm/acpi.h | 3 +--
arch/x86/kernel/acpi/sleep.c | 11 +++++++++++
arch/x86/kernel/acpi/sleep.h | 2 +-
arch/x86/kernel/ftrace.c | 1 +
arch/x86/kernel/kprobes/core.c | 1 +
arch/x86/kernel/setup.c | 1 +
arch/x86/platform/efi/quirks.c | 1 +
drivers/acpi/sleep.c | 4 ++--
drivers/firmware/efi/capsule-loader.c | 1 +
drivers/misc/vmw_balloon.c | 1 +
drivers/virt/vboxguest/vboxguest_core.c | 1 +
drivers/virt/vboxguest/vboxguest_utils.c | 1 +
sound/soc/intel/skylake/skl-sst-cldma.c | 1 +
16 files changed, 29 insertions(+), 8 deletions(-)

--
2.24.0