linux.git/arch/x86/kernel/setup.c, branch v5.15

x86/setup: Call early_reserve_memory() earlier

2021-09-21T07:52:08+00:00

Commit in Fixes introduced early_reserve_memory() to do all needed
initial memblock_reserve() calls in one function. Unfortunately, the call
of early_reserve_memory() is done too late for Xen dom0, as in some
cases a Xen hook called by e820__memory_setup() will need those memory
reservations to have happened already.

Move the call of early_reserve_memory() before the call of
e820__memory_setup() in order to avoid such problems.

Fixes: a799c2bd29d1 ("x86/setup: Consolidate early memory reservations")
Reported-by: Marek Marczykowski-Górecki 
Signed-off-by: Juergen Gross 
Signed-off-by: Borislav Petkov 
Tested-by: Marek Marczykowski-Górecki 
Tested-by: Nathan Chancellor 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210920120421.29276-1-jgross@suse.com

x86/setup: Explicitly include acpi.h

2021-09-01T17:17:05+00:00

After commit 342f43af70db ("iscsi_ibft: fix crash due to KASLR physical
memory remapping") x86_64_defconfig shows the following errors:

  arch/x86/kernel/setup.c: In function ‘setup_arch’:
  arch/x86/kernel/setup.c:916:13: error: implicit declaration of function ‘acpi_mps_check’ [-Werror=implicit-function-declaration]
    916 |         if (acpi_mps_check()) {
        |             ^~~~~~~~~~~~~~
  arch/x86/kernel/setup.c:1110:9: error: implicit declaration of function ‘acpi_table_upgrade’ [-Werror=implicit-function-declaration]
   1110 |         acpi_table_upgrade();
        |         ^~~~~~~~~~~~~~~~~~
  [... more acpi noise ...]

acpi.h was being implicitly included from iscsi_ibft.h in this
configuration so the removal of that header means these functions have
no definition or declaration.

In most other configurations,  continued to be included
through at least  if CONFIG_INTEL_TXT was enabled, and
there were probably other implicit include paths too.

Add acpi.h explicitly so there is no more error, and so that we don't
continue to depend on these unreliable implicit include paths.

Tested-by: Matthieu Baerts 
Signed-off-by: Nathan Chancellor 
Cc: Maurizio Lombardi 
Cc: Mike Rapoport 
Cc: Konrad Rzeszutek Wilk 
Signed-off-by: Linus Torvalds

Merge branch 'stable/for-linus-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/ibft

2021-08-31T22:28:21+00:00

Pull ibft updates from Konrad Rzeszutek Wilk:
 "A fix for iBFT parsing code badly interfacing when KASLR is enabled"

* 'stable/for-linus-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/ibft:
  iscsi_ibft: fix warning in reserve_ibft_region()
  iscsi_ibft: fix crash due to KASLR physical memory remapping

iscsi_ibft: fix crash due to KASLR physical memory remapping

2021-08-01T02:20:24+00:00

Starting with commit a799c2bd29d1
("x86/setup: Consolidate early memory reservations")
memory reservations have been moved earlier during the boot process,
before the execution of the Kernel Address Space Layout Randomization code.

setup_arch() calls the iscsi_ibft's find_ibft_region() function
to find and reserve the memory dedicated to the iBFT and this function
also saves a virtual pointer to the iBFT table for later use.

The problem is that if KALSR is active, the physical memory gets
remapped somewhere else in the virtual address space and the pointer is
no longer valid, this will cause a kernel panic when the iscsi driver tries
to dereference it.

 iBFT detected.
 BUG: unable to handle page fault for address: ffff888000099fd8
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] SMP PTI

..snip..

 Call Trace:
  ? ibft_create_kobject+0x1d2/0x1d2 [iscsi_ibft]
  do_one_initcall+0x44/0x1d0
  ? kmem_cache_alloc_trace+0x119/0x220
  do_init_module+0x5c/0x270
  __do_sys_init_module+0x12e/0x1b0
  do_syscall_64+0x40/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Fix this bug by saving the address of the physical location
of the ibft; later the driver will use isa_bus_to_virt() to get
the correct virtual address.

N.B. On each reboot KASLR randomizes the virtual addresses so
assuming phys_to_virt before KASLR does its deed is incorrect.

Simplify the code by renaming find_ibft_region()
to reserve_ibft_region() and remove all the wrappers.

Signed-off-by: Maurizio Lombardi 
Reviewed-by: Mike Rapoport 
Signed-off-by: Konrad Rzeszutek Wilk

x86: convert to setup_initial_init_mm()

2021-07-08T18:48:22+00:00

Use setup_initial_init_mm() helper to simplify code.

Link: https://lkml.kernel.org/r/20210608083418.137226-16-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2021-07-02T19:08:10+00:00

Merge more updates from Andrew Morton:
 "190 patches.

  Subsystems affected by this patch series: mm (hugetlb, userfaultfd,
  vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock,
  migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap,
  zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc,
  core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs,
  signals, exec, kcov, selftests, compress/decompress, and ipc"

* emailed patches from Andrew Morton : (190 commits)
  ipc/util.c: use binary search for max_idx
  ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock
  ipc: use kmalloc for msg_queue and shmid_kernel
  ipc sem: use kvmalloc for sem_undo allocation
  lib/decompressors: remove set but not used variabled 'level'
  selftests/vm/pkeys: exercise x86 XSAVE init state
  selftests/vm/pkeys: refill shadow register after implicit kernel write
  selftests/vm/pkeys: handle negative sys_pkey_alloc() return code
  selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random
  kcov: add __no_sanitize_coverage to fix noinstr for all architectures
  exec: remove checks in __register_bimfmt()
  x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned
  hfsplus: report create_date to kstat.btime
  hfsplus: remove unnecessary oom message
  nilfs2: remove redundant continue statement in a while-loop
  kprobes: remove duplicated strong free_insn_page in x86 and s390
  init: print out unknown kernel parameters
  checkpatch: do not complain about positive return values starting with EPOLL
  checkpatch: improve the indented label test
  checkpatch: scripts/spdxcheck.py now requires python3
  ...

kernel.h: split out panic and oops helpers

2021-07-01T18:06:04+00:00

kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out panic and
oops helpers.

There are several purposes of doing this:
- dropping dependency in bug.h
- dropping a loop by moving out panic_notifier.h
- unload kernel.h from something which has its own domain

At the same time convert users tree-wide to use new headers, although for
the time being include new header back to kernel.h to avoid twisted
indirected includes for existing users.

[akpm@linux-foundation.org: thread_info.h needs limits.h]
[andriy.shevchenko@linux.intel.com: ia64 fix]
  Link: https://lkml.kernel.org/r/20210520130557.55277-1-andriy.shevchenko@linux.intel.com

Link: https://lkml.kernel.org/r/20210511074137.33666-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Reviewed-by: Bjorn Andersson 
Co-developed-by: Andrew Morton 
Acked-by: Mike Rapoport 
Acked-by: Corey Minyard 
Acked-by: Christian Brauner 
Acked-by: Arnd Bergmann 
Acked-by: Kees Cook 
Acked-by: Wei Liu 
Acked-by: Rasmus Villemoes 
Signed-off-by: Andrew Morton 
Acked-by: Sebastian Reichel 
Acked-by: Luis Chamberlain 
Acked-by: Stephen Boyd 
Acked-by: Thomas Bogendoerfer 
Acked-by: Helge Deller  # parisc
Signed-off-by: Linus Torvalds

x86/setup: Document that Windows reserves the first MiB

2021-06-08T20:26:43+00:00

It does so unconditionally too, on Intel and AMD machines, to work
around BIOS bugs, as confirmed by Microsoft folks (see Link for full
details).

Reflow the paragraph, while at it.

Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/MWHPR21MB159330952629D36EEDE706B3D7379@MWHPR21MB1593.namprd21.prod.outlook.com

x86/setup: Remove CONFIG_X86_RESERVE_LOW and reservelow= options

2021-06-07T09:12:25+00:00

The CONFIG_X86_RESERVE_LOW build time and reservelow= command line option
allowed to control the amount of memory under 1M that would be reserved at
boot to avoid using memory that can be potentially clobbered by BIOS.

Since the entire range under 1M is always reserved there is no need for
these options anymore and they can be removed.

Signed-off-by: Mike Rapoport 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/20210601075354.5149-3-rppt@kernel.org

x86/setup: Always reserve the first 1M of RAM

2021-06-03T17:57:55+00:00

There are BIOSes that are known to corrupt the memory under 1M, or more
precisely under 640K because the memory above 640K is anyway reserved
for the EGA/VGA frame buffer and BIOS.

To prevent usage of the memory that will be potentially clobbered by the
kernel, the beginning of the memory is always reserved. The exact size
of the reserved area is determined by CONFIG_X86_RESERVE_LOW build time
and the "reservelow=" command line option. The reserved range may be
from 4K to 640K with the default of 64K. There are also configurations
that reserve the entire 1M range, like machines with SandyBridge graphic
devices or systems that enable crash kernel.

In addition to the potentially clobbered memory, EBDA of unknown size may
be as low as 128K and the memory above that EBDA start is also reserved
early.

It would have been possible to reserve the entire range under 1M unless for
the real mode trampoline that must reside in that area.

To accommodate placement of the real mode trampoline and keep the memory
safe from being clobbered by BIOS, reserve the first 64K of RAM before
memory allocations are possible and then, after the real mode trampoline
is allocated, reserve the entire range from 0 to 1M.

Update trim_snb_memory() and reserve_real_mode() to avoid redundant
reservations of the same memory range.

Also make sure the memory under 1M is not getting freed by
efi_free_boot_services().

 [ bp: Massage commit message and comments. ]

Fixes: a799c2bd29d1 ("x86/setup: Consolidate early memory reservations")
Signed-off-by: Mike Rapoport 
Signed-off-by: Borislav Petkov 
Tested-by: Hugh Dickins 
Link: https://bugzilla.kernel.org/show_bug.cgi?id=213177
Link: https://lkml.kernel.org/r/20210601075354.5149-2-rppt@kernel.org