Commit 3f4c8211 ("x86/mm: Use mm_alloc() in poking_init()") broke
the kernel for running as Xen PV guest.

It seems as if the new address space is never activated before being
used, resulting in Xen rejecting to accept the new CR3 value (the PGD
isn't pinned).

Fix that by adding the now missing call of paravirt_arch_dup_mmap() to
poking_init(). That call was previously done by dup_mm()->dup_mmap() and
it is a NOP for all cases but for Xen PV, where it is just doing the
pinning of the PGD.

Fixes: 3f4c8211 ("x86/mm: Use mm_alloc() in poking_init()")
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230109150922.10578-1-jgross@suse.com

Instead of duplicating init_mm, allocate a fresh mm. The advantage is
that mm_alloc() has much simpler dependencies. Additionally it makes
more conceptual sense, init_mm has no (and must not have) user state
to duplicate.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221025201057.816175235@infradead.org

We used to have swapfile_maximum_size() fetching a maximum value of
swapfile size per-arch.

As the caller of max_swapfile_size() grows, this patch introduce a
variable "swapfile_maximum_size" and cache the value of old
max_swapfile_size(), so that we don't need to calculate the value every
time.

Caching the value in swapfile_init() is safe because when reaching the
phase we should have initialized all the relevant information.  Here the
major arch to take care of is x86, which defines the max swapfile size
based on L1TF mitigation.

Here both X86_BUG_L1TF or l1tf_mitigation should have been setup properly
when reaching swapfile_init().  As a reference, the code path looks like
this for x86:

- start_kernel
  - setup_arch
    - early_cpu_init
      - early_identify_cpu --> setup X86_BUG_L1TF
  - parse_early_param
    - l1tf_cmdline --> set l1tf_mitigation
  - check_bugs
    - l1tf_select_mitigation --> set l1tf_mitigation
  - arch_call_rest_init
    - rest_init
      - kernel_init
        - kernel_init_freeable
          - do_basic_setup
            - do_initcalls --> calls swapfile_init() (initcall level 4)

The swapfile size only depends on swp pte format on non-x86 archs, so
caching it is safe too.

Since at it, rename max_swapfile_size() to arch_max_swapfile_size()
because arch can define its own function, so it's more straightforward to
have "arch_" as its prefix.  At the meantime, export swapfile_maximum_size
to replace the old usages of max_swapfile_size().

[peterx@redhat.com: declare arch_max_swapfile_size) in swapfile.h]
  Link: https://lkml.kernel.org/r/YxTh1GuC6ro5fKL5@xz-m1.local
Link: https://lkml.kernel.org/r/20220811161331.37055-7-peterx@redhat.comSigned-off-by: NPeter Xu <peterx@redhat.com>
Reviewed-by: N"Huang, Ying" <ying.huang@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

x86_has_pat_wp() is using a wrong test, as it relies on the normal
PAT configuration used by the kernel. In case the PAT MSR has been
setup by another entity (e.g. Xen hypervisor) it might return false
even if the PAT configuration is allowing WP mappings. This due to the
fact that when running as Xen PV guest the PAT MSR is setup by the
hypervisor and cannot be changed by the guest. This results in the WP
related entry to be at a different position when running as Xen PV
guest compared to the bare metal or fully virtualized case.

The correct way to test for WP support is:

1. Get the PTE protection bits needed to select WP mode by reading
   __cachemode2pte_tbl[_PAGE_CACHE_MODE_WP] (depending on the PAT MSR
   setting this might return protection bits for a stronger mode, e.g.
   UC-)
2. Translate those bits back into the real cache mode selected by those
   PTE bits by reading __pte2cachemode_tbl[__pte2cm_idx(prot)]
3. Test for the cache mode to be _PAGE_CACHE_MODE_WP

Fixes: f88a68fa ("x86/mm: Extend early_memremap() support with additional attrs")
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.14
Link: https://lore.kernel.org/r/20220503132207.17234-1-jgross@suse.com

Commit a4866aa8 ("mm: Tighten x86 /dev/mem with zeroing reads") adds a
comment to the function devmem_is_allowed() referring to a non-existing
config STRICT_IOMEM, whereas the comment very likely intended to refer to
the config STRICT_DEVMEM, as the commit adds some behavior for the config
STRICT_DEVMEM.

Most of the initial analysis was actually done by Dave Hansen in the
email thread below (see Link).

Refer to the intended and existing config STRICT_DEVMEM.

Link: https://lore.kernel.org/r/f9074e8d-9314-9d7d-7bf5-5b5538c8be8d@intel.com/Suggested-by: NDave Hansen <dave.hansen@intel.com>
Signed-off-by: NLukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220707115442.21107-1-lukas.bulwahn@gmail.com

Commit a4866aa8 ("mm: Tighten x86 /dev/mem with zeroing reads") adds a
comment to the function devmem_is_allowed() referring to a non-existing
config STRICT_IOMEM, whereas the comment very likely intended to refer to
the config STRICT_DEVMEM, as the commit adds some behavior for the config
STRICT_DEVMEM.

Most of the initial analysis was actually done by Dave Hansen in the
email thread below (see Link).

Refer to the intended and existing config STRICT_DEVMEM.
Suggested-by: NDave Hansen <dave.hansen@intel.com>
Signed-off-by: NLukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/f9074e8d-9314-9d7d-7bf5-5b5538c8be8d@intel.com/
Link: https://lkml.kernel.org/r/20220707115442.21107-1-lukas.bulwahn@gmail.com

This adds two trace events for base page and HugeTLB page migrations.
These events, closely follow the implementation details like setting and
removing of PTE migration entries, which are essential operations for
migration.  The new CREATE_TRACE_POINTS in <mm/rmap.c> covers both
<events/migration.h> and <events/tlb.h> based trace events.  Hence drop
redundant CREATE_TRACE_POINTS from other places which could have otherwise
conflicted during build.

Link: https://lkml.kernel.org/r/1643368182-9588-3-git-send-email-anshuman.khandual@arm.comSigned-off-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Reported-by: Nkernel test robot <lkp@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Document the fact that using the trampoline_pgd will result in the
creation of global TLB entries in the user range of the address
space.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211202153226.22946-2-joro@8bytes.org

Since memblock_free() operates on a physical range, make its name
reflect it and rename it to memblock_phys_free(), so it will be a
logical counterpart to memblock_phys_alloc().

The callers are updated with the below semantic patch:

    @@
    expression addr;
    expression size;
    @@
    - memblock_free(addr, size);
    + memblock_phys_free(addr, size);

Link: https://lkml.kernel.org/r/20210930185031.18648-6-rppt@kernel.orgSigned-off-by: NMike Rapoport <rppt@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Juergen Gross <jgross@suse.com>
Cc: Shahab Vahedi <Shahab.Vahedi@synopsys.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are a lot of uses of memblock_find_in_range() along with
memblock_reserve() from the times memblock allocation APIs did not exist.

memblock_find_in_range() is the very core of memblock allocations, so any
future changes to its internal behaviour would mandate updates of all the
users outside memblock.

Replace the calls to memblock_find_in_range() with an equivalent calls to
memblock_phys_alloc() and memblock_phys_alloc_range() and make
memblock_find_in_range() private method of memblock.

This simplifies the callers, ensures that (unlikely) errors in
memblock_reserve() are handled and improves maintainability of
memblock_find_in_range().

Link: https://lkml.kernel.org/r/20210816122622.30279-1-rppt@kernel.orgSigned-off-by: NMike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>		[arm64]
Acked-by: NKirill A. Shutemov <kirill.shtuemov@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>	[ACPI]
Acked-by: NRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Nick Kossifidis <mick@ics.forth.gr>			[riscv]
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix another ~42 single-word typos in arch/x86/ code comments,
missed a few in the first pass, in particular in .S files.
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org

Fix ~144 single-word typos in arch/x86/ code comments.

Doing this in a single commit should reduce the churn.
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org

cpu_tlbstate is mostly private and only the variable is_lazy is shared.
This causes some false-sharing when TLB flushes are performed.

Break cpu_tlbstate intro cpu_tlbstate and cpu_tlbstate_shared, and mark
each one accordingly.
Signed-off-by: NNadav Amit <namit@vmware.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Reviewed-by: NDave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20210220231712.2475218-6-namit@vmware.com

pgt_buf is used to allocate page tables on initial direct page mapping
which bootstraps the kernel into being able to allocate these before the
direct mapping makes further pages available.

INIT_PGD_PAGE_COUNT is set to 6 pages (doubled for KASLR) - 3 (PUD, PMD,
PTE) for the 1 MiB ISA mapping and 3 more for the first direct mapping
assignment in each case providing 2 MiB of address space.

This has not been updated for 5-level page tables which has an
additional P4D page table level above PUD.

In most instances, this will not have a material impact as the first
4 page levels allocated for the ISA mapping will provide sufficient
address space to encompass all further address mappings.

If the first direct mapping is within 512 GiB of the ISA mapping, only
a PMD and PTE needs to be added in the instance the kernel is using 4
KiB page tables (e.g. CONFIG_DEBUG_PAGEALLOC is enabled) and only a PMD
if the kernel can use 2 MiB pages (the first allocation is limited to
PMD_SIZE so a GiB page cannot be used there).

However, if the machine has more than 512 GiB of RAM and the kernel is
allocating 4 KiB page size, 3 further page tables are required.

If the machine has more than 256 TiB of RAM at 4 KiB or 2 MiB page size,
further 3 or 4 page tables are required respectively.

Update INIT_PGD_PAGE_COUNT to reflect this.

 [ bp: Sanitize text into passive voice without ambiguous personal pronouns. ]
Signed-off-by: NLorenzo Stoakes <lstoakes@gmail.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NDave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/20201215205641.34096-1-lstoakes@gmail.com

It is not required to initialize the local variable start in
memory_map_top_down(), as the variable will be initialized in any path
before it is used.

make clang-analyzer on x86_64 tinyconfig reports:

  arch/x86/mm/init.c:612:15: warning: Although the value stored to 'start' \
  is used in the enclosing expression, the value is never actually read \
  from 'start' [clang-analyzer-deadcode.DeadStores]

Move the variable declaration into the loop, where it is used.

No code changed:

  # arch/x86/mm/init.o:

   text    data     bss     dec     hex filename
   7105    1424   26768   35297    89e1 init.o.before
   7105    1424   26768   35297    89e1 init.o.after

md5:
   a8d76c1bb5fce9cae251780a7ee7730f  init.o.before.asm
   a8d76c1bb5fce9cae251780a7ee7730f  init.o.after.asm

 [ bp: Massage. ]
Signed-off-by: NLukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NDave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20200928100004.25674-1-lukas.bulwahn@gmail.com

Fix -Wmissing-prototypes warnings:

  arch/x86/mm/init.c:81:6:
  warning: no previous prototype for ‘x86_has_pat_wp’ [-Wmissing-prototypes]
  bool x86_has_pat_wp(void)

  arch/x86/mm/init.c:86:22:
  warning: no previous prototype for ‘pgprot2cachemode’ [-Wmissing-prototypes]
  enum page_cache_mode pgprot2cachemode(pgprot_t pgprot)

by including the respective header containing prototypes. Also fix:

  arch/x86/mm/init.c:893:13:
  warning: no previous prototype for ‘mem_encrypt_free_decrypted_mem’ [-Wmissing-prototypes]
  void __weak mem_encrypt_free_decrypted_mem(void) { }

by making it static inline for the !CONFIG_AMD_MEM_ENCRYPT case. This
warning happens when CONFIG_AMD_MEM_ENCRYPT is not enabled (defconfig
for example):

  ./arch/x86/include/asm/mem_encrypt.h:80:27:
  warning: inline function ‘mem_encrypt_free_decrypted_mem’ declared weak [-Wattributes]
  static inline void __weak mem_encrypt_free_decrypted_mem(void) { }
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It's ok to convert to static inline because the function is used only in
x86. Is not shared with other architectures so drop the __weak too.

 [ bp: Massage and adjust __weak comments while at it. ]
Signed-off-by: NBenjamin Thiel <b.thiel@posteo.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200606122629.2720-1-b.thiel@posteo.de

There are three cases for the trampoline initialization:
* 32-bit does nothing
* 64-bit with kaslr disabled simply copies a PGD entry from the direct map
  to the trampoline PGD
* 64-bit with kaslr enabled maps the real mode trampoline at PUD level

These cases are currently differentiated by a bunch of ifdefs inside
asm/include/pgtable.h and the case of 64-bits with kaslr on uses
pgd_index() helper.

Replacing the ifdefs with a static function in arch/x86/mm/init.c gives
clearer code and allows moving pgd_index() to the generic implementation
in include/linux/pgtable.h

[rppt@linux.ibm.com: take CONFIG_RANDOMIZE_MEMORY into account in kaslr_enabled()]
  Link: http://lkml.kernel.org/r/20200525104045.GB13212@linux.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-8-rppt@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

free_area_init() has effectively became a wrapper for
free_area_init_nodes() and there is no point of keeping it.  Still
free_area_init() name is shorter and more general as it does not imply
necessity to initialize multiple nodes.

Rename free_area_init_nodes() to free_area_init(), update the callers and
drop old version of free_area_init().
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: Hoan Tran <hoan@os.amperecomputing.com>	[arm64]
Reviewed-by: NBaoquan He <bhe@redhat.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200412194859.12663-6-rppt@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This currently leaks kernel physical addresses into userspace.
Signed-off-by: NArvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NDave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/20200229231120.1147527-1-nivedita@alum.mit.edu

Hide tlbstate, flush_tlb_info and related helpers when tlbflush.h is
included from a module. Modules have absolutely no business with these
internals.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NAlexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200421092600.328438734@linutronix.de

No point in having this exposed.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NAlexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200421092559.940978251@linutronix.de

Exporting the raw data for a table is generally a bad idea. Move
cachemode2protval() out of line given that it isn't really used in the
fast path, and then mark __cachemode2pte_tbl static.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200408152745.1565832-5-hch@lst.de

This helper is only used by x86 low-level MM code.  Also remove the
entirely pointless __pte2cachemode_tbl export as that symbol can be
marked static now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200408152745.1565832-3-hch@lst.de

Abstract the ioremap code away from the caching mode internals.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200408152745.1565832-2-hch@lst.de

In preparation to support a pgprot_t argument for arch_add_memory().

It's required to move the prototype of init_memory_mapping() seeing the
original location came before the definition of pgprot_t.
Signed-off-by: NLogan Gunthorpe <logang@deltatee.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric Badger <ebadger@gigaio.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200306170846.9333-4-logang@deltatee.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The memory freeing report wasn't very useful for figuring out which
parts of the kernel image were being freed. Add the details for clearer
reporting in dmesg.

Before:

  Freeing unused kernel image memory: 1348K
  Write protecting the kernel read-only data: 20480k
  Freeing unused kernel image memory: 2040K
  Freeing unused kernel image memory: 172K

After:

  Freeing unused kernel image (initmem) memory: 1348K
  Write protecting the kernel read-only data: 20480k
  Freeing unused kernel image (text/rodata gap) memory: 2040K
  Freeing unused kernel image (rodata/data gap) memory: 172K
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-alpha@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: x86-ml <x86@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20191029211351.13243-28-keescook@chromium.org

To prevent improper use of the PTEs that are used for text patching, the
next patches will use a temporary mm struct. Initailize it by copying
the init mm.

The address that will be used for patching is taken from the lower area
that is usually used for the task memory. Doing so prevents the need to
frequently synchronize the temporary-mm (e.g., when BPF programs are
installed), since different PGDs are used for the task memory.

Finally, randomize the address of the PTEs to harden against exploits
that use these PTEs.
Suggested-by: NAndy Lutomirski <luto@kernel.org>
Tested-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NNadav Amit <namit@vmware.com>
Signed-off-by: NRick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NMasami Hiramatsu <mhiramat@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: ard.biesheuvel@linaro.org
Cc: deneen.t.dock@intel.com
Cc: kernel-hardening@lists.openwall.com
Cc: kristen@linux.intel.com
Cc: linux_dti@icloud.com
Cc: will.deacon@arm.com
Link: https://lkml.kernel.org/r/20190426232303.28381-8-nadav.amit@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The first kmemleak_scan() call after boot would trigger the crash below
because this callpath:

  kernel_init
    free_initmem
      mem_encrypt_free_decrypted_mem
        free_init_pages

unmaps memory inside the .bss when DEBUG_PAGEALLOC=y.

kmemleak_init() will register the .data/.bss sections and then
kmemleak_scan() will scan those addresses and dereference them looking
for pointer references. If free_init_pages() frees and unmaps pages in
those sections, kmemleak_scan() will crash if referencing one of those
addresses:

  BUG: unable to handle kernel paging request at ffffffffbd402000
  CPU: 12 PID: 325 Comm: kmemleak Not tainted 5.1.0-rc4+ #4
  RIP: 0010:scan_block
  Call Trace:
   scan_gray_list
   kmemleak_scan
   kmemleak_scan_thread
   kthread
   ret_from_fork

Since kmemleak_free_part() is tolerant to unknown objects (not tracked
by kmemleak), it is fine to call it from free_init_pages() even if not
all address ranges passed to this function are known to kmemleak.

 [ bp: Massage. ]

Fixes: b3f0907c ("x86/mm: Add .bss..decrypted section to hold shared variables")
Signed-off-by: NQian Cai <cai@lca.pw>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190423165811.36699-1-cai@lca.pw

and propagate through down the call stack.

Link: http://lkml.kernel.org/r/20181124091411.GC10969@avx2Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Swap storage is restricted to max_swapfile_size (~16TB on x86_64) whenever
the system is deemed affected by L1TF vulnerability. Even though the limit
is quite high for most deployments it seems to be too restrictive for
deployments which are willing to live with the mitigation disabled.

We have a customer to deploy 8x 6,4TB PCIe/NVMe SSD swap devices which is
clearly out of the limit.

Drop the swap restriction when l1tf=off is specified. It also doesn't make
much sense to warn about too much memory for the l1tf mitigation when it is
forcefully disabled by the administrator.

[ tglx: Folded the documentation delta change ]

Fixes: 377eeaa8 ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2")
Signed-off-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NPavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NJiri Kosina <jkosina@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: <linux-mm@kvack.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181113184910.26697-1-mhocko@kernel.org

Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.

The includes were replaced with the semantic patch below and then
semi-automated removal of duplicated '#include <linux/memblock.h>

@@
@@
- #include <linux/bootmem.h>
+ #include <linux/memblock.h>

[sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h]
  Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au
[sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h]
  Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au
[sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal]
  Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au
Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kvmclock defines few static variables which are shared with the
hypervisor during the kvmclock initialization.

When SEV is active, memory is encrypted with a guest-specific key, and
if the guest OS wants to share the memory region with the hypervisor
then it must clear the C-bit before sharing it.

Currently, we use kernel_physical_mapping_init() to split large pages
before clearing the C-bit on shared pages. But it fails when called from
the kvmclock initialization (mainly because the memblock allocator is
not ready that early during boot).

Add a __bss_decrypted section attribute which can be used when defining
such shared variable. The so-defined variables will be placed in the
.bss..decrypted section. This section will be mapped with C=0 early
during boot.

The .bss..decrypted section has a big chunk of memory that may be unused
when memory encryption is not active, free it when memory encryption is
not active.
Suggested-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Radim Krčmář<rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/1536932759-12905-2-git-send-email-brijesh.singh@amd.com

Two users have reported [1] that they have an "extremely unlikely" system
with more than MAX_PA/2 memory and L1TF mitigation is not effective. In
fact it's a CPU with 36bits phys limit (64GB) and 32GB memory, but due to
holes in the e820 map, the main region is almost 500MB over the 32GB limit:

[    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000081effffff] usable

Suggestions to use 'mem=32G' to enable the L1TF mitigation while losing the
500MB revealed, that there's an off-by-one error in the check in
l1tf_select_mitigation().

l1tf_pfn_limit() returns the last usable pfn (inclusive) and the range
check in the mitigation path does not take this into account.

Instead of amending the range check, make l1tf_pfn_limit() return the first
PFN which is over the limit which is less error prone. Adjust the other
users accordingly.

[1] https://bugzilla.suse.com/show_bug.cgi?id=1105536

Fixes: 17dbca11 ("x86/speculation/l1tf: Add sysfs reporting for l1tf")
Reported-by: NGeorge Anchev <studio@anchev.net>
Reported-by: NChristopher Snowhill <kode54@gmail.com>
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180823134418.17008-1-vbabka@suse.cz

Commit 7b25b9cb ("x86/xen/time: Initialize pv xen time in
init_hypervisor_platform()") moved the mapping of the shared info area
before pagetable_init(). This breaks booting as 32-bit PV guest as the
use of set_fixmap isn't possible at this time on 32-bit.

This can be worked around by populating the needed PMD on 32-bit
kernel earlier.

In order not to reimplement populate_extra_pte() using extend_brk()
for allocating new page tables extend alloc_low_pages() to do that in
case the early page table pool is not yet available.

Fixes: 7b25b9cb ("x86/xen/time: Initialize pv xen time in init_hypervisor_platform()")
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>

On 32bit PAE kernels on 64bit hardware with enough physical bits,
l1tf_pfn_limit() will overflow unsigned long. This in turn affects
max_swapfile_size() and can lead to swapon returning -EINVAL. This has been
observed in a 32bit guest with 42 bits physical address size, where
max_swapfile_size() overflows exactly to 1 << 32, thus zero, and produces
the following warning to dmesg:

[    6.396845] Truncating oversized swap area, only using 0k out of 2047996k

Fix this by using unsigned long long instead.

Fixes: 17dbca11 ("x86/speculation/l1tf: Add sysfs reporting for l1tf")
Fixes: 377eeaa8 ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2")
Reported-by: NDominique Leuenberger <dimstar@suse.de>
Reported-by: NAdrian Schroeter <adrian@suse.de>
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180820095835.5298-1-vbabka@suse.cz

The introduction of generic_max_swapfile_size and arch-specific versions has
broken linking on x86 with CONFIG_SWAP=n due to undefined reference to
'generic_max_swapfile_size'. Fix it by compiling the x86-specific
max_swapfile_size() only with CONFIG_SWAP=y.
Reported-by: NTomas Pruzina <pruzinat@gmail.com>
Fixes: 377eeaa8 ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2")
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The kernel image is mapped into two places in the virtual address space
(addresses without KASLR, of course):

	1. The kernel direct map (0xffff880000000000)
	2. The "high kernel map" (0xffffffff81000000)

We actually execute out of #2.  If we get the address of a kernel symbol,
it points to #2, but almost all physical-to-virtual translations point to

Parts of the "high kernel map" alias are mapped in the userspace page
tables with the Global bit for performance reasons.  The parts that we map
to userspace do not (er, should not) have secrets. When PTI is enabled then
the global bit is usually not set in the high mapping and just used to
compensate for poor performance on systems which lack PCID.

This is fine, except that some areas in the kernel image that are adjacent
to the non-secret-containing areas are unused holes.  We free these holes
back into the normal page allocator and reuse them as normal kernel memory.
The memory will, of course, get *used* via the normal map, but the alias
mapping is kept.

This otherwise unused alias mapping of the holes will, by default keep the
Global bit, be mapped out to userspace, and be vulnerable to Meltdown.

Remove the alias mapping of these pages entirely.  This is likely to
fracture the 2M page mapping the kernel image near these areas, but this
should affect a minority of the area.

The pageattr code changes *all* aliases mapping the physical pages that it
operates on (by default).  We only want to modify a single alias, so we
need to tweak its behavior.

This unmapping behavior is currently dependent on PTI being in place.
Going forward, we should at least consider doing this for all
configurations.  Having an extra read-write alias for memory is not exactly
ideal for debugging things like random memory corruption and this does
undercut features like DEBUG_PAGEALLOC or future work like eXclusive Page
Frame Ownership (XPFO).

Before this patch:

current_kernel:---[ High Kernel Mapping ]---
current_kernel-0xffffffff80000000-0xffffffff81000000          16M                               pmd
current_kernel-0xffffffff81000000-0xffffffff81e00000          14M     ro         PSE     GLB x  pmd
current_kernel-0xffffffff81e00000-0xffffffff81e11000          68K     ro                 GLB x  pte
current_kernel-0xffffffff81e11000-0xffffffff82000000        1980K     RW                     NX pte
current_kernel-0xffffffff82000000-0xffffffff82600000           6M     ro         PSE     GLB NX pmd
current_kernel-0xffffffff82600000-0xffffffff82c00000           6M     RW         PSE         NX pmd
current_kernel-0xffffffff82c00000-0xffffffff82e00000           2M     RW                     NX pte
current_kernel-0xffffffff82e00000-0xffffffff83200000           4M     RW         PSE         NX pmd
current_kernel-0xffffffff83200000-0xffffffffa0000000         462M                               pmd

  current_user:---[ High Kernel Mapping ]---
  current_user-0xffffffff80000000-0xffffffff81000000          16M                               pmd
  current_user-0xffffffff81000000-0xffffffff81e00000          14M     ro         PSE     GLB x  pmd
  current_user-0xffffffff81e00000-0xffffffff81e11000          68K     ro                 GLB x  pte
  current_user-0xffffffff81e11000-0xffffffff82000000        1980K     RW                     NX pte
  current_user-0xffffffff82000000-0xffffffff82600000           6M     ro         PSE     GLB NX pmd
  current_user-0xffffffff82600000-0xffffffffa0000000         474M                               pmd

After this patch:

current_kernel:---[ High Kernel Mapping ]---
current_kernel-0xffffffff80000000-0xffffffff81000000          16M                               pmd
current_kernel-0xffffffff81000000-0xffffffff81e00000          14M     ro         PSE     GLB x  pmd
current_kernel-0xffffffff81e00000-0xffffffff81e11000          68K     ro                 GLB x  pte
current_kernel-0xffffffff81e11000-0xffffffff82000000        1980K                               pte
current_kernel-0xffffffff82000000-0xffffffff82400000           4M     ro         PSE     GLB NX pmd
current_kernel-0xffffffff82400000-0xffffffff82488000         544K     ro                     NX pte
current_kernel-0xffffffff82488000-0xffffffff82600000        1504K                               pte
current_kernel-0xffffffff82600000-0xffffffff82c00000           6M     RW         PSE         NX pmd
current_kernel-0xffffffff82c00000-0xffffffff82c0d000          52K     RW                     NX pte
current_kernel-0xffffffff82c0d000-0xffffffff82dc0000        1740K                               pte

  current_user:---[ High Kernel Mapping ]---
  current_user-0xffffffff80000000-0xffffffff81000000          16M                               pmd
  current_user-0xffffffff81000000-0xffffffff81e00000          14M     ro         PSE     GLB x  pmd
  current_user-0xffffffff81e00000-0xffffffff81e11000          68K     ro                 GLB x  pte
  current_user-0xffffffff81e11000-0xffffffff82000000        1980K                               pte
  current_user-0xffffffff82000000-0xffffffff82400000           4M     ro         PSE     GLB NX pmd
  current_user-0xffffffff82400000-0xffffffff82488000         544K     ro                     NX pte
  current_user-0xffffffff82488000-0xffffffff82600000        1504K                               pte
  current_user-0xffffffff82600000-0xffffffffa0000000         474M                               pmd

[ tglx: Do not unmap on 32bit as there is only one mapping ]

Fixes: 0f561fce ("x86/pti: Enable global pages for shared areas")
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Joerg Roedel <jroedel@suse.de>
Link: https://lkml.kernel.org/r/20180802225831.5F6A2BFC@viggo.jf.intel.com

When chunks of the kernel image are freed, free_init_pages() is used
directly.  Consolidate the three sites that do this.  Also update the
string to give an incrementally better description of that memory versus
what was there before.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: keescook@google.com
Cc: aarcange@redhat.com
Cc: jgross@suse.com
Cc: jpoimboe@redhat.com
Cc: gregkh@linuxfoundation.org
Cc: peterz@infradead.org
Cc: hughd@google.com
Cc: torvalds@linux-foundation.org
Cc: bp@alien8.de
Cc: luto@kernel.org
Cc: ak@linux.intel.com
Cc: Kees Cook <keescook@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/20180802225829.FE0E32EA@viggo.jf.intel.com

The PAE 3-level paging code currently doesn't mitigate L1TF by flipping the
offset bits, and uses the high PTE word, thus bits 32-36 for type, 37-63 for
offset. The lower word is zeroed, thus systems with less than 4GB memory are
safe. With 4GB to 128GB the swap type selects the memory locations vulnerable
to L1TF; with even more memory, also the swap offfset influences the address.
This might be a problem with 32bit PAE guests running on large 64bit hosts.

By continuing to keep the whole swap entry in either high or low 32bit word of
PTE we would limit the swap size too much. Thus this patch uses the whole PAE
PTE with the same layout as the 64bit version does. The macros just become a
bit tricky since they assume the arch-dependent swp_entry_t to be 32bit.
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMichal Hocko <mhocko@suse.com>

The previous patch has limited swap file size so that large offsets cannot
clear bits above MAX_PA/2 in the pte and interfere with L1TF mitigation.

It assumed that offsets are encoded starting with bit 12, same as pfn. But
on x86_64, offsets are encoded starting with bit 9.

Thus the limit can be raised by 3 bits. That means 16TB with 42bit MAX_PA
and 256TB with 46bit MAX_PA.

Fixes: 377eeaa8 ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2")
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>