linux.git/arch/arm64/include/asm/pgtable.h, branch v4.20

arm64: mm: Use #ifdef for the __PAGETABLE_P?D_FOLDED defines

2018-10-05T16:19:40+00:00

__is_defined(__PAGETABLE_P?D_FOLDED) doesn't quite work as intended
as these symbols are internal to asm-generic and aren't defined in the
way kconfig expects. This makes them always evaluate to false.
Switch to #ifdef.

Acked-by: Mark Rutland 
Signed-off-by: James Morse 
Signed-off-by: Catalin Marinas

arm64/mm: use fixmap to modify swapper_pg_dir

2018-09-25T14:10:55+00:00

Once swapper_pg_dir is in the rodata section, it will not be possible to
modify it directly, but we will need to modify it in some cases.

To enable this, we can use the fixmap when deliberately modifying
swapper_pg_dir. As the pgd is only transiently mapped, this provides
some resilience against illicit modification of the pgd, e.g. for
Kernel Space Mirror Attack (KSMA).

Signed-off-by: Jun Yao 
Reviewed-by: James Morse 
[Mark: simplify ifdeffery, commit message]
Signed-off-by: Mark Rutland 
Signed-off-by: Catalin Marinas

arm64/mm: Separate boot-time page tables from swapper_pg_dir

2018-09-25T14:10:54+00:00

Since the address of swapper_pg_dir is fixed for a given kernel image,
it is an attractive target for manipulation via an arbitrary write. To
mitigate this we'd like to make it read-only by moving it into the
rodata section.

We require that swapper_pg_dir is at a fixed offset from tramp_pg_dir
and reserved_ttbr0, so these will also need to move into rodata.
However, swapper_pg_dir is allocated along with some transient page
tables used for boot which we do not want to move into rodata.

As a step towards this, this patch separates the boot-time page tables
into a new init_pg_dir, and reduces swapper_pg_dir to the single page it
needs to be. This allows us to retain the relationship between
swapper_pg_dir, tramp_pg_dir, and swapper_pg_dir, while cleanly
separating these from the boot-time page tables.

The init_pg_dir holds all of the pgd/pud/pmd/pte levels needed during
boot, and all of these levels will be freed when we switch to the
swapper_pg_dir, which is initialized by the existing code in
paging_init(). Since we start off on the init_pg_dir, we no longer need
to allocate a transient page table in paging_init() in order to ensure
that swapper_pg_dir isn't live while we initialize it.

There should be no functional change as a result of this patch.

Signed-off-by: Jun Yao 
Reviewed-by: James Morse 
[Mark: place init_pg_dir after BSS, fold mm changes, commit message]
Signed-off-by: Mark Rutland 
Signed-off-by: Catalin Marinas

arm64: pgtable: Implement p[mu]d_valid() and check in set_p[mu]d()

2018-09-11T15:49:11+00:00

Now that our walk-cache invalidation routines imply a DSB before the
invalidation, we no longer need one when we are clearing an entry during
unmap.

Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Will Deacon 
Signed-off-by: Catalin Marinas

arm64: Remove unnecessary ISBs from set_{pte,pmd,pud}

2018-06-27T17:26:20+00:00

Commit 7f0b1bf04511 ("arm64: Fix barriers used for page table modifications")
fixed a reported issue with fixmap page-table entries not being visible
to the walker due to a missing DSB instruction. At the same time, it added
ISB instructions to the arm64 set_{pte,pmd,pud} functions, which are not
required by the architecture and make little sense in isolation.

Remove the redundant ISBs.

Acked-by: Catalin Marinas 
Acked-by: Mark Rutland 
Signed-off-by: Will Deacon 
Signed-off-by: Catalin Marinas

mm: introduce ARCH_HAS_PTE_SPECIAL

2018-06-08T00:34:35+00:00

Currently the PTE special supports is turned on in per architecture
header files.  Most of the time, it is defined in
arch/*/include/asm/pgtable.h depending or not on some other per
architecture static definition.

This patch introduce a new configuration variable to manage this
directly in the Kconfig files.  It would later replace
__HAVE_ARCH_PTE_SPECIAL.

Here notes for some architecture where the definition of
__HAVE_ARCH_PTE_SPECIAL is not obvious:

arm
 __HAVE_ARCH_PTE_SPECIAL which is currently defined in
arch/arm/include/asm/pgtable-3level.h which is included by
arch/arm/include/asm/pgtable.h when CONFIG_ARM_LPAE is set.
So select ARCH_HAS_PTE_SPECIAL if ARM_LPAE.

powerpc
__HAVE_ARCH_PTE_SPECIAL is defined in 2 files:
 - arch/powerpc/include/asm/book3s/64/pgtable.h
 - arch/powerpc/include/asm/pte-common.h
The first one is included if (PPC_BOOK3S & PPC64) while the second is
included in all the other cases.
So select ARCH_HAS_PTE_SPECIAL all the time.

sparc:
__HAVE_ARCH_PTE_SPECIAL is defined if defined(__sparc__) &&
defined(__arch64__) which are defined through the compiler in
sparc/Makefile if !SPARC32 which I assume to be if SPARC64.
So select ARCH_HAS_PTE_SPECIAL if SPARC64

There is no functional change introduced by this patch.

Link: http://lkml.kernel.org/r/1523433816-14460-2-git-send-email-ldufour@linux.vnet.ibm.com
Signed-off-by: Laurent Dufour 
Suggested-by: Jerome Glisse 
Reviewed-by: Jerome Glisse 
Acked-by: David Rientjes 
Cc: Michal Hocko 
Cc: "Aneesh Kumar K . V" 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Jonathan Corbet 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Yoshinori Sato 
Cc: Rich Felker 
Cc: David S. Miller 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Vineet Gupta 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: David Rientjes 
Cc: Robin Murphy 
Cc: Christophe LEROY 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

arm64: mm: drop addr parameter from sync icache and dcache

2018-04-24T08:23:00+00:00

The addr parameter isn't used for anything. Let's simplify and get rid of
it, like arm.

Cc: Catalin Marinas 
Cc: Will Deacon 
Signed-off-by: Shaokun Zhang 
Signed-off-by: Will Deacon

arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables

2018-02-16T18:13:57+00:00

In many cases, page tables can be accessed concurrently by either another
CPU (due to things like fast gup) or by the hardware page table walker
itself, which may set access/dirty bits. In such cases, it is important
to use READ_ONCE/WRITE_ONCE when accessing page table entries so that
entries cannot be torn, merged or subject to apparent loss of coherence
due to compiler transformations.

Whilst there are some scenarios where this cannot happen (e.g. pinned
kernel mappings for the linear region), the overhead of using READ_ONCE
/WRITE_ONCE everywhere is minimal and makes the code an awful lot easier
to reason about. This patch consistently uses these macros in the arch
code, as well as explicitly namespacing pointers to page table entries
from the entries themselves by using adopting a 'p' suffix for the former
(as is sometimes used elsewhere in the kernel source).

Tested-by: Yury Norov 
Tested-by: Richard Ruigrok 
Reviewed-by: Marc Zyngier 
Signed-off-by: Will Deacon 
Signed-off-by: Catalin Marinas

arm64: provide pmdp_establish() helper

2018-02-01T01:18:37+00:00

We need an atomic way to setup pmd page table entry, avoiding races with
CPU setting dirty/accessed bits.  This is required to implement
pmdp_invalidate() that doesn't lose these bits.

Link: http://lkml.kernel.org/r/20171213105756.69879-5-kirill.shutemov@linux.intel.com
Signed-off-by: Catalin Marinas 
Signed-off-by: Kirill A. Shutemov 
Cc: Vlastimil Babka 
Cc: Andrea Arcangeli 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2018-01-30T21:57:43+00:00

Pull arm64 updates from Catalin Marinas:
 "The main theme of this pull request is security covering variants 2
  and 3 for arm64. I expect to send additional patches next week
  covering an improved firmware interface (requires firmware changes)
  for variant 2 and way for KPTI to be disabled on unaffected CPUs
  (Cavium's ThunderX doesn't work properly with KPTI enabled because of
  a hardware erratum).

  Summary:

   - Security mitigations:
      - variant 2: invalidate the branch predictor with a call to
        secure firmware
      - variant 3: implement KPTI for arm64

   - 52-bit physical address support for arm64 (ARMv8.2)

   - arm64 support for RAS (firmware first only) and SDEI (software
     delegated exception interface; allows firmware to inject a RAS
     error into the OS)

   - perf support for the ARM DynamIQ Shared Unit PMU

   - CPUID and HWCAP bits updated for new floating point multiplication
     instructions in ARMv8.4

   - remove some virtual memory layout printks during boot

   - fix initial page table creation to cope with larger than 32M kernel
     images when 16K pages are enabled"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (104 commits)
  arm64: Fix TTBR + PAN + 52-bit PA logic in cpu_do_switch_mm
  arm64: Turn on KPTI only on CPUs that need it
  arm64: Branch predictor hardening for Cavium ThunderX2
  arm64: Run enable method for errata work arounds on late CPUs
  arm64: Move BP hardening to check_and_switch_context
  arm64: mm: ignore memory above supported physical address size
  arm64: kpti: Fix the interaction between ASID switching and software PAN
  KVM: arm64: Emulate RAS error registers and set HCR_EL2's TERR & TEA
  KVM: arm64: Handle RAS SErrors from EL2 on guest exit
  KVM: arm64: Handle RAS SErrors from EL1 on guest exit
  KVM: arm64: Save ESR_EL2 on guest SError
  KVM: arm64: Save/Restore guest DISR_EL1
  KVM: arm64: Set an impdef ESR for Virtual-SError using VSESR_EL2.
  KVM: arm/arm64: mask/unmask daif around VHE guests
  arm64: kernel: Prepare for a DISR user
  arm64: Unconditionally enable IESB on exception entry/return for firmware-first
  arm64: kernel: Survive corrected RAS errors notified by SError
  arm64: cpufeature: Detect CPU RAS Extentions
  arm64: sysreg: Move to use definitions for all the SCTLR bits
  arm64: cpufeature: __this_cpu_has_cap() shouldn't stop early
  ...