Commit graph

59 commits

Author SHA1 Message Date
Ard Biesheuvel b0dddf6c14 efi/arm: Fix absolute relocation detection for older toolchains
When building the ARM kernel with CONFIG_EFI=y, the following build
error may occur when using a less recent version of binutils (2.23 or
older):

   STUBCPY drivers/firmware/efi/libstub/lib-sort.stub.o
 00000000 R_ARM_ABS32       sort
 00000004 R_ARM_ABS32       __ksymtab_strings
 drivers/firmware/efi/libstub/lib-sort.stub.o: absolute symbol references not allowed in the EFI stub

(and when building with debug symbols, the list above is much longer, and
contains all the internal references between the .debug sections and the
actual code)

This issue is caused by the fact that objcopy v2.23 or earlier does not
support wildcards in its -R and -j options, which means the following
line from the Makefile:

  STUBCOPY_FLAGS-y		:= -R .debug* -R *ksymtab* -R *kcrctab*

fails to take effect, leaving harmless absolute relocations in the binary
that are indistinguishable from relocations that may cause crashes at
runtime due to the fact that these relocations are resolved at link time
using the virtual address of the kernel, which is always different from
the address at which the EFI firmware loads and invokes the stub.

So, as a workaround, disable debug symbols explicitly when building the
stub for ARM, and strip the ksymtab and kcrctab symbols for the only
exported symbol we currently reuse in the stub, which is 'sort'.

Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1476805991-7160-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-19 14:49:44 +02:00
Jeffrey Hugo ed9cc156c4 efi/libstub: Use efi_exit_boot_services() in FDT
The FDT code directly calls ExitBootServices.  This is inadvisable as the
UEFI spec details a complex set of errors, race conditions, and API
interactions that the caller of ExitBootServices must get correct.  The
FDT code does not handle EFI_INVALID_PARAMETER as required by the spec,
which causes intermittent boot failures on the Qualcomm Technologies
QDF2432.  Call the efi_exit_boot_services() helper intead, which handles
the EFI_INVALID_PARAMETER scenario properly.

Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-05 12:32:36 +01:00
Jeffrey Hugo fc07716ba8 efi/libstub: Introduce ExitBootServices helper
The spec allows ExitBootServices to fail with EFI_INVALID_PARAMETER if a
race condition has occurred where the EFI has updated the memory map after
the stub grabbed a reference to the map.  The spec defines a retry
proceedure with specific requirements to handle this scenario.

This scenario was previously observed on x86 - commit d3768d885c ("x86,
efi: retry ExitBootServices() on failure") but the current fix is not spec
compliant and the scenario is now observed on the Qualcomm Technologies
QDF2432 via the FDT stub which does not handle the error and thus causes
boot failures.  The user will notice the boot failure as the kernel is not
executed and the system may drop back to a UEFI shell, but will be
unresponsive to input and the system will require a power cycle to recover.

Add a helper to the stub library that correctly adheres to the spec in the
case of EFI_INVALID_PARAMETER from ExitBootServices and can be universally
used across all stub implementations.

Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-05 12:32:28 +01:00
Jeffrey Hugo dadb57abc3 efi/libstub: Allocate headspace in efi_get_memory_map()
efi_get_memory_map() allocates a buffer to store the memory map that it
retrieves.  This buffer may need to be reused by the client after
ExitBootServices() is called, at which point allocations are not longer
permitted.  To support this usecase, provide the allocated buffer size back
to the client, and allocate some additional headroom to account for any
reasonable growth in the map that is likely to happen between the call to
efi_get_memory_map() and the client reusing the buffer.

Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-05 12:18:17 +01:00
Linus Torvalds be092017b6 arm64 updates for 4.7:
- virt_to_page/page_address optimisations
 
 - Support for NUMA systems described using device-tree
 
 - Support for hibernate/suspend-to-disk
 
 - Proper support for maxcpus= command line parameter
 
 - Detection and graceful handling of AArch64-only CPUs
 
 - Miscellaneous cleanups and non-critical fixes
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:

 - virt_to_page/page_address optimisations

 - support for NUMA systems described using device-tree

 - support for hibernate/suspend-to-disk

 - proper support for maxcpus= command line parameter

 - detection and graceful handling of AArch64-only CPUs

 - miscellaneous cleanups and non-critical fixes

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (92 commits)
  arm64: do not enforce strict 16 byte alignment to stack pointer
  arm64: kernel: Fix incorrect brk randomization
  arm64: cpuinfo: Missing NULL terminator in compat_hwcap_str
  arm64: secondary_start_kernel: Remove unnecessary barrier
  arm64: Ensure pmd_present() returns false after pmd_mknotpresent()
  arm64: Replace hard-coded values in the pmd/pud_bad() macros
  arm64: Implement pmdp_set_access_flags() for hardware AF/DBM
  arm64: Fix typo in the pmdp_huge_get_and_clear() definition
  arm64: mm: remove unnecessary EXPORT_SYMBOL_GPL
  arm64: always use STRICT_MM_TYPECHECKS
  arm64: kvm: Fix kvm teardown for systems using the extended idmap
  arm64: kaslr: increase randomization granularity
  arm64: kconfig: drop CONFIG_RTC_LIB dependency
  arm64: make ARCH_SUPPORTS_DEBUG_PAGEALLOC depend on !HIBERNATION
  arm64: hibernate: Refuse to hibernate if the boot cpu is offline
  arm64: kernel: Add support for hibernate/suspend-to-disk
  PM / Hibernate: Call flush_icache_range() on pages restored in-place
  arm64: Add new asm macro copy_page
  arm64: Promote KERNEL_START/KERNEL_END definitions to a header file
  arm64: kernel: Include _AC definition in page.h
  ...
2016-05-16 17:17:24 -07:00
Ard Biesheuvel 6f26b36711 arm64: kaslr: increase randomization granularity
Currently, our KASLR implementation randomizes the placement of the core
kernel at 2 MB granularity. This is based on the arm64 kernel boot
protocol, which mandates that the kernel is loaded TEXT_OFFSET bytes above
a 2 MB aligned base address. This requirement is a result of the fact that
the block size used by the early mapping code may be 2 MB at the most (for
a 4 KB granule kernel)

But we can do better than that: since a KASLR kernel needs to be relocated
in any case, we can tolerate a physical misalignment as long as the virtual
misalignment relative to this 2 MB block size is equal in size, and code to
deal with this is already in place.

Since we align the kernel segments to 64 KB, let's randomize the physical
offset at 64 KB granularity as well (unless CONFIG_DEBUG_ALIGN_RODATA is
enabled). This way, the page table and TLB footprint is not affected.

The higher granularity allows for 5 bits of additional entropy to be used.

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-28 19:44:15 +01:00
Ard Biesheuvel f0827e18a7 efi/arm*/libstub: Wire up GOP protocol to 'struct screen_info'
This adds the code to the ARM and arm64 versions of the UEFI stub to
populate struct screen_info based on the information received from the
firmware via the GOP protocol.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-23-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 11:34:00 +02:00
Ard Biesheuvel 801820bee9 efi/arm/libstub: Make screen_info accessible to the UEFI stub
In order to hand over the framebuffer described by the GOP protocol and
discovered by the UEFI stub, make struct screen_info accessible by the
stub. This involves allocating a loader data buffer and passing it to the
kernel proper via a UEFI Configuration Table, since the UEFI stub executes
in the context of the decompressor, and cannot access the kernel's copy of
struct screen_info directly.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-22-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 11:33:59 +02:00
Ard Biesheuvel fc37206427 efi/libstub: Move Graphics Output Protocol handling to generic code
The Graphics Output Protocol code executes in the stub, so create a generic
version based on the x86 version in libstub so that we can move other archs
to it in subsequent patches. The new source file gop.c is added to the
libstub build for all architectures, but only wired up for x86.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-18-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 11:33:57 +02:00
Matt Fleming 78ce248faa efi: Iterate over efi.memmap in for_each_efi_memory_desc()
Most of the users of for_each_efi_memory_desc() are equally happy
iterating over the EFI memory map in efi.memmap instead of 'memmap',
since the former is usually a pointer to the latter.

For those users that want to specify an EFI memory map other than
efi.memmap, that can be done using for_each_efi_memory_desc_in_map().
One such example is in the libstub code where the firmware is queried
directly for the memory map, it gets iterated over, and then freed.

This change goes part of the way toward deleting the global 'memmap'
variable, which is not universally available on all architectures
(notably IA64) and is rather poorly named.

Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-7-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 11:33:50 +02:00
Linn Crosetto 30d7bf034c efi/arm64: Check SetupMode when determining Secure Boot status
According to the UEFI specification (version 2.5 Errata A, page 87):

    The platform firmware is operating in secure boot mode if the value of
    the SetupMode variable is 0 and the SecureBoot variable is set to 1. A
    platform cannot operate in secure boot mode if the SetupMode variable
    is set to 1.

Check the value of the SetupMode variable when determining the state of
Secure Boot.

Plus also do minor cleanup, change sizeof() use to match kernel style guidelines.

Signed-off-by: Linn Crosetto <linn@hpe.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roy Franz <roy.franz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-6-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 11:33:49 +02:00
Linn Crosetto 73a6492589 efi/arm64: Report unexpected errors when determining Secure Boot status
Certain code in the boot path may require the ability to determine whether
UEFI Secure Boot is definitely enabled, for example printing status to the
console. Other code may need to know when UEFI Secure Boot is definitely
disabled, for example restricting use of kernel parameters.

If an unexpected error is returned from GetVariable() when querying the
status of UEFI Secure Boot, return an error to the caller. This allows the
caller to determine the definite state, and to take appropriate action if
an expected error is returned.

Signed-off-by: Linn Crosetto <linn@hpe.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roy Franz <roy.franz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-5-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 11:33:48 +02:00
Ard Biesheuvel 500899c2cc efi: ARM/arm64: ignore DT memory nodes instead of removing them
There are two problems with the UEFI stub DT memory node removal
routine:
- it deletes nodes as it traverses the tree, which happens to work
  but is not supported, as deletion invalidates the node iterator;
- deleting memory nodes entirely may discard annotations in the form
  of additional properties on the nodes.

Since the discovery of DT memory nodes occurs strictly before the
UEFI init sequence, we can simply clear the memblock memory table
before parsing the UEFI memory map. This way, it is no longer
necessary to remove the nodes, so we can remove that logic from the
stub as well.

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-15 18:06:07 +01:00
Dmitry Vyukov 5c9a8750a6 kernel: add kcov code coverage
kcov provides code coverage collection for coverage-guided fuzzing
(randomized testing).  Coverage-guided fuzzing is a testing technique
that uses coverage feedback to determine new interesting inputs to a
system.  A notable user-space example is AFL
(http://lcamtuf.coredump.cx/afl/).  However, this technique is not
widely used for kernel testing due to missing compiler and kernel
support.

kcov does not aim to collect as much coverage as possible.  It aims to
collect more or less stable coverage that is function of syscall inputs.
To achieve this goal it does not collect coverage in soft/hard
interrupts and instrumentation of some inherently non-deterministic or
non-interesting parts of kernel is disbled (e.g.  scheduler, locking).

Currently there is a single coverage collection mode (tracing), but the
API anticipates additional collection modes.  Initially I also
implemented a second mode which exposes coverage in a fixed-size hash
table of counters (what Quentin used in his original patch).  I've
dropped the second mode for simplicity.

This patch adds the necessary support on kernel side.  The complimentary
compiler support was added in gcc revision 231296.

We've used this support to build syzkaller system call fuzzer, which has
found 90 kernel bugs in just 2 months:

  https://github.com/google/syzkaller/wiki/Found-Bugs

We've also found 30+ bugs in our internal systems with syzkaller.
Another (yet unexplored) direction where kcov coverage would greatly
help is more traditional "blob mutation".  For example, mounting a
random blob as a filesystem, or receiving a random blob over wire.

Why not gcov.  Typical fuzzing loop looks as follows: (1) reset
coverage, (2) execute a bit of code, (3) collect coverage, repeat.  A
typical coverage can be just a dozen of basic blocks (e.g.  an invalid
input).  In such context gcov becomes prohibitively expensive as
reset/collect coverage steps depend on total number of basic
blocks/edges in program (in case of kernel it is about 2M).  Cost of
kcov depends only on number of executed basic blocks/edges.  On top of
that, kernel requires per-thread coverage because there are always
background threads and unrelated processes that also produce coverage.
With inlined gcov instrumentation per-thread coverage is not possible.

kcov exposes kernel PCs and control flow to user-space which is
insecure.  But debugfs should not be mapped as user accessible.

Based on a patch by Quentin Casasnovas.

[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
[akpm@linux-foundation.org: unbreak allmodconfig]
[akpm@linux-foundation.org: follow x86 Makefile layout standards]
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: David Drysdale <drysdale@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Linus Torvalds 24b5e20f11 Merge branch 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull EFI updates from Ingo Molnar:
 "The main changes are:

   - Use separate EFI page tables when executing EFI firmware code.
     This isolates the EFI context from the rest of the kernel, which
     has security and general robustness advantages.  (Matt Fleming)

   - Run regular UEFI firmware with interrupts enabled.  This is already
     the status quo under other OSs.  (Ard Biesheuvel)

   - Various x86 EFI enhancements, such as the use of non-executable
     attributes for EFI memory mappings.  (Sai Praneeth Prakhya)

   - Various arm64 UEFI enhancements.  (Ard Biesheuvel)

   - ... various fixes and cleanups.

  The separate EFI page tables feature got delayed twice already,
  because it's an intrusive change and we didn't feel confident about
  it - third time's the charm we hope!"

* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
  x86/mm/pat: Fix boot crash when 1GB pages are not supported by the CPU
  x86/efi: Only map kernel text for EFI mixed mode
  x86/efi: Map EFI_MEMORY_{XP,RO} memory region bits to EFI page tables
  x86/mm/pat: Don't implicitly allow _PAGE_RW in kernel_map_pages_in_pgd()
  efi/arm*: Perform hardware compatibility check
  efi/arm64: Check for h/w support before booting a >4 KB granular kernel
  efi/arm: Check for LPAE support before booting a LPAE kernel
  efi/arm-init: Use read-only early mappings
  efi/efistub: Prevent __init annotations from being used
  arm64/vmlinux.lds.S: Handle .init.rodata.xxx and .init.bss sections
  efi/arm64: Drop __init annotation from handle_kernel_image()
  x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings
  efi/runtime-wrappers: Run UEFI Runtime Services with interrupts enabled
  efi: Reformat GUID tables to follow the format in UEFI spec
  efi: Add Persistent Memory type name
  efi: Add NV memory attribute
  x86/efi: Show actual ending addresses in efi_print_memmap
  x86/efi/bgrt: Don't ignore the BGRT if the 'valid' bit is 0
  efivars: Use to_efivar_entry
  efi: Runtime-wrapper: Get rid of the rtc_lock spinlock
  ...
2016-03-20 18:58:18 -07:00
Linus Torvalds 26660a4046 Merge branch 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull 'objtool' stack frame validation from Ingo Molnar:
 "This tree adds a new kernel build-time object file validation feature
  (ONFIG_STACK_VALIDATION=y): kernel stack frame correctness validation.
  It was written by and is maintained by Josh Poimboeuf.

  The motivation: there's a category of hard to find kernel bugs, most
  of them in assembly code (but also occasionally in C code), that
  degrades the quality of kernel stack dumps/backtraces.  These bugs are
  hard to detect at the source code level.  Such bugs result in
  incorrect/incomplete backtraces most of time - but can also in some
  rare cases result in crashes or other undefined behavior.

  The build time correctness checking is done via the new 'objtool'
  user-space utility that was written for this purpose and which is
  hosted in the kernel repository in tools/objtool/.  The tool's (very
  simple) UI and source code design is shaped after Git and perf and
  shares quite a bit of infrastructure with tools/perf (which tooling
  infrastructure sharing effort got merged via perf and is already
  upstream).  Objtool follows the well-known kernel coding style.

  Objtool does not try to check .c or .S files, it instead analyzes the
  resulting .o generated machine code from first principles: it decodes
  the instruction stream and interprets it.  (Right now objtool supports
  the x86-64 architecture.)

  From tools/objtool/Documentation/stack-validation.txt:

   "The kernel CONFIG_STACK_VALIDATION option enables a host tool named
    objtool which runs at compile time.  It has a "check" subcommand
    which analyzes every .o file and ensures the validity of its stack
    metadata.  It enforces a set of rules on asm code and C inline
    assembly code so that stack traces can be reliable.

    Currently it only checks frame pointer usage, but there are plans to
    add CFI validation for C files and CFI generation for asm files.

    For each function, it recursively follows all possible code paths
    and validates the correct frame pointer state at each instruction.

    It also follows code paths involving special sections, like
    .altinstructions, __jump_table, and __ex_table, which can add
    alternative execution paths to a given instruction (or set of
    instructions).  Similarly, it knows how to follow switch statements,
    for which gcc sometimes uses jump tables."

  When this new kernel option is enabled (it's disabled by default), the
  tool, if it finds any suspicious assembly code pattern, outputs
  warnings in compiler warning format:

    warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch
    warning: objtool: cik_tiling_mode_table_init()+0x6ce: call without frame pointer save/setup
    warning: objtool:__schedule()+0x3c0: duplicate frame pointer save
    warning: objtool:__schedule()+0x3fd: sibling call from callable instruction with changed frame pointer

  ... so that scripts that pick up compiler warnings will notice them.
  All known warnings triggered by the tool are fixed by the tree, most
  of the commits in fact prepare the kernel to be warning-free.  Most of
  them are bugfixes or cleanups that stand on their own, but there are
  also some annotations of 'special' stack frames for justified cases
  such entries to JIT-ed code (BPF) or really special boot time code.

  There are two other long-term motivations behind this tool as well:

   - To improve the quality and reliability of kernel stack frames, so
     that they can be used for optimized live patching.

   - To create independent infrastructure to check the correctness of
     CFI stack frames at build time.  CFI debuginfo is notoriously
     unreliable and we cannot use it in the kernel as-is without extra
     checking done both on the kernel side and on the build side.

  The quality of kernel stack frames matters to debuggability as well,
  so IMO we can merge this without having to consider the live patching
  or CFI debuginfo angle"

* 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  objtool: Only print one warning per function
  objtool: Add several performance improvements
  tools: Copy hashtable.h into tools directory
  objtool: Fix false positive warnings for functions with multiple switch statements
  objtool: Rename some variables and functions
  objtool: Remove superflous INIT_LIST_HEAD
  objtool: Add helper macros for traversing instructions
  objtool: Fix false positive warnings related to sibling calls
  objtool: Compile with debugging symbols
  objtool: Detect infinite recursion
  objtool: Prevent infinite recursion in noreturn detection
  objtool: Detect and warn if libelf is missing and don't break the build
  tools: Support relative directory path for 'O='
  objtool: Support CROSS_COMPILE
  x86/asm/decoder: Use explicitly signed chars
  objtool: Enable stack metadata validation on 64-bit x86
  objtool: Add CONFIG_STACK_VALIDATION option
  objtool: Add tool to perform compile-time stack metadata validation
  x86/kprobes: Mark kretprobe_trampoline() stack frame as non-standard
  sched: Always inline context_switch()
  ...
2016-03-20 18:23:21 -07:00
Josh Poimboeuf c0dd671686 objtool: Mark non-standard object files and directories
Code which runs outside the kernel's normal mode of operation often does
unusual things which can cause a static analysis tool like objtool to
emit false positive warnings:

 - boot image
 - vdso image
 - relocation
 - realmode
 - efi
 - head
 - purgatory
 - modpost

Set OBJECT_FILES_NON_STANDARD for their related files and directories,
which will tell objtool to skip checking them.  It's ok to skip them
because they don't affect runtime stack traces.

Also skip the following code which does the right thing with respect to
frame pointers, but is too "special" to be validated by a tool:

 - entry
 - mcount

Also skip the test_nx module because it modifies its exception handling
table at runtime, which objtool can't understand.  Fortunately it's
just a test module so it doesn't matter much.

Currently objtool is the only user of OBJECT_FILES_NON_STANDARD, but it
might eventually be useful for other tools.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/366c080e3844e8a5b6a0327dc7e8c2b90ca3baeb.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-29 08:35:02 +01:00
Ard Biesheuvel 2b5fe07a78 arm64: efi: invoke EFI_RNG_PROTOCOL to supply KASLR randomness
Since arm64 does not use a decompressor that supplies an execution
environment where it is feasible to some extent to provide a source of
randomness, the arm64 KASLR kernel depends on the bootloader to supply
some random bits in the /chosen/kaslr-seed DT property upon kernel entry.

On UEFI systems, we can use the EFI_RNG_PROTOCOL, if supplied, to obtain
some random bits. At the same time, use it to randomize the offset of the
kernel Image in physical memory.

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-24 14:57:29 +00:00
Ard Biesheuvel 48fcb2d021 efi: stub: use high allocation for converted command line
Before we can move the command line processing before the allocation
of the kernel, which is required for detecting the 'nokaslr' option
which controls that allocation, move the converted command line higher
up in memory, to prevent it from interfering with the kernel itself.

Since x86 needs the address to fit in 32 bits, use UINT_MAX as the upper
bound there. Otherwise, use ULONG_MAX (i.e., no limit)

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-24 14:57:28 +00:00
Ard Biesheuvel 2ddbfc81ea efi: stub: add implementation of efi_random_alloc()
This implements efi_random_alloc(), which allocates a chunk of memory of
a certain size at a certain alignment, and uses the random_seed argument
it receives to randomize the address of the allocation.

This is implemented by iterating over the UEFI memory map, counting the
number of suitable slots (aligned offsets) within each region, and picking
a random number between 0 and 'number of slots - 1' to select the slot,
This should guarantee that each possible offset is chosen equally likely.

Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-24 14:57:28 +00:00
Ard Biesheuvel e4fbf47674 efi: stub: implement efi_get_random_bytes() based on EFI_RNG_PROTOCOL
This exposes the firmware's implementation of EFI_RNG_PROTOCOL via a new
function efi_get_random_bytes().

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-24 14:57:28 +00:00
Ard Biesheuvel b9d6769b56 efi/arm*: Perform hardware compatibility check
Before proceeding with relocating the kernel and parsing the command line,
insert a call to check_platform_features() to allow an arch specific check
to be performed whether the current kernel can execute on the current
hardware.

Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-11-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-22 08:26:27 +01:00
Ard Biesheuvel 42b5573403 efi/arm64: Check for h/w support before booting a >4 KB granular kernel
A kernel built with support for a page size that is not supported by the
hardware it runs on cannot boot to a state where it can inform the user
about the failure.

If we happen to be booting via UEFI, we can fail gracefully so check
if the currently configured page size is supported by the hardware before
entering the kernel proper. Note that UEFI mandates support for 4 KB pages,
so in that case, no check is needed.

Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-10-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-22 08:26:27 +01:00
Ard Biesheuvel 2ec0f0a3a4 efi/arm: Check for LPAE support before booting a LPAE kernel
A kernel built with support for LPAE cannot boot to a state where it
can inform the user about if it has to fail due to missing LPAE support
in the hardware.

If we happen to be booting via UEFI, we can fail gracefully so check
for LPAE support in the hardware on CONFIG_ARM_LPAE builds before
entering the kernel proper.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-9-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-22 08:26:27 +01:00
Ard Biesheuvel 07e83dbb75 efi/efistub: Prevent __init annotations from being used
__init annotations should not be used in the EFI stub, since the code is
either included in the decompressor (x86, ARM) where they have no effect,
or the whole stub is __init annotated at the section level (arm64), by
renaming the sections.

In the second case the __init annotations will be redundant, and will
result in section names like .init.init.text, and our linker script does
not expect that.

So un-#define __init so that its inadvertent use will force a build error.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-7-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-22 08:26:26 +01:00
Ard Biesheuvel dae31fd2b7 efi/arm64: Drop __init annotation from handle_kernel_image()
After moving arm64-stub.c to libstub/, all of its sections are emitted
as .init.xxx sections automatically, and the __init annotation of
handle_kernel_image() causes it to end up in .init.init.text, which is
not recognized as an __init section by the linker scripts. So drop the
annotation.

Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-5-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-22 08:26:26 +01:00
Andrey Ryabinin c6d308534a UBSAN: run-time undefined behavior sanity checker
UBSAN uses compile-time instrumentation to catch undefined behavior
(UB).  Compiler inserts code that perform certain kinds of checks before
operations that could cause UB.  If check fails (i.e.  UB detected)
__ubsan_handle_* function called to print error message.

So the most of the work is done by compiler.  This patch just implements
ubsan handlers printing errors.

GCC has this capability since 4.9.x [1] (see -fsanitize=undefined
option and its suboptions).
However GCC 5.x has more checkers implemented [2].
Article [3] has a bit more details about UBSAN in the GCC.

[1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
[2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
[3] - http://developerblog.redhat.com/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan/

Issues which UBSAN has found thus far are:

Found bugs:

 * out-of-bounds access - 97840cb67f ("netfilter: nfnetlink: fix
   insufficient validation in nfnetlink_bind")

undefined shifts:

 * d48458d4a7 ("jbd2: use a better hash function for the revoke
   table")

 * 10632008b9 ("clockevents: Prevent shift out of bounds")

 * 'x << -1' shift in ext4 -
   http://lkml.kernel.org/r/<5444EF21.8020501@samsung.com>

 * undefined rol32(0) -
   http://lkml.kernel.org/r/<1449198241-20654-1-git-send-email-sasha.levin@oracle.com>

 * undefined dirty_ratelimit calculation -
   http://lkml.kernel.org/r/<566594E2.3050306@odin.com>

 * undefined roundown_pow_of_two(0) -
   http://lkml.kernel.org/r/<1449156616-11474-1-git-send-email-sasha.levin@oracle.com>

 * [WONTFIX] undefined shift in __bpf_prog_run -
   http://lkml.kernel.org/r/<CACT4Y+ZxoR3UjLgcNdUm4fECLMx2VdtfrENMtRRCdgHB2n0bJA@mail.gmail.com>

   WONTFIX here because it should be fixed in bpf program, not in kernel.

signed overflows:

 * 32a8df4e0b ("sched: Fix odd values in effective_load()
   calculations")

 * mul overflow in ntp -
   http://lkml.kernel.org/r/<1449175608-1146-1-git-send-email-sasha.levin@oracle.com>

 * incorrect conversion into rtc_time in rtc_time64_to_tm() -
   http://lkml.kernel.org/r/<1449187944-11730-1-git-send-email-sasha.levin@oracle.com>

 * unvalidated timespec in io_getevents() -
   http://lkml.kernel.org/r/<CACT4Y+bBxVYLQ6LtOKrKtnLthqLHcw-BMp3aqP3mjdAvr9FULQ@mail.gmail.com>

 * [NOTABUG] signed overflow in ktime_add_safe() -
   http://lkml.kernel.org/r/<CACT4Y+aJ4muRnWxsUe1CMnA6P8nooO33kwG-c8YZg=0Xc8rJqw@mail.gmail.com>

[akpm@linux-foundation.org: fix unused local warning]
[akpm@linux-foundation.org: fix __int128 build woes]
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yury Gribov <y.gribov@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 17:09:18 -08:00
Linus Torvalds 7d1fc01afc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  floppy: make local variable non-static
  exynos: fixes an incorrect header guard
  dt-bindings: fixes some incorrect header guards
  cpufreq-dt: correct dead link in documentation
  cpufreq: ARM big LITTLE: correct dead link in documentation
  treewide: Fix typos in printk
  Documentation: filesystem: Fix typo in fs/eventfd.c
  fs/super.c: use && instead of & for warn_on condition
  Documentation: fix sysfs-ptp
  lib: scatterlist: fix Kconfig description
2016-01-14 17:04:19 -08:00
Linus Torvalds 01e9d22638 Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King:

 - UEFI boot and runtime services support for ARM from Ard Biesheuvel
   and Roy Franz.

 - DT compatibility with old atags booting protocol for Nokia N900
   devices from Ivaylo Dimitrov.

 - PSCI firmware interface using new arm-smc calling convention from
   Jens Wiklander.

 - Runtime patching for udiv/sdiv instructions for ARMv7 CPUs that
   support these instructions from Nicolas Pitre.

 - L2x0 cache updates from Dirk B and Linus Walleij.

 - Randconfig fixes from Arnd Bergmann.

 - ARMv7M (nommu) updates from Ezequiel Garcia

* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (34 commits)
  ARM: 8481/2: drivers: psci: replace psci firmware calls
  ARM: 8480/2: arm64: add implementation for arm-smccc
  ARM: 8479/2: add implementation for arm-smccc
  ARM: 8478/2: arm/arm64: add arm-smccc
  ARM: 8494/1: mm: Enable PXN when running non-LPAE kernel on LPAE processor
  ARM: 8496/1: OMAP: RX51: save ATAGS data in the early boot stage
  ARM: 8495/1: ATAGS: move save_atags() to arch/arm/include/asm/setup.h
  ARM: 8452/3: PJ4: make coprocessor access sequences buildable in Thumb2 mode
  ARM: 8482/1: l2x0: make it possible to disable outer sync from DT
  ARM: 8488/1: Make IPI_CPU_BACKTRACE a "non-secure" SGI
  ARM: 8487/1: Remove IPI_CALL_FUNC_SINGLE
  ARM: 8485/1: cpuidle: remove cpu parameter from the cpuidle_ops suspend hook
  ARM: 8484/1: Documentation: l2c2x0: Mention separate controllers explicitly
  ARM: 8483/1: Documentation: l2c: Rename l2cc to l2c2x0
  ARM: 8477/1: runtime patch udiv/sdiv instructions into __aeabi_{u}idiv()
  ARM: 8476/1: VDSO: use PTR_ERR_OR_ZERO for vma check
  ARM: 8453/2: proc-v7.S: don't locate temporary stack space in .text section
  ARM: add UEFI stub support
  ARM: wire up UEFI init and runtime support
  ARM: only consider memblocks with NOMAP cleared for linear mapping
  ...
2016-01-12 12:39:07 -08:00
Ard Biesheuvel b523e185bb efi: stub: define DISABLE_BRANCH_PROFILING for all architectures
This moves the DISABLE_BRANCH_PROFILING define from the x86 specific
to the general CFLAGS definition for the stub. This fixes build errors
when building for arm64 with CONFIG_PROFILE_ALL_BRANCHES_ENABLED.

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-01-06 15:42:12 +00:00
Roy Franz 81a0bc39ea ARM: add UEFI stub support
This patch adds EFI stub support for the ARM Linux kernel.

The EFI stub operates similarly to the x86 and arm64 stubs: it is a
shim between the EFI firmware and the normal zImage entry point, and
sets up the environment that the zImage is expecting. This includes
optionally loading the initrd and device tree from the system partition
based on the kernel command line.

Signed-off-by: Roy Franz <roy.franz@linaro.org>
Tested-by: Ryan Harkin <ryan.harkin@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
2015-12-14 10:38:21 +01:00
Masanari Iida e3d132d123 treewide: Fix typos in printk
This patch fix multiple spelling typos found in
various part of kernel.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2015-12-08 14:59:19 +01:00
Linus Torvalds 2dc10ad81f arm64 updates for 4.4:
- "genirq: Introduce generic irq migration for cpu hotunplugged" patch
   merged from tip/irq/for-arm to allow the arm64-specific part to be
   upstreamed via the arm64 tree
 
 - CPU feature detection reworked to cope with heterogeneous systems
   where CPUs may not have exactly the same features. The features
   reported by the kernel via internal data structures or ELF_HWCAP are
   delayed until all the CPUs are up (and before user space starts)
 
 - Support for 16KB pages, with the additional bonus of a 36-bit VA
   space, though the latter only depending on EXPERT
 
 - Implement native {relaxed, acquire, release} atomics for arm64
 
 - New ASID allocation algorithm which avoids IPI on roll-over, together
   with TLB invalidation optimisations (using local vs global where
   feasible)
 
 - KASan support for arm64
 
 - EFI_STUB clean-up and isolation for the kernel proper (required by
   KASan)
 
 - copy_{to,from,in}_user optimisations (sharing the memcpy template)
 
 - perf: moving arm64 to the arm32/64 shared PMU framework
 
 - L1_CACHE_BYTES increased to 128 to accommodate Cavium hardware
 
 - Support for the contiguous PTE hint on kernel mapping (16 consecutive
   entries may be able to use a single TLB entry)
 
 - Generic CONFIG_HZ now used on arm64
 
 - defconfig updates
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:

 - "genirq: Introduce generic irq migration for cpu hotunplugged" patch
   merged from tip/irq/for-arm to allow the arm64-specific part to be
   upstreamed via the arm64 tree

 - CPU feature detection reworked to cope with heterogeneous systems
   where CPUs may not have exactly the same features.  The features
   reported by the kernel via internal data structures or ELF_HWCAP are
   delayed until all the CPUs are up (and before user space starts)

 - Support for 16KB pages, with the additional bonus of a 36-bit VA
   space, though the latter only depending on EXPERT

 - Implement native {relaxed, acquire, release} atomics for arm64

 - New ASID allocation algorithm which avoids IPI on roll-over, together
   with TLB invalidation optimisations (using local vs global where
   feasible)

 - KASan support for arm64

 - EFI_STUB clean-up and isolation for the kernel proper (required by
   KASan)

 - copy_{to,from,in}_user optimisations (sharing the memcpy template)

 - perf: moving arm64 to the arm32/64 shared PMU framework

 - L1_CACHE_BYTES increased to 128 to accommodate Cavium hardware

 - Support for the contiguous PTE hint on kernel mapping (16 consecutive
   entries may be able to use a single TLB entry)

 - Generic CONFIG_HZ now used on arm64

 - defconfig updates

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (91 commits)
  arm64/efi: fix libstub build under CONFIG_MODVERSIONS
  ARM64: Enable multi-core scheduler support by default
  arm64/efi: move arm64 specific stub C code to libstub
  arm64: page-align sections for DEBUG_RODATA
  arm64: Fix build with CONFIG_ZONE_DMA=n
  arm64: Fix compat register mappings
  arm64: Increase the max granular size
  arm64: remove bogus TASK_SIZE_64 check
  arm64: make Timer Interrupt Frequency selectable
  arm64/mm: use PAGE_ALIGNED instead of IS_ALIGNED
  arm64: cachetype: fix definitions of ICACHEF_* flags
  arm64: cpufeature: declare enable_cpu_capabilities as static
  genirq: Make the cpuhotplug migration code less noisy
  arm64: Constify hwcap name string arrays
  arm64/kvm: Make use of the system wide safe values
  arm64/debug: Make use of the system wide safe value
  arm64: Move FP/ASIMD hwcap handling to common code
  arm64/HWCAP: Use system wide safe values
  arm64/capabilities: Make use of system wide safe value
  arm64: Delay cpu feature capability checks
  ...
2015-11-04 14:47:13 -08:00
Ard Biesheuvel f8f8bdc488 arm64/efi: fix libstub build under CONFIG_MODVERSIONS
Now that we strictly forbid absolute relocations in libstub code,
make sure that we don't emit any when CONFIG_MODVERSIONS is enabled,
by stripping the kcrctab sections from the object file. This fixes
a build problem under CONFIG_MODVERSIONS=y.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-11-02 13:50:17 +00:00
Ard Biesheuvel bf457786f5 arm64/efi: move arm64 specific stub C code to libstub
Now that we added special handling to the C files in libstub, move
the one remaining arm64 specific EFI stub C file to libstub as
well, so that it gets the same treatment. This should prevent future
changes from resulting in binaries that may execute incorrectly in
UEFI context.

With efi-entry.S the only remaining EFI stub source file under
arch/arm64, we can also simplify the Makefile logic somewhat.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-30 16:02:52 +00:00
Ard Biesheuvel e8f3010f73 arm64/efi: isolate EFI stub from the kernel proper
Since arm64 does not use a builtin decompressor, the EFI stub is built
into the kernel proper. So far, this has been working fine, but actually,
since the stub is in fact a PE/COFF relocatable binary that is executed
at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
should not be seamlessly sharing code with the kernel proper, which is a
position dependent executable linked at a high virtual offset.

So instead, separate the contents of libstub and its dependencies, by
putting them into their own namespace by prefixing all of its symbols
with __efistub. This way, we have tight control over what parts of the
kernel proper are referenced by the stub.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 16:20:12 +01:00
Ard Biesheuvel d4dddfdbbc arm64/efi: remove /chosen/linux, uefi-stub-kern-ver DT property
With the stub to kernel interface being promoted to a proper interface
so that other agents than the stub can boot the kernel proper in EFI
mode, we can remove the linux,uefi-stub-kern-ver field, considering
that its original purpose was to prevent this from happening in the
first place.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 16:19:33 +01:00
Ard Biesheuvel 0ce3cc008e arm64/efi: Fix boot crash by not padding between EFI_MEMORY_RUNTIME regions
The new Properties Table feature introduced in UEFIv2.5 may
split memory regions that cover PE/COFF memory images into
separate code and data regions. Since these regions only differ
in the type (runtime code vs runtime data) and the permission
bits, but not in the memory type attributes (UC/WC/WT/WB), the
spec does not require them to be aligned to 64 KB.

Since the relative offset of PE/COFF .text and .data segments
cannot be changed on the fly, this means that we can no longer
pad out those regions to be mappable using 64 KB pages.
Unfortunately, there is no annotation in the UEFI memory map
that identifies data regions that were split off from a code
region, so we must apply this logic to all adjacent runtime
regions whose attributes only differ in the permission bits.

So instead of rounding each memory region to 64 KB alignment at
both ends, only round down regions that are not directly
preceded by another runtime region with the same type
attributes. Since the UEFI spec does not mandate that the memory
map be sorted, this means we also need to sort it first.

Note that this change will result in all EFI_MEMORY_RUNTIME
regions whose start addresses are not aligned to the OS page
size to be mapped with executable permissions (i.e., on kernels
compiled with 64 KB pages). However, since these mappings are
only active during the time that UEFI Runtime Services are being
invoked, the window for abuse is rather small.

Tested-by: Mark Salter <msalter@redhat.com>
Tested-by: Mark Rutland <mark.rutland@arm.com> [UEFI 2.4 only]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Reviewed-by: Mark Salter <msalter@redhat.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org> # v4.0+
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1443218539-7610-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-01 12:51:28 +02:00
Andrey Ryabinin 769a8089c1 x86, efi, kasan: #undef memset/memcpy/memmove per arch
In not-instrumented code KASAN replaces instrumented memset/memcpy/memmove
with not-instrumented analogues __memset/__memcpy/__memove.

However, on x86 the EFI stub is not linked with the kernel.  It uses
not-instrumented mem*() functions from arch/x86/boot/compressed/string.c

So we don't replace them with __mem*() variants in EFI stub.

On ARM64 the EFI stub is linked with the kernel, so we should replace
mem*() functions with __mem*(), because the EFI stub runs before KASAN
sets up early shadow.

So let's move these #undef mem* into arch's asm/efi.h which is also
included by the EFI stub.

Also, this will fix the warning in 32-bit build reported by kbuild test
robot:

	efi-stub-helper.c:599:2: warning: implicit declaration of function 'memcpy'

[akpm@linux-foundation.org: use 80 cols in comment]
Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Reported-by: Fengguang Wu <fengguang.wu@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-22 15:09:53 -07:00
Rob Herring 63a4aea556 of: clean-up unnecessary libfdt include paths
With the libfdt include fixups to use "" instead of <> in the
latest dtc import in commit 4760597 (scripts/dtc: Update to upstream
version 9d3649bd3be245c9), it is no longer necessary to add explicit
include paths to use libfdt. Remove these across the kernel.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Grant Likely <grant.likely@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linuxppc-dev@lists.ozlabs.org
2015-06-04 20:16:47 -05:00
Ard Biesheuvel a643375f4b efi/libstub: Retrieve FDT size when loaded from UEFI config table
When allocating memory for the copy of the FDT that the stub
modifies and passes to the kernel, it uses the current size as
an estimate of how much memory to allocate, and increases it page
by page if it turns out to be too small. However, when loading
the FDT from a UEFI configuration table, the estimated size is
left at its default value of zero, and the allocation loop runs
starting from zero all the way up to the allocation size that
finally fits the updated FDT.

Instead, retrieve the size of the FDT from the FDT header when
loading it from the UEFI config table.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Roy Franz <roy.franz@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2015-04-01 12:46:23 +01:00
Ingo Molnar be482d624c * Fix regression in DMI sysfs code for handling "End of Table" entry
and a type bug that could lead to integer overflow - Ivan Khoronzhuk
 
  * Fix boundary checking in efi_high_alloc() which can lead to memory
    corruption in the EFI boot stubs - Yinghai Lu
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Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/urgent

Pull EFI fixes from Matt Fleming:

" - Fix regression in DMI sysfs code for handling "End of Table" entry
    and a type bug that could lead to integer overflow. (Ivan Khoronzhuk)

  - Fix boundary checking in efi_high_alloc() which can lead to memory
    corruption in the EFI boot stubs. (Yinghai Lu)"

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-02 14:18:57 +01:00
Yinghai Lu 7ed620bb34 efi/libstub: Fix boundary checking in efi_high_alloc()
While adding support loading kernel and initrd above 4G to grub2 in legacy
mode, I was referring to efi_high_alloc().
That will allocate buffer for kernel and then initrd, and initrd will
use kernel buffer start as limit.

During testing found two buffers will be overlapped when initrd size is
very big like 400M.

It turns out efi_high_alloc() boundary checking is not right.
end - size will be the new start, and should not compare new
start with max, we need to make sure end is smaller than max.

[ Basically, with the current efi_high_alloc() code it's possible to
  allocate memory above 'max', because efi_high_alloc() doesn't check
  that the tail of the allocation is below 'max'.

  If you have an EFI memory map with a single entry that looks like so,

   [0xc0000000-0xc0004000]

  And want to allocate 0x3000 bytes below 0xc0003000 the current code
  will allocate [0xc0001000-0xc0004000], not [0xc0000000-0xc0003000]
  like you would expect. - Matt ]

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2015-02-24 18:46:03 +00:00
Linus Torvalds 5fbe4c224c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull misc x86 fixes from Ingo Molnar:
 "This contains:

   - EFI fixes
   - a boot printout fix
   - ASLR/kASLR fixes
   - intel microcode driver fixes
   - other misc fixes

  Most of the linecount comes from an EFI revert"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/ASLR: Avoid PAGE_SIZE redefinition for UML subarch
  x86/microcode/intel: Handle truncated microcode images more robustly
  x86/microcode/intel: Guard against stack overflow in the loader
  x86, mm/ASLR: Fix stack randomization on 64-bit systems
  x86/mm/init: Fix incorrect page size in init_memory_mapping() printks
  x86/mm/ASLR: Propagate base load address calculation
  Documentation/x86: Fix path in zero-page.txt
  x86/apic: Fix the devicetree build in certain configs
  Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes"
  x86/efi: Avoid triple faults during EFI mixed mode calls
2015-02-21 10:41:29 -08:00
Matt Fleming 43a9f69692 Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes"
This reverts commit d1a8d66b91.

Ard reported a boot failure when running UEFI under Qemu and Xen and
experimenting with various Tianocore build options,

 "As it turns out, when allocating room for the UEFI memory map using
  UEFI's AllocatePool (), it may result in two new memory map entries
  being created, for instance, when using Tianocore's preallocated region
  feature. For example, the following region

  0x00005ead5000-0x00005ebfffff [Conventional Memory|   |  |  |  |  |WB|WT|WC|UC]

  may be split like this

  0x00005ead5000-0x00005eae2fff [Conventional Memory|   |  |  |  |  |WB|WT|WC|UC]
  0x00005eae3000-0x00005eae4fff [Loader Data        |   |  |  |  |  |WB|WT|WC|UC]
  0x00005eae5000-0x00005ebfffff [Conventional Memory|   |  |  |  |  |WB|WT|WC|UC]

  if the preallocated Loader Data region was chosen to be right in the
  middle of the original free space.

  After patch d1a8d66b91 ("efi/libstub: Call get_memory_map() to
  obtain map and desc sizes"), this is not being dealt with correctly
  anymore, as the existing logic to allocate room for a single additional
  entry has become insufficient."

Mark requested to reinstate the old loop we had before commit
d1a8d66b91, which grows the memory map buffer until it's big enough to
hold the EFI memory map.

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2015-02-18 11:38:13 +00:00
Andrey Ryabinin 393f203f5f x86_64: kasan: add interceptors for memset/memmove/memcpy functions
Recently instrumentation of builtin functions calls was removed from GCC
5.0.  To check the memory accessed by such functions, userspace asan
always uses interceptors for them.

So now we should do this as well.  This patch declares
memset/memmove/memcpy as weak symbols.  In mm/kasan/kasan.c we have our
own implementation of those functions which checks memory before accessing
it.

Default memset/memmove/memcpy now now always have aliases with '__'
prefix.  For files that built without kasan instrumentation (e.g.
mm/slub.c) original mem* replaced (via #define) with prefixed variants,
cause we don't want to check memory accesses there.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:41 -08:00
Andrey Ryabinin 0b24becc81 kasan: add kernel address sanitizer infrastructure
Kernel Address sanitizer (KASan) is a dynamic memory error detector.  It
provides fast and comprehensive solution for finding use-after-free and
out-of-bounds bugs.

KASAN uses compile-time instrumentation for checking every memory access,
therefore GCC > v4.9.2 required.  v4.9.2 almost works, but has issues with
putting symbol aliases into the wrong section, which breaks kasan
instrumentation of globals.

This patch only adds infrastructure for kernel address sanitizer.  It's
not available for use yet.  The idea and some code was borrowed from [1].

Basic idea:

The main idea of KASAN is to use shadow memory to record whether each byte
of memory is safe to access or not, and use compiler's instrumentation to
check the shadow memory on each memory access.

Address sanitizer uses 1/8 of the memory addressable in kernel for shadow
memory and uses direct mapping with a scale and offset to translate a
memory address to its corresponding shadow address.

Here is function to translate address to corresponding shadow address:

     unsigned long kasan_mem_to_shadow(unsigned long addr)
     {
                return (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET;
     }

where KASAN_SHADOW_SCALE_SHIFT = 3.

So for every 8 bytes there is one corresponding byte of shadow memory.
The following encoding used for each shadow byte: 0 means that all 8 bytes
of the corresponding memory region are valid for access; k (1 <= k <= 7)
means that the first k bytes are valid for access, and other (8 - k) bytes
are not; Any negative value indicates that the entire 8-bytes are
inaccessible.  Different negative values used to distinguish between
different kinds of inaccessible memory (redzones, freed memory) (see
mm/kasan/kasan.h).

To be able to detect accesses to bad memory we need a special compiler.
Such compiler inserts a specific function calls (__asan_load*(addr),
__asan_store*(addr)) before each memory access of size 1, 2, 4, 8 or 16.

These functions check whether memory region is valid to access or not by
checking corresponding shadow memory.  If access is not valid an error
printed.

Historical background of the address sanitizer from Dmitry Vyukov:

	"We've developed the set of tools, AddressSanitizer (Asan),
	ThreadSanitizer and MemorySanitizer, for user space. We actively use
	them for testing inside of Google (continuous testing, fuzzing,
	running prod services). To date the tools have found more than 10'000
	scary bugs in Chromium, Google internal codebase and various
	open-source projects (Firefox, OpenSSL, gcc, clang, ffmpeg, MySQL and
	lots of others): [2] [3] [4].
	The tools are part of both gcc and clang compilers.

	We have not yet done massive testing under the Kernel AddressSanitizer
	(it's kind of chicken and egg problem, you need it to be upstream to
	start applying it extensively). To date it has found about 50 bugs.
	Bugs that we've found in upstream kernel are listed in [5].
	We've also found ~20 bugs in out internal version of the kernel. Also
	people from Samsung and Oracle have found some.

	[...]

	As others noted, the main feature of AddressSanitizer is its
	performance due to inline compiler instrumentation and simple linear
	shadow memory. User-space Asan has ~2x slowdown on computational
	programs and ~2x memory consumption increase. Taking into account that
	kernel usually consumes only small fraction of CPU and memory when
	running real user-space programs, I would expect that kernel Asan will
	have ~10-30% slowdown and similar memory consumption increase (when we
	finish all tuning).

	I agree that Asan can well replace kmemcheck. We have plans to start
	working on Kernel MemorySanitizer that finds uses of unitialized
	memory. Asan+Msan will provide feature-parity with kmemcheck. As
	others noted, Asan will unlikely replace debug slab and pagealloc that
	can be enabled at runtime. Asan uses compiler instrumentation, so even
	if it is disabled, it still incurs visible overheads.

	Asan technology is easily portable to other architectures. Compiler
	instrumentation is fully portable. Runtime has some arch-dependent
	parts like shadow mapping and atomic operation interception. They are
	relatively easy to port."

Comparison with other debugging features:
========================================

KMEMCHECK:

  - KASan can do almost everything that kmemcheck can.  KASan uses
    compile-time instrumentation, which makes it significantly faster than
    kmemcheck.  The only advantage of kmemcheck over KASan is detection of
    uninitialized memory reads.

    Some brief performance testing showed that kasan could be
    x500-x600 times faster than kmemcheck:

$ netperf -l 30
		MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost (127.0.0.1) port 0 AF_INET
		Recv   Send    Send
		Socket Socket  Message  Elapsed
		Size   Size    Size     Time     Throughput
		bytes  bytes   bytes    secs.    10^6bits/sec

no debug:	87380  16384  16384    30.00    41624.72

kasan inline:	87380  16384  16384    30.00    12870.54

kasan outline:	87380  16384  16384    30.00    10586.39

kmemcheck: 	87380  16384  16384    30.03      20.23

  - Also kmemcheck couldn't work on several CPUs.  It always sets
    number of CPUs to 1.  KASan doesn't have such limitation.

DEBUG_PAGEALLOC:
	- KASan is slower than DEBUG_PAGEALLOC, but KASan works on sub-page
	  granularity level, so it able to find more bugs.

SLUB_DEBUG (poisoning, redzones):
	- SLUB_DEBUG has lower overhead than KASan.

	- SLUB_DEBUG in most cases are not able to detect bad reads,
	  KASan able to detect both reads and writes.

	- In some cases (e.g. redzone overwritten) SLUB_DEBUG detect
	  bugs only on allocation/freeing of object. KASan catch
	  bugs right before it will happen, so we always know exact
	  place of first bad read/write.

[1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel
[2] https://code.google.com/p/address-sanitizer/wiki/FoundBugs
[3] https://code.google.com/p/thread-sanitizer/wiki/FoundBugs
[4] https://code.google.com/p/memory-sanitizer/wiki/FoundBugs
[5] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel#Trophies

Based on work by Andrey Konovalov.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:40 -08:00
Linus Torvalds 6b00f7efb5 arm64 updates for 3.20:
- reimplementation of the virtual remapping of UEFI Runtime Services in
   a way that is stable across kexec
 - emulation of the "setend" instruction for 32-bit tasks (user
   endianness switching trapped in the kernel, SCTLR_EL1.E0E bit set
   accordingly)
 - compat_sys_call_table implemented in C (from asm) and made it a
   constant array together with sys_call_table
 - export CPU cache information via /sys (like other architectures)
 - DMA API implementation clean-up in preparation for IOMMU support
 - macros clean-up for KVM
 - dropped some unnecessary cache+tlb maintenance
 - CONFIG_ARM64_CPU_SUSPEND clean-up
 - defconfig update (CPU_IDLE)
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 "arm64 updates for 3.20:

   - reimplementation of the virtual remapping of UEFI Runtime Services
     in a way that is stable across kexec
   - emulation of the "setend" instruction for 32-bit tasks (user
     endianness switching trapped in the kernel, SCTLR_EL1.E0E bit set
     accordingly)
   - compat_sys_call_table implemented in C (from asm) and made it a
     constant array together with sys_call_table
   - export CPU cache information via /sys (like other architectures)
   - DMA API implementation clean-up in preparation for IOMMU support
   - macros clean-up for KVM
   - dropped some unnecessary cache+tlb maintenance
   - CONFIG_ARM64_CPU_SUSPEND clean-up
   - defconfig update (CPU_IDLE)

  The EFI changes going via the arm64 tree have been acked by Matt
  Fleming.  There is also a patch adding sys_*stat64 prototypes to
  include/linux/syscalls.h, acked by Andrew Morton"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (47 commits)
  arm64: compat: Remove incorrect comment in compat_siginfo
  arm64: Fix section mismatch on alloc_init_p[mu]d()
  arm64: Avoid breakage caused by .altmacro in fpsimd save/restore macros
  arm64: mm: use *_sect to check for section maps
  arm64: drop unnecessary cache+tlb maintenance
  arm64:mm: free the useless initial page table
  arm64: Enable CPU_IDLE in defconfig
  arm64: kernel: remove ARM64_CPU_SUSPEND config option
  arm64: make sys_call_table const
  arm64: Remove asm/syscalls.h
  arm64: Implement the compat_sys_call_table in C
  syscalls: Declare sys_*stat64 prototypes if __ARCH_WANT_(COMPAT_)STAT64
  compat: Declare compat_sys_sigpending and compat_sys_sigprocmask prototypes
  arm64: uapi: expose our struct ucontext to the uapi headers
  smp, ARM64: Kill SMP single function call interrupt
  arm64: Emulate SETEND for AArch32 tasks
  arm64: Consolidate hotplug notifier for instruction emulation
  arm64: Track system support for mixed endian EL0
  arm64: implement generic IOMMU configuration
  arm64: Combine coherent and non-coherent swiotlb dma_ops
  ...
2015-02-11 18:03:54 -08:00
Ingo Molnar 3c01b74e81 * Move efivarfs from the misc filesystem section to pseudo filesystem,
since that's a more logical and accurate place - Leif Lindholm
 
  * Update efibootmgr URL in Kconfig help - Peter Jones
 
  * Improve accuracy of EFI guid function names - Borislav Petkov
 
  * Expose firmware platform size in sysfs for the benefit of EFI boot
    loader installers and other utilities - Steve McIntyre
 
  * Cleanup __init annotations for arm64/efi code - Ard Biesheuvel
 
  * Mark the UIE as unsupported for rtc-efi - Ard Biesheuvel
 
  * Fix memory leak in error code path of runtime map code - Dan Carpenter
 
  * Improve robustness of get_memory_map() by removing assumptions on the
    size of efi_memory_desc_t (which could change in future spec
    versions) and querying the firmware instead of guessing about the
    memmap size - Ard Biesheuvel
 
  * Remove superfluous guid unparse calls - Ivan Khoronzhuk
 
  * Delete unnecessary chosen@0 DT node FDT code since was duplicated
    from code in drivers/of and is entirely unnecessary - Leif Lindholm
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Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/efi

Pull EFI updates from Matt Fleming:

" - Move efivarfs from the misc filesystem section to pseudo filesystem,
    since that's a more logical and accurate place - Leif Lindholm

  - Update efibootmgr URL in Kconfig help - Peter Jones

  - Improve accuracy of EFI guid function names - Borislav Petkov

  - Expose firmware platform size in sysfs for the benefit of EFI boot
    loader installers and other utilities - Steve McIntyre

  - Cleanup __init annotations for arm64/efi code - Ard Biesheuvel

  - Mark the UIE as unsupported for rtc-efi - Ard Biesheuvel

  - Fix memory leak in error code path of runtime map code - Dan Carpenter

  - Improve robustness of get_memory_map() by removing assumptions on the
    size of efi_memory_desc_t (which could change in future spec
    versions) and querying the firmware instead of guessing about the
    memmap size - Ard Biesheuvel

  - Remove superfluous guid unparse calls - Ivan Khoronzhuk

  - Delete unnecessary chosen@0 DT node FDT code since was duplicated
    from code in drivers/of and is entirely unnecessary - Leif Lindholm

   There's nothing super scary, mainly cleanups, and a merge from Ricardo who
   kindly picked up some patches from the linux-efi mailing list while I
   was out on annual leave in December.

   Perhaps the biggest risk is the get_memory_map() change from Ard, which
   changes the way that both the arm64 and x86 EFI boot stub build the
   early memory map. It would be good to have it bake in linux-next for a
   while.
"

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-01-29 19:16:40 +01:00
Ard Biesheuvel d1a8d66b91 efi/libstub: Call get_memory_map() to obtain map and desc sizes
This fixes two minor issues in the implementation of get_memory_map():
- Currently, it assumes that sizeof(efi_memory_desc_t) == desc_size,
  which is usually true, but not mandated by the spec. (This was added
  intentionally to allow future additions to the definition of
  efi_memory_desc_t). The way the loop is implemented currently, the
  added slack space may be insufficient if desc_size is larger, which in
  some corner cases could result in the loop never terminating.
- It allocates 32 efi_memory_desc_t entries first (again, using the size
  of the struct instead of desc_size), and frees and reallocates if it
  turns out to be insufficient. Few implementations of UEFI have such small
  memory maps, which results in a unnecessary allocate/free pair on each
  invocation.

Fix this by calling the get_memory_map() boot service first with a '0'
input value for map size to retrieve the map size and desc size from the
firmware and only then perform the allocation, using desc_size rather
than sizeof(efi_memory_desc_t).

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2015-01-20 22:13:33 +00:00