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  • jan.koester jan.koester jan.koester
1 author
  1. Sep 29, 2020
    • Marc Zyngier's avatar
      arm64: Run ARCH_WORKAROUND_2 enabling code on all CPUs · 39533e12
      Marc Zyngier authored 
      
Commit 606f8e7b ("arm64: capabilities: Use linear array for
detection and verification") changed the way we deal with per-CPU errata
by only calling the .matches() callback until one CPU is found to be
affected. At this point, .matches() stop being called, and .cpu_enable()
will be called on all CPUs.

This breaks the ARCH_WORKAROUND_2 handling, as only a single CPU will be
mitigated.

In order to address this, forcefully call the .matches() callback from a
.cpu_enable() callback, which brings us back to the original behaviour.

Fixes: 606f8e7b ("arm64: capabilities: Use linear array for detection and verification")
Cc: <stable@vger.kernel.org>
Reviewed-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
      39533e12
  3. Sep 21, 2020
  5. Aug 28, 2020
    • James Morse's avatar
      KVM: arm64: Add kvm_extable for vaxorcism code · e9ee186b
      James Morse authored 
      
KVM has a one instruction window where it will allow an SError exception
to be consumed by the hypervisor without treating it as a hypervisor bug.
This is used to consume asynchronous external abort that were caused by
the guest.

As we are about to add another location that survives unexpected exceptions,
generalise this code to make it behave like the host's extable.

KVM's version has to be mapped to EL2 to be accessible on nVHE systems.

The SError vaxorcism code is a one instruction window, so has two entries
in the extable. Because the KVM code is copied for VHE and nVHE, we end up
with four entries, half of which correspond with code that isn't mapped.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      e9ee186b
  7. Aug 27, 2020
  9. Aug 26, 2020
  11. Aug 23, 2020
  13. Aug 21, 2020
  15. Aug 12, 2020
  17. Aug 08, 2020
  19. Aug 07, 2020
    • Andrey Konovalov's avatar
      kasan, arm64: don't instrument functions that enable kasan · f9409d58
      Andrey Konovalov authored 
      This patch prepares Software Tag-Based KASAN for stack tagging support.

With stack tagging enabled, KASAN tags stack variable in each function in
its prologue.  In start_kernel() stack variables get tagged before KASAN
is enabled via setup_arch()->kasan_init().  As the result the tags for
start_kernel()'s stack variables end up in the temporary shadow memory.
Later when KASAN gets enabled, switched to normal shadow, and starts
checking tags, this leads to false-positive reports, as proper tags are
missing in normal shadow.

Disable KASAN instrumentation for start_kernel().  Also disable it for
arm64's setup_arch() as a precaution (it doesn't have any stack variables
right now).

[andreyknvl@google.com: reorder attributes for start_kernel()]
  Link: http://lkml.kernel.org/r/26fb6165a17abcf61222eda5184c030fb6b133d1.1596544734.git.andreyknvl@google.com



Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Walter Wu <walter-zh.wu@mediatek.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Link: http://lkml.kernel.org/r/55d432671a92e931ab8234b03dc36b14d4c21bfb.1596199677.git.andreyknvl@google.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f9409d58
    • Mike Rapoport's avatar
      mm: remove unneeded includes of <asm/pgalloc.h> · ca15ca40
      Mike Rapoport authored 
      
Patch series "mm: cleanup usage of <asm/pgalloc.h>"

Most architectures have very similar versions of pXd_alloc_one() and
pXd_free_one() for intermediate levels of page table.  These patches add
generic versions of these functions in <asm-generic/pgalloc.h> and enable
use of the generic functions where appropriate.

In addition, functions declared and defined in <asm/pgalloc.h> headers are
used mostly by core mm and early mm initialization in arch and there is no
actual reason to have the <asm/pgalloc.h> included all over the place.
The first patch in this series removes unneeded includes of
<asm/pgalloc.h>

In the end it didn't work out as neatly as I hoped and moving
pXd_alloc_track() definitions to <asm-generic/pgalloc.h> would require
unnecessary changes to arches that have custom page table allocations, so
I've decided to move lib/ioremap.c to mm/ and make pgalloc-track.h local
to mm/.

This patch (of 8):

In most cases <asm/pgalloc.h> header is required only for allocations of
page table memory.  Most of the .c files that include that header do not
use symbols declared in <asm/pgalloc.h> and do not require that header.

As for the other header files that used to include <asm/pgalloc.h>, it is
possible to move that include into the .c file that actually uses symbols
from <asm/pgalloc.h> and drop the include from the header file.

The process was somewhat automated using

	sed -i -E '/[<"]asm\/pgalloc\.h/d' \
                $(grep -L -w -f /tmp/xx \
                        $(git grep -E -l '[<"]asm/pgalloc\.h'))

where /tmp/xx contains all the symbols defined in
arch/*/include/asm/pgalloc.h.

[rppt@linux.ibm.com: fix powerpc warning]

Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarPekka Enberg <penberg@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200627143453.31835-2-rppt@kernel.org


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ca15ca40
    • Guenter Roeck's avatar
      arm64: kaslr: Use standard early random function · 9bceb80b
      Guenter Roeck authored 
      
Commit 58552408 ("random: random.h should include archrandom.h, not
the other way around") tries to fix a problem with recursive inclusion
of linux/random.h and arch/archrandom.h for arm64.  Unfortunately, this
results in the following compile error if ARCH_RANDOM is disabled.

  arch/arm64/kernel/kaslr.c: In function 'kaslr_early_init':
  arch/arm64/kernel/kaslr.c:128:6: error: implicit declaration of function '__early_cpu_has_rndr'; did you mean '__early_pfn_to_nid'? [-Werror=implicit-function-declaration]
    if (__early_cpu_has_rndr()) {
        ^~~~~~~~~~~~~~~~~~~~
        __early_pfn_to_nid
  arch/arm64/kernel/kaslr.c:131:7: error: implicit declaration of function '__arm64_rndr' [-Werror=implicit-function-declaration]
     if (__arm64_rndr(&raw))
         ^~~~~~~~~~~~

The problem is that arch/archrandom.h is only included from
linux/random.h if ARCH_RANDOM is enabled.  If not, __arm64_rndr() and
__early_cpu_has_rndr() are undeclared, causing the problem.

Use arch_get_random_seed_long_early() instead of arm64 specific
functions to solve the problem.

Reported-by: default avatarQian Cai <cai@lca.pw>
Fixes: 58552408 ("random: random.h should include archrandom.h, not the other way around")
Cc: Qian Cai <cai@lca.pw>
Cc: Mark Brown <broonie@kernel.org>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarMark Brown <broonie@kernel.org>
Tested-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9bceb80b
  21. Aug 05, 2020
  23. Jul 31, 2020
  25. Jul 28, 2020
  27. Jul 27, 2020
  29. Jul 24, 2020
  31. Jul 23, 2020
  33. Jul 21, 2020
  35. Jul 20, 2020
  37. Jul 16, 2020
    • Will Deacon's avatar
      arm64: Use test_tsk_thread_flag() for checking TIF_SINGLESTEP · 5afc7855
      Will Deacon authored 
      
Rather than open-code test_tsk_thread_flag() at each callsite, simply
replace the couple of offenders with calls to test_tsk_thread_flag()
directly.

Signed-off-by: default avatarWill Deacon <will@kernel.org>
      5afc7855
    • Will Deacon's avatar
      arm64: ptrace: Use NO_SYSCALL instead of -1 in syscall_trace_enter() · d83ee6e3
      Will Deacon authored 
      
Setting a system call number of -1 is special, as it indicates that the
current system call should be skipped.

Use NO_SYSCALL instead of -1 when checking for this scenario, which is
different from the -1 returned due to a seccomp failure.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Keno Fischer <keno@juliacomputing.com>
Cc: Luis Machado <luis.machado@linaro.org>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
      d83ee6e3
    • Will Deacon's avatar
      arm64: syscall: Expand the comment about ptrace and syscall(-1) · 139dbe5d
      Will Deacon authored 
      
If a task executes syscall(-1), we intercept this early and force x0 to
be -ENOSYS so that we don't need to distinguish this scenario from one
where the scno is -1 because a tracer wants to skip the system call
using ptrace. With the return value set, the return path is the same as
the skip case.

Although there is a one-line comment noting this in el0_svc_common(), it
misses out most of the detail. Expand the comment to describe a bit more
about what is going on.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Keno Fischer <keno@juliacomputing.com>
Cc: Luis Machado <luis.machado@linaro.org>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
      139dbe5d
    • Will Deacon's avatar
      arm64: ptrace: Add a comment describing our syscall entry/exit trap ABI · 59ee987e
      Will Deacon authored 
      
Our tracehook logic for syscall entry/exit raises a SIGTRAP back to the
tracer following a ptrace request such as PTRACE_SYSCALL. As part of this
procedure, we clobber the reported value of one of the tracee's general
purpose registers (x7 for native tasks, r12 for compat) to indicate
whether the stop occurred on syscall entry or exit. This is a slightly
unfortunate ABI, as it prevents the tracer from accessing the real
register value and is at odds with other similar stops such as seccomp
traps.

Since we're stuck with this ABI, expand the comment in our tracehook
logic to acknowledge the issue and describe the behaviour in more detail.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Luis Machado <luis.machado@linaro.org>
Reported-by: default avatarKeno Fischer <keno@juliacomputing.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
      59ee987e
    • Will Deacon's avatar
      arm64: compat: Ensure upper 32 bits of x0 are zero on syscall return · 15956689
      Will Deacon authored 
      
Although we zero the upper bits of x0 on entry to the kernel from an
AArch32 task, we do not clear them on the exception return path and can
therefore expose 64-bit sign extended syscall return values to userspace
via interfaces such as the 'perf_regs' ABI, which deal exclusively with
64-bit registers.

Explicitly clear the upper 32 bits of x0 on return from a compat system
call.

Cc: <stable@vger.kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Keno Fischer <keno@juliacomputing.com>
Cc: Luis Machado <luis.machado@linaro.org>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
      15956689
    • Will Deacon's avatar
      arm64: ptrace: Override SPSR.SS when single-stepping is enabled · 3a5a4366
      Will Deacon authored 
      Luis reports that, when reverse debugging with GDB, single-step does not
function as expected on arm64:

  | I've noticed, under very specific conditions, that a PTRACE_SINGLESTEP
  | request by GDB won't execute the underlying instruction. As a consequence,
  | the PC doesn't move, but we return a SIGTRAP just like we would for a
  | regular successful PTRACE_SINGLESTEP request.

The underlying problem is that when the CPU register state is restored
as part of a reverse step, the SPSR.SS bit is cleared and so the hardware
single-step state can transition to the "active-pending" state, causing
an unexpected step exception to be taken immediately if a step operation
is attempted.

In hindsight, we probably shouldn't have exposed SPSR.SS in the pstate
accessible by the GPR regset, but it's a bit late for that now. Instead,
simply prevent userspace from configuring the bit to a value which is
inconsistent with the TIF_SINGLESTEP state for the task being traced.

Cc: <stable@vger.kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Keno Fischer <keno@juliacomputing.com>
Link: https://lore.kernel.org/r/1eed6d69-d53d-9657-1fc9-c089be07f98c@linaro.org


Reported-by: default avatarLuis Machado <luis.machado@linaro.org>
Tested-by: default avatarLuis Machado <luis.machado@linaro.org>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
      3a5a4366