linux.git/arch/arm/include/asm/thread_info.h, branch v5.4.272

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Enrico Weigelt 
Reviewed-by: Kate Stewart 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman

ARM: smp: add support for per-task stack canaries

2018-12-12T21:20:07+00:00

On ARM, we currently only change the value of the stack canary when
switching tasks if the kernel was built for UP. On SMP kernels, this
is impossible since the stack canary value is obtained via a global
symbol reference, which means
a) all running tasks on all CPUs must use the same value
b) we can only modify the value when no kernel stack frames are live
   on any CPU, which is effectively never.

So instead, use a GCC plugin to add a RTL pass that replaces each
reference to the address of the __stack_chk_guard symbol with an
expression that produces the address of the 'stack_canary' field
that is added to struct thread_info. This way, each task will use
its own randomized value.

Cc: Russell King 
Cc: Kees Cook 
Cc: Emese Revfy 
Cc: Arnd Bergmann 
Cc: Laura Abbott 
Cc: kernel-hardening@lists.openwall.com
Acked-by: Nicolas Pitre 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Kees Cook

ARM: 8791/1: vfp: use __copy_to_user() when saving VFP state

2018-10-05T09:51:15+00:00

Use __copy_to_user() rather than __put_user_error() for individual
members when saving VFP state.
This has the benefit of disabling/enabling PAN once per copied struct
intead of once per write.

Signed-off-by: Julien Thierry 
Signed-off-by: Russell King

ARM: vfp: use __copy_from_user() when restoring VFP state

2018-08-02T16:41:37+00:00

__get_user_error() is used as a fast accessor to make copying structure
members in the signal handling path as efficient as possible.  However,
with software PAN and the recent Spectre variant 1, the efficiency is
reduced as these are no longer fast accessors.

In the case of software PAN, it has to switch the domain register around
each access, and with Spectre variant 1, it would have to repeat the
access_ok() check for each access.

Use __copy_from_user() rather than __get_user_err() for individual
members when restoring VFP state.

Acked-by: Mark Rutland 
Signed-off-by: Russell King

Construct init thread stack in the linker script rather than by union

2018-01-09T23:21:02+00:00

Construct the init thread stack in the linker script rather than doing it
by means of a union so that ia64's init_task.c can be got rid of.

The following symbols are then made available from INIT_TASK_DATA() linker
script macro:

	init_thread_union
	init_stack

INIT_TASK_DATA() also expands the region to THREAD_SIZE to accommodate the
size of the init stack.  init_thread_union is given its own section so that
it can be placed into the stack space in the right order.  I'm assuming
that the ia64 ordering is correct and that the task_struct is first and the
thread_info second.

Signed-off-by: David Howells 
Tested-by: Tony Luck 
Tested-by: Will Deacon  (arm64)
Tested-by: Palmer Dabbelt 
Acked-by: Thomas Gleixner

Revert "arm/syscalls: Check address limit on user-mode return"

2017-09-17T17:45:33+00:00

This reverts commit 73ac5d6a2b6ac3ae8d1e1818f3e9946f97489bc9.

The work pending loop can call set_fs after addr_limit_user_check
removed the _TIF_FSCHECK flag. This may happen at anytime based on how
ARM handles alignment exceptions. It leads to an infinite loop condition.

After discussion, it has been agreed that the generic approach is not
tailored to the ARM architecture and any fix might not be complete. This
patch will be replaced by an architecture specific implementation. The
work flag approach will be kept for other architectures.

Reported-by: Leonard Crestez 
Signed-off-by: Thomas Garnier 
Signed-off-by: Kees Cook 
Signed-off-by: Thomas Gleixner 
Cc: Pratyush Anand 
Cc: Dave Martin 
Cc: Will Drewry 
Cc: Arnd Bergmann 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Russell King 
Cc: Andy Lutomirski 
Cc: David Howells 
Cc: Dave Hansen 
Cc: Al Viro 
Cc: linux-api@vger.kernel.org
Cc: Yonghong Song 
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1504798247-48833-3-git-send-email-keescook@chromium.org

arm/syscalls: Check address limit on user-mode return

2017-07-08T12:05:33+00:00

Ensure the address limit is a user-mode segment before returning to
user-mode. Otherwise a process can corrupt kernel-mode memory and
elevate privileges [1].

The set_fs function sets the TIF_SETFS flag to force a slow path on
return. In the slow path, the address limit is checked to be USER_DS if
needed.

The TIF_SETFS flag is added to _TIF_WORK_MASK shifting _TIF_SYSCALL_WORK
for arm instruction immediate support. The global work mask is too big
to used on a single instruction so adapt ret_fast_syscall.

[1] https://bugs.chromium.org/p/project-zero/issues/detail?id=990

Signed-off-by: Thomas Garnier 
Signed-off-by: Thomas Gleixner 
Cc: Mark Rutland 
Cc: kernel-hardening@lists.openwall.com
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: David Howells 
Cc: Dave Hansen 
Cc: Miroslav Benes 
Cc: Chris Metcalf 
Cc: Pratyush Anand 
Cc: Russell King 
Cc: Petr Mladek 
Cc: Rik van Riel 
Cc: Kees Cook 
Cc: Arnd Bergmann 
Cc: Al Viro 
Cc: Andy Lutomirski 
Cc: Josh Poimboeuf 
Cc: linux-arm-kernel@lists.infradead.org
Cc: Will Drewry 
Cc: linux-api@vger.kernel.org
Cc: Oleg Nesterov 
Cc: Andy Lutomirski 
Cc: Paolo Bonzini 
Link: http://lkml.kernel.org/r/20170615011203.144108-2-thgarnie@google.com

Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm

2015-09-14T19:24:10+00:00

Pull ARM fixes from Russell King:
 "A number of fixes for the merge window, fixing a number of cases
  missed when testing the uaccess code, particularly cases which only
  show up with certain compiler versions"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8431/1: fix alignement of __bug_table section entries
  arm/xen: Enable user access to the kernel before issuing a privcmd call
  ARM: domains: add memory dependencies to get_domain/set_domain
  ARM: domains: thread_info.h no longer needs asm/domains.h
  ARM: uaccess: fix undefined instruction on ARMv7M/noMMU
  ARM: uaccess: remove unneeded uaccess_save_and_disable macro
  ARM: swpan: fix nwfpe for uaccess changes
  ARM: 8429/1: disable GCC SRA optimization

ARM: domains: thread_info.h no longer needs asm/domains.h

2015-09-11T15:07:47+00:00

As of 1eef5d2f1b46 ("ARM: domains: switch to keeping domain value in
register") we no longer need to include asm/domains.h into
asm/thread_info.h.  Remove it.

Tested-by: Robert Jarzmik 
Signed-off-by: Russell King

Merge branches 'cleanup', 'fixes', 'misc', 'omap-barrier' and 'uaccess' into for-linus

2015-09-03T14:28:37+00:00