- Rework phys/virt translation
- Add KASan support
- Move DT out of linear map region
- Use more PC-relative addressing in assembly
- Remove FP emulation handling while in kernel mode
- Link with '-z norelro'
- remove old check for GCC <= 4.2 in ARM unwinder code
- disable big endian if using clang's linker
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Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux
Pull ARM updates from Russell King:
- Rework phys/virt translation
- Add KASan support
- Move DT out of linear map region
- Use more PC-relative addressing in assembly
- Remove FP emulation handling while in kernel mode
- Link with '-z norelro'
- remove old check for GCC <= 4.2 in ARM unwinder code
- disable big endian if using clang's linker
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (46 commits)
ARM: 9027/1: head.S: explicitly map DT even if it lives in the first physical section
ARM: 9038/1: Link with '-z norelro'
ARM: 9037/1: uncompress: Add OF_DT_MAGIC macro
ARM: 9036/1: uncompress: Fix dbgadtb size parameter name
ARM: 9035/1: uncompress: Add be32tocpu macro
ARM: 9033/1: arm/smp: Drop the macro S(x,s)
ARM: 9032/1: arm/mm: Convert PUD level pgtable helper macros into functions
ARM: 9031/1: hyp-stub: remove unused .L__boot_cpu_mode_offset symbol
ARM: 9044/1: vfp: use undef hook for VFP support detection
ARM: 9034/1: __div64_32(): straighten up inline asm constraints
ARM: 9030/1: entry: omit FP emulation for UND exceptions taken in kernel mode
ARM: 9029/1: Make iwmmxt.S support Clang's integrated assembler
ARM: 9028/1: disable KASAN in call stack capturing routines
ARM: 9026/1: unwind: remove old check for GCC <= 4.2
ARM: 9025/1: Kconfig: CPU_BIG_ENDIAN depends on !LD_IS_LLD
ARM: 9024/1: Drop useless cast of "u64" to "long long"
ARM: 9023/1: Spelling s/mmeory/memory/
ARM: 9022/1: Change arch/arm/lib/mem*.S to use WEAK instead of .weak
ARM: kvm: replace open coded VA->PA calculations with adr_l call
ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET
...
Wire up TIF_NOTIFY_SIGNAL handling for arm.
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch initializes KASan shadow region's page table and memory.
There are two stage for KASan initializing:
1. At early boot stage the whole shadow region is mapped to just
one physical page (kasan_zero_page). It is finished by the function
kasan_early_init which is called by __mmap_switched(arch/arm/kernel/
head-common.S)
2. After the calling of paging_init, we use kasan_zero_page as zero
shadow for some memory that KASan does not need to track, and we
allocate a new shadow space for the other memory that KASan need to
track. These issues are finished by the function kasan_init which is
call by setup_arch.
When using KASan we also need to increase the THREAD_SIZE_ORDER
from 1 to 2 as the extra calls for shadow memory uses quite a bit
of stack.
As we need to make a temporary copy of the PGD when setting up
shadow memory we create a helpful PGD_SIZE definition for both
LPAE and non-LPAE setups.
The KASan core code unconditionally calls pud_populate() so this
needs to be changed from BUG() to do {} while (0) when building
with KASan enabled.
After the initial development by Andre Ryabinin several modifications
have been made to this code:
Abbott Liu <liuwenliang@huawei.com>
- Add support ARM LPAE: If LPAE is enabled, KASan shadow region's
mapping table need be copied in the pgd_alloc() function.
- Change kasan_pte_populate,kasan_pmd_populate,kasan_pud_populate,
kasan_pgd_populate from .meminit.text section to .init.text section.
Reported by Florian Fainelli <f.fainelli@gmail.com>
Linus Walleij <linus.walleij@linaro.org>:
- Drop the custom mainpulation of TTBR0 and just use
cpu_switch_mm() to switch the pgd table.
- Adopt to handle 4th level page tabel folding.
- Rewrite the entire page directory and page entry initialization
sequence to be recursive based on ARM64:s kasan_init.c.
Ard Biesheuvel <ardb@kernel.org>:
- Necessary underlying fixes.
- Crucial bug fixes to the memory set-up code.
Co-developed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Co-developed-by: Abbott Liu <liuwenliang@huawei.com>
Co-developed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: kasan-dev@googlegroups.com
Cc: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Ard Biesheuvel <ardb@kernel.org> # QEMU/KVM/mach-virt/LPAE/8G
Tested-by: Florian Fainelli <f.fainelli@gmail.com> # Brahma SoCs
Tested-by: Ahmad Fatoum <a.fatoum@pengutronix.de> # i.MX6Q
Reported-by: Russell King - ARM Linux <rmk+kernel@armlinux.org.uk>
Reported-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Abbott Liu <liuwenliang@huawei.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
In order to use <asm/percpu.h> in irqflags.h, we need to make sure
asm/percpu.h does not itself depend on irqflags.h.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/20200623083721.454517573@infradead.org
Arm entry code calls context tracking from fast path. TIF_NOHZ is unused
and can be safely removed.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
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 <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <linux@armlinux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Laura Abbott <labbott@redhat.com>
Cc: kernel-hardening@lists.openwall.com
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
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 <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
__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 <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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 <dhowells@redhat.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Tested-by: Will Deacon <will.deacon@arm.com> (arm64)
Tested-by: Palmer Dabbelt <palmer@sifive.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
This reverts commit 73ac5d6a2b.
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 <leonard.crestez@nxp.com>
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Will Drewry <wad@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-api@vger.kernel.org
Cc: Yonghong Song <yhs@fb.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1504798247-48833-3-git-send-email-keescook@chromium.org
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 <thgarnie@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: kernel-hardening@lists.openwall.com
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Will Drewry <wad@chromium.org>
Cc: linux-api@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: http://lkml.kernel.org/r/20170615011203.144108-2-thgarnie@google.com
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
As of 1eef5d2f1b ("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 <robert.jarzmik@free.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Make the "fast" syscall return path fast again. The addition of IRQ
tracing and context tracking has made this path grossly inefficient.
We can do much better if these options are enabled if we save the
syscall return code on the stack - we then don't need to save a bunch
of registers around every single callout to C code.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rather than modifying both the domain access control register and our
per-thread copy, modify only the domain access control register, and
use the per-thread copy to save and restore the register over context
switches. We can also avoid the explicit initialisation of the
init thread_info structure.
This allows us to avoid needing to gain access to the thread information
at the uaccess control sites.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
As execution domain support is gone we can remove
signal translation from the signal code and remove
exec_domain from thread_info.
Signed-off-by: Richard Weinberger <richard@nod.at>
If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target. This is because the
restart_block is held in the same memory allocation as the kernel stack.
Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.
Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.
It's also a decent simplification, since the restart code is more or less
identical on all architectures.
[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Acked-by: Richard Weinberger <richard@nod.at>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We cannot restart cacheflush safely if a process provides user-defined
signal handler and signal is pending. In this case -EINTR is returned
and it is expected that process re-invokes syscall. However, there are
a few problems with that:
* looks like nobody bothers checking return value from cacheflush
* but if it did, we don't provide the restart address for that, so the
process has to use the same range again
* ...and again, what might lead to looping forever
So, remove cacheflush restarting code and terminate cache flushing
as early as fatal signal is pending.
Cc: stable@vger.kernel.org # 3.12+
Reported-by: Chanho Min <chanho.min@lge.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Use the global current_stack_pointer to get the value of the stack pointer.
This change supports being able to compile the kernel with both gcc and clang.
Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Define a global named register for current_stack_pointer. The use of this new
variable guarantees that both gcc and clang can access this register in C code.
Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Changing kernel stack size on arm is not as simple as it should be:
1) THREAD_SIZE macro doesn't respect PAGE_SIZE and THREAD_SIZE_ORDER
2) stack size is hardcoded in get_thread_info macro
This patch fixes it by calculating THREAD_SIZE and thread_info address
taking into account PAGE_SIZE and THREAD_SIZE_ORDER.
Now changing stack size becomes simply changing THREAD_SIZE_ORDER.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The thread_save_fp macro has been defined so that it always reads the fp member
of the cpu_context_save struct. However, in the case of THUMB2 the fp is saved
not in the fp (r11) member but rather in r7.
This patch changes the way the macro is defined such that FP is read from the
correct place depending on whether we are a THUMB2 kernel or not. This enables
the backtrace in sitaution such as "echo t > /proc/sysrq-trigger" or the
function in which a process sleeping when "ps -Al" is invoked.
Signed-off-by: Nikolay Borisov <Nikolay.Borisov@arm.com>
Reviewed-by: Anurag Aggarwal <anurag19aggarwal@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Using Rabin Vincent's ARM uprobes patches as a base, enable uprobes
support on ARM.
Caveats:
- Thumb is not supported
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: David A. Long <dave.long@linaro.org>
Flushing a large, non-faulting VMA from userspace can potentially result
in a long time spent flushing the cache line-by-line without preemption
occurring (in the case of CONFIG_PREEMPT=n).
Whilst this doesn't affect the stability of the system, it can certainly
affect the responsiveness and CPU availability for other tasks.
This patch splits up the user cacheflush code so that it flushes in
chunks of a page. After each chunk has been flushed, we may reschedule
if appropriate and, before processing the next chunk, we allow any
pending signals to be handled before resuming from where we left off.
Signed-off-by: Will Deacon <will.deacon@arm.com>
As of commit b9d4d42ad9 (ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on
pre-ARMv6 CPUs), the mm switching on VIVT processors is done in the
finish_arch_post_lock_switch() function to avoid whole cache flushing
with interrupts disabled. The need for deferred mm switch is stored as a
thread flag (TIF_SWITCH_MM). However, with preemption enabled, we can
have another thread switch before finish_arch_post_lock_switch(). If the
new thread has the same mm as the previous 'next' thread, the scheduler
will not call switch_mm() and the TIF_SWITCH_MM flag won't be set for
the new thread.
This patch moves the switch pending flag to the mm_context_t structure
since this is specific to the mm rather than thread.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: <stable@vger.kernel.org> # 3.5+
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Since commit 6a1c53124a the user writeable TLS register was zeroed to
prevent it from being used as a covert channel between two tasks.
There are more and more applications coming to Windows RT,
Wine could support them, but mostly they expect to have
the thread environment block (TEB) in TPIDRURW.
This patch preserves that register per thread instead of clearing it.
Unlike the TPIDRURO, which is already switched, the TPIDRURW
can be updated from userspace so needs careful treatment in the case that we
modify TPIDRURW and call fork(). To avoid this we must always read
TPIDRURW in copy_thread.
Signed-off-by: André Hentschel <nerv@dawncrow.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
commit 91d1aa43 (context_tracking: New context tracking susbsystem)
generalized parts of the RCU userspace extended quiescent state into
the context tracking subsystem. Context tracking is then used
to implement adaptive tickless (a.k.a extended nohz)
To support the new context tracking subsystem on ARM, the user/kernel
boundary transtions need to be instrumented.
For exceptions and IRQs in usermode, the existing usr_entry macro is
used to instrument the user->kernel transition. For the return to
usermode path, the ret_to_user* path is instrumented. Using the
usr_entry macro, this covers interrupts in userspace, data abort and
prefetch abort exceptions in userspace as well as undefined exceptions
in userspace (which is where FP emulation and VFP are handled.)
For syscalls, the slow return path is covered by instrumenting the
ret_to_user path. In addition, the syscall entry point is
instrumented which covers the user->kernel transition for both fast
and slow syscalls, and an additional instrumentation point is added
for the fast syscall return path (ret_fast_syscall).
Cc: Mats Liljegren <mats.liljegren@enea.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There is very little difference in the TIF_SECCOMP and TIF_SYSCALL_WORK
path in entry-common.S, so merge TIF_SECCOMP into TIF_SYSCALL_WORK and
move seccomp into the syscall_trace_enter() handler.
Expanded some of the tracehook logic into the callers to make this code
more readable. Since tracehook needs to do register changing, this portion
is best left in its own function instead of copy/pasting into the callers.
Additionally, the return value for secure_computing() is now checked
and a -1 value will result in the system call being skipped.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Drewry <wad@chromium.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Pull pile 2 of execve and kernel_thread unification work from Al Viro:
"Stuff in there: kernel_thread/kernel_execve/sys_execve conversions for
several more architectures plus assorted signal fixes and cleanups.
There'll be more (in particular, real fixes for the alpha
do_notify_resume() irq mess)..."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (43 commits)
alpha: don't open-code trace_report_syscall_{enter,exit}
Uninclude linux/freezer.h
m32r: trim masks
avr32: trim masks
tile: don't bother with SIGTRAP in setup_frame
microblaze: don't bother with SIGTRAP in setup_rt_frame()
mn10300: don't bother with SIGTRAP in setup_frame()
frv: no need to raise SIGTRAP in setup_frame()
x86: get rid of duplicate code in case of CONFIG_VM86
unicore32: remove pointless test
h8300: trim _TIF_WORK_MASK
parisc: decide whether to go to slow path (tracesys) based on thread flags
parisc: don't bother looping in do_signal()
parisc: fix double restarts
bury the rest of TIF_IRET
sanitize tsk_is_polling()
bury _TIF_RESTORE_SIGMASK
unicore32: unobfuscate _TIF_WORK_MASK
mips: NOTIFY_RESUME is not needed in TIF masks
mips: merge the identical "return from syscall" per-ABI code
...
Conflicts:
arch/arm/include/asm/thread_info.h
Make default just return 0. The current default (checking
TIF_POLLING_NRFLAG) is taken to architectures that need it;
ones that don't do polling in their idle threads don't need
to defined TIF_POLLING_NRFLAG at all.
ia64 defined both TS_POLLING (used by its tsk_is_polling())
and TIF_POLLING_NRFLAG (not used at all). Killed the latter...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
As specified by ftrace-design.txt, TIF_SYSCALL_TRACEPOINT was
added, as well as NR_syscalls in asm/unistd.h. Additionally,
__sys_trace was modified to call trace_sys_enter and
trace_sys_exit when appropriate.
Tests #2 - #4 of "perf test" now complete successfully.
Signed-off-by: Steven Walter <stevenrwalter@gmail.com>
Signed-off-by: Wade Farnsworth <wade_farnsworth@mentor.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There is no point reserving space at the bottom of the kernel stack for
per-thread crunch state, and per-thread VFP state if these are not being
supported by the kernel being built. Remove these members from the
thread union when these features are disabled.
Reported-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This reverts commit 6b5c8045ec.
Conflicts:
arch/arm/kernel/ptrace.c
The new syscall restarting code can lead to problems if we take an
interrupt in userspace just before restarting the svc instruction. If
a signal is delivered when returning from the interrupt, the
TIF_SYSCALL_RESTARTSYS will remain set and cause any syscalls executed
from the signal handler to be treated as a restart of the previously
interrupted system call. This includes the final sigreturn call, meaning
that we may fail to exit from the signal context. Furthermore, if a
system call made from the signal handler requires a restart via the
restart_block, it is possible to clear the thread flag and fail to
restart the originally interrupted system call.
The right solution to this problem is to perform the restarting in the
kernel, avoiding the possibility of handling a further signal before the
restart is complete. Since we're almost at -rc6, let's revert the new
method for now and aim for in-kernel restarting at a later date.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
new "syscall start" flag; handled in syscall_trace() by switching
syscall number to that of syscall_restart(2). Restarts of that
kind (ERESTART_RESTARTBLOCK) are handled by setting that bit;
syscall number is not modified until the actual call.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The user VFP state must be preserved (subject to ucontext modifications)
across invocation of a signal handler and this is currently handled by
vfp_{preserve,restore}_context in signal.c
Since this code requires intimate low-level knowledge of the VFP state,
this patch moves it into vfpmodule.c.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Since the ASIDs must be unique to an mm across all the CPUs in a system,
the __new_context() function needs to broadcast a context reset event to
all the CPUs during ASID allocation if a roll-over occurred. Such IPIs
cannot be issued with interrupts disabled and ARM had to define
__ARCH_WANT_INTERRUPTS_ON_CTXSW.
This patch changes the check_context() function to
check_and_switch_context() called from switch_mm(). In case of
ASID-capable CPUs (ARMv6 onwards), if a new ASID is needed and the
interrupts are disabled, it defers the __new_context() and
cpu_switch_mm() calls to the post-lock switch hook where the interrupts
are enabled. Setting the reserved TTBR0 was also moved to
check_and_switch_context() from cpu_v7_switch_mm().
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Tested-by: Marc Zyngier <Marc.Zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch provides functionality to audit system call events on the
ARM platform. The implementation was based off the structure of the
MIPS platform and information in this
(http://lists.fedoraproject.org/pipermail/arm/2009-October/000382.html)
mailing list thread. The required audit_syscall_exit and
audit_syscall_entry checks were added to ptrace using the standard
registers for system call values (r0 through r3). A thread information
flag was added for auditing (TIF_SYSCALL_AUDIT) and a meta-flag was
added (_TIF_SYSCALL_WORK) to simplify modifications to the syscall
entry/exit. Now, if either the TRACE flag is set or the AUDIT flag is
set, the syscall_trace function will be executed. The prober changes
were made to Kconfig to allow CONFIG_AUDITSYSCALL to be enabled.
Due to platform availability limitations, this patch was only tested
on the Android platform running the modified "android-goldfish-2.6.29"
kernel. A test compile was performed using Code Sourcery's
cross-compilation toolset and the current linux-3.0 stable kernel. The
changes compile without error. I'm hoping, due to the simple modifications,
the patch is "obviously correct".
Signed-off-by: Nathaniel Husted <nhusted@gmail.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Linus Torvalds