Commit Graph

162 Commits

Author SHA1 Message Date
Russell King db695c0509 ARM: remove user cmpxchg syscall
Mark Brand reports that a NEEDS_SYSCALL_FOR_CMPXCHG enabled kernel would
open a security hole in the ghost syscall used to implement cmpxchg, as
it fails to validate the user pointer.

However, in order for this option to be enabled, you'd need to be
building a pre-ARMv6 kernel with SMP support.  There is only one system
known which fits that, which is an early ARM SMP FPGA implementation
based on the ARM926T.

In any case, the Kconfig does not allow SMP to be enabled for pre-ARMv6
systems.

Moreover, even if NEEDS_SYSCALL_FOR_CMPXCHG were to be enabled, the
kernel would not build as __ARM_NR_cmpxchg64 is not defined.

The simple answer is to remove the buggy code.

Reported-by: Mark Brand <markbrand@google.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-10-03 16:36:45 +01:00
Russell King 40d3f02851 Merge branches 'cleanup', 'fixes', 'misc', 'omap-barrier' and 'uaccess' into for-linus 2015-09-03 15:28:37 +01:00
Russell King 2190fed67b ARM: entry: provide uaccess assembly macro hooks
Provide hooks into the kernel entry and exit paths to permit control
of userspace visibility to the kernel.  The intended use is:

- on entry to kernel from user, uaccess_disable will be called to
  disable userspace visibility
- on exit from kernel to user, uaccess_enable will be called to
  enable userspace visibility
- on entry from a kernel exception, uaccess_save_and_disable will be
  called to save the current userspace visibility setting, and disable
  access
- on exit from a kernel exception, uaccess_restore will be called to
  restore the userspace visibility as it was before the exception
  occurred.

These hooks allows us to keep userspace visibility disabled for the
vast majority of the kernel, except for localised regions where we
want to explicitly access userspace.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-08-26 20:27:02 +01:00
Russell King 1eef5d2f1b ARM: domains: switch to keeping domain value in register
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>
2015-08-21 13:55:49 +01:00
Linus Torvalds d6ac4ffc61 Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King:
 "These are late by a week; they should have been merged during the
  merge window, but unfortunately, the ARM kernel build/boot farms were
  indicating random failures, and it wasn't clear whether the cause was
  something in these changes or something during the merge window.

  This is a set of merge window fixes with some documentation additions"

* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: avoid unwanted GCC memset()/memcpy() optimisations for IO variants
  ARM: pgtable: document mapping types
  ARM: io: convert ioremap*() to functions
  ARM: io: fix ioremap_wt() implementation
  ARM: io: document ARM specific behaviour of ioremap*() implementations
  ARM: fix lockdep unannotated irqs-off warning
  ARM: 8397/1: fix vdsomunge not to depend on glibc specific error.h
  ARM: add helpful message when truncating physical memory
  ARM: add help text for HIGHPTE configuration entry
  ARM: fix DEBUG_SET_MODULE_RONX build dependencies
  ARM: 8396/1: use phys_addr_t in pfn_to_kaddr()
  ARM: 8394/1: update memblock limit after mapping lowmem
  ARM: 8393/1: smp: Fix suspicious RCU usage with ipi tracepoints
2015-07-07 15:19:09 -07:00
Russell King 06be5eefe1 Merge branches 'fixes' and 'ioremap' into for-linus 2015-07-07 12:35:33 +01:00
Russell King 11b8b25ce4 ARM: fix lockdep unannotated irqs-off warning
Wolfram Sang reported an unannotated irqs-off warning from lockdep:

WARNING: CPU: 0 PID: 282 at kernel/locking/lockdep.c:3557 check_flags+0x84/0x1f4()
DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)
CPU: 0 PID: 282 Comm: rcS Tainted: G        W 4.1.0-00002-g5b076054611833 #179
Hardware name: Generic Emma Mobile EV2 (Flattened Device Tree)
Backtrace:
[<c0012c94>] (dump_backtrace) from [<c0012e3c>] (show_stack+0x18/0x1c)
 r6:c02dcc67 r5:00000009 r4:00000000 r3:00400000
[<c0012e24>] (show_stack) from [<c02510c8>] (dump_stack+0x20/0x28)
[<c02510a8>] (dump_stack) from [<c0022c44>] (warn_slowpath_common+0x8c/0xb4)
[<c0022bb8>] (warn_slowpath_common) from [<c0022cd8>] (warn_slowpath_fmt+0x38/0x40)
 r8:c780f470 r7:00000000 r6:00000000 r5:c03b0570 r4:c0b7ec04
[<c0022ca4>] (warn_slowpath_fmt) from [<c004cd38>] (check_flags+0x84/0x1f4)
 r3:c02e13d8 r2:c02dceaa
[<c004ccb4>] (check_flags) from [<c0050e50>] (lock_acquire+0x4c/0xbc)
 r5:00000000 r4:60000193
[<c0050e04>] (lock_acquire) from [<c0256000>] (_raw_spin_lock+0x34/0x44)
 r9:000a8d5c r8:00000001 r7:c7806000 r6:c780f460 r5:c03b06a0 r4:c780f460
[<c0255fcc>] (_raw_spin_lock) from [<c005a8cc>] (handle_fasteoi_irq+0x20/0x11c)
 r4:c780f400
[<c005a8ac>] (handle_fasteoi_irq) from [<c0057a4c>] (generic_handle_irq+0x28/0x38)
 r6:00000000 r5:c03b038c r4:00000012 r3:c005a8ac
[<c0057a24>] (generic_handle_irq) from [<c0057ae4>] (__handle_domain_irq+0x88/0xa8)
 r4:00000000 r3:00000026
[<c0057a5c>] (__handle_domain_irq) from [<c000a3cc>] (gic_handle_irq+0x40/0x58)
 r8:10c5347d r7:10c5347d r6:c35b1fb0 r5:c03a6304 r4:c8802000 r3:c35b1fb0
[<c000a38c>] (gic_handle_irq) from [<c0013bc8>] (__irq_usr+0x48/0x60)
Exception stack(0xc35b1fb0 to 0xc35b1ff8)
1fa0:                                     00000061 00000000 000ab736 00000066
1fc0: 00000061 000aa1f0 000a8d54 000a8d54 000a8d88 000a8d5c 000a8cc8 000a8d68
1fe0: 72727272 bef8a528 000398c0 00031334 20000010 ffffffff
 r6:ffffffff r5:20000010 r4:00031334 r3:00000061
---[ end trace cb88537fdc8fa202 ]---
possible reason: unannotated irqs-off.
irq event stamp: 769
hardirqs last  enabled at (769): [<c000f82c>] ret_fast_syscall+0x2c/0x54
hardirqs last disabled at (768): [<c000f80c>] ret_fast_syscall+0xc/0x54
softirqs last  enabled at (0): [<c0020ec4>] copy_process.part.65+0x2e8/0x11dc
softirqs last disabled at (0): [<  (null)>]   (null)

His kernel configuration had:
CONFIG_PROVE_LOCKING=y
CONFIG_TRACE_IRQFLAGS=y
but no IRQSOFF_TRACER, which means entry from userspace can result in the
kernel seeing IRQs off without being notified of that change of state.
Change the IRQSOFF ifdef in the usr_entry macro to TRACE_IRQFLAGS instead.

Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-07-03 12:42:36 +01:00
Linus Torvalds a611fb75d0 Fixup various init.h misuses that are fragile wrt code moving to module.h
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Merge tag 'module-misc-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

Pull init.h/module.h fragility fixes from Paul Gortmaker:
 "Fixup various init.h misuses that are fragile wrt code moving to
  module.h

  What started as a removal of no longer required include <linux/init.h>
  due to the earlier __cpuinit and __devinit removal led to the
  observation that some module specfic support was living in init.h
  itself, thus preventing the full removal from introducing compile
  regressions.

  This series includes a few final fixups needed prior to the relocation
  of the modular init code from <init.h> to <module.h>.  These are
  things that weren't easily categorized into any of the other previous
  series categories already requested for pull.

  That said, each fixup branch (including this one) is independent and
  there are no ordering constraints.  Only the final code relocation
  (which is NOT in this pull) requires that all my cleanup branches be
  merged first"

* tag 'module-misc-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
  tile: add init.h to usb.c to avoid compile failure
  arm: fix implicit #include <linux/init.h> in entry asm.
  x86: replace __init_or_module with __init in non-modular vsmp_64.c
2015-07-02 11:07:27 -07:00
Paul Gortmaker 9b9cf81a2d arm: fix implicit #include <linux/init.h> in entry asm.
They use the "_INIT" macro and friends, and hence need to
source this header file, vs. relying on getting it implicitly.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2015-06-16 14:12:41 -04:00
Russell King 14327c6628 ARM: replace BSYM() with badr assembly macro
BSYM() was invented to allow us to work around a problem with the
assembler, where local symbols resolved by the assembler for the 'adr'
instruction did not take account of their ISA.

Since we don't want BSYM() used elsewhere, replace BSYM() with a new
macro 'badr', which is like the 'adr' pseudo-op, but with the BSYM()
mechanics integrated into it.  This ensures that the BSYM()-ification
is only used in conjunction with 'adr'.

Acked-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-05-08 17:33:50 +01:00
Ard Biesheuvel c4a84ae39b ARM: 8322/1: keep .text and .fixup regions closer together
This moves all fixup snippets to the .text.fixup section, which is
a special section that gets emitted along with the .text section
for each input object file, i.e., the snippets are kept much closer
to the code they refer to, which helps prevent linker failure on
large kernels.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-03-29 23:11:56 +01:00
Wang Nan a0266c214f ARM: kprobes: disallow probing stack consuming instructions
This patch prohibits probing instructions for which the stack
requirements are unable to be determined statically. Some test cases
are found not work again after the modification, this patch also
removes them.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
2015-01-13 16:10:15 +00:00
Russell King d5d1689224 Merge branches 'fiq' (early part), 'fixes', 'l2c' (early part) and 'misc' into for-next 2014-10-02 21:47:02 +01:00
Russell King 195b58add4 ARM: Avoid writing to control register on every exception
If we are not changing the control register value, avoid writing to it.
Writes to the control register can be very expensive, taking around a
hundred cycles or so.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-09-26 14:39:54 +01:00
Daniel Thompson c0e7f7ee71 ARM: 8150/3: fiq: Replace default FIQ handler
This patch introduces a new default FIQ handler that is structured in a
similar way to the existing ARM exception handler and result in the FIQ
being handled by C code running on the SVC stack (despite this code run
in the FIQ handler is subject to severe limitations with respect to
locking making normal interaction with the kernel impossible).

This default handler allows concepts that on x86 would be handled using
NMIs to be realized on ARM.

Credit:

    This patch is a near complete re-write of a patch originally
    provided by Anton Vorontsov. Today only a couple of small fragments
    survive, however without Anton's work to build from this patch would
    not exist. Thanks also to Russell King for spoonfeeding me a variety
    of fixes during the review cycle.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-09-18 00:35:18 +01:00
Russell King 6ebbf2ce43 ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+
ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls.  Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).

We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.

Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code.  This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.

Reported-by: Will Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: Shawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-07-18 12:29:04 +01:00
Russell King 1fb333489f Merge branches 'alignment', 'fixes', 'l2c' (early part) and 'misc' into for-next 2014-06-05 12:35:52 +01:00
Russell King 8229c54fa1 ARM: consolidate last remaining open-coded alignment trap enable
We can use the alignment_trap assembly macro here too.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-02 09:20:20 +01:00
Russell King 0aeb3408ca ARM: remove global cr_no_alignment
cr_no_alignment is really only used by the alignment code.  Since we no
longer change the setting of cr_alignment after boot, we can localise
this to alignment.c

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-02 09:20:18 +01:00
Arun K S 3780f7ab49 ARM: 8062/1: Modify ldrt fixup handler to re-execute the userspace instruction
We will reach fixup handler when one thread(say cpu0) caused an undefined exception, while another thread(say cpu1) is unmmaping the page.

Fixup handler returns to the next userspace instruction which has caused the undef execption, rather than going to the same instruction.

ARM ARM says that after undefined exception, the PC will be pointing
to the next instruction. ie +4 offset in case of ARM and +2 in case of Thumb

And there is no correction offset passed to vector_stub in case of
undef exception.

File: arch/arm/kernel/entry-armv.S +1085
vector_stub     und, UND_MODE

During an undefined exception, in normal scenario(ie when ldrt
instruction does not cause an abort) after resorting the context in
VFP hardware, the PC is modified as show below before jumping to
ret_from_exception which is in r9.

File: arch/arm/vfp/vfphw.S +169
@ The context stored in the VFP hardware is up to date with this thread
vfp_hw_state_valid:
   tst     r1, #FPEXC_EX
   bne     process_exception     @ might as well handle the pending
                                 @ exception before retrying branch
                                 @ out before setting an FPEXC that
                                 @ stops us reading stuff
        VFPFMXR FPEXC, r1        @ Restore FPEXC last
        sub     r2, r2, #4       @ Retry current instruction - if Thumb
        str     r2, [sp, #S_PC]  @ mode it's two 16-bit instructions,
                                 @ else it's one 32-bit instruction, so
                                 @ always subtract 4 from the following
                                 @ instruction address.

But if ldrt results in an abort, we reach the fixup handler and return
to ret_from_execption without correcting the pc.

This patch modifes the fixup handler to re-execute the same instruction which caused undefined execption.

Signed-off-by: Vinayak Menon <vinayakm.list@gmail.com>
Signed-off-by: Arun KS <getarunks@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-05-30 01:12:28 +01:00
Catalin Marinas 1417a6b8dc ARM: 8036/1: Enable IRQs before attempting to read user space in __und_usr
The Undef abort handler in the kernel reads the undefined instruction
from user space. If the page table was modified from another CPU, the
user access could fail and do_page_fault() will be executed with
interrupts disabled. This can potentially deadlock on ARM11MPCore or on
Cortex-A15 with erratum 798181 workaround enabled (both implying IPI for
TLB maintenance with page table lock held).

This patch enables the IRQs in __und_usr before attempting to read the
instruction from user space.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Arun KS <getarunks@gmail.com>
Cc: Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ryan Mallon <rmallon@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-04-25 12:06:38 +01:00
Victor Kamensky f8fe23ec4e ARM: 7946/1: asm: __und_usr_thumb need byteswap instructions in BE case
__und_usr_thumb function deals with thumb2 opcodes. In case of BE
image, it needs to byteswap half word thumb2 encoded instructions
before further processing them.

Without this fix BE image user-land thread executing first VFP
instruction encoded in thumb2 fails with SIGILL, because kernel
does not recognize instruction and does not enable VFP.

Reported-by: Corey Melton <comelton@cisco.com>
Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-01-28 14:34:02 +00:00
Russell King 42cbe8271c Merge branches 'fixes', 'mmci' and 'sa11x0' into for-next 2013-11-12 10:59:08 +00:00
Marc Zyngier e16b31bf47 ARM: 7876/1: clear Thumb-2 IT state on exception handling
The exception handling code fails to clear the IT state, potentially
leading to incorrect execution of the fixup if the size of the IT
block is more than one.

Let fixup_exception do the IT sanitizing if a fixup has been found,
and restore CPSR from the stack when returning from a data abort.

Cc: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-11-07 00:15:49 +00:00
Ben Dooks 457c2403c5 ARM: asm: Add ARM_BE8() assembly helper
Add ARM_BE8() helper to wrap any code conditional on being
compile when CONFIG_ARM_ENDIAN_BE8 is selected and convert
existing places where this is to use it.

Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
2013-10-19 20:46:33 +01:00
Russell King 1b16c4bcf8 ARM: Fix !kuser helpers case
Fix yet another build failure caused by a weird set of configuration
settings:

  LD      init/built-in.o
arch/arm/kernel/built-in.o: In function `__dabt_usr':
/home/tom3q/kernel/arch/arm/kernel/entry-armv.S:377: undefined reference to `kuser_cmpxchg64_fixup'
arch/arm/kernel/built-in.o: In function `__irq_usr':
/home/tom3q/kernel/arch/arm/kernel/entry-armv.S:387: undefined reference to `kuser_cmpxchg64_fixup'

caused by:
CONFIG_KUSER_HELPERS=n
CONFIG_CPU_32v6K=n
CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG=n

Reported-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-08-07 14:00:11 +01:00
Russell King f6f91b0d9f ARM: allow kuser helpers to be removed from the vector page
Provide a kernel configuration option to allow the kernel user helpers
to be removed from the vector page, thereby preventing their use with
ROP (return orientated programming) attacks.  This option is only
visible for CPU architectures which natively support all the operations
which kernel user helpers would normally provide, and must be enabled
with caution.

Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-07-31 22:01:48 +01:00
Russell King e39e3f3ebf ARM: update FIQ support for relocation of vectors
FIQ should no longer copy the FIQ code into the user visible vector
page.  Instead, it should use the hidden page.  This change makes
that happen.

Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-07-31 21:34:56 +01:00
Russell King b9b32bf70f ARM: use linker magic for vectors and vector stubs
Use linker magic to create the vectors and vector stubs: we can tell the
linker to place them at an appropriate VMA, but keep the LMA within the
kernel.  This gets rid of some unnecessary symbol manipulation, and
have the linker calculate the relocations appropriately.

Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-07-31 21:34:24 +01:00
Russell King 19accfd373 ARM: move vector stubs
Move the machine vector stubs into the page above the vector page,
which we can prevent from being visible to userspace.  Also move
the reset stub, and place the swi vector at a location that the
'ldr' can get to it.

This hides pointers into the kernel which could give valuable
information to attackers, and reduces the number of exploitable
instructions at a fixed address.

Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-07-31 21:31:36 +01:00
Russell King 5b43e7a383 ARM: poison memory between kuser helpers
Poison the memory between each kuser helper.  This ensures that any
branch between the kuser helpers will be appropriately trapped.

Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-07-31 21:31:09 +01:00
André Hentschel a4780adeef ARM: 7735/2: Preserve the user r/w register TPIDRURW on context switch and fork
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>
2013-06-24 15:21:59 +01:00
Russell King 33b9f582c5 Merge branch 'cleanup' into for-linus
Conflicts:
	arch/arm/plat-omap/dmtimer.c
2013-05-02 21:31:29 +01:00
Russell King 946342d03e Merge branches 'devel-stable', 'entry', 'fixes', 'mach-types', 'misc' and 'smp-hotplug' into for-linus 2013-05-02 21:30:36 +01:00
Kevin Hilman b008848020 ARM: 7688/1: add support for context tracking subsystem
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>
2013-04-03 17:00:01 +01:00
Russell King f8f02ec25c ARM: entry: move disable_irq_notrace into svc_exit
All svc exit paths need IRQs off.  Rather than placing this before
every user of svc_exit, combine it into this macro.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-04-03 16:50:23 +01:00
Russell King 9b56febea2 ARM: entry: move IRQ tracing exit into svc_exit
The IRQ tracing exit path is much the same between all SVC mode
exits, so move this into the svc_exit macro.  Use a macro parameter
to identify the IRQ case, which is the only different case there is.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-04-03 16:50:13 +01:00
Russell King d3f79584a8 ARM: cleanup undefined instruction entry code
We don't need to keep reloading the thread into into r10 - we can do
this once and keep the value cached in the register.  Also, schedule
some instructions better so that the pipeline doesn't stall after a
load in the neon code.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-02-23 17:53:52 +00:00
Russell King 15ac49b650 ARM: Fix undefined instruction exception handling
While trying to get a v3.5 kernel booted on the cubox, I noticed that
VFP does not work correctly with VFP bounce handling.  This is because
of the confusion over 16-bit vs 32-bit instructions, and where PC is
supposed to point to.

The rule is that FP handlers are entered with regs->ARM_pc pointing at
the _next_ instruction to be executed.  However, if the exception is
not handled, regs->ARM_pc points at the faulting instruction.

This is easy for ARM mode, because we know that the next instruction and
previous instructions are separated by four bytes.  This is not true of
Thumb2 though.

Since all FP instructions are 32-bit in Thumb2, it makes things easy.
We just need to select the appropriate adjustment.  Do this by moving
the adjustment out of do_undefinstr() into the assembly code, as only
the assembly code knows whether it's dealing with a 32-bit or 16-bit
instruction.

Cc: <stable@vger.kernel.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-07-31 12:04:30 +01:00
Will Deacon 667d1b48bc ARM: 7425/1: extable: ensure fixup entries are 4-byte aligned
Fixup entries in the kernel exception tables should be 4-byte aligned
since we return directly to them when handling a faulting instruction in
the kernel.

This patch adds the missing align directives to the fixup entries.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-06-16 16:30:25 +01:00
Russell King 357c9c1f07 ARM: Remove support for ARMv3 ARM610 and ARM710 CPUs
This patch removes support for ARMv3 CPUs, which haven't worked properly
for quite some time (see the FIXME comment in arch/arm/mm/fault.c).  The
only V3 parts left is the cache model for ARMv3, which is needed for some
odd reason by ARM740T CPUs, and being able to build with -march=armv3,
which is required for the RiscPC platform due to its bus structure.

Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-05-05 05:50:50 +01:00
Linus Torvalds 820d41cf0c ARM: cleanups of io includes
Rob Herring has done a sweeping change cleaning up all of the mach/io.h includes,
 moving some of the oft-repeated macros to a common location and removing a bunch of
 boiler plate. This is another step closer to a common zImage for multiple platforms.
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Merge tag 'cleanup2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

Pull "ARM: cleanups of io includes" from Olof Johansson:
 "Rob Herring has done a sweeping change cleaning up all of the
  mach/io.h includes, moving some of the oft-repeated macros to a common
  location and removing a bunch of boiler plate.  This is another step
  closer to a common zImage for multiple platforms."

Fix up various fairly trivial conflicts (<mach/io.h> removal vs changes
around it, tegra localtimer.o is *still* gone, yadda-yadda).

* tag 'cleanup2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (29 commits)
  ARM: tegra: Include assembler.h in sleep.S to fix build break
  ARM: pxa: use common IOMEM definition
  ARM: dma-mapping: convert ARCH_HAS_DMA_SET_COHERENT_MASK to kconfig symbol
  ARM: __io abuse cleanup
  ARM: create a common IOMEM definition
  ARM: iop13xx: fix missing declaration of iop13xx_init_early
  ARM: fix ioremap/iounmap for !CONFIG_MMU
  ARM: kill off __mem_pci
  ARM: remove bunch of now unused mach/io.h files
  ARM: make mach/io.h include optional
  ARM: clps711x: remove unneeded include of mach/io.h
  ARM: dove: add explicit include of dove.h to addr-map.c
  ARM: at91: add explicit include of hardware.h to uncompressor
  ARM: ep93xx: clean-up mach/io.h
  ARM: tegra: clean-up mach/io.h
  ARM: orion5x: clean-up mach/io.h
  ARM: davinci: remove unneeded mach/io.h include
  [media] davinci: remove includes of mach/io.h
  ARM: OMAP: Remove remaining includes for mach/io.h
  ARM: msm: clean-up mach/io.h
  ...
2012-03-29 18:02:10 -07:00
Linus Torvalds 0195c00244 Disintegrate and delete asm/system.h
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Merge tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system

Pull "Disintegrate and delete asm/system.h" from David Howells:
 "Here are a bunch of patches to disintegrate asm/system.h into a set of
  separate bits to relieve the problem of circular inclusion
  dependencies.

  I've built all the working defconfigs from all the arches that I can
  and made sure that they don't break.

  The reason for these patches is that I recently encountered a circular
  dependency problem that came about when I produced some patches to
  optimise get_order() by rewriting it to use ilog2().

  This uses bitops - and on the SH arch asm/bitops.h drags in
  asm-generic/get_order.h by a circuituous route involving asm/system.h.

  The main difficulty seems to be asm/system.h.  It holds a number of
  low level bits with no/few dependencies that are commonly used (eg.
  memory barriers) and a number of bits with more dependencies that
  aren't used in many places (eg.  switch_to()).

  These patches break asm/system.h up into the following core pieces:

    (1) asm/barrier.h

        Move memory barriers here.  This already done for MIPS and Alpha.

    (2) asm/switch_to.h

        Move switch_to() and related stuff here.

    (3) asm/exec.h

        Move arch_align_stack() here.  Other process execution related bits
        could perhaps go here from asm/processor.h.

    (4) asm/cmpxchg.h

        Move xchg() and cmpxchg() here as they're full word atomic ops and
        frequently used by atomic_xchg() and atomic_cmpxchg().

    (5) asm/bug.h

        Move die() and related bits.

    (6) asm/auxvec.h

        Move AT_VECTOR_SIZE_ARCH here.

  Other arch headers are created as needed on a per-arch basis."

Fixed up some conflicts from other header file cleanups and moving code
around that has happened in the meantime, so David's testing is somewhat
weakened by that.  We'll find out anything that got broken and fix it..

* tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits)
  Delete all instances of asm/system.h
  Remove all #inclusions of asm/system.h
  Add #includes needed to permit the removal of asm/system.h
  Move all declarations of free_initmem() to linux/mm.h
  Disintegrate asm/system.h for OpenRISC
  Split arch_align_stack() out from asm-generic/system.h
  Split the switch_to() wrapper out of asm-generic/system.h
  Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h
  Create asm-generic/barrier.h
  Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h
  Disintegrate asm/system.h for Xtensa
  Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt]
  Disintegrate asm/system.h for Tile
  Disintegrate asm/system.h for Sparc
  Disintegrate asm/system.h for SH
  Disintegrate asm/system.h for Score
  Disintegrate asm/system.h for S390
  Disintegrate asm/system.h for PowerPC
  Disintegrate asm/system.h for PA-RISC
  Disintegrate asm/system.h for MN10300
  ...
2012-03-28 15:58:21 -07:00
David Howells 9f97da78bf Disintegrate asm/system.h for ARM
Disintegrate asm/system.h for ARM.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Russell King <linux@arm.linux.org.uk>
cc: linux-arm-kernel@lists.infradead.org
2012-03-28 18:30:01 +01:00
Rob Herring 6f6f6a7029 ARM: create a common IOMEM definition
Several platforms create IOMEM defines for casting to 'void __iomem *',
and other platforms are incorrectly using __io() macro for the same
purpose. This creates a common definition and removes all the platform
specific versions. Rather than try to make linux/io.h and asm/io.h
assembly safe, the assembly version of IOMEM is moved into
asm/assembler.h.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Haojian Zhuang <haojian.zhuang@marvell.com>
Acked-by: David Brown <davidb@codeaurora.org>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Viresh Kumar <viresh.kumar@st.com>
Cc: Rajeev Kumar <rajeev-dlh.kumar@st.com>
Cc: Colin Cross <ccross@android.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Stephen Warren <swarren@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2012-03-13 21:22:09 -05:00
Rob Herring 243c86542a ARM: make entry-macro.S depend on !MULTI_IRQ_HANDLER
With the removal of disable_fiq on rpc and addition MULTI_IRQ_HANDLER,
entry-macro.S is no longer needed for platforms that select
MULTI_IRQ_HANDLER and the include of it can be conditional.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
2012-02-21 17:04:59 -06:00
Will Deacon 5a97d0ae5b ARM: 7314/1: kuser: consistently use usr_ret for returning from helpers
__kuser_cmpxchg64 has a return path using bx lr to get back to the caller.
This is actually ok since the code in question is predicated on
CONFIG_CPU_32v6K, but for the sake of consistency using the usr_ret
macro is probably better.

Acked-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-02-03 15:58:46 +00:00
Russell King 742eaa6a6e Merge branch 'for-rmk' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable
Conflicts:
	arch/arm/common/gic.c
	arch/arm/plat-omap/include/plat/common.h
2011-12-05 23:20:17 +00:00
Guennadi Liakhovetski c89cefed35 ARM: 7170/2: fix compilation breakage in entry-armv.S
Fix compilation failure, when Thumb support is not enabled:

arch/arm/kernel/entry-armv.S: Assembler messages:
arch/arm/kernel/entry-armv.S:501: Error: backward ref to unknown label "2:"
arch/arm/kernel/entry-armv.S:502: Error: backward ref to unknown label "3:"
make[2]: *** [arch/arm/kernel/entry-armv.o] Error 1

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Reviewed-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-11-26 21:58:52 +00:00
Marc Zyngier abeb24ae4d ARM: Make global handler and CONFIG_MULTI_IRQ_HANDLER mutually exclusive
Even when CONFIG_MULTI_IRQ_HANDLER is selected, the core code
requires the arch_irq_handler_default macro to be defined as
a fallback.

It turns out nobody is using that particular feature as both PXA
and shmobile have all their machine descriptors populated with
the interrupt handler, leaving unused code (or empty macros) in
their entry-macro.S file just to be able to compile entry-armv.S.

Make CONFIG_MULTI_IRQ_HANDLER exclusive wrt arch_irq_handler_default,
which allows to remove one test from the hot path. Also cleanup both
PXA and shmobile entry-macro.S.

Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Eric Miao <eric.y.miao@gmail.com>
Tested-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2011-11-15 18:13:03 +00:00