17 May, 2012
1 commit
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Commit ff9a184c ("ARM: 7400/1: vfp: clear fpscr length and stride bits
on entry to sig handler") flushes the VFP state prior to entering a
signal handler so that a VFP operation inside the handler will trap and
force a restore of ABI-compliant registers. Reflushing and disabling VFP
on the sigreturn path is predicated on the saved thread state indicating
that VFP was used by the handler -- however for SMP platforms this is
only set on context-switch, making the check unreliable and causing VFP
register corruption in userspace since the register values are not
necessarily those restored from the sigframe.This patch unconditionally flushes the VFP state after a signal handler.
Since we already perform the flush before the handler and the flushing
itself happens lazily, the redundant flush when VFP is not used by the
handler is essentially a nop.Reported-by: Jon Medhurst
Signed-off-by: Jon Medhurst
Signed-off-by: Will Deacon
Signed-off-by: Russell King
12 May, 2012
1 commit
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The vfp_enable function enables access to the VFP co-processor register
space (cp10 and cp11) on the current CPU and must be called with
preemption disabled. Unfortunately, the vfp_init late initcall does not
disable preemption and can lead to an oops during boot if thread
migration occurs at the wrong time and we end up attempting to access
the FPSID on a CPU with VFP access disabled.This patch fixes the initcall to call vfp_enable from a non-preemptible
context on each CPU and adds a BUG_ON(preemptible) to ensure that any
similar problems are easily spotted in the future.Cc: stable@vger.kernel.org
Reported-by: Hyungwoo Yang
Signed-off-by: Hyungwoo Yang
Signed-off-by: Will Deacon
Signed-off-by: Russell King
23 Apr, 2012
2 commits
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The ARM PCS mandates that the length and stride bits of the fpscr are
cleared on entry to and return from a public interface. Although signal
handlers run asynchronously with respect to the interrupted function,
the handler itself expects to run as though it has been called like a
normal function.This patch updates the state mirroring the VFP hardware before entry to
a signal handler so that it adheres to the PCS. Furthermore, we disable
VFP to ensure that we trap on any floating point operation performed by
the signal handler and synchronise the hardware appropriately. A check
is inserted after the signal handler to avoid redundant flushing if VFP
was not used.Reported-by: Peter Maydell
Signed-off-by: Will Deacon
Signed-off-by: Russell King -
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.cSince this code requires intimate low-level knowledge of the VFP state,
this patch moves it into vfpmodule.c.Signed-off-by: Will Deacon
Signed-off-by: Russell King
29 Mar, 2012
2 commits
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Disintegrate asm/system.h for ARM.
Signed-off-by: David Howells
cc: Russell King
cc: linux-arm-kernel@lists.infradead.org -
Avoid namespace conflicts with drivers over the CP15 definitions by
moving CP15 related prototypes and definitions to a private header
file.Acked-by: Stephen Warren
Tested-by: Stephen Warren [Tegra]
Acked-by: H Hartley Sweeten
Tested-by: H Hartley Sweeten [EP93xx]
Acked-by: Nicolas Pitre
Acked-by: Kukjin Kim
Signed-off-by: Russell King
Signed-off-by: David Howells
01 Nov, 2011
1 commit
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Building these files does not reveal a hidden need for
any of these. Since module.h brings in the whole kitchen
sink, it just needlessly adds 30k+ lines to the cpp burden.There are probably lots more, but ARM files of mach-* and plat-*
don't get coverage via a simple yesconfig build. They will have
to be cleaned up and tested via using their respective configs.Signed-off-by: Paul Gortmaker
29 Oct, 2011
1 commit
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…git-cur/linux-2.6-arm
* 'devel-stable' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm: (178 commits)
ARM: 7139/1: fix compilation with CONFIG_ARM_ATAG_DTB_COMPAT and large TEXT_OFFSET
ARM: gic, local timers: use the request_percpu_irq() interface
ARM: gic: consolidate PPI handling
ARM: switch from NO_MACH_MEMORY_H to NEED_MACH_MEMORY_H
ARM: mach-s5p64x0: remove mach/memory.h
ARM: mach-s3c64xx: remove mach/memory.h
ARM: plat-mxc: remove mach/memory.h
ARM: mach-prima2: remove mach/memory.h
ARM: mach-zynq: remove mach/memory.h
ARM: mach-bcmring: remove mach/memory.h
ARM: mach-davinci: remove mach/memory.h
ARM: mach-pxa: remove mach/memory.h
ARM: mach-ixp4xx: remove mach/memory.h
ARM: mach-h720x: remove mach/memory.h
ARM: mach-vt8500: remove mach/memory.h
ARM: mach-s5pc100: remove mach/memory.h
ARM: mach-tegra: remove mach/memory.h
ARM: plat-tcc: remove mach/memory.h
ARM: mach-mmp: remove mach/memory.h
ARM: mach-cns3xxx: remove mach/memory.h
...Fix up mostly pretty trivial conflicts in:
- arch/arm/Kconfig
- arch/arm/include/asm/localtimer.h
- arch/arm/kernel/Makefile
- arch/arm/mach-shmobile/board-ap4evb.c
- arch/arm/mach-u300/core.c
- arch/arm/mm/dma-mapping.c
- arch/arm/mm/proc-v7.S
- arch/arm/plat-omap/Kconfig
largely due to some CONFIG option renaming (ie CONFIG_PM_SLEEP ->
CONFIG_ARM_CPU_SUSPEND for the arm-specific suspend code etc) and
addition of NEED_MACH_MEMORY_H next to HAVE_IDE.
02 Oct, 2011
1 commit
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Distros are starting to ship with toolchains defaulting to
hardfloat. Using such a compiler to build the kernel fails
in the VFP directory witharch/arm/vfp/entry.S:1:0: sorry, unimplemented: -mfloat-abi=hard and VFP
Adding -mfloat-abi=soft to the gcc command line fixes this.
Signed-off-by: Arnd Bergmann
23 Sep, 2011
2 commits
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Function vfp_force_reload() clears vfp_current_hw_state, so
update the comment accordingly.Signed-off-by: Santosh Shilimkar
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When the cpu is powered down in a low power mode, the vfp
registers may be reset.This patch uses CPU_PM_ENTER and CPU_PM_EXIT notifiers to save
and restore the cpu's vfp registers.Signed-off-by: Colin Cross
Signed-off-by: Santosh Shilimkar
Reviewed-by: Kevin Hilman
Tested-and-Acked-by: Shawn Guo
Tested-by: Vishwanath BS
23 Jul, 2011
1 commit
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Conflicts:
arch/arm/kernel/entry-armv.S
10 Jul, 2011
4 commits
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Prevent a preemption event causing the initialized VFP state being
overwritten by ensuring that the VFP hardware access is disabled
prior to starting initialization. We can then do this in safety
while still allowing preemption to occur.Signed-off-by: Russell King
-
Fix a hole in the VFP thread migration. Lets define two threads.
Thread 1, we'll call 'interesting_thread' which is a thread which is
running on CPU0, using VFP (so vfp_current_hw_state[0] =
&interesting_thread->vfpstate) and gets migrated off to CPU1, where
it continues execution of VFP instructions.Thread 2, we'll call 'new_cpu0_thread' which is the thread which takes
over on CPU0. This has also been using VFP, and last used VFP on CPU0,
but doesn't use it again.The following code will be executed twice:
cpu = thread->cpu;
/*
* On SMP, if VFP is enabled, save the old state in
* case the thread migrates to a different CPU. The
* restoring is done lazily.
*/
if ((fpexc & FPEXC_EN) && vfp_current_hw_state[cpu]) {
vfp_save_state(vfp_current_hw_state[cpu], fpexc);
vfp_current_hw_state[cpu]->hard.cpu = cpu;
}
/*
* Thread migration, just force the reloading of the
* state on the new CPU in case the VFP registers
* contain stale data.
*/
if (thread->vfpstate.hard.cpu != cpu)
vfp_current_hw_state[cpu] = NULL;The first execution will be on CPU0 to switch away from 'interesting_thread'.
interesting_thread->cpu will be 0.So, vfp_current_hw_state[0] points at interesting_thread->vfpstate.
The hardware state will be saved, along with the CPU number (0) that
it was executing on.'thread' will be 'new_cpu0_thread' with new_cpu0_thread->cpu = 0.
Also, because it was executing on CPU0, new_cpu0_thread->vfpstate.hard.cpu = 0,
and so the thread migration check is not triggered.This means that vfp_current_hw_state[0] remains pointing at interesting_thread.
The second execution will be on CPU1 to switch _to_ 'interesting_thread'.
So, 'thread' will be 'interesting_thread' and interesting_thread->cpu now
will be 1. The previous thread executing on CPU1 is not relevant to this
so we shall ignore that.We get to the thread migration check. Here, we discover that
interesting_thread->vfpstate.hard.cpu = 0, yet interesting_thread->cpu is
now 1, indicating thread migration. We set vfp_current_hw_state[1] to
NULL.So, at this point vfp_current_hw_state[] contains the following:
[0] = &interesting_thread->vfpstate
[1] = NULLOur interesting thread now executes a VFP instruction, takes a fault
which loads the state into the VFP hardware. Now, through the assembly
we now have:[0] = &interesting_thread->vfpstate
[1] = &interesting_thread->vfpstateCPU1 stops due to ptrace (and so saves its VFP state) using the thread
switch code above), and CPU0 calls vfp_sync_hwstate().if (vfp_current_hw_state[cpu] == &thread->vfpstate) {
vfp_save_state(&thread->vfpstate, fpexc | FPEXC_EN);BANG, we corrupt interesting_thread's VFP state by overwriting the
more up-to-date state saved by CPU1 with the old VFP state from CPU0.Fix this by ensuring that we have sane semantics for the various state
describing variables:1. vfp_current_hw_state[] points to the current owner of the context
information stored in each CPUs hardware, or NULL if that state
information is invalid.
2. thread->vfpstate.hard.cpu always contains the most recent CPU number
which the state was loaded into or NR_CPUS if no CPU owns the state.So, for a particular CPU to be a valid owner of the VFP state for a
particular thread t, two things must be true:vfp_current_hw_state[cpu] == &t->vfpstate && t->vfpstate.hard.cpu == cpu.
and that is valid from the moment a CPU loads the saved VFP context
into the hardware. This gives clear and consistent semantics to
interpreting these variables.This patch also fixes thread copying, ensuring that t->vfpstate.hard.cpu
is invalidated, otherwise CPU0 may believe it was the last owner. The
hole can happen thus:- thread1 runs on CPU2 using VFP, migrates to CPU3, exits and thread_info
freed.
- New thread allocated from a previously running thread on CPU2, reusing
memory for thread1 and copying vfp.hard.cpu.At this point, the following are true:
new_thread1->vfpstate.hard.cpu == 2
&new_thread1->vfpstate == vfp_current_hw_state[2]Lastly, this also addresses thread flushing in a similar way to thread
copying. Hole is:- thread runs on CPU0, using VFP, migrates to CPU1 but does not use VFP.
- thread calls execve(), so thread flush happens, leaving
vfp_current_hw_state[0] intact. This vfpstate is memset to 0 causing
thread->vfpstate.hard.cpu = 0.
- thread migrates back to CPU0 before using VFP.At this point, the following are true:
thread->vfpstate.hard.cpu == 0
&thread->vfpstate == vfp_current_hw_state[0]Signed-off-by: Russell King
-
Rename this branch to more accurately reflect why its taken, rather
than what the following code does. It is the only caller of this code.
This helps to clarify following changes, yet this change results in no
actual code change.Document the VFP hardware state at the target of this branch.
Signed-off-by: Russell King
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Rename the slightly confusing 'last_VFP_context' variable to be more
descriptive of what it actually is. This variable stores a pointer
to the current owner's vfpstate structure for the context held in the
VFP hardware.Signed-off-by: Russell King
08 Jul, 2011
1 commit
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The presence of VFPv4 cannot be detected simply by looking at the FPSID
subarchitecture field, as a value >= 2 signifies the architecture as
VFPv3 or later.This patch reads from MVFR1 to check whether or not the fused multiply
accumulate instructions are supported. Since these are introduced with
VFPv4, this tells us what we need to know.Signed-off-by: Will Deacon
25 Apr, 2011
1 commit
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Convert some ARM architecture's common code to using
struct syscore_ops objects for power management instead of sysdev
classes and sysdevs.This simplifies the code and reduces the kernel's memory footprint.
It also is necessary for removing sysdevs from the kernel entirely in
the future.Signed-off-by: Rafael J. Wysocki
Acked-by: Greg Kroah-Hartman
11 Apr, 2011
2 commits
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VFP registers d16-d31 are callee saved registers and must be preserved
during function calls, including fork(). The VFP configuration should
also be preserved. The patch copies the full VFP state to the child
process.Reported-by: Paul Wright
Signed-off-by: Catalin Marinas
Signed-off-by: Russell King -
This patch adds THREAD_NOTIFY_COPY for calling registered handlers
during the copy_thread() function call. It also changes the VFP handler
to use a switch statement rather than if..else and ignore this event.Signed-off-by: Catalin Marinas
Signed-off-by: Russell King
21 Mar, 2011
1 commit
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* 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6: (25 commits)
video: change to new flag variable
scsi: change to new flag variable
rtc: change to new flag variable
rapidio: change to new flag variable
pps: change to new flag variable
net: change to new flag variable
misc: change to new flag variable
message: change to new flag variable
memstick: change to new flag variable
isdn: change to new flag variable
ieee802154: change to new flag variable
ide: change to new flag variable
hwmon: change to new flag variable
dma: change to new flag variable
char: change to new flag variable
fs: change to new flag variable
xtensa: change to new flag variable
um: change to new flag variables
s390: change to new flag variable
mips: change to new flag variable
...Fix up trivial conflict in drivers/hwmon/Makefile
17 Mar, 2011
1 commit
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Replace EXTRA_CFLAGS with ccflags-y and EXTRA_AFLAGS with asflags-y.
Signed-off-by: matt mooney
Acked-by: WANG Cong
Signed-off-by: Michal Marek
24 Feb, 2011
2 commits
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Improve the documentation for the VFP hotplug notifier handler, so
that people better understand what's going on there and what has
been done for them.Signed-off-by: Russell King
-
arch/arm/kernel/return_address.c:37:6: warning: symbol 'return_address' was not declared. Should it be static?
arch/arm/kernel/setup.c:76:14: warning: symbol 'processor_id' was not declared. Should it be static?
arch/arm/kernel/traps.c:259:1: warning: symbol 'die_lock' was not declared. Should it be static?
arch/arm/vfp/vfpmodule.c:156:6: warning: symbol 'vfp_raise_sigfpe' was not declared. Should it be static?Signed-off-by: Russell King
07 Jan, 2011
1 commit
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Conflicts:
arch/arm/Kconfig
arch/arm/common/Makefile
arch/arm/kernel/Makefile
arch/arm/kernel/smp.c
20 Dec, 2010
1 commit
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We can not guarantee that VFP will be enabled when CPU hotplug brings
a CPU back online from a reset state. Add a hotplug CPU notifier to
ensure that the VFP coprocessor access is enabled whenever a CPU comes
back online.Signed-off-by: Russell King
30 Nov, 2010
1 commit
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Directives such as .long and .word do not magically cause the
assembler location counter to become aligned in gas. As a result,
using these directives in code sections can result in misaligned
data words when building a Thumb-2 kernel (CONFIG_THUMB2_KERNEL).This is a Bad Thing, since the ABI permits the compiler to assume
that fundamental types of word size or above are word- aligned when
accessing them from C. If the data is not really word-aligned,
this can cause impaired performance and stray alignment faults in
some circumstances.In general, the following rules should be applied when using data
word declaration directives inside code sections:* .quad and .double:
.align 3* .long, .word, .single, .float:
.align (or .align 2)* .short:
No explicit alignment required, since Thumb-2
instructions are always 2 or 4 bytes in size.
immediately after an instruction.Reviewed-by: Will Deacon
Signed-off-by: Dave Martin
Acked-by: Catalin Marinas
Signed-off-by: Russell King
09 Jul, 2010
1 commit
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MVFR0 and MVFR1 are only available starting with ARM1136 r1p0 release
according to "B.5 VFP changes" in DDI0211F_arm1136_r1p0_trm.pdf. This is
also when TLS register got added, so we can use HAS_TLS also to test for
MVFR0 and MVFR1.Otherwise VFPFMRX and VFPFMXR access fails and we get:
Internal error: Oops - undefined instruction: 0 [#1]
PC is at no_old_VFP_process+0x8/0x3c
LR is at __und_svc+0x48/0x80
...Signed-off-by: Tony Lindgren
Acked-by: Catalin Marinas
Signed-off-by: Russell King
27 May, 2010
1 commit
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vfp_put_double() takes the double value in r0,r1 not r1,r2.
Reported-by: Tarun Kanti DebBarma
Cc:
Signed-off-by: Russell King
14 Apr, 2010
1 commit
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From: Imre Deak
Recently the UP versions of these functions were refactored and as
a side effect it became possible to call them for the current thread.
This isn't true for the SMP versions however, so fix this up.Signed-off-by: Imre Deak
Signed-off-by: Russell King
28 Mar, 2010
1 commit
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A CPU has VFPv3 hardware if the FPSID[19:16] bits are 2 or more.
Currently Linux was only checking for 3 or more.Signed-off-by: Catalin Marinas
Signed-off-by: Russell King
02 Mar, 2010
1 commit
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* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (100 commits)
ARM: Eliminate decompressor -Dstatic= PIC hack
ARM: 5958/1: ARM: U300: fix inverted clk round rate
ARM: 5956/1: misplaced parentheses
ARM: 5955/1: ep93xx: move timer defines into core.c and document
ARM: 5954/1: ep93xx: move gpio interrupt support to gpio.c
ARM: 5953/1: ep93xx: fix broken build of clock.c
ARM: 5952/1: ARM: MM: Add ARM_L1_CACHE_SHIFT_6 for handle inside each ARCH Kconfig
ARM: 5949/1: NUC900 add gpio virtual memory map
ARM: 5948/1: Enable timer0 to time4 clock support for nuc910
ARM: 5940/2: ARM: MMCI: remove custom DBG macro and printk
ARM: make_coherent(): fix problems with highpte, part 2
MM: Pass a PTE pointer to update_mmu_cache() rather than the PTE itself
ARM: 5945/1: ep93xx: include correct irq.h in core.c
ARM: 5933/1: amba-pl011: support hardware flow control
ARM: 5930/1: Add PKMAP area description to memory.txt.
ARM: 5929/1: Add checks to detect overlap of memory regions.
ARM: 5928/1: Change type of VMALLOC_END to unsigned long.
ARM: 5927/1: Make delimiters of DMA area globally visibly.
ARM: 5926/1: Add "Virtual kernel memory..." printout.
ARM: 5920/1: OMAP4: Enable L2 Cache
...Fix up trivial conflict in arch/arm/mach-mx25/clock.c
16 Feb, 2010
2 commits
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If we're only reading the VFP context via the ptrace call, there's
no need to invalidate the hardware context - we only need to do that
on PTRACE_SETVFPREGS. This allows more efficient monitoring of a
traced task.Signed-off-by: Russell King
-
The more I look at vfp_sync_state(), the more I believe it's trying
to do its job in a really obscure way.Essentially, last_VFP_context[] tracks who owns the state in the VFP
hardware. If last_VFP_context[] is the context for the thread which
we're interested in, then the VFP hardware has context which is not
saved in the software state - so we need to bring the software state
up to date.If last_VFP_context[] is for some other thread, we really don't care
what state the VFP hardware is in; it doesn't contain any information
pertinent to the thread we're trying to deal with - so don't touch
the hardware.Signed-off-by: Russell King
02 Feb, 2010
1 commit
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Commit c98929c07a removed the clearing of the FPSCR[31:28] bits from the
vfp_raise_exceptions() function and the new bits are or'ed with the old
FPSCR bits leading to unexpected results (the original commit was
referring to the cumulative bits - FPSCR[4:0]).Reported-by: Tom Hameenanttila
Signed-off-by: Catalin Marinas
Signed-off-by: Russell King
18 Dec, 2009
1 commit
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This avoids races in the VFP code where the dead thread may have
state on another CPU. By moving this code to exit_thread(), we
will be running as the thread, and therefore be running on the
current CPU.This means that we can ensure that the only local state is accessed
in the thread notifiers.Acked-by: Catalin Marinas
Signed-off-by: Russell King
14 Dec, 2009
1 commit
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When the VFP notifier is called for flush_thread(), we may be
preemptible, meaning we might migrate to another CPU, which means
referencing the current CPU number without some form of locking is
invalid, and can cause data corruption.For the most cases, this isn't a problem since atomic notifiers are run
under rcu lock, which for most configurations results in preemption
being disabled - except when the preemptable tree-based rcu
implementation is selected.Let's make it safe anyway.
Signed-off-by: Russell King
24 Jul, 2009
2 commits
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This patch modifies the VFP files for the ARM/Thumb-2 unified
assembly syntax.Signed-off-by: Catalin Marinas
-
Since the Thumb-2 instructions can be 16-bit wide, data in the .text
sections may not be aligned to a 32-bit word and this leads to unaligned
exceptions. This patch does not affect the ARM code generation.Signed-off-by: Catalin Marinas
30 May, 2009
1 commit
-
This CPU generates synchronous VFP exceptions in a non-standard way -
the FPEXC.EX bit set but without the FPSCR.IXE bit being set like in the
VFP subarchitecture 1 or just the FPEXC.DEX bit like in VFP
subarchitecture 2. The main problem is that the faulty instruction
(which needs to be emulated in software) will be restarted several times
(normally until a context switch disables the VFP). This patch ensures
that the VFP exception is treated as synchronous.Signed-off-by: Catalin Marinas
Cc: Nicolas Pitre