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2012-10-29ARM: 7566/1: vfp: fix save and restore when running on pre-VFPv3 and ↵Paul Walmsley1-3/+6
CONFIG_VFPv3 set After commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 ("ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels"), the OMAP 2430SDP board started crashing during boot with omap2plus_defconfig: [ 3.875122] mmcblk0: mmc0:e624 SD04G 3.69 GiB [ 3.915954] mmcblk0: p1 [ 4.086639] Internal error: Oops - undefined instruction: 0 [#1] SMP ARM [ 4.093719] Modules linked in: [ 4.096954] CPU: 0 Not tainted (3.6.0-02232-g759e00b #570) [ 4.103149] PC is at vfp_reload_hw+0x1c/0x44 [ 4.107666] LR is at __und_usr_fault_32+0x0/0x8 It turns out that the context save/restore fix unmasked a latent bug in commit 5aaf254409f8d58229107b59507a8235b715a960 ("ARM: 6203/1: Make VFPv3 usable on ARMv6"). When CONFIG_VFPv3 is set, but the kernel is booted on a pre-VFPv3 core, the code attempts to save and restore the d16-d31 VFP registers. These are only present on non-D16 VFPv3+, so this results in an undefined instruction exception. The code didn't crash before commit 846a136 because the save and restore code was only touching d0-d15, present on all VFP. Fix by implementing a request from Russell King to add a new HWCAP flag that affirmatively indicates the presence of the d16-d31 registers: http://marc.info/?l=linux-arm-kernel&m=135013547905283&w=2 and some feedback from Måns to clarify the name of the HWCAP flag. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Tony Lindgren <tony@atomide.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Martin <dave.martin@linaro.org> Cc: Måns Rullgård <mans.rullgard@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-08-11ARM: 7483/1: vfp: only advertise VFPv4 in hwcaps if CONFIG_VFPv3 is enabledWill Deacon1-0/+2
VFPv4 support depends on the VFPv3 context save/restore code, so only advertise support in the hwcaps if the kernel can actually handle it. Cc: <stable@vger.kernel.org> # 3.1+ Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-07-31ARM: 7477/1: vfp: Always save VFP state in vfp_pm_suspend on UPColin Cross1-0/+6
vfp_pm_suspend should save the VFP state in suspend after any lazy context switch. If it only saves when the VFP is enabled, the state can get lost when, on a UP system: Thread 1 uses the VFP Context switch occurs to thread 2, VFP is disabled but the VFP context is not saved Thread 2 initiates suspend vfp_pm_suspend is called with the VFP disabled, and the unsaved VFP context of Thread 1 in the registers Modify vfp_pm_suspend to save the VFP context whenever vfp_current_hw_state is not NULL. Includes a fix from Ido Yariv <ido@wizery.com>, who pointed out that on SMP systems, the state pointer can be pointing to a freed task struct if a task exited on another cpu, fixed by using #ifndef CONFIG_SMP in the new if clause. Cc: Barry Song <bs14@csr.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ido Yariv <ido@wizery.com> Cc: Daniel Drake <dsd@laptop.org> Cc: Will Deacon <will.deacon@arm.com> Cc: stable@vger.kernel.org Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-07-31ARM: 7476/1: vfp: only clear vfp state for current cpu in vfp_pm_suspendColin Cross1-1/+1
vfp_pm_suspend runs on each cpu, only clear the hardware state pointer for the current cpu. Prevents a possible crash if one cpu clears the hw state pointer when another cpu has already checked if it is valid. Cc: stable@vger.kernel.org Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-05-21Merge branch 'misc' into for-linusRussell King1-8/+8
Conflicts: arch/arm/kernel/ptrace.c
2012-05-17ARM: 7419/1: vfp: fix VFP flushing regression on sigreturn pathWill Deacon1-12/+2
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 <tixy@linaro.org> Signed-off-by: Jon Medhurst <tixy@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-05-12ARM: 7417/1: vfp: ensure preemption is disabled when enabling VFP accessWill Deacon1-4/+6
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 <hwoo.yang@gmail.com> Signed-off-by: Hyungwoo Yang <hyungwooy@nvidia.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-05-11ARM: 7415/1: vfp: convert printk's to pr_*'sNicolas Pitre1-8/+8
This is mainly to get rid of the "vfp_pm_suspend: saving vfp state" message flooding the kernel message ring by default. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-04-23ARM: 7400/1: vfp: clear fpscr length and stride bits on entry to sig handlerWill Deacon1-1/+21
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 <peter.maydell@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-04-23ARM: 7399/1: vfp: move user vfp state save/restore code out of signal.cWill Deacon1-0/+79
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>
2012-03-28Disintegrate asm/system.h for ARMDavid Howells1-0/+1
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
2012-03-28ARM: move CP15 definitions to separate header fileRussell King1-0/+1
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 <swarren@nvidia.com> Tested-by: Stephen Warren <swarren@nvidia.com> [Tegra] Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com> Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com> [EP93xx] Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com>
2011-10-31arm: remove several unnecessary module.h include instancesPaul Gortmaker1-1/+0
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 <paul.gortmaker@windriver.com>
2011-09-23ARM: vfp: Fix the comment to make it consistent with the code.Santosh Shilimkar1-1/+1
Function vfp_force_reload() clears vfp_current_hw_state, so update the comment accordingly. Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
2011-09-23ARM: vfp: Use cpu pm notifiers to save vfp stateColin Cross1-8/+21
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 <ccross@android.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Kevin Hilman <khilman@ti.com> Tested-and-Acked-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
2011-07-22Merge branch 'devel-stable' into for-nextRussell King1-2/+4
Conflicts: arch/arm/kernel/entry-armv.S
2011-07-09ARM: vfp: ensure that thread flushing works if preemptedRussell King1-10/+13
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 <rmk+kernel@arm.linux.org.uk>
2011-07-09ARM: vfp: fix a hole in VFP thread migrationRussell King1-46/+52
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] = NULL Our 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->vfpstate CPU1 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 <rmk+kernel@arm.linux.org.uk>
2011-07-09ARM: vfp: rename last_VFP_context to vfp_current_hw_stateRussell King1-15/+21
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 <rmk+kernel@arm.linux.org.uk>
2011-07-07ARM: vfp: add VFPv4 capability detection and populate elf_hwcapWill Deacon1-2/+4
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 <will.deacon@arm.com>
2011-04-24ARM: Use struct syscore_ops instead of sysdevs for PM in common codeRafael J. Wysocki1-14/+5
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 <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-10ARM: 6868/1: Preserve the VFP state during forkCatalin Marinas1-0/+12
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 <paul.wright@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-04-10ARM: 6867/1: Introduce THREAD_NOTIFY_COPY for copy_thread() hooksCatalin Marinas1-7/+15
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 <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-02-23ARM: vfp: improve commentry for hotplug eventsRussell King1-2/+5
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 <rmk+kernel@arm.linux.org.uk>
2011-02-23ARM: fix some sparse errors in generic ARM codeRussell King1-1/+1
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 <rmk+kernel@arm.linux.org.uk>
2010-12-20ARM: VFP: re-initialize VFP coprocessor access enables on CPU hotplugRussell King1-1/+23
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 <rmk+kernel@arm.linux.org.uk>
2010-07-09ARM: 6203/1: Make VFPv3 usable on ARMv6Tony Lindgren1-3/+7
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 <tony@atomide.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-04-14ARM: 6050/1: VFP: fix the SMP versions of vfp_{sync,flush}_hwstateImre Deak1-21/+10
From: Imre Deak <imre.deak@nokia.com> 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 <imre.deak@nokia.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-03-28ARM: 5997/1: ARM: Correct the VFPv3 detectionCatalin Marinas1-1/+1
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 <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-03-01Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-armLinus Torvalds1-19/+36
* '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
2010-02-15ARM: vfp ptrace: no point flushing hw context for PTRACE_GETVFPREGSRussell King1-2/+23
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 <rmk+kernel@arm.linux.org.uk>
2010-02-15ARM: vfp: fix vfp_sync_state()Russell King1-20/+16
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 <rmk+kernel@arm.linux.org.uk>
2010-02-01ARM: 5909/1: ARM: Correct the FPSCR bits setting when raising exceptionsCatalin Marinas1-1/+4
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 <tmhameen@marvell.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-18ARM: Convert VFP/Crunch/XscaleCP thread_release() to exit_thread()Russell King1-8/+11
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 <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-13ARM: VFP: fix vfp thread init bug and document vfp notifier entry conditionsRussell King1-21/+62
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 <rmk+kernel@arm.linux.org.uk>
2009-05-30Fix the VFP handling on the Feroceon CPUCatalin Marinas1-0/+2
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 <catalin.marinas@arm.com> Cc: Nicolas Pitre <nico@cam.org>
2009-04-01[ARM] 5440/1: Fix VFP state corruption due to preemption during VFP exceptionsGeorge G. Davis1-2/+4
We've observed that ARM VFP state can be corrupted during VFP exception handling when PREEMPT is enabled. The exact conditions are difficult to reproduce but appear to occur during VFP exception handling when a task causes a VFP exception which is handled via VFP_bounce and is then preempted by yet another task which in turn causes yet another VFP exception. Since the VFP_bounce code is not preempt safe, VFP state then becomes corrupt. In order to prevent preemption from occuring while handling a VFP exception, this patch disables preemption while handling VFP exceptions. Signed-off-by: George G. Davis <gdavis@mvista.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12[ARM] 5388/1: Add hwcap bits for VFPv3 and VFPv3D16Catalin Marinas1-0/+12
The VFPv3D16 is a VFPv3 CPU configuration where only 16 double registers are present, as the VFPv2 configuration. This patch adds the corresponding hwcap bits so that applications or debuggers have more information about the supported features. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12[ARM] 5387/1: Add ptrace VFP support on ARMCatalin Marinas1-0/+49
This patch adds ptrace support for setting and getting the VFP registers using PTRACE_SETVFPREGS and PTRACE_GETVFPREGS. The user_vfp structure defined in asm/user.h contains 32 double registers (to cover VFPv3 and Neon hardware) and the FPSCR register. Cc: Paul Brook <paul@codesourcery.com> Cc: Daniel Jacobowitz <dan@codesourcery.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-12-18[ARM] 5349/1: VFP: Add PM code to save and restore current VFP stateBen Dooks1-0/+56
When CONFIG_PM is selected, the VFP code does not have any handler installed to deal with either saving the VFP state of the current task, nor does it do anything to try and restore the VFP after a resume. On resume, the VFP will have been reset and the co-processor access control registers are in an indeterminate state (very probably the CP10 and CP11 the VFP uses will have been disabled by the ARM core reset). When this happens, resume will break as soon as it tries to unfreeze the tasks and restart scheduling. Add a sys device to allow us to hook the suspend call to save the current thread state if the thread is using VFP and a resume hook which restores the CP10/CP11 access and ensures the VFP is disabled so that the lazy swapping will take place on next access. Signed-off-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-06Add HWCAP_NEON to the ARM hwcap.h fileCatalin Marinas1-0/+9
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2008-06-26smp_call_function: get rid of the unused nonatomic/retry argumentJens Axboe1-1/+1
It's never used and the comments refer to nonatomic and retry interchangably. So get rid of it. Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-01-26[ARM] 4582/2: Add support for the common VFP subarchitectureCatalin Marinas1-43/+55
This patch allows the VFP support code to run correctly on CPUs compatible with the common VFP subarchitecture specification (Appendix B in the ARM ARM v7-A and v7-R edition). It implements support for VFP subarchitecture 2 while being backwards compatible with subarchitecture 1. On VFP subarchitecture 1, the arithmetic exceptions are asynchronous (or imprecise as described in the old ARM ARM) unless the FPSCR.IXE bit is 1. The exceptional instructions can be read from FPINST and FPINST2 registers. With VFP subarchitecture 2, the arithmetic exceptions can also be synchronous and marked by the FPEXC.DEX bit (the FPEXC.EX bit is cleared). CPUs implementing the synchronous arithmetic exceptions don't have the FPINST and FPINST2 registers and accessing them would trigger and undefined exception. Note that FPEXC.EX bit has an additional meaning on subarchitecture 1 - if it isn't set, there is no additional information in FPINST and FPINST2 that needs to be saved at context switch or when lazy-loading the VFP state of a different thread. The patch also removes the clearing of the cumulative exception flags in FPSCR when additional exceptions were raised. It is up to the user application to clear these bits. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-10-20[ARM] 4629/1: Fix VFP emulation code to clear all exception flags of FPEXCTakashi Ohmasa1-1/+1
All exception flags of the FPEXC register must be cleared before returning from exception code to user code, including FP2V and OFC. Signed-off-by: Takashi Ohmasa <ohmasa.takashi@jp.panasonic.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-09-13[ARM] 4567/1: Fix 'Oops - undefined instruction' when CONFIG_VFP=y on non ↵Tzachi Perelstein1-0/+1
VFP device vfp_init() takes care of the condition when CONFIG_VFP=y but no real VFP device exists. However, when this condition is true, a compiler might misplace code lines in a way that will break this support. (To be more specific - fmrx(FPSID) might be executed before vfp_testing_entry assignment, which will end up with Oops - undefined instruction). This patch adds a barrier() to guarantee the right execution ordering. Signed-off-by: Assaf Hoffman Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-07-20[ARM] vfp: make fpexc bit names less verboseRussell King1-6/+6
Use the fpexc abbreviated names instead of long verbose names for fpexc bits. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-06-10[ARM] VFP: fix section mismatch errorRussell King1-1/+4
Fix a real section mismatch issue; the test code is thrown away after initialisation, but if we do not detect the VFP hardware, it is left hooked into the exception handler. Any VFP instructions which are subsequently executed risk calling the discarded exception handler. Introduce a new "null" handler which returns to the "unrecognised fault" return address. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-01-25[ARM] 4111/1: Allow VFP to work with thread migration on SMPCatalin Marinas1-4/+26
The current lazy saving of the VFP registers is no longer possible with thread migration on SMP. This patch implements a per-CPU vfp-state pointer and the saving of the VFP registers at every context switch. The registers restoring is still performed in a lazy way. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-01-02[ARM] Fix VFP initialisation issue for SMP systemsRussell King1-0/+15
When we install the handlers for context switching, we must enable VFP on all CPU cores, otherwise undefined (and random) effects occur. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-08[ARM] Handle HWCAP_VFP in VFP support codeRussell King1-1/+25
Don't set HWCAP_VFP in the processor support file; not only does it depend on the processor features, but it also depends on the support code being present. Therefore, only set it if the support code detects that we have a VFP coprocessor attached. Also, move the VFP handling of the coprocessor access register into the VFP support code. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>