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* ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+Russell King2014-07-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* ARM: 8053/1: kernel: sleep: restore HYP mode configuration in cpu_resumeLorenzo Pieralisi2014-05-251-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | On CPUs with virtualization extensions the kernel installs HYP mode configuration on both primary and secondary cpus upon cold boot. On platforms where CPUs are shutdown in idle paths (ie CPU core gating), when a CPU resumes from low-power states it currently does not execute code that reinstalls the HYP configuration, which means that the kernel cannot run eg KVM properly on such machines. This patch, mirroring cold-boot behaviour, executes position independent code that reinstalls HYP configuration and drops to SVC mode safely on warmboot, so that deep idle states can be enabled in kernel running as hosts on platforms with power management HW. Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Dave Martin <dave.martin@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Nicolas Pitre <nico@linaro.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* Merge branch 'baserock/bjdooks/312-rc4/be/core-v3' of ↵Russell King2013-10-301-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | git://git.baserock.org/delta/linux into devel-stable Conflicts: arch/arm/kernel/head.S This series has been well tested and it would be great to get this merged now. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
| * ARM: set BE8 if LE in head codeBen Dooks2013-10-191-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we are booting in LE and compiled for BE8, then add code to set the state to bE8. Since the instruction stream is always LE, we do not need to do anything special to the instruction. Also ensure that the secondary processors are started in the same mode. Note, we do add about 20 bytes to the kernel image, but it seems easier to do this than adding another configuration to change. Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Reviewed-by: Dave Martin <Dave.Martin@arm.com> Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
* | ARM: suspend: use hash of cpu_logical_map value to index into save arrayNicolas Pitre2013-07-301-15/+11
|/ | | | | | | | | | | | | | | | | | | | | | | | Currently we hash the MPIDR of the CPU being suspended to determine which entry in the sleep_save_sp array to use. In some situations, such as when we want to resume on another physical CPU, the MPIDR of another CPU should be used instead. So let's use the value of cpu_logical_map(smp_processor_id()) in place of the MPIDR in the suspend path. This will result in the same index being used as with the previous code unless the caller has modified cpu_logical_map() beforehand with the MPIDR of the physical CPU the suspending logical CPU will resume on. Consequently, if doing a physical CPU migration, cpu_logical_map() must be updated appropriately somewhere between cpu_pm_enter() and cpu_suspend(). The register allocation in __cpu_suspend is reworked in order to better accommodate the additional argument. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Dave Martin <Dave.Martin@arm.com>
* ARM: kernel: implement stack pointer save array through MPIDR hashingLorenzo Pieralisi2013-06-201-18/+79
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current implementation of cpu_{suspend}/cpu_{resume} relies on the MPIDR to index the array of pointers where the context is saved and restored. The current approach works as long as the MPIDR can be considered a linear index, so that the pointers array can simply be dereferenced by using the MPIDR[7:0] value. On ARM multi-cluster systems, where the MPIDR may not be a linear index, to properly dereference the stack pointer array, a mapping function should be applied to it so that it can be used for arrays look-ups. This patch adds code in the cpu_{suspend}/cpu_{resume} implementation that relies on shifting and ORing hashing method to map a MPIDR value to a set of buckets precomputed at boot to have a collision free mapping from MPIDR to context pointers. The hashing algorithm must be simple, fast, and implementable with few instructions since in the cpu_resume path the mapping is carried out with the MMU off and the I-cache off, hence code and data are fetched from DRAM with no-caching available. Simplicity is counterbalanced with a little increase of memory (allocated dynamically) for stack pointers buckets, that should be anyway fairly limited on most systems. Memory for context pointers is allocated in a early_initcall with size precomputed and stashed previously in kernel data structures. Memory for context pointers is allocated through kmalloc; this guarantees contiguous physical addresses for the allocated memory which is fundamental to the correct functioning of the resume mechanism that relies on the context pointer array to be a chunk of contiguous physical memory. Virtual to physical address conversion for the context pointer array base is carried out at boot to avoid fiddling with virt_to_phys conversions in the cpu_resume path which is quite fragile and should be optimized to execute as few instructions as possible. Virtual and physical context pointer base array addresses are stashed in a struct that is accessible from assembly using values generated through the asm-offsets.c mechanism. Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Colin Cross <ccross@android.com> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Amit Kucheria <amit.kucheria@linaro.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Kevin Hilman <khilman@linaro.org> Tested-by: Stephen Warren <swarren@wwwdotorg.org>
* Disintegrate asm/system.h for ARMDavid Howells2012-03-281-1/+0
| | | | | | | | 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
* ARM: LPAE: add ISBs around MMU enabling codeWill Deacon2011-12-081-0/+2
| | | | | | | | | | | | | Before we enable the MMU, we must ensure that the TTBR registers contain sane values. After the MMU has been enabled, we jump to the *virtual* address of the following function, so we also need to ensure that the SCTLR write has taken effect. This patch adds ISB instructions around the SCTLR write to ensure the visibility of the above. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* ARM: suspend: use idmap_pgd instead of suspend_pgdWill Deacon2011-12-061-0/+2
| | | | | | | | | | | | | | | | The ARM CPU suspend code requires cpu_resume_mmu to be identity mapped in order to re-enable the MMU when coming out of suspend. Currently, this is accomplished by maintaining a suspend_pgd with the relevant mapping put in place at init time. This patch replaces the use of suspend_pgd with the new idmap_pgd. cpu_resume_mmu is placed in the .idmap.text section so that it is included in the identity map. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Dave Martin <dave.martin@linaro.org> Tested-by: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* ARM: pm: convert some assembly to CRussell King2011-09-201-36/+17
| | | | | | | | | | | | | | | | Convert some of the sleep.S guts to C code, which makes it easier to use our macros and to add L2 cache handling. We provide a helper function, __cpu_suspend_save(), which deals with saving the common state, setting up for resume, and flushing caches. The remainder left as assembly code is the saving of the CPU general purpose registers, and allocating space on the stack to save the CPU specific registers and resume state. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: get rid of cpu_resume_turn_mmu_onRussell King2011-09-201-6/+2
| | | | | | | | | | | | | We don't require cpu_resume_turn_mmu_on as we can combine the ldr instruction with the following code provided we ensure that cpu_resume_mmu is aligned for older CPUs. Note that we also align to a 32-byte boundary to ensure that the code can't cross a section boundary. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: only use preallocated page table during resumeRussell King2011-09-201-10/+9
| | | | | | | | | | | Only use the preallocated page table during the resume, not while suspending. This avoids the overhead of having to switch unnecessarily to the resume page table in the suspend path. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: preallocate a page table for suspend/resumeRussell King2011-09-201-21/+12
| | | | | | | | | | | Preallocate a page table and setup an identity mapping for the MMU enable code. This means we don't have to "borrow" a page table to do this, avoiding complexities with L2 cache coherency. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: force non-zero return value from __cpu_suspend when abortingRussell King2011-09-201-0/+2
| | | | | | | | | | Ensure that the return value from __cpu_suspend is non-zero when aborting. Zero indicates a successful suspend occurred. Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: allow suspend finisher to return error codesRussell King2011-07-021-2/+9
| | | | | | | | | | | | | | There are SoCs where attempting to enter a low power state is ignored, and the CPU continues executing instructions with all state preserved. It is over-complex at that point to disable the MMU just to call the resume path. Instead, allow the suspend finisher to return error codes to abort suspend in this circumstance, where the cpu_suspend internals will then unwind the saved state on the stack. Also omit the tlb flush as no changes to the page tables will have happened. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: hide 1st and 2nd arguments to cpu_suspend from platform codeRussell King2011-06-241-2/+2
| | | | | | | | | The first and second arguments shouldn't concern platform code, so hide them from each platforms caller. Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: move cpu_init() call into core codeRussell King2011-06-241-0/+1
| | | | | | | | | | | As we have core code dealing with CPU suspend/resume, we can re-initialize the CPUs exception banked registers via that code rather than having platforms deal with that level of detail. So, move the call to cpu_init() out of platform code into core code. Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: convert cpu_suspend() to a normal functionRussell King2011-06-241-6/+4
| | | | | | | | | | | | | | | | | cpu_suspend() has a weird calling method which makes it only possible to call from assembly code: it returns with a modified stack pointer to finish the suspend, but on resume, it 'returns' via a provided pointer. We can make cpu_suspend() appear to be a normal function merely by swapping the resume pointer argument and the link register. Do so, and update all callers to take account of this more traditional behaviour. Acked-by: Frank Hofmann <frank.hofmann@tomtom.com> Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: rejig suspend follow-on function calling conventionRussell King2011-06-241-4/+5
| | | | | | | | | | Save the suspend function pointer onto the stack for use when returning. Allocate r2 to pass an argument to the suspend function. Acked-by: Frank Hofmann <frank.hofmann@tomtom.com> Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: reallocate registers to avoid r2, r3Russell King2011-06-241-9/+9
| | | | | | | | | | Avoid using r2 and r3 in the suspend code, allowing these to be passed further into the function as arguments. Acked-by: Frank Hofmann <frank.hofmann@tomtom.com> Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: preserve r4 - r11 across a suspendRussell King2011-06-241-2/+3
| | | | | | | | | | | Make cpu_suspend()..return function preserve r4 to r11 across a suspend cycle. This is in preparation of relieving platform support code from this task. Acked-by: Frank Hofmann <frank.hofmann@tomtom.com> Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: extract common code from MULTI_CPU/!MULTI_CPU pathsRussell King2011-06-241-18/+6
| | | | | | | | | | Very little code is different between these two paths now, so extract the common code. Acked-by: Frank Hofmann <frank.hofmann@tomtom.com> Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: move return address (for cpu_resume) to top of stackRussell King2011-06-241-8/+8
| | | | | | | | | | Move the return address for cpu_resume to the top of stack so that cpu_resume looks more like a normal function. Acked-by: Frank Hofmann <frank.hofmann@tomtom.com> Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: make MULTI_CPU and !MULTI_CPU resume paths the sameRussell King2011-06-241-9/+3
| | | | | | | | | | | Eliminate the differences between MULTI_CPU and non-MULTI_CPU resume paths, making the saved structure identical irrespective of the way the kernel was configured. Acked-by: Frank Hofmann <frank.hofmann@tomtom.com> Tested-by: Kevin Hilman <khilman@ti.com> Acked-by: Jean Pihet <j-pihet@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: 6825/1: kernel/sleep.S: fix Thumb2 compilation issuesNicolas Pitre2011-03-261-3/+11
| | | | | | Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> Reviewed-by: Dave Martin <dave.martin@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: allow generic sleep code to be used with SMP CPU idleRussell King2011-02-221-1/+26
| | | | | | | | | Allow the generic sleep code to be used with SMP CPU idle by storing N CPU stack pointers rather than just one. Tested on Assabet and Tegra 2. Tested-by: Colin Cross <ccross@android.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: pm: add generic CPU suspend/resume supportRussell King2011-02-221-0/+109
This adds core support for saving and restoring CPU coprocessor registers for suspend/resume support. This contains support for suspend with ARM920, ARM926, SA11x0, PXA25x, PXA27x, PXA3xx, V6 and V7 CPUs. Tested on Assabet and Tegra 2. Tested-by: Colin Cross <ccross@android.com> Tested-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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