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2007-05-09[POWERPC] Don't use SLAB/SLUB for PTE pagesHugh Dickins
The SLUB allocator relies on struct page fields first_page and slab, overwritten by ptl when SPLIT_PTLOCK: so the SLUB allocator cannot then be used for the lowest level of pagetable pages. This was obstructing SLUB on PowerPC, which uses kmem_caches for its pagetables. So convert its pte level to use normal gfp pages (whereas pmd, pud and 64k-page pgd want partpages, so continue to use kmem_caches for pmd, pud and pgd). Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-09[POWERPC] Add ability to 4K kernel to hash in 64K pagesBenjamin Herrenschmidt
This adds the ability for a kernel compiled with 4K page size to have special slices containing 64K pages and hash the right type of hash PTEs. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-09[POWERPC] Introduce address space "slices"Benjamin Herrenschmidt
The basic issue is to be able to do what hugetlbfs does but with different page sizes for some other special filesystems; more specifically, my need is: - Huge pages - SPE local store mappings using 64K pages on a 4K base page size kernel on Cell - Some special 4K segments in 64K-page kernels for mapping a dodgy type of powerpc-specific infiniband hardware that requires 4K MMU mappings for various reasons I won't explain here. The main issues are: - To maintain/keep track of the page size per "segment" (as we can only have one page size per segment on powerpc, which are 256MB divisions of the address space). - To make sure special mappings stay within their allotted "segments" (including MAP_FIXED crap) - To make sure everybody else doesn't mmap/brk/grow_stack into a "segment" that is used for a special mapping Some of the necessary mechanisms to handle that were present in the hugetlbfs code, but mostly in ways not suitable for anything else. The patch relies on some changes to the generic get_unmapped_area() that just got merged. It still hijacks hugetlb callbacks here or there as the generic code hasn't been entirely cleaned up yet but that shouldn't be a problem. So what is a slice ? Well, I re-used the mechanism used formerly by our hugetlbfs implementation which divides the address space in "meta-segments" which I called "slices". The division is done using 256MB slices below 4G, and 1T slices above. Thus the address space is divided currently into 16 "low" slices and 16 "high" slices. (Special case: high slice 0 is the area between 4G and 1T). Doing so simplifies significantly the tracking of segments and avoids having to keep track of all the 256MB segments in the address space. While I used the "concepts" of hugetlbfs, I mostly re-implemented everything in a more generic way and "ported" hugetlbfs to it. Slices can have an associated page size, which is encoded in the mmu context and used by the SLB miss handler to set the segment sizes. The hash code currently doesn't care, it has a specific check for hugepages, though I might add a mechanism to provide per-slice hash mapping functions in the future. The slice code provide a pair of "generic" get_unmapped_area() (bottomup and topdown) functions that should work with any slice size. There is some trickiness here so I would appreciate people to have a look at the implementation of these and let me know if I got something wrong. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-08[POWERPC] Support for the Ebony 440GP reference board in arch/powerpcDavid Gibson
This adds platform support code for the Ebony (440GP) evaluation board. This includes both code in arch/powerpc/platforms/44x for board initialization, and zImage wrapper code to correctly tweak the flattened device tree based on information from the firmware. The zImage supports both IBM OpenBIOS (aka "treeboot") and old versions of uboot which don't support a flattened device tree. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-08[POWERPC] PowerPC MSI infrastructureMichael Ellerman
This provides the architecture specific hooks to support MSI on powerpc. We implement the newly added arch_setup_msi_irqs() and arch_teardown_msi_irqs(), and then delegate to ppc_md routines. Platforms that don't implement MSI will leave the ppc_md calls blank, arch_msi_check_device() will detect this and return ENOSYS. Drivers should detect this error and continue to use LSI. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-08Merge branch 'linux-2.6'Paul Mackerras
2007-05-08[POWERPC] Add support for 750CL Holly boardJosh Boyer
Add PowerPC 750 Holly/Hickory platform support Signed-off-by: Stephen Winiecki <stevewin@us.ibm.com> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com> Acked-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-07PowerPC: Disable SLUB for configurations in which slab page structs are modifiedChristoph Lameter
PowerPC uses the slab allocator to manage the lowest level of the page table. In high cpu configurations we also use the page struct to split the page table lock. Disallow the selection of SLUB for that case. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07[POWERPC] powermac: Suspend to disk on G5Johannes Berg
Powermac G5 suspend to disk implementation. The code is platform agnostic but only tested on powermac, no other 64-bit powerpc machines. Because nvidiafb still breaks suspend I have marked it EXPERIMENTAL on powermac and because I can't test it and some lowlevel code will need changes it is BROKEN on all other 64-bit platforms. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-02[POWERPC] apm_emu: Use generic apm-emulationJohannes Berg
This patch removes a huge amount of code that is now in common code in drivers/char/apm-emulation.c Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-04-27[POWERPC] bootwrapper: cuImage for 85xxScott Wood
Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-04-24[POWERPC] bootwrapper: Add CONFIG_DEVICE_TREEScott Wood
This provides a way to tell the bootwrapper makefile which device tree to include by default. The wrapper can still be invoked standalone to wrap with a different device tree without reconfiguring the kernel, if that is desired. The user will only be asked to provide a device tree if the platform selects CONFIG_WANT_DEVICE_TREE. Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-04-12[POWERPC] Miscellaneous arch/powerpc Kconfig and platform/Kconfig cleanupKumar Gala
* Cleaned up some whitespace in arch/powerpc/Kconfig * Moved sourcing of platforms/embedded6xx/Kconfig into platform/Kconfig * Moved sourcing of platforms/4xx/Kconfig into platform/Kconfig and disabled it * Removed EMBEDDEDBOOT since its not supported in arch/powerpc * Removed PC_KEYBOARD since its not used anywhere * Moved a few CONFIG options around in platform/Kconfig * Moved interrupt controllers into platform/Kconfig out of bus section Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-04-12[POWERPC] Convert 85xx platform to unified platform KconfigKumar Gala
Moved 85xx platform Kconfig over to being sourced by the unified arch/powerpc/platforms/Kconfig. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-04-12[POWERPC] Convert 8xx platform to unified platform KconfigKumar Gala
Moved 8xx platform Kconfig over to being sourced by the unified arch/powerpc/platforms/Kconfig. Also, cleaned up whitespace issues in 8xx Kconfig. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-04-12[POWERPC] Convert 82xx platform to unified platform KconfigKumar Gala
Moved 82xx platform Kconfig over to being sourced by the unified arch/powerpc/platforms/Kconfig. Also, cleaned up whitespace issues in 82xx Kconfig. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-04-12[POWERPC] Convert 83xx platform to unified platform KconfigKumar Gala
Moved 83xx platform Kconfig over to being sourced by the unified arch/powerpc/platforms/Kconfig. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-04-12[POWERPC] Convert 86xx platform to unified platform KconfigKumar Gala
Moved 86xx platform Kconfig over to being sourced by the unified arch/powerpc/platforms/Kconfig. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-03-26[POWERPC] 86xx/85xx: Move 8641 PCI-Express to arch/powerpc/sysdev/fsl_pcie.c.Jon Loeliger
This move sets the stage for the use of generic PCI Express code in 85xx and 86xx parts from FSL. Subsequent patches for 8548 and 8544 will be able to use this shared code. Signed-off-by: Jon Loeliger <jdl@freescale.com> Acked-by: Andy Fleming <afleming@freescale.com> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-03-26Merge branch 'ppc_kconfig' of ↵Paul Mackerras
master.kernel.org:/pub/scm/linux/kernel/git/galak/powerpc into for-2.6.22
2007-03-26[POWERPC] Generic time suspend/resume codeJohannes Berg
This removes the time suspend/restore code that was done through a PMU notifier in arch/platforms/powermac/time.c. Instead, introduce arch/powerpc/sysdev/timer.c which creates a sys device and handles time of day suspend/resume through that. This should probably be replaced by using the generic RTC framework but for now it gets rid of the arcane powermac specific hack. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-22[POWERPC] Created arch/powerpc/platforms/Kconfig for "Platform support"Kumar Gala
Split "Platform support" menu out from arch/powerpc/Kconfig into arch/powerpc/platforms/Kconfig in prep for allowing other sub-arches to be configured via a single "Platform support" menu. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-03-22[POWERPC] Split several platforms into their respective Kconfig fileKumar Gala
Moved pseries, iseries, chrp, prep, maple and pasemi into their respective arch/powerpc/platform/*/Kconfig files out of arch/powerpc/Kconfig Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-03-22[POWERPC] Split cell platforms into their respective Kconfig fileKumar Gala
Cleaning up arch/powerpc/Kconfig platform support. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-03-22[POWERPC] Split powermac platforms into their own Kconfig fileKumar Gala
Cleaning up arch/powerpc/Kconfig platform support. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-03-22[POWERPC] Split 52xx platforms into their own Kconfig fileKumar Gala
Cleaning up arch/powerpc/Kconfig platform support. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-03-09[POWERPC] Allow pSeries to build without CONFIG_PCIStephen Rothwell
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-16[POWERPC] Add PMI driver for cell bladeChristian Krafft
This adds driver code for the PMI device found in future IBM products. PMI stands for "Platform Management Interrupt" and is a way to communicate with the BMC (Baseboard Management Controller). It provides bidirectional communication with a low latency. Signed-off-by: Christian Krafft <krafft@de.ibm.com> Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com> Acked-by: Heiko J Schick <schickhj@de.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-13[POWERPC] spufs: remove need for struct page for SPEsBenjamin Herrenschmidt
This patch removes the need for struct page for SPE local store and registers from spufs. It also makes the locking much more obvious and no longer relying on the truncate logic black magic for protecting against races between unmap_mapping_range() and new pages faulted in. It does so by switching to a nopfn() handler and using the new vm_insert_pfn() to setup the PTEs itself while holding a lock on the SPE. The nice thing is that this patch actually removes a lot more code than it adds :-) Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-11[PATCH] Set CONFIG_ZONE_DMA for arches with GENERIC_ISA_DMAChristoph Lameter
As Andi pointed out: CONFIG_GENERIC_ISA_DMA only disables the ISA DMA channel management. Other functionality may still expect GFP_DMA to provide memory below 16M. So we need to make sure that CONFIG_ZONE_DMA is set independent of CONFIG_GENERIC_ISA_DMA. Undo the modifications to mm/Kconfig where we made ZONE_DMA dependent on GENERIC_ISA_DMA and set theses explicitly in each arches Kconfig. Reviews must occur for each arch in order to determine if ZONE_DMA can be switched off. It can only be switched off if we know that all devices supported by a platform are capable of performing DMA transfers to all of memory (Some arches already support this: uml, avr32, sh sh64, parisc and IA64/Altix). In order to switch ZONE_DMA off conditionally, one would have to establish a scheme by which one can assure that no drivers are enabled that are only capable of doing I/O to a part of memory, or one needs to provide an alternate means of performing an allocation from a specific range of memory (like provided by alloc_pages_range()) and insure that all drivers use that call. In that case the arches alloc_dma_coherent() may need to be modified to call alloc_pages_range() instead of relying on GFP_DMA. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-08Merge master.kernel.org:/pub/scm/linux/kernel/git/paulus/powerpcLinus Torvalds
* master.kernel.org:/pub/scm/linux/kernel/git/paulus/powerpc: (116 commits) [POWERPC] Add export of vgacon_remap_base [POWERPC] Remove bogus comment about page_is_ram [POWERPC] windfarm: don't die on suspend thread signal [POWERPC] Fix comment in kernel/irq.c [POWERPC] ppc: Fix booke watchdog initialization [POWERPC] PPC: Use ARRAY_SIZE macro when appropriate [POWERPC] Use ARRAY_SIZE macro when appropriate [POWERPC] Fix ppc64's writing to struct file_operations [POWERPC] ppc: use syslog macro for the printk log level [POWERPC] ppc: cs4218_tdm remove extra brace [POWERPC] Add mpc52xx/lite5200 PCI support [POWERPC] Only use H_BULK_REMOVE if the firmware supports it [POWERPC] Fixup error handling when emulating a floating point instruction [POWERPC] Enable interrupts if we are doing fp math emulation [POWERPC] Added kprobes support to ppc32 [POWERPC] Make pSeries use the H_BULK_REMOVE hypervisor call [POWERPC] Clear RI bit in MSR before restoring r13 when returning to userspace [POWERPC] Fix performance monitor exception [POWERPC] Compile fixes for arch/powerpc dcr code [POWERPC] Maple: use mmio nvram ...
2007-02-08[POWERPC] Add mpc52xx/lite5200 PCI supportGrant Likely
Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Sylvain Munaut <tnt@246tNt.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07USB: ps3 ohci bus glueGeoff Levand
USB OHCI driver bus glue for the PS3 game console. Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com> Cc: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-02-07USB: ps3 ehci bus glueGeoff Levand
USB EHCI driver bus glue for the PS3 game console. Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com> Cc: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-02-06[POWERPC] Added kprobes support to ppc32Kumar Gala
Added kprobes to ppc32 platforms that have use single_step_exception. This excludes 4xx and anything Book-E since their debug mechanisms for single stepping are completely different. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-02-07Merge branch 'linux-2.6'Paul Mackerras
2007-02-07[POWERPC] Maple: use mmio nvramNathan Lynch
Some systems supported by the maple platform (e.g. JS2x blades running SLOF) are able to use the mmio_nvram backend for reading and writing nvram. This is an improvement over the current situation -- no nvram access from userspace at all. Select MMIO_NVRAM for the maple platform. Initialize the mmio_nvram backend from maple setup code. Signed-off-by: Nathan Lynch <ntl@pobox.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07[POWERPC] pasemi: iommu supportOlof Johansson
I/O TLB support for PA6T-1682M. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07[POWERPC] Celleb: basic supportIshizaki Kou
This patch adds base support for Celleb platform. Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp> Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07[POWERPC] 8xx: generic 8xx code arch/powerpc portVitaly Bordug
Including support for non-coherent cache, some mm-related things + relevant field in Kconfig and Makefiles. Also included rheap.o compilation if 8xx is defined. Non-coherent mapping were refined and renamed according to Cristoph Hellwig. Orphaned functions were cleaned up. [Also removed arch/ppc/kernel/dma-mapping.c, because otherwise compiling with ARCH=ppc for a non DMA-cache-coherent platform ends up with two copies of __dma_alloc_coherent etc. -- paulus.] Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-01-28Merge branch 'merge' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc * 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: [POWERPC] Fix sys_pciconfig_iobase bus matching [POWERPC] PS3: add not complete comment to kconfig [POWERPC] ps3_free_io_irq: Fix inverted error check [POWERPC] PS3: Fix uniprocessor kernel build
2007-01-28[POWERPC] PS3: add not complete comment to kconfigGeoff Levand
Add a comment to the PS3 config option to inform users that the current implementation is not yet complete. Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-01-26Fix Maple PATA IRQ assignment.David Woodhouse
On the Maple board, the AMD8111 IDE is in legacy mode... except that it appears on IRQ 20 instead of IRQ 15. For drivers/ide this was handled by the architecture's "pci_get_legacy_ide_irq()" function, but in libata we just hard-code the numbers 14 and 15. This patch provides asm-powerpc/libata-portmap.h which maps the IRQ as appropriate, having added a pci_dev argument to the ATA_{PRIM,SECOND}ARY_IRQ macros. There's probably a better way to do this -- especially if we observe that the _only_ case in which this seemingly-generic "pci_get_legacy_ide_irq()" function returns anything other than 14 and 15 for primary and secondary respectively is the case of the AMD8111 on the Maple board -- couldn't we handle that with a special case in the pata_amd driver, or perhaps with a PCI quirk for Maple to switch it into native mode during early boot and assign resources properly? Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-01-26[POWERPC] 83xx: Fix Kconfig to only enable FP math emulation for the MPC832xKumar Gala
Updated MATH_EMULATION depends to be on PPC_MPC832x instead of PPC_83xx. Only the the MPC832x has no floating point unit in the core. Updated the other 83xx defconfigs that got math emulation turned on incorrectly. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-01-09[POWERPC] disable PReP and EFIKA during make oldconfigOlaf Hering
New boards should not be enabled per default. Disable EFIKA and PReP per default. Anyone who really needes the new code can enable it during make oldconfig. Signed-off-by: Olaf Hering <olaf@aepfle.de> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-12-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpcLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (36 commits) [POWERPC] Generic BUG for powerpc [PPC] Fix compile failure do to introduction of PHY_POLL [POWERPC] Only export __mtdcr/__mfdcr if CONFIG_PPC_DCR is set [POWERPC] Remove old dcr.S [POWERPC] Fix SPU coredump code for max_fdset removal [POWERPC] Fix irq routing on some 32-bit PowerMacs [POWERPC] ps3: Add vuart support [POWERPC] Support ibm,dynamic-reconfiguration-memory nodes [POWERPC] dont allow pSeries_probe to succeed without initialising MMU [POWERPC] micro optimise pSeries_probe [POWERPC] Add SPURR SPR to sysfs [POWERPC] Add DSCR SPR to sysfs [POWERPC] Fix 440SPe CPU table entry [POWERPC] Add support for FP emulation for the e300c2 core [POWERPC] of_device_register: propagate device_create_file return code [POWERPC] Fix mmap of PCI resource with hack for X [POWERPC] iSeries: head_64.o needs to depend on lparmap.s [POWERPC] cbe_thermal: Fix initialization of sysfs attribute_group [POWERPC] Remove QE header files from lite5200.c [POWERPC] of_platform_make_bus_id(): make `magic' int ...
2006-12-11[POWERPC] Generic BUG for powerpcJeremy Fitzhardinge
This makes powerpc use the generic BUG machinery. The biggest reports the function name, since it is redundant with kallsyms, and not needed in general. There is an overall reduction of code, since module_32/64 duplicated several functions. Unfortunately there's no way to tell gcc that BUG won't return, so the BUG macro includes a goto loop. This will generate a real jmp instruction, which is never used. [akpm@osdl.org: build fix] [paulus@samba.org: remove infinite loop in BUG_ON] Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Andi Kleen <ak@muc.de> Cc: Hugh Dickens <hugh@veritas.com> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-12-11Merge branch 'for_paulus' of ↵Paul Mackerras
master.kernel.org:/pub/scm/linux/kernel/git/galak/powerpc
2006-12-08[PATCH] LOG2: Provide ilog2() fallbacks for powerpcDavid Howells
Provide ilog2() fallbacks for powerpc for 32-bit numbers and 64-bit numbers on ppc64. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08[PATCH] LOG2: Implement a general integer log2 facility in the kernelDavid Howells
This facility provides three entry points: ilog2() Log base 2 of unsigned long ilog2_u32() Log base 2 of u32 ilog2_u64() Log base 2 of u64 These facilities can either be used inside functions on dynamic data: int do_something(long q) { ...; y = ilog2(x) ...; } Or can be used to statically initialise global variables with constant values: unsigned n = ilog2(27); When performing static initialisation, the compiler will report "error: initializer element is not constant" if asked to take a log of zero or of something not reducible to a constant. They treat negative numbers as unsigned. When not dealing with a constant, they fall back to using fls() which permits them to use arch-specific log calculation instructions - such as BSR on x86/x86_64 or SCAN on FRV - if available. [akpm@osdl.org: MMC fix] Signed-off-by: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: David Howells <dhowells@redhat.com> Cc: Wojtek Kaniewski <wojtekka@toxygen.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>