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2008-09-15powerpc: Make the irq reverse mapping radix tree locklessSebastien Dugue
The radix trees used by interrupt controllers for their irq reverse mapping (currently only the XICS found on pSeries) have a complex locking scheme dating back to before the advent of the lockless radix tree. This takes advantage of the lockless radix tree and of the fact that the items of the tree are pointers to a static array (irq_map) elements which can never go under us to simplify the locking. Concurrency between readers and writers is handled by the intrinsic properties of the lockless radix tree. Concurrency between writers is handled with a global mutex. Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-09-15powerpc: Separate the irq radix tree insertion and lookupSebastien Dugue
irq_radix_revmap() currently serves 2 purposes, irq mapping lookup and insertion which happen in interrupt and process context respectively. Separate the function into its 2 components, one for lookup only and one for insertion only. Fix the only user of the revmap tree (XICS) to use the new functions. Also, move the insertion into the radix tree of those irqs that were requested before it was initialized at said tree initialization. Mutual exclusion between the tree initialization and readers/writers is handled via a state variable (revmap_trees_allocated) set to 1 when the tree has been initialized and set to 2 after the already requested irqs have been inserted in the tree by the init path. This state is checked before any reader or writer access just like we used to check for tree.gfp_mask != 0 before. Finally, now that we're not any longer inserting nodes into the radix-tree in interrupt context, turn the GFP_ATOMIC allocations into GFP_KERNEL ones. Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-08-04powerpc: Remove use of CONFIG_PPC_MERGEKumar Gala
Now that arch/ppc is gone and CONFIG_PPC_MERGE is always set, remove the dead code associated with !CONFIG_PPC_MERGE from arch/powerpc and include/asm-powerpc. Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-15Merge commit '85082fd7cbe3173198aac0eb5e85ab1edcc6352c' into test-buildBenjamin Herrenschmidt
Manual fixup of: arch/powerpc/Kconfig
2008-06-30Merge branch 'linux-2.6'Paul Mackerras
2008-06-23Merge branch 'linus' into tracing/ftraceIngo Molnar
2008-06-16[POWERPC] Fix return value check logic in debugfs virq_mapping setupEmil Medve
debugfs_create_file() returns a non-NULL (non-zero) value in case of success, not a NULL value. This fixes this non-critical boot-time debugging error message: [ 1.316386] calling irq_debugfs_init+0x0/0x50 [ 1.316399] initcall irq_debugfs_init+0x0/0x50 returned -12 after 0 msecs [ 1.316411] initcall irq_debugfs_init+0x0/0x50 returned with error code -12 Signed-off-by: Emil Medve <Emilian.Medve@Freescale.com> Acked-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-09powerpc: Fix irq_alloc_host() reference counting and callersMichael Ellerman
When I changed irq_alloc_host() to take an of_node (52964f87c64e6c6ea671b5bf3030fb1494090a48: "Add an optional device_node pointer to the irq_host"), I botched the reference counting semantics. Stephen pointed out that it's irq_alloc_host()'s business if it needs to take an additional reference to the device_node, the caller shouldn't need to care. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-02[POWERPC] Move to runtime allocated exception stacksKumar Gala
For the additonal exception levels (critical, debug, machine check) on 40x/book-e we were using "static" allocations of the stack in the associated head.S. Move to a runtime allocation to make the code a bit easier to read as we mimic how we handle IRQ stacks. Its also a bit easier to setup the stack with a "dummy" thread_info in C code. Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Acked-by: Paul Mackerras <paulus@samba.org>
2008-05-23ftrace: support for PowerPCSteven Rostedt
This patch adds full support for ftrace for PowerPC (both 64 and 32 bit). This includes dynamic tracing and function filtering. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-29[POWERPC] Add IRQSTACKS support on ppc32Kumar Gala
This makes it possible to use separate stacks for hard and soft IRQs on 32-bit powerpc as well as on 64-bit. The code for 32-bit is just the 32-bit analog of the 64-bit code. * Added allocation and initialization of the irq stacks. We limit the stacks to be in lowmem for ppc32. * Implemented ppc32 versions of call_do_softirq() and call_handle_irq() to switch the stack pointers * Reworked how we do stack overflow detection. We now keep around the limit of the stack in the thread_struct and compare against the limit to see if we've overflowed. We can now use this on ppc64 if desired. [ paulus@samba.org: Fixed bug on 6xx where we need to reload r9 with the thread_info pointer. ] Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-18[POWERPC] irqtrace support for 64-bit powerpcBenjamin Herrenschmidt
This adds the low level irq tracing hooks to the powerpc architecture needed to enable full lockdep functionality. This is partly based on Johannes Berg's initial version. I removed the asm trampoline that isn't needed (thus improving performance) and modified all sorts of bits and pieces, reworking most of the assembly, etc... Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17[POWERPC] Fixup softirq preempt countBenjamin Herrenschmidt
This fixes the handling of the preempt count when switching interrupt stacks so that HW interrupt properly get the softirq mask copied over from the previous stack. It also initializes the softirq stack preempt_count to 0 instead of SOFTIRQ_OFFSET, like x86, as __do_softirq() does the increment, and we hit some lockdep checks if we have it twice. That means we do run for a little while off the softirq stack with the preempt-count set to 0, which could be deadly if we try to take a softirq at that point, however we do so with interrupts disabled, so I think we are ok. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-03[POWERPC] Fix iSeries hard irq enabling regressionBenjamin Herrenschmidt
A subtle bug sneaked into iSeries recently. On this platform, we must not normally clear MSR:EE (the hardware external interrupt enable) except for short periods of time. Taking an interrupt while soft-disabled doesn't cause us to clear it for example. The iSeries kernel expects to mostly run with MSR:EE enabled at all times except in a few exception entry/exit code paths. Thus local_irq_enable() doesn't check if it needs to hard-enable as it expects this to be unnecessary on iSeries. However, hard_irq_disable() _does_ cause MSR:EE to be cleared, including on iSeries. A call to it was recently added to the context switch code, thus causing interrupts to become disabled for a long periods of time, causing the iSeries watchdog to kick in under some circumstances and other nasty things. This patch fixes it by making local_irq_enable() properly re-enable MSR:EE on iSeries. It basically removes a return statement here to make iSeries use the same code path as everybody else. That does mean that we might occasionally get spurious decrementer interrupts but I don't think that matters. Another option would have been to make hard_irq_disable() a nop on iSeries but I didn't like it much, in case we have good reasons to hard-disable. Part of the patch is fixes to make sure the hard_enabled PACA field is properly set on iSeries as it used not to be before, since it was mostly unused. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-19Spelling fix: explicitlyJean Delvare
From: Jean Delvare <khali@linux-fr.org> Signed-off-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Adrian Bunk <bunk@kernel.org>
2007-10-11Merge branch 'master' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc * 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (408 commits) [POWERPC] Add memchr() to the bootwrapper [POWERPC] Implement logging of unhandled signals [POWERPC] Add legacy serial support for OPB with flattened device tree [POWERPC] Use 1TB segments [POWERPC] XilinxFB: Allow fixed framebuffer base address [POWERPC] XilinxFB: Add support for custom screen resolution [POWERPC] XilinxFB: Use pdata to pass around framebuffer parameters [POWERPC] PCI: Add 64-bit physical address support to setup_indirect_pci [POWERPC] 4xx: Kilauea defconfig file [POWERPC] 4xx: Kilauea DTS [POWERPC] 4xx: Add AMCC Kilauea eval board support to platforms/40x [POWERPC] 4xx: Add AMCC 405EX support to cputable.c [POWERPC] Adjust TASK_SIZE on ppc32 systems to 3GB that are capable [POWERPC] Use PAGE_OFFSET to tell if an address is user/kernel in SW TLB handlers [POWERPC] 85xx: Enable FP emulation in MPC8560 ADS defconfig [POWERPC] 85xx: Killed <asm/mpc85xx.h> [POWERPC] 85xx: Add cpm nodes for 8541/8555 CDS [POWERPC] 85xx: Convert mpc8560ads to the new CPM binding. [POWERPC] mpc8272ads: Remove muram from the CPM reg property. [POWERPC] Make clockevents work on PPC601 processors ... Fixed up conflict in Documentation/powerpc/booting-without-of.txt manually.
2007-10-10[SOFTIRQ]: Remove do_softirq() symbol export.Robert Olsson
As noted by Christoph Hellwig, pktgen was the only user so it can now be removed. [ Add missing cases caught by Adrian Bunk. -DaveM ] Signed-off-by: Robert Olsson <robert.olsson@its.uu.se> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-03[POWERPC] Limit range of __init_ref_ok somewhatStephen Rothwell
This patch introduces zalloc_maybe_bootmem and uses it so that we don't have to mark a whole (largish) routine as __init_ref_ok. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-09-14[POWERPC] Export virq mapping via debugfsMichael Ellerman
This adds a debugfs file "powerpc/virq_mapping", which shows the virtual to real mapping of irq numbers. Enable it with CONFIG_VIRQ_DEBUG. Signed-off-by: Zhang Wei <wei.zhang@freescale.com> Signed-off-by: Chen Gong <G.Chen@freescale.com> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-09-14[POWERPC] Initialise hwirq for legacy irqsMichael Ellerman
Although no one uses the hwirq value for legacy irqs at the moment, we should really setup the correct value in the irq_map. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-09-14[POWERPC] Provide a default irq_host match, which matches on an exact of_nodeMichael Ellerman
The most common match semantic is an exact match based on the device node. So provide a default implementation that does this, and hook it up if no match routine is specified. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-09-14[POWERPC] Invert null match behaviour for irq_hostsMichael Ellerman
Currently if you don't specify a match callback for your irq_host it's assumed you match everything. This is a kind of opt-out approach, and turns out to be the exception rather than the rule. So change the semantics to be opt-in, ie. you don't match anything unless you provide a match callback. This in itself isn't very useful, but will allow us to provide a default match implementation in a subsequent patch. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-09-14[POWERPC] Add an optional device_node pointer to the irq_hostMichael Ellerman
The majority of irq_host implementations (3 out of 4) are associated with a device_node, and need to stash it somewhere. Rather than having it somewhere different for each host, add an optional device_node pointer to the irq_host structure. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-08-22[POWERPC] Whitespace cleanup in arch/powerpcScott Wood
Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-07-26[POWREPC] Fixup a number of modpost warnings on ppc32Kumar Gala
Fixed the following warnings: WARNING: vmlinux.o(.text+0x2934): Section mismatch: reference to .init.text:__alloc_bootmem (between 'irq_alloc_host' and 'irq_set_default_host') WARNING: vmlinux.o(.text+0xb2aa): Section mismatch: reference to .init.data:boot_command_line (between 'register_early_udbg_console' and 'udbg_printf') WARNING: vmlinux.o(.text+0xb2b2): Section mismatch: reference to .init.data:boot_command_line (between 'register_early_udbg_console' and 'udbg_printf') WARNING: vmlinux.o(.text+0xe354): Section mismatch: reference to .init.text:__alloc_bootmem (between 'pcibios_alloc_controller' and 'pci_domain_nr') WARNING: vmlinux.o(.text+0x12768): Section mismatch: reference to .init.text:update_bridge_resource (between 'quirk_fsl_pcie_transparent' and 'indirect_read_config') WARNING: vmlinux.o(.text+0x127a8): Section mismatch: reference to .init.text:update_bridge_resource (between 'quirk_fsl_pcie_transparent' and 'indirect_read_config') WARNING: vmlinux.o(.text+0x17566c): Section mismatch: reference to .init.text:pcibios_fixup_bus (between 'pci_scan_child_bus' and 'pci_scan_bus_parented') Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-07-10[POWERPC] Check for NULL ppc_md.init_IRQ() before callingSonny Rao
Check to make sure ppc_md.init_IRQ has been set before calling it. Signed-off-by: Sonny Rao <sonny@burdell.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-25[POWERPC] Add irq_create_direct_mapping()Michael Ellerman
This patch adds irq_create_direct_mapping(). This routine is an alternative to irq_create_mapping(), for irq controllers that can use linux virq numbers directly as hardware numbers. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-25[POWERPC] Split virq setup logic out into irq_setup_virq()Michael Ellerman
A future patch will need the logic at the end of irq_create_mapping() which setups a virq and installs it in the irq_map. So split it out into a new function irq_setup_virq(). Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-25[POWERPC] Uninline and export virq_to_hw()Olof Johansson
Uninline virq_to_hw and export it so modules can use it. The alternative would be to export the irq_map array instead, but it's an infrequently called function, and keeping the array unexported seems considerably cleaner. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-14[POWERPC] Remove the dregs of APUS support from arch/powerpcDavid Gibson
APUS (the Amiga Power-Up System) is not supported under arch/powerpc and it's unlikely it ever will be. Therefore, this patch removes the fragments of APUS support code from arch/powerpc which have been copied from arch/ppc. A few APUS references are left in asm-powerpc in .h files which are still used from arch/ppc. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-02[POWERPC] Compare irq numbers with NO_IRQ not IRQ_NONEMichael Ellerman
There is a thinko in the irq code, it uses IRQ_NONE to indicate no irq, whereas it should be using NO_IRQ. IRQ_NONE is returned from irq handlers to say "not handled". As it happens they currently have the same value (0), so this is just for future proof-ness. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-11powerpc: fixup hard_irq_disable semanticsBenjamin Herrenschmidt
This patch renames the raw hard_irq_{enable,disable} into __hard_irq_{enable,disable} and introduces a higher level hard_irq_disable() function that can be used by any code to enforce that IRQs are fully disabled, not only lazy disabled. The difference with the __ versions is that it will update some per-processor fields so that the kernel keeps track and properly re-enables them in the next local_irq_disable(); This prepares powerpc for my next patch that introduces hard_irq_disable() generically. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08[POWERPC] Rip out the existing powerpc msi stubsMichael Ellerman
Rip out the existing powerpc msi stubs. These were the start of an implementation based on ppc_md calls, but were never used in mainline. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-02[POWERPC] PS3: Fix system slowdownTakao Shinohara
The PS3 HV will deliver soft-disabled interrupts at the next HV call or interrupt. Add an HV call to local_irq_restore() to force the timely delivery of any pending interrupts. This fixes the system slowdown bug reported here http://bugzilla.kernel.org/show_bug.cgi?id=8260 Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-04-30[POWERPC] Spinlock initializer cleanupThomas Gleixner
Use DEFINE_SPINLOCK instead of initializing spinlocks to SPIN_LOCK_UNLOCKED, since DEFINE_SPINLOCK is better for lockdep. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-05[PATCH] msi: sanely support hardware level msi disablingEric W. Biederman
In some cases when we are not using msi we need a way to ensure that the hardware does not have an msi capability enabled. Currently the code has been calling disable_msi_mode to try and achieve that. However disable_msi_mode has several other side effects and is only available when msi support is compiled in so it isn't really appropriate. Instead this patch implements pci_msi_off which disables all msi and msix capabilities unconditionally with no additional side effects. pci_disable_device was redundantly clearing the bus master enable flag and clearing the msi enable bit. A device that is not allowed to perform bus mastering operations cannot generate intx or msi interrupt messages as those are essentially a special case of dma, and require bus mastering. So the call in pci_disable_device to disable msi capabilities was redundant. quirk_pcie_pxh also called disable_msi_mode and is updated to use pci_msi_off. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-08[POWERPC] Fix comment in kernel/irq.cJohannes Berg
kernel/irq.c contains a comment that speaks of -1 and -2 as interrupt numbers, but this is actually dependent on configuration options now. Replace by NO_IRQ and NO_IRQ_ENABLED. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-01-24[POWERPC] Add IRQ remapping hookIshizaki Kou
This patch adds irq remapping hook. On interrupt mechanism on Beat, when an irq outlet which has an id which is formerly used is created, remapping the irq is required. Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-12-04[POWERPC] Make soft_enabled irqs preempt safeHugh Dickins
Rewrite local_get_flags and local_irq_disable to use r13 explicitly, to avoid the risk that gcc will split get_paca()->soft_enabled into a sequence unsafe against preemption. Similar care in local_irq_restore. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-12-04[POWERPC] iSeries: fix irq.c for combined buildStephen Rothwell
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-10-25[POWERPC] Make irq_dispose_mapping(NO_IRQ) a nopMichael Ellerman
It makes for a friendlier API if irq_dispose_mapping(NO_IRQ) is a nop, rather than triggering a WARN_ON. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-10-16[POWERPC] Lazy interrupt disabling for 64-bit machinesPaul Mackerras
This implements a lazy strategy for disabling interrupts. This means that local_irq_disable() et al. just clear the 'interrupts are enabled' flag in the paca. If an interrupt comes along, the interrupt entry code notices that interrupts are supposed to be disabled, and clears the EE bit in SRR1, clears the 'interrupts are hard-enabled' flag in the paca, and returns. This means that interrupts only actually get disabled in the processor when an interrupt comes along. When interrupts are enabled by local_irq_enable() et al., the code sets the interrupts-enabled flag in the paca, and then checks whether interrupts got hard-disabled. If so, it also sets the EE bit in the MSR to hard-enable the interrupts. This has the potential to improve performance, and also makes it easier to make a kernel that can boot on iSeries and on other 64-bit machines, since this lazy-disable strategy is very similar to the soft-disable strategy that iSeries already uses. This version renames paca->proc_enabled to paca->soft_enabled, and changes a couple of soft-disables in the kexec code to hard-disables, which should fix the crash that Michael Ellerman saw. This doesn't yet use a reserved CR field for the soft_enabled and hard_enabled flags. This applies on top of Stephen Rothwell's patches to make it possible to build a combined iSeries/other kernel. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-10-09[PATCH] extern doesn't make sense on a definition of function...Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-07[POWERPC] Fix up after irq changesOlaf Hering
Remove struct pt_regs * from all handlers. Also remove the regs argument from get_irq() functions. Compile tested with arch/powerpc/config/* and arch/ppc/configs/prep_defconfig Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-10-05IRQ: Maintain regs pointer globally rather than passing to IRQ handlersDavid Howells
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-09-26[POWERPC] Fix loop logic in irq_alloc_virt()Michael Ellerman
There's a bug in irq_alloc_virt() if it's asked for more than 1 interrupt, if it can't find a slot it might look past the end of the irq_map. To be clear: the bug is that the continue affects the inner for loop, not the outer one, so i becomes j + 1 and then we continue the inner loop without checking if i is still <= limit. This fixes it. No one in the kernel actually calls this with count > 1, so it's not critical. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-08-31Merge branch 'merge'Paul Mackerras
2006-08-30[POWERPC] Fix performance regression in IRQ radix tree lockingBenjamin Herrenschmidt
When reworking the powerpc irq code, I figured out that we were using the radix tree in a racy way. As a temporary fix, I put a spinlock in there. However, this can have a significant impact on performances. This patch reworks that to use a smarter technique based on the fact that what we need is in fact a rwlock with extremely rare writers (thus optimized for the read path). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-08-25Merge branch 'merge'Paul Mackerras
2006-08-17[POWERPC] Fix irq radix tree remapping typoBenjamin Herrenschmidt
The code for using the radix tree for reverse mapping of interrupts has a typo that causes it to create incorrect mappings if the software and hardware numbers happen to be different. This would, among others, cause the IDE interrupt to fail on js20's. This fixes it. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>