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* tile: Replace __get_cpu_var usesChristoph Lameter2014-08-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Acked-by: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* tile: support CONFIG_PREEMPTChris Metcalf2013-08-13
| | | | | | | | | | This change adds support for CONFIG_PREEMPT (full kernel preemption). In addition to the core support, this change includes a number of places where we fix up uses of smp_processor_id() and per-cpu variables. I also eliminate the PAGE_HOME_HERE and PAGE_HOME_UNKNOWN values for page homing, as it turns out they weren't being used. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
* tile: comment assumption about __insn_mtspr for <asm/irqflags.h>Chris Metcalf2013-04-09
| | | | | | | | | | | | The arch_local_irq_save(), etc., routines are required to function as compiler barriers. They do, but it's subtle and requires knowing that the gcc builtin __insn_mtspr() is marked as a memory clobber. Provide a comment explaining the assumption. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> [ This came about from me wondering about the synchronization rules of __insn_mtspr() - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tile: avoid defining INT_MASK macro in <arch/interrupts.h>Chris Metcalf2013-02-04
| | | | | | | | | | | | Unfortunately, this name conflicts with a different use of the name in various places through the tree, so don't provide it for the kernel. We preserve it for userspace to avoid breaking any userspace code that relies on this definition. This fixes a number of compile errors for various drivers that are enabled by "allyesconfig". Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
* arch/tile: use interrupt critical sections lessChris Metcalf2012-05-25
| | | | | | | | | | | | | | | | | | | | | | In general we want to avoid ever touching memory while within an interrupt critical section, since the page fault path goes through a different path from the hypervisor when in an interrupt critical section, and we carefully decided with tilegx that we didn't need to support this path in the kernel. (On tilepro we did implement that path as part of supporting atomic instructions in software.) In practice we always need to touch the kernel stack, since that's where we store the interrupt state before releasing the critical section, but this change cleans up a few things. The IRQ_ENABLE macro is split up so that when we want to enable interrupts in a deferred way (e.g. for cpu_idle or for interrupt return) we can read the per-cpu enable mask before entering the critical section. The cache-migration code is changed to use interrupt masking instead of interrupt critical sections. And, the interrupt-entry code is changed so that we defer loading "tp" from per-cpu data until after we have released the interrupt critical section. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
* arch/tile: support newer binutils assembler shift semanticsChris Metcalf2011-03-17
| | | | | | | | This change supports building the kernel with newer binutils where a shift of greater than the word size is no longer interpreted silently as modulo the word size, but instead generates a warning. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tileLinus Torvalds2010-10-26
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: arch/tile: convert a BUG_ON to BUILD_BUG_ON arch/tile: make ptrace() work properly for TILE-Gx COMPAT mode arch/tile: support new info op generated by compiler arch/tile: minor whitespace/naming changes for string support files arch/tile: enable single-step support for TILE-Gx arch/tile: parameterize system PLs to support KVM port arch/tile: add Tilera's <arch/sim.h> header as an open-source header arch/tile: Bomb C99 comments to C89 comments in tile's <arch/sim_def.h> arch/tile: prevent corrupt top frame from causing backtracer runaway arch/tile: various top-level Makefile cleanups arch/tile: change lower bound on syscall error return to -4095 arch/tile: properly export __mb_incoherent for modules arch/tile: provide a definition of MAP_STACK kmemleak: add TILE to the list of supported architectures. char: hvc: check for error case arch/tile: Add a warning if we try to allocate too much vmalloc memory. arch/tile: update some comments to clarify register usage. arch/tile: use better "punctuation" for VMSPLIT_3_5G and friends arch/tile: Use <asm-generic/syscalls.h> tile: replace some BUG_ON checks with BUILD_BUG_ON checks
| * arch/tile: parameterize system PLs to support KVM portChris Metcalf2010-10-15
| | | | | | | | | | | | | | | | | | While not a port to KVM (yet), this change modifies the kernel to be able to build either at PL1 or at PL2 with a suitable config switch. Pushing up this change avoids handling branch merge issues going forward with the KVM work. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
* | Fix IRQ flag handling namingDavid Howells2010-10-07
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix the IRQ flag handling naming. In linux/irqflags.h under one configuration, it maps: local_irq_enable() -> raw_local_irq_enable() local_irq_disable() -> raw_local_irq_disable() local_irq_save() -> raw_local_irq_save() ... and under the other configuration, it maps: raw_local_irq_enable() -> local_irq_enable() raw_local_irq_disable() -> local_irq_disable() raw_local_irq_save() -> local_irq_save() ... This is quite confusing. There should be one set of names expected of the arch, and this should be wrapped to give another set of names that are expected by users of this facility. Change this to have the arch provide: flags = arch_local_save_flags() flags = arch_local_irq_save() arch_local_irq_restore(flags) arch_local_irq_disable() arch_local_irq_enable() arch_irqs_disabled_flags(flags) arch_irqs_disabled() arch_safe_halt() Then linux/irqflags.h wraps these to provide: raw_local_save_flags(flags) raw_local_irq_save(flags) raw_local_irq_restore(flags) raw_local_irq_disable() raw_local_irq_enable() raw_irqs_disabled_flags(flags) raw_irqs_disabled() raw_safe_halt() with type checking on the flags 'arguments', and then wraps those to provide: local_save_flags(flags) local_irq_save(flags) local_irq_restore(flags) local_irq_disable() local_irq_enable() irqs_disabled_flags(flags) irqs_disabled() safe_halt() with tracing included if enabled. The arch functions can now all be inline functions rather than some of them having to be macros. Signed-off-by: David Howells <dhowells@redhat.com> [X86, FRV, MN10300] Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> [Tile] Signed-off-by: Michal Simek <monstr@monstr.eu> [Microblaze] Tested-by: Catalin Marinas <catalin.marinas@arm.com> [ARM] Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> [AVR] Acked-by: Tony Luck <tony.luck@intel.com> [IA-64] Acked-by: Hirokazu Takata <takata@linux-m32r.org> [M32R] Acked-by: Greg Ungerer <gerg@uclinux.org> [M68K/M68KNOMMU] Acked-by: Ralf Baechle <ralf@linux-mips.org> [MIPS] Acked-by: Kyle McMartin <kyle@mcmartin.ca> [PA-RISC] Acked-by: Paul Mackerras <paulus@samba.org> [PowerPC] Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [S390] Acked-by: Chen Liqin <liqin.chen@sunplusct.com> [Score] Acked-by: Matt Fleming <matt@console-pimps.org> [SH] Acked-by: David S. Miller <davem@davemloft.net> [Sparc] Acked-by: Chris Zankel <chris@zankel.net> [Xtensa] Reviewed-by: Richard Henderson <rth@twiddle.net> [Alpha] Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp> [H8300] Cc: starvik@axis.com [CRIS] Cc: jesper.nilsson@axis.com [CRIS] Cc: linux-cris-kernel@axis.com
* arch/tile: catch up on various minor cleanups.Chris Metcalf2010-07-06
| | | | | | | | | | | | | None of these changes fix any actual bugs, but are just various cleanups that fell out along the way. In particular, some unused #defines and includes are removed, PREFETCH_STRIDE is added (the default is right for our shipping chips, but wrong for our next generation), our tile-specific prefetching code is removed so the (identical) generic prefetching code can be used instead, a comment is fixed to be proper GPL and not just a "paste GPL here" token, a "//" comment is converted to "/* */", etc. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
* arch/tile: core support for Tilera 32-bit chips.Chris Metcalf2010-06-04
This change is the core kernel support for TILEPro and TILE64 chips. No driver support (except the console driver) is included yet. This includes the relevant Linux headers in asm/; the low-level low-level "Tile architecture" headers in arch/, which are shared with the hypervisor, etc., and are build-system agnostic; and the relevant hypervisor headers in hv/. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Reviewed-by: Paul Mundt <lethal@linux-sh.org>