BMC/Intel-BMC/linux.git/arch/sparc/kernel/sun4d_smp.c, branch dev

sparc: Replace __get_cpu_var uses

2014-08-26T17:45:55+00:00

__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) Cc: sparclinux@vger.kernel.org Acked-by: David S. Miller Signed-off-by: Christoph Lameter Signed-off-by: Tejun Heo

sparc: delete cpuinit/CPUINIT usage from all users

2013-07-14T23:36:52+00:00

The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. Note that some harmless section mismatch warnings may result, since notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c) are flagged as __cpuinit -- so if we remove the __cpuinit from arch specific callers, we will also get section mismatch warnings. As an intermediate step, we intend to turn the linux/init.h cpuinit content into no-ops as early as possible, since that will get rid of these warnings. In any case, they are temporary and harmless. This removes all the arch/sparc uses of the __cpuinit macros from C files and removes __CPUINIT from assembly files. Note that even though arch/sparc/kernel/trampoline_64.S has instances of ".previous" in it, they are all paired off against explicit ".section" directives, and not implicitly paired with __CPUINIT (unlike mips and arm were). [1] https://lkml.org/lkml/2013/5/20/589 Cc: "David S. Miller" Cc: sparclinux@vger.kernel.org Signed-off-by: Paul Gortmaker

sparc32: refactor smp boot

2013-02-20T21:36:50+00:00

Introduce a common smp_callin() function to call from trampoline_32.S. Add platform specific functions to handle the platform details. This is in preparation for a patch that will unify the smp boot stuff for all architectures. sparc32 was significantly different to warrant this patch in preparation. Signed-off-by: Sam Ravnborg Acked-by: David S. Miller Cc: "Srivatsa S. Bhat" Acked-by: Srivatsa S. Bhat Signed-off-by: David S. Miller

Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-05-22T02:43:57+00:00

Pull smp hotplug cleanups from Thomas Gleixner: "This series is merily a cleanup of code copied around in arch/* and not changing any of the real cpu hotplug horrors yet. I wish I'd had something more substantial for 3.5, but I underestimated the lurking horror..." Fix up trivial conflicts in arch/{arm,sparc,x86}/Kconfig and arch/sparc/include/asm/thread_info_32.h * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits) um: Remove leftover declaration of alloc_task_struct_node() task_allocator: Use config switches instead of magic defines sparc: Use common threadinfo allocator score: Use common threadinfo allocator sh-use-common-threadinfo-allocator mn10300: Use common threadinfo allocator powerpc: Use common threadinfo allocator mips: Use common threadinfo allocator hexagon: Use common threadinfo allocator m32r: Use common threadinfo allocator frv: Use common threadinfo allocator cris: Use common threadinfo allocator x86: Use common threadinfo allocator c6x: Use common threadinfo allocator fork: Provide kmemcache based thread_info allocator tile: Use common threadinfo allocator fork: Provide weak arch_release_[task_struct|thread_info] functions fork: Move thread info gfp flags to header fork: Remove the weak insanity sh: Remove cpu_idle_wait() ...

sparc32: move smp ipi to method ops

2012-05-14T21:05:07+00:00

I ended up renaming set_cpu_int to send_ipi to be consistent all way around. send_ipi was moved to the *_smp.c files so we could call the relevant method direct, without any _ops indirection. Signed-off-by: Sam Ravnborg Signed-off-by: David S. Miller

sparc32: Implement hard_smp_processor_id() via instruction patching.

2012-05-14T20:31:38+00:00

This is the last non-trivial user of btfixup. Like sparc64, use a special patch section to resolve the various implementations of how to read the current CPU's ID when we don't have current_thread_info()->cpu necessarily available. Signed-off-by: David S. Miller Tested-by: Sam Ravnborg

sparc32: Move cache and TLB flushes over to method ops.

2012-05-14T03:49:31+00:00

This eliminated most of the remaining users of btfixup. There are some complications because of the special cases we have for sun4d, leon, and some flavors of viking. It was found that there are no cases where a flush_page_for_dma method was not hooked up to something, so the "noflush" iommu methods were removed. Add some documentation to the viking_sun4d_smp_ops to describe exactly the hardware bug which causes us to need special TLB flushing on sun4d. Signed-off-by: David S. Miller

sparc: Use generic idle thread allocation

2012-04-26T10:06:12+00:00

Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Rusty Russell Cc: Paul E. McKenney Cc: Srivatsa S. Bhat Tested-by: David S. Miller Link: http://lkml.kernel.org/r/20120420124558.055198736@linutronix.de

sparc32: generic clockevent support

2012-04-15T17:28:50+00:00

The kernel uses l14 timers as clockevents. l10 timer is used as clocksource if platform master_l10_counter isn't constantly zero. The clocksource is continuous, so it's possible to use high resolution timers. l10 timer is also used as clockevent on UP configurations. This realization is for sun4m, sun4d, sun4c, microsparc-IIep and LEON platforms. The appropriate LEON changes was made by Konrad Eisele. In case of sun4m's oneshot mode, profile irq is zeroed in smp4m_percpu_timer_interrupt(). It is maybe needless (double, triple etc overflow does nothing). sun4d is able to have oneshot mode too, but I haven't any way to test it. So code of its percpu timer handler is made as much equal to the current code as possible. The patch is tested on sun4m box in SMP mode by me, and tested by Konrad on leon in up mode (leon smp is broken atm - due to other reasons). Signed-off-by: Tkhai Kirill Tested-by: Konrad Eisele [leon up] [sam: revised patch to provide generic support for leon] Signed-off-by: Sam Ravnborg Signed-off-by: David S. Miller

sparc32: fix fallout from system.h removal

2012-03-31T01:16:58+00:00

Build failures for the typical configs I use Signed-off-by: Sam Ravnborg Signed-off-by: David S. Miller