ia64: remove support for the SGI SN2 platform

2019-08-16T18:33:57Z

The SGI SN2 (early Altix) is a very non-standard IA64 platform that was at the very high end of even IA64 hardware, and has been discontinued a long time ago. Remove it because there no upstream users left, and it has magic hooks all over the kernel. Signed-off-by: Christoph Hellwig Link: https://lkml.kernel.org/r/20190813072514.23299-16-hch@lst.de Signed-off-by: Tony Luck

ia64: Replace __get_cpu_var uses

2014-08-26T17:45:52Z

__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: Tony Luck Cc: Fenghua Yu Cc: linux-ia64@vger.kernel.org Signed-off-by: Christoph Lameter Signed-off-by: Tejun Heo

[IA64] Move include/asm-ia64 to arch/ia64/include/asm

2008-08-01T17:21:21Z

After moving the the include files there were a few clean-ups: 1) Some files used #include , changed to 2) Some comments alerted maintainers to look at various header files to make matching updates if certain code were to be changed. Updated these comments to use the new include paths. 3) Some header files mentioned their own names in initial comments. Just deleted these self references. Signed-off-by: Tony Luck

linux-dev/arch/ia64/include/asm/sn/arch.h, branch master

ia64: remove support for the SGI SN2 platform

ia64: Replace __get_cpu_var uses

[IA64] Move include/asm-ia64 to arch/ia64/include/asm