From: Dmitry Adamushko Date: Mon, 11 May 2009 21:48:27 +0000 (+0200) Subject: x86: microcode: use smp_call_function_single instead of set_cpus_allowed, cleanup... X-Git-Tag: v2.6.31-rc1~415^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=871b72dd1e12afc3f024479531d25a9339d2e3f9;p=pandora-kernel.git x86: microcode: use smp_call_function_single instead of set_cpus_allowed, cleanup of synchronization logic * Solve issues described in 6f66cbc63081fd70e3191b4dbb796746780e5ae1 in a way that doesn't resort to set_cpus_allowed(); * in fact, only collect_cpu_info and apply_microcode callbacks must run on a target cpu, others will do just fine on any other. smp_call_function_single() (as suggested by Ingo) is used to run these callbacks on a target cpu. * cleanup of synchronization logic of the 'microcode_core' part The generic 'microcode_core' part guarantees that only a single cpu (be it a full-fledged cpu, one of the cores or HT) is being updated at any particular moment of time. In general, there is no need for any additional sync. mechanism in arch-specific parts (the patch removes existing spinlocks). See also the "Synchronization" section in microcode_core.c. * return -EINVAL instead of -1 (which is translated into -EPERM) in microcode_write(), reload_cpu() and mc_sysdev_add(). Other suggestions for an error code? * use 'enum ucode_state' as return value of request_microcode_{fw, user} to gain more flexibility by distinguishing between real error cases and situations when an appropriate ucode was not found (which is not an error per-se). * some minor cleanups Thanks a lot to Hugh Dickins for review/suggestions/testing! Reference: http://marc.info/?l=linux-kernel&m=124025889012541&w=2 [ Impact: refactor and clean up microcode driver locking code ] Signed-off-by: Dmitry Adamushko Acked-by: Hugh Dickins Cc: Andrew Morton Cc: Rusty Russell Cc: Andreas Herrmann Cc: Peter Oruba Cc: Arjan van de Ven LKML-Reference: <1242078507.5560.9.camel@earth> [ did some more cleanups ] Signed-off-by: Ingo Molnar arch/x86/include/asm/microcode.h | 25 ++ arch/x86/kernel/microcode_amd.c | 58 ++---- arch/x86/kernel/microcode_core.c | 326 +++++++++++++++++++++----------------- arch/x86/kernel/microcode_intel.c | 92 +++------- 4 files changed, 261 insertions(+), 240 deletions(-) (~20 new comment lines) --- Reading git-diff-tree failed