From 41195d236e84458bebd4fdc218610a92231ac791 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 18 Jan 2013 15:12:23 +0530 Subject: ARC: SMP support ARC common code to enable a SMP system + ISS provided SMP extensions. ARC700 natively lacks SMP support, hence some of the core features are are only enabled if SoCs have the necessary h/w pixie-dust. This includes: -Inter Processor Interrupts (IPI) -Cache coherency -load-locked/store-conditional ... The low level exception handling would be completely broken in SMP because we don't have hardware assisted stack switching. Thus a fair bit of this code is repurposing the MMU_SCRATCH reg for event handler prologues to keep them re-entrant. Many thanks to Rajeshwar Ranga for his initial "major" contributions to SMP Port (back in 2008), and to Noam Camus and Gilad Ben-Yossef for help with resurrecting that in 3.2 kernel (2012). Note that this platform code is again singleton design pattern - so multiple SMP platforms won't build at the moment - this deficiency is addressed in subsequent patches within this series. Signed-off-by: Vineet Gupta Cc: Arnd Bergmann Cc: Thomas Gleixner Cc: Rajeshwar Ranga Cc: Noam Camus Cc: Gilad Ben-Yossef --- arch/arc/Kconfig | 39 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-) (limited to 'arch/arc/Kconfig') diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 68350aa3d297..52f5c072f6da 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -116,9 +116,42 @@ config CPU_BIG_ENDIAN help Build kernel for Big Endian Mode of ARC CPU +config SMP + bool "Symmetric Multi-Processing (Incomplete)" + default n + select USE_GENERIC_SMP_HELPERS + help + This enables support for systems with more than one CPU. If you have + a system with only one CPU, like most personal computers, say N. If + you have a system with more than one CPU, say Y. + +if SMP + +config ARC_HAS_COH_CACHES + def_bool n + +config ARC_HAS_COH_LLSC + def_bool n + +config ARC_HAS_COH_RTSC + def_bool n + +config ARC_HAS_REENTRANT_IRQ_LV2 + def_bool n + +endif + +config NR_CPUS + int "Maximum number of CPUs (2-32)" + range 2 32 + depends on SMP + default "2" + menuconfig ARC_CACHE bool "Enable Cache Support" default y + # if SMP, cache enabled ONLY if ARC implementation has cache coherency + depends on !SMP || ARC_HAS_COH_CACHES if ARC_CACHE @@ -213,6 +246,8 @@ config ARC_COMPACT_IRQ_LEVELS default n # Timer HAS to be high priority, for any other high priority config select ARC_IRQ3_LV2 + # if SMP, LV2 enabled ONLY if ARC implementation has LV2 re-entrancy + depends on !SMP || ARC_HAS_REENTRANT_IRQ_LV2 if ARC_COMPACT_IRQ_LEVELS @@ -261,6 +296,8 @@ config ARC_HAS_RTSC bool "Insn: RTSC (64-bit r/o cycle counter)" default y depends on ARC_CPU_REL_4_10 + # if SMP, enable RTSC only if counter is coherent across cores + depends on !SMP || ARC_HAS_COH_RTSC endmenu # "ARC CPU Configuration" @@ -309,7 +346,7 @@ menuconfig ARC_DBG config ARC_DBG_TLB_PARANOIA bool "Paranoia Checks in Low Level TLB Handlers" - depends on ARC_DBG + depends on ARC_DBG && !SMP default n config ARC_DBG_TLB_MISS_COUNT -- cgit v1.2.3