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/include/asm/pgtable.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/arc/include/asm/pgtable.h') diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h index dcb0701528a..b7e36684c09 100644 --- a/arch/arc/include/asm/pgtable.h +++ b/arch/arc/include/asm/pgtable.h @@ -354,11 +354,15 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, * Thus use this macro only when you are certain that "current" is current * e.g. when dealing with signal frame setup code etc */ +#ifndef CONFIG_SMP #define pgd_offset_fast(mm, addr) \ ({ \ pgd_t *pgd_base = (pgd_t *) read_aux_reg(ARC_REG_SCRATCH_DATA0); \ pgd_base + pgd_index(addr); \ }) +#else +#define pgd_offset_fast(mm, addr) pgd_offset(mm, addr) +#endif extern void paging_init(void); extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE); -- cgit v1.2.3-18-g5258