From 851d2e2fe8dbcbe3afcad6fc4569c881d8ad4ce9 Mon Sep 17 00:00:00 2001 From: "Tseng-Hui (Frank) Lin" Date: Mon, 2 May 2011 20:43:04 +0000 Subject: powerpc: Add Initiate Coprocessor Store Word (icswx) support Icswx is a PowerPC instruction to send data to a co-processor. On Book-S processors the LPAR_ID and process ID (PID) of the owning process are registered in the window context of the co-processor at initialization time. When the icswx instruction is executed the L2 generates a cop-reg transaction on PowerBus. The transaction has no address and the processor does not perform an MMU access to authenticate the transaction. The co-processor compares the LPAR_ID and the PID included in the transaction and the LPAR_ID and PID held in the window context to determine if the process is authorized to generate the transaction. The OS needs to assign a 16-bit PID for the process. This cop-PID needs to be updated during context switch. The cop-PID needs to be destroyed when the context is destroyed. Signed-off-by: Sonny Rao Signed-off-by: Tseng-Hui (Frank) Lin Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/mmu_context.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/powerpc/include/asm/mmu_context.h') diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 8e13f65b498c..a73668a5f30d 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -32,6 +32,10 @@ extern void __destroy_context(unsigned long context_id); extern void mmu_context_init(void); #endif +extern void switch_cop(struct mm_struct *next); +extern int use_cop(unsigned long acop, struct mm_struct *mm); +extern void drop_cop(unsigned long acop, struct mm_struct *mm); + /* * switch_mm is the entry point called from the architecture independent * code in kernel/sched.c @@ -55,6 +59,12 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, if (prev == next) return; +#ifdef CONFIG_PPC_ICSWX + /* Switch coprocessor context only if prev or next uses a coprocessor */ + if (prev->context.acop || next->context.acop) + switch_cop(next); +#endif /* CONFIG_PPC_ICSWX */ + /* We must stop all altivec streams before changing the HW * context */ -- cgit v1.2.1