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| author | Tseng-Hui (Frank) Lin <thlin@linux.vnet.ibm.com> | 2011-05-02 20:43:04 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-05-04 15:19:26 +1000 |
| commit | 851d2e2fe8dbcbe3afcad6fc4569c881d8ad4ce9 (patch) | |
| tree | 94082e7751a66236febed1cf18a1f01a02084ae9 /arch/powerpc/include/asm/mmu_context.h | |
| parent | a32e252f7cdfb3675a4e50215cfac356ed8952c4 (diff) | |
| download | op-kernel-dev-851d2e2fe8dbcbe3afcad6fc4569c881d8ad4ce9.zip op-kernel-dev-851d2e2fe8dbcbe3afcad6fc4569c881d8ad4ce9.tar.gz | |
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 <sonnyrao@linux.vnet.ibm.com>
Signed-off-by: Tseng-Hui (Frank) Lin <thlin@linux.vnet.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/include/asm/mmu_context.h')
| -rw-r--r-- | arch/powerpc/include/asm/mmu_context.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 8e13f65..a73668a 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 */ |
