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>
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 1f9ac12..632e78e 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -188,6 +188,7 @@
#define SPRN_CTR 0x009 /* Count Register */
#define SPRN_DSCR 0x11
+#define SPRN_ACOP 0x1F /* Available Coprocessor Register */
#define SPRN_CTRLF 0x088
#define SPRN_CTRLT 0x098
#define CTRL_CT 0xc0000000 /* current thread */