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/cputable.h b/arch/powerpc/include/asm/cputable.h
index 3db2476..a3e1a9e 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -197,6 +197,7 @@
#define CPU_FTR_STCX_CHECKS_ADDRESS LONG_ASM_CONST(0x0200000000000000)
#define CPU_FTR_POPCNTB LONG_ASM_CONST(0x0400000000000000)
#define CPU_FTR_POPCNTD LONG_ASM_CONST(0x0800000000000000)
+#define CPU_FTR_ICSWX LONG_ASM_CONST(0x1000000000000000)
#ifndef __ASSEMBLY__
@@ -418,7 +419,8 @@
CPU_FTR_COHERENT_ICACHE | \
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
CPU_FTR_DSCR | CPU_FTR_SAO | CPU_FTR_ASYM_SMT | \
- CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD)
+ CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
+ CPU_FTR_ICSWX)
#define CPU_FTRS_CELL (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \
CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \
diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index ae7b3ef..d865bd9 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -408,6 +408,7 @@
#endif /* CONFIG_PPC_SUBPAGE_PROT */
typedef unsigned long mm_context_id_t;
+struct spinlock;
typedef struct {
mm_context_id_t id;
@@ -423,6 +424,11 @@
#ifdef CONFIG_PPC_SUBPAGE_PROT
struct subpage_prot_table spt;
#endif /* CONFIG_PPC_SUBPAGE_PROT */
+#ifdef CONFIG_PPC_ICSWX
+ struct spinlock *cop_lockp; /* guard acop and cop_pid */
+ unsigned long acop; /* mask of enabled coprocessor types */
+ unsigned int cop_pid; /* pid value used with coprocessors */
+#endif /* CONFIG_PPC_ICSWX */
} mm_context_t;
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 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 @@
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
*/
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 */