[PATCH] add icswx support

["Tseng-Hui (Frank) Lin" <thlin@linux.vnet.ibm.com>]

Add Power7 icswx co-processor instruction support.

Signed-off-by: Sonny Rao <sonnyrao@linux.vnet.ibm.com>
Signed-off-by: Tseng-Hui (Frank) Lin <thlin@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/mmu-hash64.h  |    3 +
 arch/powerpc/include/asm/mmu_context.h |    4 ++
 arch/powerpc/include/asm/reg.h         |    3 +
 arch/powerpc/mm/mmu_context_hash64.c   |   79
++++++++++++++++++++++++++++++++
 4 files changed, 89 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu-hash64.h
b/arch/powerpc/include/asm/mmu-hash64.h
index 2102b21..ba5727d 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -421,6 +421,9 @@ typedef struct {
 #ifdef CONFIG_PPC_SUBPAGE_PROT
 	struct subpage_prot_table spt;
 #endif /* CONFIG_PPC_SUBPAGE_PROT */
+	unsigned long acop;
+#define HASH64_MAX_PID (0xFFFF)
+	unsigned int pid;
 } mm_context_t;
 
 
diff --git a/arch/powerpc/include/asm/mmu_context.h
b/arch/powerpc/include/asm/mmu_context.h
index 26383e0..d6c8841 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -78,6 +78,10 @@ static inline void switch_mm(struct mm_struct *prev,
struct mm_struct *next,
 
 #define deactivate_mm(tsk,mm)	do { } while (0)
 
+extern void switch_cop(struct mm_struct *next);
+extern int  use_cop(unsigned long acop, struct task_struct *task);
+extern void disuse_cop(unsigned long acop, struct mm_struct *mm);
+
 /*
  * After we have set current->mm to a new value, this activates
  * the context for the new mm so we see the new mappings.
diff --git a/arch/powerpc/include/asm/reg.h
b/arch/powerpc/include/asm/reg.h
index 5572e86..30503f8 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -516,6 +516,9 @@
 #define SPRN_SIAR	780
 #define SPRN_SDAR	781
 
+#define SPRN_ACOP	 31
+#define SPRN_PID	 48
+
 #define SPRN_PA6T_MMCR0 795
 #define   PA6T_MMCR0_EN0	0x0000000000000001UL
 #define   PA6T_MMCR0_EN1	0x0000000000000002UL
diff --git a/arch/powerpc/mm/mmu_context_hash64.c
b/arch/powerpc/mm/mmu_context_hash64.c
index 2535828..d0a79f6 100644
--- a/arch/powerpc/mm/mmu_context_hash64.c
+++ b/arch/powerpc/mm/mmu_context_hash64.c
@@ -18,6 +18,7 @@
 #include <linux/mm.h>
 #include <linux/spinlock.h>
 #include <linux/idr.h>
+#include <linux/percpu.h>
 #include <linux/module.h>
 #include <linux/gfp.h>
 
@@ -25,6 +26,82 @@
 
 static DEFINE_SPINLOCK(mmu_context_lock);
 static DEFINE_IDA(mmu_context_ida);
+static DEFINE_IDA(cop_ida);
+
+/* Lazy switch the ACOP register */
+static DEFINE_PER_CPU(unsigned long, acop_reg);
+
+void switch_cop(struct mm_struct *next)
+{
+	mtspr(SPRN_PID, next->context.pid);
+	if (next->context.pid &&
+	    __get_cpu_var(acop_reg) != next->context.acop) {
+		mtspr(SPRN_ACOP, next->context.acop);
+		__get_cpu_var(acop_reg) = next->context.acop;
+	}
+}
+
+int use_cop(unsigned long acop, struct task_struct *task)
+{
+	int pid;
+	int err;
+	struct mm_struct *mm = get_task_mm(task);
+
+	if (!mm)
+		return -EINVAL;
+
+	if (!mm->context.pid) {
+		if (!ida_pre_get(&cop_ida, GFP_KERNEL))
+			return -ENOMEM;
+again:
+		spin_lock(&mmu_context_lock);
+		err = ida_get_new_above(&cop_ida, 1, &pid);
+		spin_unlock(&mmu_context_lock);
+
+		if (err == -EAGAIN)
+			goto again;
+		else if (err)
+			return err;
+
+		if (pid > HASH64_MAX_PID) {
+			spin_lock(&mmu_context_lock);
+			ida_remove(&cop_ida, pid);
+			spin_unlock(&mmu_context_lock);
+			return -EBUSY;
+		}
+		mm->context.pid = pid;
+		mtspr(SPRN_PID,  mm->context.pid);
+	}
+	mm->context.acop |= acop;
+
+	get_cpu_var(acop_reg) = mm->context.acop;
+	mtspr(SPRN_ACOP, mm->context.acop);
+	put_cpu_var(acop_reg);
+
+	return mm->context.pid;
+}
+EXPORT_SYMBOL(use_cop);
+
+void disuse_cop(unsigned long acop, struct mm_struct *mm)
+{
+	if (WARN_ON(!mm))
+		return;
+
+	mm->context.acop &= ~acop;
+	if (!mm->context.acop) {
+		spin_lock(&mmu_context_lock);
+		ida_remove(&cop_ida, mm->context.pid);
+		spin_unlock(&mmu_context_lock);
+		mm->context.pid = 0;
+		mtspr(SPRN_PID, 0);
+	} else {
+		get_cpu_var(acop_reg) = mm->context.acop;
+		mtspr(SPRN_ACOP, mm->context.acop);
+		put_cpu_var(acop_reg);
+	}
+	mmput(mm);
+}
+EXPORT_SYMBOL(disuse_cop);
 
 /*
  * The proto-VSID space has 2^35 - 1 segments available for user
mappings.
@@ -94,6 +171,8 @@ EXPORT_SYMBOL_GPL(__destroy_context);
 void destroy_context(struct mm_struct *mm)
 {
 	__destroy_context(mm->context.id);
+	if (mm->context.pid)
+		ida_remove(&cop_ida, mm->context.pid);
 	subpage_prot_free(mm);
 	mm->context.id = NO_CONTEXT;
 }