[POWERPC] Implement SLB shadow buffer

This adds a shadow buffer for the SLBs and regsiters it with PHYP.
Only the bolted SLB entries (top 3) are shadowed.

The SLB shadow buffer tells the hypervisor what the kernel needs to
have in the SLB for the kernel to be able to function.  The hypervisor
can use this information to speed up partition context switches.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 14 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index c68741fed14b..55f1a25085cd 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -17,6 +17,7 @@
 #include <asm/lppaca.h>
 #include <asm/iseries/it_lp_reg_save.h>
 #include <asm/paca.h>
+#include <asm/mmu.h>
 
 
 /* This symbol is provided by the linker - let it fill in the paca
@@ -45,6 +46,17 @@ struct lppaca lppaca[] = {
         },
 };
 
+/*
+ * 3 persistent SLBs are registered here.  The buffer will be zero
+ * initially, hence will all be invaild until we actually write them.
+ */
+struct slb_shadow slb_shadow[] __cacheline_aligned = {
+        [0 ... (NR_CPUS-1)] = {
+                .persistent = SLB_NUM_BOLTED,
+                .buffer_length = sizeof(struct slb_shadow),
+        },
+};
+
 /* The Paca is an array with one entry per processor.  Each contains an
  * lppaca, which contains the information shared between the
  * hypervisor and Linux.
@@ -59,7 +71,8 @@ struct lppaca lppaca[] = {
         .lock_token = 0x8000,                                               \
         .paca_index = (number),         /* Paca Index */                    \
         .kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL,             \
-        .hw_cpu_id = 0xffff,
+        .hw_cpu_id = 0xffff,                                                \
+        .slb_shadow_ptr = &slb_shadow[number],
 
 #ifdef CONFIG_PPC_ISERIES
 #define PACA_INIT_ISERIES(number)                                           \