7 files changed, 102 insertions, 11 deletions

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index ac0631958b20..2ef7ea860379 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -135,11 +135,13 @@ int main(void)
         DEFINE(PACA_STARTPURR, offsetof(struct paca_struct, startpurr));
         DEFINE(PACA_USER_TIME, offsetof(struct paca_struct, user_time));
         DEFINE(PACA_SYSTEM_TIME, offsetof(struct paca_struct, system_time));
+        DEFINE(PACA_SLBSHADOWPTR, offsetof(struct paca_struct, slb_shadow_ptr));
 
         DEFINE(LPPACASRR0, offsetof(struct lppaca, saved_srr0));
         DEFINE(LPPACASRR1, offsetof(struct lppaca, saved_srr1));
         DEFINE(LPPACAANYINT, offsetof(struct lppaca, int_dword.any_int));
         DEFINE(LPPACADECRINT, offsetof(struct lppaca, int_dword.fields.decr_int));
+        DEFINE(SLBSHADOW_SAVEAREA, offsetof(struct slb_shadow, save_area));
 #endif /* CONFIG_PPC64 */
 
         /* RTAS */
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 54d9f5cdaab4..5baea498ea64 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -323,6 +323,11 @@ _GLOBAL(ret_from_fork)
  * The code which creates the new task context is in 'copy_thread'
  * in arch/powerpc/kernel/process.c 
  */
+#define SHADOW_SLB_BOLTED_STACK_ESID \
+                (SLBSHADOW_SAVEAREA + 0x10*(SLB_NUM_BOLTED-1))
+#define SHADOW_SLB_BOLTED_STACK_VSID \
+                (SLBSHADOW_SAVEAREA + 0x10*(SLB_NUM_BOLTED-1) + 8)
+
         .align  7
 _GLOBAL(_switch)
         mflr    r0
@@ -375,6 +380,14 @@ BEGIN_FTR_SECTION
         ld      r7,KSP_VSID(r4) /* Get new stack's VSID */
         oris    r0,r6,(SLB_ESID_V)@h
         ori     r0,r0,(SLB_NUM_BOLTED-1)@l
+
+        /* Update the last bolted SLB */
+        ld      r9,PACA_SLBSHADOWPTR(r13)
+        li      r12,0
+        std     r12,SHADOW_SLB_BOLTED_STACK_ESID(r9) /* Clear ESID */
+        std     r7,SHADOW_SLB_BOLTED_STACK_VSID(r9)  /* Save VSID */
+        std     r0,SHADOW_SLB_BOLTED_STACK_ESID(r9)  /* Save ESID */
+
         slbie   r6
         slbie   r6              /* Workaround POWER5 < DD2.1 issue */
         slbmte  r7,r0
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)                                           \
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index de0c8842415c..d3733912adb4 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -22,6 +22,8 @@
 #include <asm/paca.h>
 #include <asm/cputable.h>
 #include <asm/cacheflush.h>
+#include <asm/smp.h>
+#include <linux/compiler.h>
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)
@@ -50,9 +52,32 @@ static inline unsigned long mk_vsid_data(unsigned long ea, unsigned long flags)
         return (get_kernel_vsid(ea) << SLB_VSID_SHIFT) | flags;
 }
 
-static inline void create_slbe(unsigned long ea, unsigned long flags,
-                               unsigned long entry)
+static inline void slb_shadow_update(unsigned long esid, unsigned long vsid,
+                                     unsigned long entry)
 {
+        /*
+         * Clear the ESID first so the entry is not valid while we are
+         * updating it.
+         */
+        get_slb_shadow()->save_area[entry].esid = 0;
+        barrier();
+        get_slb_shadow()->save_area[entry].vsid = vsid;
+        barrier();
+        get_slb_shadow()->save_area[entry].esid = esid;
+
+}
+
+static inline void create_shadowed_slbe(unsigned long ea, unsigned long flags,
+                                        unsigned long entry)
+{
+        /*
+         * Updating the shadow buffer before writing the SLB ensures
+         * we don't get a stale entry here if we get preempted by PHYP
+         * between these two statements.
+         */
+        slb_shadow_update(mk_esid_data(ea, entry), mk_vsid_data(ea, flags),
+                          entry);
+
         asm volatile("slbmte  %0,%1" :
                      : "r" (mk_vsid_data(ea, flags)),
                        "r" (mk_esid_data(ea, entry))
@@ -77,6 +102,10 @@ void slb_flush_and_rebolt(void)
         if ((ksp_esid_data & ESID_MASK) == PAGE_OFFSET)
                 ksp_esid_data &= ~SLB_ESID_V;
 
+        /* Only third entry (stack) may change here so only resave that */
+        slb_shadow_update(ksp_esid_data,
+                          mk_vsid_data(ksp_esid_data, lflags), 2);
+
         /* We need to do this all in asm, so we're sure we don't touch
          * the stack between the slbia and rebolting it. */
         asm volatile("isync\n"
@@ -209,9 +238,9 @@ void slb_initialize(void)
         asm volatile("isync":::"memory");
         asm volatile("slbmte  %0,%0"::"r" (0) : "memory");
         asm volatile("isync; slbia; isync":::"memory");
-        create_slbe(PAGE_OFFSET, lflags, 0);
+        create_shadowed_slbe(PAGE_OFFSET, lflags, 0);
 
-        create_slbe(VMALLOC_START, vflags, 1);
+        create_shadowed_slbe(VMALLOC_START, vflags, 1);
 
         /* We don't bolt the stack for the time being - we're in boot,
          * so the stack is in the bolted segment.  By the time it goes
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 6cbf14266d5e..1820a0b0a8c6 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -252,18 +252,34 @@ out:
 void vpa_init(int cpu)
 {
         int hwcpu = get_hard_smp_processor_id(cpu);
-        unsigned long vpa = __pa(&lppaca[cpu]);
+        unsigned long addr;
         long ret;
 
         if (cpu_has_feature(CPU_FTR_ALTIVEC))
                 lppaca[cpu].vmxregs_in_use = 1;
 
-        ret = register_vpa(hwcpu, vpa);
+        addr = __pa(&lppaca[cpu]);
+        ret = register_vpa(hwcpu, addr);
 
-        if (ret)
+        if (ret) {
                 printk(KERN_ERR "WARNING: vpa_init: VPA registration for "
                                 "cpu %d (hw %d) of area %lx returns %ld\n",
-                                cpu, hwcpu, vpa, ret);
+                                cpu, hwcpu, addr, ret);
+                return;
+        }
+        /*
+         * PAPR says this feature is SLB-Buffer but firmware never
+         * reports that.  All SPLPAR support SLB shadow buffer.
+         */
+        addr = __pa(&slb_shadow[cpu]);
+        if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
+                ret = register_slb_shadow(hwcpu, addr);
+                if (ret)
+                        printk(KERN_ERR
+                               "WARNING: vpa_init: SLB shadow buffer "
+                               "registration for cpu %d (hw %d) of area %lx "
+                               "returns %ld\n", cpu, hwcpu, addr, ret);
+        }
 }
 
 long pSeries_lpar_hpte_insert(unsigned long hpte_group,
diff --git a/arch/powerpc/platforms/pseries/plpar_wrappers.h b/arch/powerpc/platforms/pseries/plpar_wrappers.h
index ebd15de7597e..3eb7b294d92f 100644
--- a/arch/powerpc/platforms/pseries/plpar_wrappers.h
+++ b/arch/powerpc/platforms/pseries/plpar_wrappers.h
@@ -37,6 +37,16 @@ static inline long register_vpa(unsigned long cpu, unsigned long vpa)
         return vpa_call(0x1, cpu, vpa);
 }
 
+static inline long unregister_slb_shadow(unsigned long cpu, unsigned long vpa)
+{
+        return vpa_call(0x7, cpu, vpa);
+}
+
+static inline long register_slb_shadow(unsigned long cpu, unsigned long vpa)
+{
+        return vpa_call(0x3, cpu, vpa);
+}
+
 extern void vpa_init(int cpu);
 
 static inline long plpar_pte_enter(unsigned long flags,
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index de214d86ff44..6ebeecfd6bcb 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -234,9 +234,17 @@ static void pseries_kexec_cpu_down_xics(int crash_shutdown, int secondary)
 {
         /* Don't risk a hypervisor call if we're crashing */
         if (firmware_has_feature(FW_FEATURE_SPLPAR) && !crash_shutdown) {
-                unsigned long vpa = __pa(get_lppaca());
+                unsigned long addr;
 
-                if (unregister_vpa(hard_smp_processor_id(), vpa)) {
+                addr = __pa(get_slb_shadow());
+                if (unregister_slb_shadow(hard_smp_processor_id(), addr))
+                        printk("SLB shadow buffer deregistration of "
+                               "cpu %u (hw_cpu_id %d) failed\n",
+                               smp_processor_id(),
+                               hard_smp_processor_id());
+
+                addr = __pa(get_lppaca());
+                if (unregister_vpa(hard_smp_processor_id(), addr)) {
                         printk("VPA deregistration of cpu %u (hw_cpu_id %d) "
                                         "failed\n", smp_processor_id(),
                                         hard_smp_processor_id());