powerpc: In HV mode, use HSPRG0 for PACA

When running in Hypervisor mode (arch 2.06 or later), we store the PACA
in HSPRG0 instead of SPRG1. The architecture specifies that SPRGs may be
lost during a "nap" power management operation (though they aren't
currently on POWER7) and this enables use of SPRG1 by KVM guests.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

4 files changed, 20 insertions, 9 deletions

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index d82878c4daa6..dbf5bfafd7bc 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -838,7 +838,7 @@ _GLOBAL(enter_rtas)
 
 _STATIC(rtas_return_loc)
         /* relocation is off at this point */
-        mfspr   r4,SPRN_SPRG_PACA       /* Get PACA */
+        GET_PACA(r4)
         clrldi  r4,r4,2                 /* convert to realmode address */
 
         bcl     20,31,$+4
@@ -869,7 +869,7 @@ _STATIC(rtas_restore_regs)
         REST_8GPRS(14, r1)              /* Restore the non-volatiles */
         REST_10GPRS(22, r1)             /* ditto */
 
-        mfspr   r13,SPRN_SPRG_PACA
+        GET_PACA(r13)
 
         ld      r4,_CCR(r1)
         mtcr    r4
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index aeb739e18769..6784bf7090f6 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -53,7 +53,7 @@ data_access_pSeries:
         DO_KVM  0x300
         mtspr   SPRN_SPRG_SCRATCH0,r13
 BEGIN_FTR_SECTION
-        mfspr   r13,SPRN_SPRG_PACA
+        GET_PACA(r13)
         std     r9,PACA_EXSLB+EX_R9(r13)
         std     r10,PACA_EXSLB+EX_R10(r13)
         mfspr   r10,SPRN_DAR
@@ -82,7 +82,7 @@ data_access_slb_pSeries:
         HMT_MEDIUM
         DO_KVM  0x380
         mtspr   SPRN_SPRG_SCRATCH0,r13
-        mfspr   r13,SPRN_SPRG_PACA              /* get paca address into r13 */
+        GET_PACA(r13)
         std     r3,PACA_EXSLB+EX_R3(r13)
         mfspr   r3,SPRN_DAR
         std     r9,PACA_EXSLB+EX_R9(r13)        /* save r9 - r12 */
@@ -121,7 +121,7 @@ instruction_access_slb_pSeries:
         HMT_MEDIUM
         DO_KVM  0x480
         mtspr   SPRN_SPRG_SCRATCH0,r13
-        mfspr   r13,SPRN_SPRG_PACA              /* get paca address into r13 */
+        GET_PACA(r13)
         std     r3,PACA_EXSLB+EX_R3(r13)
         mfspr   r3,SPRN_SRR0            /* SRR0 is faulting address */
         std     r9,PACA_EXSLB+EX_R9(r13)        /* save r9 - r12 */
@@ -165,7 +165,7 @@ BEGIN_FTR_SECTION
         beq-    1f
 END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE)
         mr      r9,r13
-        mfspr   r13,SPRN_SPRG_PACA
+        GET_PACA(r13)
         mfspr   r11,SPRN_SRR0
         ld      r12,PACAKBASE(r13)
         ld      r10,PACAKMSR(r13)
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 3a319f9c9d3e..39a40400f3f2 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -228,7 +228,7 @@ generic_secondary_common_init:
         mr      r3,r24                  /* not found, copy phys to r3    */
         b       .kexec_wait             /* next kernel might do better   */
 
-2:      mtspr   SPRN_SPRG_PACA,r13      /* Save vaddr of paca in an SPRG */
+2:      SET_PACA(r13)
 #ifdef CONFIG_PPC_BOOK3E
         addi    r12,r13,PACA_EXTLB      /* and TLB exc frame in another  */
         mtspr   SPRN_SPRG_TLB_EXFRAME,r12
@@ -534,7 +534,7 @@ _GLOBAL(pmac_secondary_start)
         ld      r4,0(r4)                /* Get base vaddr of paca array */
         mulli   r13,r24,PACA_SIZE       /* Calculate vaddr of right paca */
         add     r13,r13,r4              /* for this processor.          */
-        mtspr   SPRN_SPRG_PACA,r13      /* Save vaddr of paca in an SPRG*/
+        SET_PACA(r13)                   /* Save vaddr of paca in an SPRG*/
 
         /* Mark interrupts soft and hard disabled (they might be enabled
          * in the PACA when doing hotplug)
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 10f0aadee95b..102244edecf0 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -156,11 +156,22 @@ void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 /* Put the paca pointer into r13 and SPRG_PACA */
 void setup_paca(struct paca_struct *new_paca)
 {
+        /* Setup r13 */
         local_paca = new_paca;
-        mtspr(SPRN_SPRG_PACA, local_paca);
+
 #ifdef CONFIG_PPC_BOOK3E
+        /* On Book3E, initialize the TLB miss exception frames */
         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
+#else
+        /* In HV mode, we setup both HPACA and PACA to avoid problems
+         * if we do a GET_PACA() before the feature fixups have been
+         * applied
+         */
+        if (cpu_has_feature(CPU_FTR_HVMODE_206))
+                mtspr(SPRN_SPRG_HPACA, local_paca);
 #endif
+        mtspr(SPRN_SPRG_PACA, local_paca);
+
 }
 
 static int __initdata paca_size;