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 d82878c4daa..dbf5bfafd7b 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 aeb739e1876..6784bf7090f 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 3a319f9c9d3..39a40400f3f 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 10f0aadee95..102244edecf 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;