[POWERPC] iSeries: Use alternate paca structure for booting

The iSeries HV only needs the first two fields of the paca statically
initialised, so create an alternate paca that contains only those and
switch to our real paca immediately after boot.

This is in order to make the 1024 cpu patches easier since they will no
longer have to statically initialise the pacas for iSeries.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 53 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index e932b43bd82..292c6d8db0e 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -44,6 +44,9 @@
 #include <asm/mmu.h>
 #include <asm/hvcall.h>
 #endif
+#ifdef CONFIG_PPC_ISERIES
+#include <asm/iseries/alpaca.h>
+#endif
 
 #define DEFINE(sym, val) \
 	asm volatile("\n->" #sym " %0 " #val : : "i" (val))
@@ -321,6 +324,9 @@ int main(void)
 	DEFINE(PAGE_OFFSET_VSID, KERNEL_VSID(PAGE_OFFSET));
 	DEFINE(VMALLOC_START_ESID, GET_ESID(VMALLOC_START));
 	DEFINE(VMALLOC_START_VSID, KERNEL_VSID(VMALLOC_START));
+
+	/* alpaca */
+	DEFINE(ALPACA_SIZE, sizeof(struct alpaca));
 #endif
 
 	DEFINE(PGD_TABLE_SIZE, PGD_TABLE_SIZE);
diff --git a/arch/powerpc/platforms/iseries/exception.S b/arch/powerpc/platforms/iseries/exception.S
index 5381038f088..c775cd4b3d6 100644
--- a/arch/powerpc/platforms/iseries/exception.S
+++ b/arch/powerpc/platforms/iseries/exception.S
@@ -38,11 +38,19 @@
 
 	.globl system_reset_iSeries
 system_reset_iSeries:
-	mfspr	r13,SPRN_SPRG3		/* Get paca address */
+	mfspr	r13,SPRN_SPRG3		/* Get alpaca address */
+	LOAD_REG_IMMEDIATE(r23, alpaca)
+	li	r0,ALPACA_SIZE
+	sub	r23,r13,r23
+	divdu	r23,r23,r0		/* r23 has cpu number */
+	LOAD_REG_IMMEDIATE(r13, paca)
+	mulli	r0,r23,PACA_SIZE
+	add	r13,r13,r0
+	mtspr	SPRN_SPRG3,r13		/* Save it away for the future */
 	mfmsr	r24
 	ori	r24,r24,MSR_RI
 	mtmsrd	r24			/* RI on */
-	lhz	r24,PACAPACAINDEX(r13)	/* Get processor # */
+	mr	r24,r23
 	cmpwi	0,r24,0			/* Are we processor 0? */
 	bne	1f
 	b	.__start_initialization_iSeries	/* Start up the first processor */
diff --git a/arch/powerpc/platforms/iseries/lpardata.c b/arch/powerpc/platforms/iseries/lpardata.c
index 8162049bb04..dc8470850a8 100644
--- a/arch/powerpc/platforms/iseries/lpardata.c
+++ b/arch/powerpc/platforms/iseries/lpardata.c
@@ -18,6 +18,7 @@
 #include <asm/paca.h>
 #include <asm/iseries/lpar_map.h>
 #include <asm/iseries/it_lp_queue.h>
+#include <asm/iseries/alpaca.h>
 
 #include "naca.h"
 #include "vpd_areas.h"
@@ -159,6 +160,40 @@ struct SpCommArea xSpCommArea = {
 	.xFormat = 1,
 };
 
+#define ALPACA_INIT(number)						\
+{									\
+	.lppaca_ptr = &lppaca[number],					\
+	.reg_save_ptr = &iseries_reg_save[number],			\
+}
+
+struct alpaca alpaca[] = {
+	ALPACA_INIT( 0),
+#if NR_CPUS > 1
+	ALPACA_INIT( 1), ALPACA_INIT( 2), ALPACA_INIT( 3),
+#if NR_CPUS > 4
+	ALPACA_INIT( 4), ALPACA_INIT( 5), ALPACA_INIT( 6), ALPACA_INIT( 7),
+#if NR_CPUS > 8
+	ALPACA_INIT( 8), ALPACA_INIT( 9), ALPACA_INIT(10), ALPACA_INIT(11),
+	ALPACA_INIT(12), ALPACA_INIT(13), ALPACA_INIT(14), ALPACA_INIT(15),
+	ALPACA_INIT(16), ALPACA_INIT(17), ALPACA_INIT(18), ALPACA_INIT(19),
+	ALPACA_INIT(20), ALPACA_INIT(21), ALPACA_INIT(22), ALPACA_INIT(23),
+	ALPACA_INIT(24), ALPACA_INIT(25), ALPACA_INIT(26), ALPACA_INIT(27),
+	ALPACA_INIT(28), ALPACA_INIT(29), ALPACA_INIT(30), ALPACA_INIT(31),
+#if NR_CPUS > 32
+	ALPACA_INIT(32), ALPACA_INIT(33), ALPACA_INIT(34), ALPACA_INIT(35),
+	ALPACA_INIT(36), ALPACA_INIT(37), ALPACA_INIT(38), ALPACA_INIT(39),
+	ALPACA_INIT(40), ALPACA_INIT(41), ALPACA_INIT(42), ALPACA_INIT(43),
+	ALPACA_INIT(44), ALPACA_INIT(45), ALPACA_INIT(46), ALPACA_INIT(47),
+	ALPACA_INIT(48), ALPACA_INIT(49), ALPACA_INIT(50), ALPACA_INIT(51),
+	ALPACA_INIT(52), ALPACA_INIT(53), ALPACA_INIT(54), ALPACA_INIT(55),
+	ALPACA_INIT(56), ALPACA_INIT(57), ALPACA_INIT(58), ALPACA_INIT(59),
+	ALPACA_INIT(60), ALPACA_INIT(61), ALPACA_INIT(62), ALPACA_INIT(63),
+#endif
+#endif
+#endif
+#endif
+};
+
 /* The LparMap data is now located at offset 0x6000 in head.S
  * It was put there so that the HvReleaseData could address it
  * with a 32-bit offset as required by the iSeries hypervisor
@@ -185,7 +220,7 @@ struct ItVpdAreas itVpdAreas = {
 	.xSlicVpdLens = {			/* VPD lengths */
 	        0,0,0,		        /*  0 - 2 */
 		sizeof(xItExtVpdPanel), /*       3 Extended VPD   */
-		sizeof(struct paca_struct),	/*       4 length of Paca  */
+		sizeof(struct alpaca),	/*       4 length of (fake) Paca  */
 		0,			/*       5 */
 		sizeof(struct ItIplParmsReal),/* 6 length of IPL parms */
 		26992,			/*	 7 length of MS VPD */
@@ -203,7 +238,7 @@ struct ItVpdAreas itVpdAreas = {
 	.xSlicVpdAdrs = {			/* VPD addresses */
 		0,0,0,			/*	 0 -  2 */
 		&xItExtVpdPanel,        /*       3 Extended VPD */
-		&paca[0],		/*       4 first Paca */
+		&alpaca[0],		/*       4 first (fake) Paca */
 		0,			/*       5 */
 		&xItIplParmsReal,	/*	 6 IPL parms */
 		&xMsVpd,		/*	 7 MS Vpd */