[PATCH] powerpc: Remove lppaca structure from the PACA

At present the lppaca - the structure shared with the iSeries
hypervisor and phyp - is contained within the PACA, our own low-level
per-cpu structure.  This doesn't have to be so, the patch below
removes it, making a separate array of lppaca structures.

This saves approximately 500*NR_CPUS bytes of image size and kernel
memory, because we don't need aligning gap between the Linux and
hypervisor portions of every PACA.  On the other hand it means an
extra level of dereference in many accesses to the lppaca.

The patch also gets rid of several places where we assign the paca
address to a local variable for no particular reason.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 11 insertions, 13 deletions

diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 1fe445ab78a6..8952528d31ac 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -254,11 +254,11 @@ out:
 void vpa_init(int cpu)
 {
         int hwcpu = get_hard_smp_processor_id(cpu);
-        unsigned long vpa = __pa(&paca[cpu].lppaca);
+        unsigned long vpa = __pa(&lppaca[cpu]);
         long ret;
 
         if (cpu_has_feature(CPU_FTR_ALTIVEC))
-                paca[cpu].lppaca.vmxregs_in_use = 1;
+                lppaca[cpu].vmxregs_in_use = 1;
 
         ret = register_vpa(hwcpu, vpa);
 
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 68b7f086d63d..da6cebaf72cd 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -190,7 +190,7 @@ static void pseries_lpar_enable_pmcs(void)
 
         /* instruct hypervisor to maintain PMCs */
         if (firmware_has_feature(FW_FEATURE_SPLPAR))
-                get_paca()->lppaca.pmcregs_in_use = 1;
+                get_lppaca()->pmcregs_in_use = 1;
 }
 
 static void __init pSeries_setup_arch(void)
@@ -234,7 +234,7 @@ static void __init pSeries_setup_arch(void)
         /* Choose an idle loop */
         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
                 vpa_init(boot_cpuid);
-                if (get_paca()->lppaca.shared_proc) {
+                if (get_lppaca()->shared_proc) {
                         printk(KERN_INFO "Using shared processor idle loop\n");
                         ppc_md.idle_loop = pseries_shared_idle;
                 } else {
@@ -444,10 +444,10 @@ DECLARE_PER_CPU(unsigned long, smt_snooze_delay);
 
 static inline void dedicated_idle_sleep(unsigned int cpu)
 {
-        struct paca_struct *ppaca = &paca[cpu ^ 1];
+        struct lppaca *plppaca = &lppaca[cpu ^ 1];
 
         /* Only sleep if the other thread is not idle */
-        if (!(ppaca->lppaca.idle)) {
+        if (!(plppaca->idle)) {
                 local_irq_disable();
 
                 /*
@@ -480,7 +480,6 @@ static inline void dedicated_idle_sleep(unsigned int cpu)
 
 static void pseries_dedicated_idle(void)
 { 
-        struct paca_struct *lpaca = get_paca();
         unsigned int cpu = smp_processor_id();
         unsigned long start_snooze;
         unsigned long *smt_snooze_delay = &__get_cpu_var(smt_snooze_delay);
@@ -491,7 +490,7 @@ static void pseries_dedicated_idle(void)
                  * Indicate to the HV that we are idle. Now would be
                  * a good time to find other work to dispatch.
                  */
-                lpaca->lppaca.idle = 1;
+                get_lppaca()->idle = 1;
 
                 if (!need_resched()) {
                         start_snooze = get_tb() +
@@ -518,7 +517,7 @@ static void pseries_dedicated_idle(void)
                         HMT_medium();
                 }
 
-                lpaca->lppaca.idle = 0;
+                get_lppaca()->idle = 0;
                 ppc64_runlatch_on();
 
                 preempt_enable_no_resched();
@@ -532,7 +531,6 @@ static void pseries_dedicated_idle(void)
 
 static void pseries_shared_idle(void)
 {
-        struct paca_struct *lpaca = get_paca();
         unsigned int cpu = smp_processor_id();
 
         while (1) {
@@ -540,7 +538,7 @@ static void pseries_shared_idle(void)
                  * Indicate to the HV that we are idle. Now would be
                  * a good time to find other work to dispatch.
                  */
-                lpaca->lppaca.idle = 1;
+                get_lppaca()->idle = 1;
 
                 while (!need_resched() && !cpu_is_offline(cpu)) {
                         local_irq_disable();
@@ -564,7 +562,7 @@ static void pseries_shared_idle(void)
                         HMT_medium();
                 }
 
-                lpaca->lppaca.idle = 0;
+                get_lppaca()->idle = 0;
                 ppc64_runlatch_on();
 
                 preempt_enable_no_resched();
@@ -588,7 +586,7 @@ static void pseries_kexec_cpu_down(int crash_shutdown, int secondary)
 {
         /* Don't risk a hypervisor call if we're crashing */
         if (!crash_shutdown) {
-                unsigned long vpa = __pa(&get_paca()->lppaca);
+                unsigned long vpa = __pa(get_lppaca());
 
                 if (unregister_vpa(hard_smp_processor_id(), vpa)) {
                         printk("VPA deregistration of cpu %u (hw_cpu_id %d) "