[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>

7 files changed, 53 insertions, 40 deletions

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 56399c5c931a..840aad43a98b 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -135,7 +135,7 @@ int main(void)
         DEFINE(PACA_EXMC, offsetof(struct paca_struct, exmc));
         DEFINE(PACA_EXSLB, offsetof(struct paca_struct, exslb));
         DEFINE(PACAEMERGSP, offsetof(struct paca_struct, emergency_sp));
-        DEFINE(PACALPPACA, offsetof(struct paca_struct, lppaca));
+        DEFINE(PACALPPACAPTR, offsetof(struct paca_struct, lppaca_ptr));
         DEFINE(PACAHWCPUID, offsetof(struct paca_struct, hw_cpu_id));
 
         DEFINE(LPPACASRR0, offsetof(struct lppaca, saved_srr0));
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 4ba81e1b6bf1..542036318866 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -511,7 +511,8 @@ restore:
         cmpdi   0,r5,0
         beq     4f
         /* Check for pending interrupts (iSeries) */
-        ld      r3,PACALPPACA+LPPACAANYINT(r13)
+        ld      r3,PACALPPACAPTR(r13)
+        ld      r3,LPPACAANYINT(r3)
         cmpdi   r3,0
         beq+    4f                      /* skip do_IRQ if no interrupts */
 
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index b3718f3eb7b5..308268466342 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -255,8 +255,9 @@ exception_marker:
 
 #define EXCEPTION_PROLOG_ISERIES_2                                      \
         mfmsr   r10;                                                    \
-        ld      r11,PACALPPACA+LPPACASRR0(r13);                         \
-        ld      r12,PACALPPACA+LPPACASRR1(r13);                         \
+        ld      r12,PACALPPACAPTR(r13);                                 \
+        ld      r11,LPPACASRR0(r12);                                    \
+        ld      r12,LPPACASRR1(r12);                                    \
         ori     r10,r10,MSR_RI;                                         \
         mtmsrd  r10,1
 
@@ -635,7 +636,8 @@ data_access_slb_iSeries:
         std     r12,PACA_EXSLB+EX_R12(r13)
         mfspr   r10,SPRN_SPRG1
         std     r10,PACA_EXSLB+EX_R13(r13)
-        ld      r12,PACALPPACA+LPPACASRR1(r13);
+        ld      r12,PACALPPACAPTR(r13)
+        ld      r12,LPPACASRR1(r12)
         b       .slb_miss_realmode
 
         STD_EXCEPTION_ISERIES(0x400, instruction_access, PACA_EXGEN)
@@ -645,7 +647,8 @@ instruction_access_slb_iSeries:
         mtspr   SPRN_SPRG1,r13          /* save r13 */
         mfspr   r13,SPRN_SPRG3          /* get paca address into r13 */
         std     r3,PACA_EXSLB+EX_R3(r13)
-        ld      r3,PACALPPACA+LPPACASRR0(r13)   /* get SRR0 value */
+        ld      r3,PACALPPACAPTR(r13)
+        ld      r3,LPPACASRR0(r3)       /* get SRR0 value */
         std     r9,PACA_EXSLB+EX_R9(r13)
         mfcr    r9
 #ifdef __DISABLED__
@@ -657,7 +660,8 @@ instruction_access_slb_iSeries:
         std     r12,PACA_EXSLB+EX_R12(r13)
         mfspr   r10,SPRN_SPRG1
         std     r10,PACA_EXSLB+EX_R13(r13)
-        ld      r12,PACALPPACA+LPPACASRR1(r13);
+        ld      r12,PACALPPACAPTR(r13)
+        ld      r12,LPPACASRR1(r12)
         b       .slb_miss_realmode
 
 #ifdef __DISABLED__
@@ -746,7 +750,8 @@ iSeries_secondary_smp_loop:
         .globl decrementer_iSeries_masked
 decrementer_iSeries_masked:
         li      r11,1
-        stb     r11,PACALPPACA+LPPACADECRINT(r13)
+        ld      r12,PACALPPACAPTR(r13)
+        stb     r11,LPPACADECRINT(r12)
         LOAD_REG_ADDRBASE(r12,tb_ticks_per_jiffy)
         lwz     r12,ADDROFF(tb_ticks_per_jiffy)(r12)
         mtspr   SPRN_DEC,r12
@@ -755,8 +760,9 @@ decrementer_iSeries_masked:
         .globl hardware_interrupt_iSeries_masked
 hardware_interrupt_iSeries_masked:
         mtcrf   0x80,r9         /* Restore regs */
-        ld      r11,PACALPPACA+LPPACASRR0(r13)
-        ld      r12,PACALPPACA+LPPACASRR1(r13)
+        ld      r12,PACALPPACAPTR(r13)
+        ld      r11,LPPACASRR0(r12)
+        ld      r12,LPPACASRR1(r12)
         mtspr   SPRN_SRR0,r11
         mtspr   SPRN_SRR1,r12
         ld      r9,PACA_EXGEN+EX_R9(r13)
@@ -995,7 +1001,8 @@ _GLOBAL(slb_miss_realmode)
         ld      r3,PACA_EXSLB+EX_R3(r13)
         lwz     r9,PACA_EXSLB+EX_CCR(r13)       /* get saved CR */
 #ifdef CONFIG_PPC_ISERIES
-        ld      r11,PACALPPACA+LPPACASRR0(r13)  /* get SRR0 value */
+        ld      r11,PACALPPACAPTR(r13)
+        ld      r11,LPPACASRR0(r11)             /* get SRR0 value */
 #endif /* CONFIG_PPC_ISERIES */
 
         mtlr    r10
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 5651032d8706..d1fffce86df9 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -238,14 +238,10 @@ void do_IRQ(struct pt_regs *regs)
         irq_exit();
 
 #ifdef CONFIG_PPC_ISERIES
-        {
-                struct paca_struct *lpaca = get_paca();
-
-                if (lpaca->lppaca.int_dword.fields.decr_int) {
-                        lpaca->lppaca.int_dword.fields.decr_int = 0;
-                        /* Signal a fake decrementer interrupt */
-                        timer_interrupt(regs);
-                }
+        if (get_lppaca()->int_dword.fields.decr_int) {
+                get_lppaca()->int_dword.fields.decr_int = 0;
+                /* Signal a fake decrementer interrupt */
+                timer_interrupt(regs);
         }
 #endif
 }
diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
index 9dda16ccde78..1ae96a8ed7e2 100644
--- a/arch/powerpc/kernel/lparcfg.c
+++ b/arch/powerpc/kernel/lparcfg.c
@@ -55,15 +55,13 @@ static unsigned long get_purr(void)
 {
         unsigned long sum_purr = 0;
         int cpu;
-        struct paca_struct *lpaca;
 
         for_each_cpu(cpu) {
-                lpaca = paca + cpu;
-                sum_purr += lpaca->lppaca.emulated_time_base;
+                sum_purr += lppaca[cpu].emulated_time_base;
 
 #ifdef PURR_DEBUG
                 printk(KERN_INFO "get_purr for cpu (%d) has value (%ld) \n",
-                        cpu, lpaca->lppaca.emulated_time_base);
+                        cpu, lppaca[cpu].emulated_time_base);
 #endif
         }
         return sum_purr;
@@ -79,12 +77,11 @@ static int lparcfg_data(struct seq_file *m, void *v)
         unsigned long pool_id, lp_index;
         int shared, entitled_capacity, max_entitled_capacity;
         int processors, max_processors;
-        struct paca_struct *lpaca = get_paca();
         unsigned long purr = get_purr();
 
         seq_printf(m, "%s %s \n", MODULE_NAME, MODULE_VERS);
 
-        shared = (int)(lpaca->lppaca_ptr->shared_proc);
+        shared = (int)(get_lppaca()->shared_proc);
         seq_printf(m, "serial_number=%c%c%c%c%c%c%c\n",
                    e2a(xItExtVpdPanel.mfgID[2]),
                    e2a(xItExtVpdPanel.mfgID[3]),
@@ -402,7 +399,7 @@ static int lparcfg_data(struct seq_file *m, void *v)
                            (h_resource >> 0 * 8) & 0xffff);
 
                 /* pool related entries are apropriate for shared configs */
-                if (paca[0].lppaca.shared_proc) {
+                if (lppaca[0].shared_proc) {
 
                         h_pic(&pool_idle_time, &pool_procs);
 
@@ -451,7 +448,7 @@ static int lparcfg_data(struct seq_file *m, void *v)
         seq_printf(m, "partition_potential_processors=%d\n",
                    partition_potential_processors);
 
-        seq_printf(m, "shared_processor_mode=%d\n", paca[0].lppaca.shared_proc);
+        seq_printf(m, "shared_processor_mode=%d\n", lppaca[0].shared_proc);
 
         return 0;
 }
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 999bdd816769..5d1b708086bd 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -25,6 +25,28 @@
  * field correctly */
 extern unsigned long __toc_start;
 
+/*
+ * iSeries structure which the hypervisor knows about - this structure
+ * should not cross a page boundary.  The vpa_init/register_vpa call
+ * is now known to fail if the lppaca structure crosses a page
+ * boundary.  The lppaca is also used on POWER5 pSeries boxes.  The
+ * lppaca is 640 bytes long, and cannot readily change since the
+ * hypervisor knows its layout, so a 1kB alignment will suffice to
+ * ensure that it doesn't cross a page boundary.
+ */
+struct lppaca lppaca[] = {
+        [0 ... (NR_CPUS-1)] = {
+                .desc = 0xd397d781,     /* "LpPa" */
+                .size = sizeof(struct lppaca),
+                .dyn_proc_status = 2,
+                .decr_val = 0x00ff0000,
+                .fpregs_in_use = 1,
+                .end_of_quantum = 0xfffffffffffffffful,
+                .slb_count = 64,
+                .vmxregs_in_use = 0,
+        },
+};
+
 /* The Paca is an array with one entry per processor.  Each contains an
  * lppaca, which contains the information shared between the
  * hypervisor and Linux.
@@ -35,27 +57,17 @@ extern unsigned long __toc_start;
  * processor (not thread).
  */
 #define PACA_INIT_COMMON(number, start, asrr, asrv)                         \
+        .lppaca_ptr = &lppaca[number],                                      \
         .lock_token = 0x8000,                                               \
         .paca_index = (number),         /* Paca Index */                    \
         .kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL,             \
         .stab_real = (asrr),            /* Real pointer to segment table */ \
         .stab_addr = (asrv),            /* Virt pointer to segment table */ \
         .cpu_start = (start),           /* Processor start */               \
-        .hw_cpu_id = 0xffff,                                                \
-        .lppaca = {                                                         \
-                .desc = 0xd397d781,     /* "LpPa" */                        \
-                .size = sizeof(struct lppaca),                              \
-                .dyn_proc_status = 2,                                       \
-                .decr_val = 0x00ff0000,                                     \
-                .fpregs_in_use = 1,                                         \
-                .end_of_quantum = 0xfffffffffffffffful,                     \
-                .slb_count = 64,                                            \
-                .vmxregs_in_use = 0,                                        \
-        },                                                                  \
+        .hw_cpu_id = 0xffff,
 
 #ifdef CONFIG_PPC_ISERIES
 #define PACA_INIT_ISERIES(number)                                           \
-        .lppaca_ptr = &paca[number].lppaca,                                 \
         .reg_save_ptr = &iseries_reg_save[number],
 
 #define PACA_INIT(number)                                                   \
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 56f50e91bddb..c4a294d657b9 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -431,7 +431,7 @@ void timer_interrupt(struct pt_regs * regs)
         profile_tick(CPU_PROFILING, regs);
 
 #ifdef CONFIG_PPC_ISERIES
-        get_paca()->lppaca.int_dword.fields.decr_int = 0;
+        get_lppaca()->int_dword.fields.decr_int = 0;
 #endif
 
         while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu)))