Shifted left by 16 bits, so the low 16 bits of r14 remain available.
This allows per-cpu pointers to be dereferenced with a single extra
shift whereas previously it was a load and add.
---
arch/powerpc/include/asm/paca.h | 5 +++++
arch/powerpc/include/asm/percpu.h | 2 +-
arch/powerpc/kernel/entry_64.S | 5 -----
arch/powerpc/kernel/head_64.S | 5 +----
arch/powerpc/kernel/setup_64.c | 11 +++++++++--
5 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index cd6a9a010895..4dd4ac69e84f 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -35,6 +35,11 @@
register struct paca_struct *local_paca asm("r13");
#ifdef CONFIG_PPC_BOOK3S
+/*
+ * The top 32-bits of r14 is used as the per-cpu offset, shifted by PAGE_SHIFT.
+ * The per-cpu could be moved completely to vmalloc space if we had large
+ * vmalloc page mapping? (no, must access it in real mode).
+ */
register u64 local_r14 asm("r14");
#endif
diff --git a/arch/powerpc/include/asm/percpu.h
b/arch/powerpc/include/asm/percpu.h
index dce863a7635c..1e0d79d30eac 100644
--- a/arch/powerpc/include/asm/percpu.h
+++ b/arch/powerpc/include/asm/percpu.h
@@ -12,7 +12,7 @@
#include <asm/paca.h>
-#define __my_cpu_offset local_paca->data_offset
+#define __my_cpu_offset (local_r14 >> 16)
#endif /* CONFIG_SMP */
#endif /* __powerpc64__ */
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 592e4b36065f..6b0e3ac311e8 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -262,11 +262,6 @@ system_call_exit:
BEGIN_FTR_SECTION
stdcx. r0,0,r1 /* to clear the reservation */
END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
- LOAD_REG_IMMEDIATE(r10, 0xdeadbeefULL << 32)
- mfspr r11,SPRN_PIR
- or r10,r10,r11
- tdne r10,r14
-
andi. r6,r8,MSR_PR
ld r4,_LINK(r1)
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 5a9ec06eab14..cdb710f43681 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -413,10 +413,7 @@ generic_secondary_common_init:
b kexec_wait /* next kernel might do better */
2: SET_PACA(r13)
- LOAD_REG_IMMEDIATE(r14, 0xdeadbeef << 32)
- mfspr r3,SPRN_PIR
- or r14,r14,r3
- std r14,PACA_R14(r13)
+ ld r14,PACA_R14(r13)
#ifdef CONFIG_PPC_BOOK3E
addi r12,r13,PACA_EXTLB /* and TLB exc frame in another */
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 9a4c5bf35d92..f4a96ebb523a 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -192,8 +192,8 @@ static void __init fixup_boot_paca(void)
get_paca()->data_offset = 0;
/* Mark interrupts disabled in PACA */
irq_soft_mask_set(IRQ_SOFT_MASK_STD);
- /* Set r14 and paca_r14 to debug value */
- get_paca()->r14 = (0xdeadbeefULL << 32) | mfspr(SPRN_PIR);
+ /* Set r14 and paca_r14 to zero */
+ get_paca()->r14 = 0;
local_r14 = get_paca()->r14;
}
@@ -761,7 +761,14 @@ void __init setup_per_cpu_areas(void)
for_each_possible_cpu(cpu) {
__per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
paca[cpu].data_offset = __per_cpu_offset[cpu];
+
+ BUG_ON(paca[cpu].data_offset & (PAGE_SIZE-1));
+ BUG_ON(paca[cpu].data_offset >= (1UL << (64 - 16)));
+
+ /* The top 48 bits are used for per-cpu data */
+ paca[cpu].r14 |= paca[cpu].data_offset << 16;
}
+ local_r14 = paca[smp_processor_id()].r14;
}
#endif
--
2.15.0
