powerpc: Create a helper for getting the kernel toc value

Move the logic to work out the kernel toc pointer into a header. This is
a good cleanup, and also means we can use it elsewhere in future.

Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reviewed-by: Torsten Duwe <duwe@suse.de>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>

diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index a5e930a..abf5866 100644 (file)
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -22,6 +22,18 @@ static inline int in_kernel_text(unsigned long addr)
        return 0;
 }
 
+static inline unsigned long kernel_toc_addr(void)
+{
+       /* Defined by the linker, see vmlinux.lds.S */
+       extern unsigned long __toc_start;
+
+       /*
+        * The TOC register (r2) points 32kB into the TOC, so that 64kB of
+        * the TOC can be addressed using a single machine instruction.
+        */
+       return (unsigned long)(&__toc_start) + 0x8000UL;
+}
+
 static inline int overlaps_interrupt_vector_text(unsigned long start,
                                                        unsigned long end)
 {

diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 01ea0ed..93dae29 100644 (file)
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -17,10 +17,6 @@
 #include <asm/pgtable.h>
 #include <asm/kexec.h>
 
-/* This symbol is provided by the linker - let it fill in the paca
- * field correctly */
-extern unsigned long __toc_start;
-
 #ifdef CONFIG_PPC_BOOK3S
 
 /*
@@ -149,11 +145,6 @@ EXPORT_SYMBOL(paca);
 
 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 {
-       /* The TOC register (GPR2) points 32kB into the TOC, so that 64kB
-       * of the TOC can be addressed using a single machine instruction.
-       */
-       unsigned long kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL;
-
 #ifdef CONFIG_PPC_BOOK3S
        new_paca->lppaca_ptr = new_lppaca(cpu);
 #else
@@ -161,7 +152,7 @@ void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 #endif
        new_paca->lock_token = 0x8000;
        new_paca->paca_index = cpu;
-       new_paca->kernel_toc = kernel_toc;
+       new_paca->kernel_toc = kernel_toc_addr();
        new_paca->kernelbase = (unsigned long) _stext;
        /* Only set MSR:IR/DR when MMU is initialized */
        new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);