powerpc: Introduce toreal/fromreal assembly macros

On 32-bit platforms, these convert from kernel virtual addresses
to real (physical addresses), like tophys/tovirt but they use
the same register for the source and destination.  On 64-bit
platforms, they do nothing because the hardware ignores the top
two bits of the address in real mode.

These new macros are used in fpu.S now.

Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 19 insertions, 18 deletions

diff --git a/arch/powerpc/kernel/fpu.S b/arch/powerpc/kernel/fpu.S
index 51fd78da25b7..4d6001fa1cf2 100644
--- a/arch/powerpc/kernel/fpu.S
+++ b/arch/powerpc/kernel/fpu.S
@@ -40,17 +40,17 @@ _GLOBAL(load_up_fpu)
  */
 #ifndef CONFIG_SMP
         LOADBASE(r3, last_task_used_math)
-        tophys(r3,r3)
+        toreal(r3)
         LDL     r4,OFF(last_task_used_math)(r3)
         CMPI    0,r4,0
         beq     1f
-        tophys(r4,r4)
+        toreal(r4)
         addi    r4,r4,THREAD            /* want last_task_used_math->thread */
         SAVE_32FPRS(0, r4)
         mffs    fr0
         stfd    fr0,THREAD_FPSCR(r4)
         LDL     r5,PT_REGS(r4)
-        tophys(r5,r5)
+        toreal(r5)
         LDL     r4,_MSR-STACK_FRAME_OVERHEAD(r5)
         li      r10,MSR_FP|MSR_FE0|MSR_FE1
         andc    r4,r4,r10               /* disable FP for previous task */
@@ -76,7 +76,7 @@ _GLOBAL(load_up_fpu)
         REST_32FPRS(0, r5)
 #ifndef CONFIG_SMP
         subi    r4,r5,THREAD
-        tovirt(r4,r4)
+        fromreal(r4)
         STL     r4,OFF(last_task_used_math)(r3)
 #endif /* CONFIG_SMP */
         /* restore registers and return */
diff --git a/include/asm-powerpc/ppc_asm.h b/include/asm-powerpc/ppc_asm.h
index f8ad5df6ebef..470d7400ac59 100644
--- a/include/asm-powerpc/ppc_asm.h
+++ b/include/asm-powerpc/ppc_asm.h
@@ -154,7 +154,7 @@ n:
  *   loads the address of 'name' into 'rn'
  *
  * LOADBASE( rn, name )
- *   loads the address (less the low 16 bits) of 'name' into 'rn'
+ *   loads the address (possibly without the low 16 bits) of 'name' into 'rn'
  *   suitable for base+disp addressing
  */
 #ifdef __powerpc64__
@@ -166,10 +166,7 @@ n:
         ori     rn,rn,name##@l
 
 #define LOADBASE(rn,name)               \
-        .section .toc,"aw";             \
-1:      .tc     name[TC],name;          \
-        .previous;                      \
-        ld      rn,1b@toc(r2)
+        ld      rn,name@got(r2)
 
 #define OFF(name)       0
 
@@ -278,6 +275,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_601)
 
 
 #if defined(CONFIG_BOOKE)
+#define toreal(rd)
+#define fromreal(rd)
+
 #define tophys(rd,rs)                           \
         addis   rd,rs,0
 
@@ -285,23 +285,24 @@ END_FTR_SECTION_IFCLR(CPU_FTR_601)
         addis   rd,rs,0
 
 #elif defined(CONFIG_PPC64)
-/* PPPBBB - DRENG  If KERNELBASE is always 0xC0...,
- * Then we can easily do this with one asm insn. -Peter
- */
+#define toreal(rd)              /* we can access c000... in real mode */
+#define fromreal(rd)
+
 #define tophys(rd,rs)                           \
-        lis     rd,((KERNELBASE>>48)&0xFFFF);   \
-        rldicr  rd,rd,32,31;                    \
-        sub     rd,rs,rd
+        clrldi  rd,rs,2
 
 #define tovirt(rd,rs)                           \
-        lis     rd,((KERNELBASE>>48)&0xFFFF);   \
-        rldicr  rd,rd,32,31;                    \
-        add     rd,rs,rd
+        rotldi  rd,rs,16;                       \
+        ori     rd,rd,((KERNELBASE>>48)&0xFFFF);\
+        rotldi  rd,rd,48
 #else
 /*
  * On APUS (Amiga PowerPC cpu upgrade board), we don't know the
  * physical base address of RAM at compile time.
  */
+#define toreal(rd)      tophys(rd,rd)
+#define fromreal(rd)    tovirt(rd,rd)
+
 #define tophys(rd,rs)                           \
 0:      addis   rd,rs,-KERNELBASE@h;            \
         .section ".vtop_fixup","aw";            \