[PATCH 1/4] powerpc: Convert some mftb/mftbu into mfspr
Scott Wood
scottwood at freescale.com
Wed Aug 21 12:12:39 EST 2013
Some CPUs (such as e500v1/v2) don't implement mftb and will take a
trap. mfspr should work on everything that has a timebase, and is the
preferred instruction according to ISA v2.06.
Currently we get away with mftb on 85xx because the assembler converts
it to mfspr due to -Wa,-me500. However, that flag has other effects
that are undesireable for certain targets (e.g. lwsync is converted to
sync), and is hostile to multiplatform kernels. Thus we would like to
stop setting it for all e500-family builds.
mftb/mftbu instances which are in 85xx code or common code are
converted. Instances which will never run on 85xx are left alone.
Signed-off-by: Scott Wood <scottwood at freescale.com>
---
arch/powerpc/boot/ppc_asm.h | 3 +++
arch/powerpc/boot/util.S | 10 +++++-----
arch/powerpc/include/asm/ppc_asm.h | 4 ++--
arch/powerpc/include/asm/reg.h | 15 ++++++++++-----
arch/powerpc/include/asm/timex.h | 4 ++--
arch/powerpc/kernel/vdso32/gettimeofday.S | 6 +++---
arch/powerpc/platforms/85xx/smp.c | 6 ++++--
7 files changed, 29 insertions(+), 19 deletions(-)
diff --git a/arch/powerpc/boot/ppc_asm.h b/arch/powerpc/boot/ppc_asm.h
index 1c2c281..eb0e98b 100644
--- a/arch/powerpc/boot/ppc_asm.h
+++ b/arch/powerpc/boot/ppc_asm.h
@@ -59,4 +59,7 @@
#define r30 30
#define r31 31
+#define SPRN_TBRL 268
+#define SPRN_TBRU 269
+
#endif /* _PPC64_PPC_ASM_H */
diff --git a/arch/powerpc/boot/util.S b/arch/powerpc/boot/util.S
index 427ddfc..5143228 100644
--- a/arch/powerpc/boot/util.S
+++ b/arch/powerpc/boot/util.S
@@ -71,18 +71,18 @@ udelay:
add r4,r4,r5
addi r4,r4,-1
divw r4,r4,r5 /* BUS ticks */
-1: mftbu r5
- mftb r6
- mftbu r7
+1: mfspr r5, SPRN_TBRU
+ mfspr r6, SPRN_TBRL
+ mfspr r7, SPRN_TBRU
cmpw 0,r5,r7
bne 1b /* Get [synced] base time */
addc r9,r6,r4 /* Compute end time */
addze r8,r5
-2: mftbu r5
+2: mfspr r5, SPRN_TBRU
cmpw 0,r5,r8
blt 2b
bgt 3f
- mftb r6
+ mfspr r6, SPRN_TBRL
cmpw 0,r6,r9
blt 2b
3: blr
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index 8fdd3da..5995457 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -433,13 +433,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_601)
#if defined(CONFIG_PPC_CELL) || defined(CONFIG_PPC_FSL_BOOK3E)
#define MFTB(dest) \
-90: mftb dest; \
+90: mfspr dest, SPRN_TBRL; \
BEGIN_FTR_SECTION_NESTED(96); \
cmpwi dest,0; \
beq- 90b; \
END_FTR_SECTION_NESTED(CPU_FTR_CELL_TB_BUG, CPU_FTR_CELL_TB_BUG, 96)
#else
-#define MFTB(dest) mftb dest
+#define MFTB(dest) mfspr dest, SPRN_TBRL
#endif
#ifndef CONFIG_SMP
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 55b0307..64264bf 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1120,7 +1120,7 @@
#if defined(CONFIG_PPC_CELL) || defined(CONFIG_PPC_FSL_BOOK3E)
#define mftb() ({unsigned long rval; \
asm volatile( \
- "90: mftb %0;\n" \
+ "90: mfspr %0, %2;\n" \
"97: cmpwi %0,0;\n" \
" beq- 90b;\n" \
"99:\n" \
@@ -1134,18 +1134,23 @@
" .llong 0\n" \
" .llong 0\n" \
".previous" \
- : "=r" (rval) : "i" (CPU_FTR_CELL_TB_BUG)); rval;})
+ : "=r" (rval) \
+ : "i" (CPU_FTR_CELL_TB_BUG), "i" (SPRN_TBRL)); \
+ rval;})
#else
#define mftb() ({unsigned long rval; \
- asm volatile("mftb %0" : "=r" (rval)); rval;})
+ asm volatile("mfspr %0, %1" : \
+ "=r" (rval) : "i" (SPRN_TBRL)); rval;})
#endif /* !CONFIG_PPC_CELL */
#else /* __powerpc64__ */
#define mftbl() ({unsigned long rval; \
- asm volatile("mftbl %0" : "=r" (rval)); rval;})
+ asm volatile("mfspr %0, %1" : "=r" (rval) : \
+ "i" (SPRN_TBRL)); rval;})
#define mftbu() ({unsigned long rval; \
- asm volatile("mftbu %0" : "=r" (rval)); rval;})
+ asm volatile("mfspr %0, %1" : "=r" (rval) : \
+ "i" (SPRN_TBRU)); rval;})
#endif /* !__powerpc64__ */
#define mttbl(v) asm volatile("mttbl %0":: "r"(v))
diff --git a/arch/powerpc/include/asm/timex.h b/arch/powerpc/include/asm/timex.h
index c55e14f..18908ca 100644
--- a/arch/powerpc/include/asm/timex.h
+++ b/arch/powerpc/include/asm/timex.h
@@ -29,7 +29,7 @@ static inline cycles_t get_cycles(void)
ret = 0;
__asm__ __volatile__(
- "97: mftb %0\n"
+ "97: mfspr %0, %2\n"
"99:\n"
".section __ftr_fixup,\"a\"\n"
".align 2\n"
@@ -41,7 +41,7 @@ static inline cycles_t get_cycles(void)
" .long 0\n"
" .long 0\n"
".previous"
- : "=r" (ret) : "i" (CPU_FTR_601));
+ : "=r" (ret) : "i" (CPU_FTR_601), "i" (SPRN_TBRL));
return ret;
#endif
}
diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index 27e2f62..6b1f2a6 100644
--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
@@ -232,9 +232,9 @@ __do_get_tspec:
lwz r6,(CFG_TB_ORIG_STAMP+4)(r9)
/* Get a stable TB value */
-2: mftbu r3
- mftbl r4
- mftbu r0
+2: mfspr r3, SPRN_TBRU
+ mfspr r4, SPRN_TBRL
+ mfspr r0, SPRN_TBRU
cmplw cr0,r3,r0
bne- 2b
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
index ea7e629..281b7f0 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -83,11 +83,13 @@ static void mpc85xx_give_timebase(void)
{
u64 prev;
- asm volatile("mftb %0" : "=r" (timebase));
+ asm volatile("mfspr %0, %1" : "=r" (timebase) :
+ "i" (SPRN_TBRL));
do {
prev = timebase;
- asm volatile("mftb %0" : "=r" (timebase));
+ asm volatile("mfspr %0, %1" : "=r" (timebase) :
+ "i" (SPRN_TBRL));
} while (prev != timebase);
}
#else
--
1.8.1.2
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