From f007cacffc8870702a1473d83ba5e4922d54e17c Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Wed, 13 Sep 2006 22:08:26 +1000 Subject: [POWERPC] Fix MMIO ops to provide expected barrier behaviour This changes the writeX family of functions to have a sync instruction before the MMIO store rather than after, because the generally expected behaviour is that the device receiving the MMIO store can be guaranteed to see the effects of any preceding writes to normal memory. To preserve ordering between writeX and readX, and to preserve ordering between preceding stores and the readX, the readX family of functions have had an sync added before the load. Although writeX followed by spin_unlock is not officially guaranteed to keep the writeX inside the spin-locked region unless an mmiowb() is used, there are currently drivers that depend on the previous behaviour on powerpc, which was that the mmiowb wasn't actually required. Therefore we have a per-cpu flag that is set by writeX, cleared by __raw_spin_lock and mmiowb, and tested by __raw_spin_unlock. If it is set, __raw_spin_unlock does a sync and clears it. This changes both 32-bit and 64-bit readX/writeX. 32-bit already has a sync in __raw_spin_unlock (since lwsync doesn't exist on 32-bit), and thus doesn't need the per-cpu flag. Tested on G5 (PPC970) and POWER5. Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/misc.S | 49 +++++++++++++++++++++++----------------------- 1 file changed, 25 insertions(+), 24 deletions(-) (limited to 'arch') diff --git a/arch/powerpc/kernel/misc.S b/arch/powerpc/kernel/misc.S index fc23040d5a26..f770805f1215 100644 --- a/arch/powerpc/kernel/misc.S +++ b/arch/powerpc/kernel/misc.S @@ -17,15 +17,6 @@ .text -#ifdef CONFIG_PPC64 -#define IN_SYNC twi 0,r5,0; isync -#define EIEIO_32 -#define SYNC_64 sync -#else /* CONFIG_PPC32 */ -#define IN_SYNC -#define EIEIO_32 eieio -#define SYNC_64 -#endif /* * Returns (address we are running at) - (address we were linked at) * for use before the text and data are mapped to KERNELBASE. @@ -70,6 +61,7 @@ _GLOBAL(add_reloc_offset) * The *_ns versions don't do byte-swapping. */ _GLOBAL(_insb) + sync cmpwi 0,r5,0 mtctr r5 subi r4,r4,1 @@ -78,7 +70,8 @@ _GLOBAL(_insb) eieio stbu r5,1(r4) bdnz 00b - IN_SYNC + twi 0,r5,0 + isync blr _GLOBAL(_outsb) @@ -86,14 +79,15 @@ _GLOBAL(_outsb) mtctr r5 subi r4,r4,1 blelr- + sync 00: lbzu r5,1(r4) stb r5,0(r3) - EIEIO_32 bdnz 00b - SYNC_64 + sync blr _GLOBAL(_insw) + sync cmpwi 0,r5,0 mtctr r5 subi r4,r4,2 @@ -102,7 +96,8 @@ _GLOBAL(_insw) eieio sthu r5,2(r4) bdnz 00b - IN_SYNC + twi 0,r5,0 + isync blr _GLOBAL(_outsw) @@ -110,14 +105,15 @@ _GLOBAL(_outsw) mtctr r5 subi r4,r4,2 blelr- + sync 00: lhzu r5,2(r4) - EIEIO_32 sthbrx r5,0,r3 bdnz 00b - SYNC_64 + sync blr _GLOBAL(_insl) + sync cmpwi 0,r5,0 mtctr r5 subi r4,r4,4 @@ -126,7 +122,8 @@ _GLOBAL(_insl) eieio stwu r5,4(r4) bdnz 00b - IN_SYNC + twi 0,r5,0 + isync blr _GLOBAL(_outsl) @@ -134,17 +131,18 @@ _GLOBAL(_outsl) mtctr r5 subi r4,r4,4 blelr- + sync 00: lwzu r5,4(r4) stwbrx r5,0,r3 - EIEIO_32 bdnz 00b - SYNC_64 + sync blr #ifdef CONFIG_PPC32 _GLOBAL(__ide_mm_insw) #endif _GLOBAL(_insw_ns) + sync cmpwi 0,r5,0 mtctr r5 subi r4,r4,2 @@ -153,7 +151,8 @@ _GLOBAL(_insw_ns) eieio sthu r5,2(r4) bdnz 00b - IN_SYNC + twi 0,r5,0 + isync blr #ifdef CONFIG_PPC32 @@ -164,17 +163,18 @@ _GLOBAL(_outsw_ns) mtctr r5 subi r4,r4,2 blelr- + sync 00: lhzu r5,2(r4) sth r5,0(r3) - EIEIO_32 bdnz 00b - SYNC_64 + sync blr #ifdef CONFIG_PPC32 _GLOBAL(__ide_mm_insl) #endif _GLOBAL(_insl_ns) + sync cmpwi 0,r5,0 mtctr r5 subi r4,r4,4 @@ -183,7 +183,8 @@ _GLOBAL(_insl_ns) eieio stwu r5,4(r4) bdnz 00b - IN_SYNC + twi 0,r5,0 + isync blr #ifdef CONFIG_PPC32 @@ -194,10 +195,10 @@ _GLOBAL(_outsl_ns) mtctr r5 subi r4,r4,4 blelr- + sync 00: lwzu r5,4(r4) stw r5,0(r3) - EIEIO_32 bdnz 00b - SYNC_64 + sync blr -- cgit v1.2.3-59-g8ed1b