From dbee8a0affd5e6eaa5d7c816c4bc233f6f110f50 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Tue, 24 May 2011 17:13:09 -0700 Subject: x86: remove 32-bit versions of readq()/writeq() The presense of a writeq() implementation on 32-bit x86 that splits the 64-bit write into two 32-bit writes turns out to break the mpt2sas driver (and in general is risky for drivers as was discussed in ). To fix this, revert 2c5643b1c5c7 ("x86: provide readq()/writeq() on 32-bit too") and follow-on cleanups. This unfortunately leads to pushing non-atomic definitions of readq() and write() to various x86-only drivers that in the meantime started using the definitions in the x86 version of . However as discussed exhaustively, this is actually the right thing to do, because the right way to split a 64-bit transaction is hardware dependent and therefore belongs in the hardware driver (eg mpt2sas needs a spinlock to make sure no other accesses occur in between the two halves of the access). Build tested on 32- and 64-bit x86 allmodconfig. Link: http://lkml.kernel.org/r/x86-32-writeq-is-broken@mdm.bga.com Acked-by: Hitoshi Mitake Cc: Kashyap Desai Cc: Len Brown Cc: Ravi Anand Cc: Vikas Chaudhary Cc: Matthew Garrett Cc: Jason Uhlenkott Acked-by: James Bottomley Acked-by: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Signed-off-by: Roland Dreier Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/Kconfig | 2 -- arch/x86/include/asm/io.h | 24 ++---------------------- 2 files changed, 2 insertions(+), 24 deletions(-) (limited to 'arch') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 880fcb6c86f4..fa2cc8c5d01c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -17,8 +17,6 @@ config X86_64 config X86 def_bool y select HAVE_AOUT if X86_32 - select HAVE_READQ - select HAVE_WRITEQ select HAVE_UNSTABLE_SCHED_CLOCK select HAVE_IDE select HAVE_OPROFILE diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 072273082528..d02804d650c4 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -38,7 +38,6 @@ #include #include -#include #include #include @@ -87,27 +86,6 @@ build_mmio_write(__writel, "l", unsigned int, "r", ) build_mmio_read(readq, "q", unsigned long, "=r", :"memory") build_mmio_write(writeq, "q", unsigned long, "r", :"memory") -#else - -static inline __u64 readq(const volatile void __iomem *addr) -{ - const volatile u32 __iomem *p = addr; - u32 low, high; - - low = readl(p); - high = readl(p + 1); - - return low + ((u64)high << 32); -} - -static inline void writeq(__u64 val, volatile void __iomem *addr) -{ - writel(val, addr); - writel(val >> 32, addr+4); -} - -#endif - #define readq_relaxed(a) readq(a) #define __raw_readq(a) readq(a) @@ -117,6 +95,8 @@ static inline void writeq(__u64 val, volatile void __iomem *addr) #define readq readq #define writeq writeq +#endif + /** * virt_to_phys - map virtual addresses to physical * @address: address to remap -- cgit v1.2.3