diff options
| author | Jason Baron <jbaron@akamai.com> | 2014-07-04 15:27:04 +0400 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2014-07-04 15:27:30 +0400 |
| commit | 3a044178cccfeb8664423c2950c499c3a209ed9f (patch) | |
| tree | 8e9f4ba1747353932ed218157d05915b28b920c7 /include/asm-generic/io-64-nonatomic-hi-lo.h | |
| parent | 6866b390562b2c948c6f6fc2a5c103f090a02e01 (diff) | |
| download | linux-3a044178cccfeb8664423c2950c499c3a209ed9f.tar.xz | |
readq/writeq: Add explicit lo_hi_[read|write]_q and hi_lo_[read|write]_q
Even on x86-64, I've found the need to break up a readq() into 2 readl()
calls. According to the Intel datasheet for the E3-1200 processor:
"
Software must not access B0/D0/F0 32-bit memory-mapped registers with
requests that cross a DW boundary.
"
(http://www.intel.com/content/www/us/en/processors/xeon/xeon-e3-1200-family-vol-2-datasheet.html p. 16)
I can confirm this is true via several hard machine lockups.
Thus, add explicit hi_lo_[readq|write]_q and lo_hi_[read|write]_q so that these
uses are spelled out.
Signed-off-by: Jason Baron <jbaron@akamai.com>
Link: http://lkml.kernel.org/r/281f09da7ad01e5cea99737ec34d2399bdbbbf63.1403818526.git.jbaron@akamai.com
Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'include/asm-generic/io-64-nonatomic-hi-lo.h')
| -rw-r--r-- | include/asm-generic/io-64-nonatomic-hi-lo.h | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/include/asm-generic/io-64-nonatomic-hi-lo.h b/include/asm-generic/io-64-nonatomic-hi-lo.h index a6806a94250d..2e29d13fc154 100644 --- a/include/asm-generic/io-64-nonatomic-hi-lo.h +++ b/include/asm-generic/io-64-nonatomic-hi-lo.h @@ -4,8 +4,7 @@ #include <linux/io.h> #include <asm-generic/int-ll64.h> -#ifndef readq -static inline __u64 readq(const volatile void __iomem *addr) +static inline __u64 hi_lo_readq(const volatile void __iomem *addr) { const volatile u32 __iomem *p = addr; u32 low, high; @@ -15,14 +14,19 @@ static inline __u64 readq(const volatile void __iomem *addr) return low + ((u64)high << 32); } -#endif -#ifndef writeq -static inline void writeq(__u64 val, volatile void __iomem *addr) +static inline void hi_lo_writeq(__u64 val, volatile void __iomem *addr) { writel(val >> 32, addr + 4); writel(val, addr); } + +#ifndef readq +#define readq hi_lo_readq +#endif + +#ifndef writeq +#define writeq hi_lo_writeq #endif #endif /* _ASM_IO_64_NONATOMIC_HI_LO_H_ */ |