[PATCH 1/2] asm-generic/io: Pass result on inX() accessor to __io_par()

Will Deacon
2019-02-11T17:45:55Z

The inX() I/O accessors must enforce ordering against subsequent calls
to the delay() routines, so that a read-back from a device can be used
to postpone a subsequent write to the same device.

On some architectures, including arm64, this ordering can only be
achieved by creating a dependency on the value returned by the inX()
operation, so we need to pass the value we read to the __io_par()
macro in this case.

Reported-by: Andrew Murray <andrew.murray@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
include/asm-generic/io.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index d356f802945a..b5737c0d8316 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -65,7 +65,7 @@
#endif

#ifndef __io_par
-#define __io_par() __io_ar()
+#define __io_par(v) __io_ar()
#endif

@@ -471,7 +471,7 @@ static inline u8 inb(unsigned long addr)

__io_pbr();
val = __raw_readb(PCI_IOBASE + addr);
- __io_par();
+ __io_par(val);
return val;
}
#endif
@@ -484,7 +484,7 @@ static inline u16 inw(unsigned long addr)

__io_pbr();
val = __le16_to_cpu(__raw_readw(PCI_IOBASE + addr));
- __io_par();
+ __io_par(val);
return val;
}
#endif
@@ -497,7 +497,7 @@ static inline u32 inl(unsigned long addr)

__io_pbr();
val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr));
- __io_par();
+ __io_par(val);
return val;
}
#endif
--
2.11.0