From: Will Deacon <will.deacon@arm.com>
To: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, andrew.murray@arm.com,
arnd@arndb.de, catalin.marinas@arm.com,
Will Deacon <will.deacon@arm.com>
Subject: [PATCH 1/2] asm-generic/io: Pass result on inX() accessor to __io_par()
Date: Mon, 11 Feb 2019 17:45:43 +0000 [thread overview]
Message-ID: <20190211174544.4302-2-will.deacon@arm.com> (raw)
In-Reply-To: <20190211174544.4302-1-will.deacon@arm.com>
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
next prev parent reply other threads:[~2019-02-11 17:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-11 17:45 [PATCH 0/2] Ensure inX() is ordered wrt delay() routines Will Deacon
2019-02-11 17:45 ` Will Deacon [this message]
2019-02-12 11:55 ` [PATCH 1/2] asm-generic/io: Pass result on inX() accessor to __io_par() Arnd Bergmann
2019-02-13 17:46 ` Will Deacon
2019-02-13 20:59 ` Arnd Bergmann
2019-02-13 21:57 ` Palmer Dabbelt
2019-02-18 15:56 ` Will Deacon
2019-02-11 17:45 ` [PATCH 2/2] arm64: io: Hook up __io_par() for inX() ordering Will Deacon
2019-02-12 10:42 ` Geert Uytterhoeven
2019-02-13 17:25 ` Will Deacon
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