lkml.org 
[lkml]   [2018]   [Apr]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering
From
Date
On 4/2/2018 1:48 PM, Sinan Kaya wrote:
> memory-barriers.txt has been updated with the following requirement.
>
> "When using writel(), a prior wmb() is not needed to guarantee that the
> cache coherent memory writes have completed before writing to the MMIO
> region."
>
> Current writeX() and iowriteX() implementations on alpha are not
> satisfying this requirement as the barrier is after the register write.
>
> Move mb() in writeX() and iowriteX() functions to guarantee that HW
> observes memory changes before performing register operations.
>
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> ---
> arch/alpha/include/asm/io.h | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/arch/alpha/include/asm/io.h b/arch/alpha/include/asm/io.h
> index d123ff9..4c533fc 100644
> --- a/arch/alpha/include/asm/io.h
> +++ b/arch/alpha/include/asm/io.h
> @@ -341,14 +341,14 @@ extern inline unsigned int ioread16(void __iomem *addr)
>
> extern inline void iowrite8(u8 b, void __iomem *addr)
> {
> - IO_CONCAT(__IO_PREFIX,iowrite8)(b, addr);
> mb();
> + IO_CONCAT(__IO_PREFIX, iowrite8)(b, addr);
> }
>
> extern inline void iowrite16(u16 b, void __iomem *addr)
> {
> - IO_CONCAT(__IO_PREFIX,iowrite16)(b, addr);
> mb();
> + IO_CONCAT(__IO_PREFIX, iowrite16)(b, addr);
> }
>
> extern inline u8 inb(unsigned long port)
> @@ -382,8 +382,8 @@ extern inline unsigned int ioread32(void __iomem *addr)
>
> extern inline void iowrite32(u32 b, void __iomem *addr)
> {
> - IO_CONCAT(__IO_PREFIX,iowrite32)(b, addr);
> mb();
> + IO_CONCAT(__IO_PREFIX, iowrite32)(b, addr);
> }
>
> extern inline u32 inl(unsigned long port)
> @@ -434,14 +434,14 @@ extern inline u16 readw(const volatile void __iomem *addr)
>
> extern inline void writeb(u8 b, volatile void __iomem *addr)
> {
> - __raw_writeb(b, addr);
> mb();
> + __raw_writeb(b, addr);
> }
>
> extern inline void writew(u16 b, volatile void __iomem *addr)
> {
> - __raw_writew(b, addr);
> mb();
> + __raw_writew(b, addr);
> }
> #endif
>
> @@ -482,14 +482,14 @@ extern inline u64 readq(const volatile void __iomem *addr)
>
> extern inline void writel(u32 b, volatile void __iomem *addr)
> {
> - __raw_writel(b, addr);
> mb();
> + __raw_writel(b, addr);
> }
>
> extern inline void writeq(u64 b, volatile void __iomem *addr)
> {
> - __raw_writeq(b, addr);
> mb();
> + __raw_writeq(b, addr);
> }
> #endif
>
>


Can we get these merged to 4.17?

There was a consensus to fix the architectures having API violation issues.
https://www.mail-archive.com/netdev@vger.kernel.org/msg225971.html



--
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

\
 
 \ /
  Last update: 2018-04-06 03:35    [W:0.052 / U:1.216 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site