* [PATCH] alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering
@ 2018-04-02 17:48 Sinan Kaya
2018-04-06 1:35 ` Sinan Kaya
0 siblings, 1 reply; 3+ messages in thread
From: Sinan Kaya @ 2018-04-02 17:48 UTC (permalink / raw)
To: linux-alpha, timur, sulrich
Cc: arnd, linux-arm-msm, linux-arm-kernel, Sinan Kaya,
Richard Henderson, Ivan Kokshaysky, Matt Turner,
Philippe Ombredanne, Greg Kroah-Hartman, Guenter Roeck,
Kate Stewart, linux-kernel
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
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering
2018-04-02 17:48 [PATCH] alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering Sinan Kaya
@ 2018-04-06 1:35 ` Sinan Kaya
2018-04-06 2:48 ` Matt Turner
0 siblings, 1 reply; 3+ messages in thread
From: Sinan Kaya @ 2018-04-06 1:35 UTC (permalink / raw)
To: linux-alpha, timur, sulrich
Cc: arnd, linux-arm-msm, linux-arm-kernel, Richard Henderson,
Ivan Kokshaysky, Matt Turner, Philippe Ombredanne,
Greg Kroah-Hartman, Guenter Roeck, Kate Stewart, linux-kernel
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.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering
2018-04-06 1:35 ` Sinan Kaya
@ 2018-04-06 2:48 ` Matt Turner
0 siblings, 0 replies; 3+ messages in thread
From: Matt Turner @ 2018-04-06 2:48 UTC (permalink / raw)
To: Sinan Kaya
Cc: linux-alpha, timur, sulrich, Arnd Bergmann, linux-arm-msm,
linux-arm-kernel, Richard Henderson, Ivan Kokshaysky,
Philippe Ombredanne, Greg Kroah-Hartman, Guenter Roeck,
Kate Stewart, LKML
On Thu, Apr 5, 2018 at 6:35 PM, Sinan Kaya <okaya@codeaurora.org> wrote:
> 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
I expect so. Sorry I haven't had time to collect patches yet. I think
tomorrow or the next day I will.
^ permalink raw reply [flat|nested] 3+ messages in thread
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