Re: [PATCH v14 3/9] fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()

2018-02-15 Thread Michael S. Tsirkin 
On Thu, Feb 15, 2018 at 10:34:28AM +0100, Marc-Andre Lureau wrote:
> On Wed, Feb 14, 2018 at 9:46 PM, Michael S. Tsirkin  wrote:
> > On Wed, Feb 14, 2018 at 03:18:44PM +0100, Marc-André Lureau wrote:
> >> The function is used for both LE & BE target type, use __force casting.
> >>
> >> Fixes:
> >> $ make C=1 CF=-D__CHECK_ENDIAN__ drivers/firmware/qemu_fw_cfg.o
> >>
> >> drivers/firmware/qemu_fw_cfg.c:55:33: warning: restricted __be16 degrades 
> >> to integer
> >> drivers/firmware/qemu_fw_cfg.c:55:52: warning: restricted __le16 degrades 
> >> to integer
> >>
> >> Signed-off-by: Marc-André Lureau 
> >> ---
> >>  drivers/firmware/qemu_fw_cfg.c | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/firmware/qemu_fw_cfg.c 
> >> b/drivers/firmware/qemu_fw_cfg.c
> >> index 90f467232777..85e693287d87 100644
> >> --- a/drivers/firmware/qemu_fw_cfg.c
> >> +++ b/drivers/firmware/qemu_fw_cfg.c
> >> @@ -52,7 +52,9 @@ static DEFINE_MUTEX(fw_cfg_dev_lock);
> >>  /* pick appropriate endianness for selector key */
> >>  static inline u16 fw_cfg_sel_endianness(u16 key)
> >>  {
> >> - return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
> >> + return fw_cfg_is_mmio ?
> >> + (u16 __force)cpu_to_be16(key) :
> >> + (u16 __force)cpu_to_le16(key);
> >>  }
> >>
> >>  /* read chunk of given fw_cfg blob (caller responsible for sanity-check) 
> >> */
> >
> > Well the caller does cpu_to_le16 on the result ...
> > All this makes my head spin.
> >
> > IMHO what you want is a wrapper that does iowrite and iowritebe
> > rather than __force.
> 
> iowrite16(key) is the same as iowrite16(cpu_to_le16(key)) ? There is
> no iowrite16le()...

Yes.

> Is this equivalent, and not introducing regressions?
> 
> static inline u16 fw_cfg_sel_endianness(u16 key)
> +static void fw_cfg_sel_endianness(u16 key)
>  {
> -   return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);

For mmio on LE it does 1 swap. On BE 1 swap.
For non mmio on LE it does no swaps. On BE 1 swap.

Fair summary?

And is this actually the intended behaviour.

> +   if (fw_cfg_is_mmio)
> +   iowrite16be(key, fw_cfg_reg_ctrl);
> +   else
> +   iowrite16(key, fw_cfg_reg_ctrl);


this behaves differently. donnu if that's a bug or
a feature. You will have to find out.

>  }
> 
>  /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
> @@ -74,7 +77,7 @@ static inline void fw_cfg_read_blob(u16 key,
> }
> 
> mutex_lock(_cfg_dev_lock);
> -   iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
> +   fw_cfg_sel_endianness(key);
> 
> >
> >
> >> --
> >> 2.16.1.73.g5832b7e9f2

Re: [PATCH v14 3/9] fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()

2018-02-15 Thread Michael S. Tsirkin 
On Thu, Feb 15, 2018 at 10:34:28AM +0100, Marc-Andre Lureau wrote:
> On Wed, Feb 14, 2018 at 9:46 PM, Michael S. Tsirkin  wrote:
> > On Wed, Feb 14, 2018 at 03:18:44PM +0100, Marc-André Lureau wrote:
> >> The function is used for both LE & BE target type, use __force casting.
> >>
> >> Fixes:
> >> $ make C=1 CF=-D__CHECK_ENDIAN__ drivers/firmware/qemu_fw_cfg.o
> >>
> >> drivers/firmware/qemu_fw_cfg.c:55:33: warning: restricted __be16 degrades 
> >> to integer
> >> drivers/firmware/qemu_fw_cfg.c:55:52: warning: restricted __le16 degrades 
> >> to integer
> >>
> >> Signed-off-by: Marc-André Lureau 
> >> ---
> >>  drivers/firmware/qemu_fw_cfg.c | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/firmware/qemu_fw_cfg.c 
> >> b/drivers/firmware/qemu_fw_cfg.c
> >> index 90f467232777..85e693287d87 100644
> >> --- a/drivers/firmware/qemu_fw_cfg.c
> >> +++ b/drivers/firmware/qemu_fw_cfg.c
> >> @@ -52,7 +52,9 @@ static DEFINE_MUTEX(fw_cfg_dev_lock);
> >>  /* pick appropriate endianness for selector key */
> >>  static inline u16 fw_cfg_sel_endianness(u16 key)
> >>  {
> >> - return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
> >> + return fw_cfg_is_mmio ?
> >> + (u16 __force)cpu_to_be16(key) :
> >> + (u16 __force)cpu_to_le16(key);
> >>  }
> >>
> >>  /* read chunk of given fw_cfg blob (caller responsible for sanity-check) 
> >> */
> >
> > Well the caller does cpu_to_le16 on the result ...
> > All this makes my head spin.
> >
> > IMHO what you want is a wrapper that does iowrite and iowritebe
> > rather than __force.
> 
> iowrite16(key) is the same as iowrite16(cpu_to_le16(key)) ? There is
> no iowrite16le()...

Yes.

> Is this equivalent, and not introducing regressions?
> 
> static inline u16 fw_cfg_sel_endianness(u16 key)
> +static void fw_cfg_sel_endianness(u16 key)
>  {
> -   return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);

For mmio on LE it does 1 swap. On BE 1 swap.
For non mmio on LE it does no swaps. On BE 1 swap.

Fair summary?

And is this actually the intended behaviour.

> +   if (fw_cfg_is_mmio)
> +   iowrite16be(key, fw_cfg_reg_ctrl);
> +   else
> +   iowrite16(key, fw_cfg_reg_ctrl);


this behaves differently. donnu if that's a bug or
a feature. You will have to find out.

>  }
> 
>  /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
> @@ -74,7 +77,7 @@ static inline void fw_cfg_read_blob(u16 key,
> }
> 
> mutex_lock(_cfg_dev_lock);
> -   iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
> +   fw_cfg_sel_endianness(key);
> 
> >
> >
> >> --
> >> 2.16.1.73.g5832b7e9f2

Re: [PATCH v14 3/9] fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()

2018-02-15 Thread Marc-Andre Lureau 
On Wed, Feb 14, 2018 at 9:46 PM, Michael S. Tsirkin  wrote:
> On Wed, Feb 14, 2018 at 03:18:44PM +0100, Marc-André Lureau wrote:
>> The function is used for both LE & BE target type, use __force casting.
>>
>> Fixes:
>> $ make C=1 CF=-D__CHECK_ENDIAN__ drivers/firmware/qemu_fw_cfg.o
>>
>> drivers/firmware/qemu_fw_cfg.c:55:33: warning: restricted __be16 degrades to 
>> integer
>> drivers/firmware/qemu_fw_cfg.c:55:52: warning: restricted __le16 degrades to 
>> integer
>>
>> Signed-off-by: Marc-André Lureau 
>> ---
>>  drivers/firmware/qemu_fw_cfg.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
>> index 90f467232777..85e693287d87 100644
>> --- a/drivers/firmware/qemu_fw_cfg.c
>> +++ b/drivers/firmware/qemu_fw_cfg.c
>> @@ -52,7 +52,9 @@ static DEFINE_MUTEX(fw_cfg_dev_lock);
>>  /* pick appropriate endianness for selector key */
>>  static inline u16 fw_cfg_sel_endianness(u16 key)
>>  {
>> - return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
>> + return fw_cfg_is_mmio ?
>> + (u16 __force)cpu_to_be16(key) :
>> + (u16 __force)cpu_to_le16(key);
>>  }
>>
>>  /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
>
> Well the caller does cpu_to_le16 on the result ...
> All this makes my head spin.
>
> IMHO what you want is a wrapper that does iowrite and iowritebe
> rather than __force.

iowrite16(key) is the same as iowrite16(cpu_to_le16(key)) ? There is
no iowrite16le()...

Is this equivalent, and not introducing regressions?

static inline u16 fw_cfg_sel_endianness(u16 key)
+static void fw_cfg_sel_endianness(u16 key)
 {
-   return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
+   if (fw_cfg_is_mmio)
+   iowrite16be(key, fw_cfg_reg_ctrl);
+   else
+   iowrite16(key, fw_cfg_reg_ctrl);
 }

 /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
@@ -74,7 +77,7 @@ static inline void fw_cfg_read_blob(u16 key,
}

mutex_lock(_cfg_dev_lock);
-   iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
+   fw_cfg_sel_endianness(key);

>
>
>> --
>> 2.16.1.73.g5832b7e9f2

Re: [PATCH v14 3/9] fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()

2018-02-15 Thread Marc-Andre Lureau 
On Wed, Feb 14, 2018 at 9:46 PM, Michael S. Tsirkin  wrote:
> On Wed, Feb 14, 2018 at 03:18:44PM +0100, Marc-André Lureau wrote:
>> The function is used for both LE & BE target type, use __force casting.
>>
>> Fixes:
>> $ make C=1 CF=-D__CHECK_ENDIAN__ drivers/firmware/qemu_fw_cfg.o
>>
>> drivers/firmware/qemu_fw_cfg.c:55:33: warning: restricted __be16 degrades to 
>> integer
>> drivers/firmware/qemu_fw_cfg.c:55:52: warning: restricted __le16 degrades to 
>> integer
>>
>> Signed-off-by: Marc-André Lureau 
>> ---
>>  drivers/firmware/qemu_fw_cfg.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
>> index 90f467232777..85e693287d87 100644
>> --- a/drivers/firmware/qemu_fw_cfg.c
>> +++ b/drivers/firmware/qemu_fw_cfg.c
>> @@ -52,7 +52,9 @@ static DEFINE_MUTEX(fw_cfg_dev_lock);
>>  /* pick appropriate endianness for selector key */
>>  static inline u16 fw_cfg_sel_endianness(u16 key)
>>  {
>> - return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
>> + return fw_cfg_is_mmio ?
>> + (u16 __force)cpu_to_be16(key) :
>> + (u16 __force)cpu_to_le16(key);
>>  }
>>
>>  /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
>
> Well the caller does cpu_to_le16 on the result ...
> All this makes my head spin.
>
> IMHO what you want is a wrapper that does iowrite and iowritebe
> rather than __force.

iowrite16(key) is the same as iowrite16(cpu_to_le16(key)) ? There is
no iowrite16le()...

Is this equivalent, and not introducing regressions?

static inline u16 fw_cfg_sel_endianness(u16 key)
+static void fw_cfg_sel_endianness(u16 key)
 {
-   return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
+   if (fw_cfg_is_mmio)
+   iowrite16be(key, fw_cfg_reg_ctrl);
+   else
+   iowrite16(key, fw_cfg_reg_ctrl);
 }

 /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
@@ -74,7 +77,7 @@ static inline void fw_cfg_read_blob(u16 key,
}

mutex_lock(_cfg_dev_lock);
-   iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
+   fw_cfg_sel_endianness(key);

>
>
>> --
>> 2.16.1.73.g5832b7e9f2

Re: [PATCH v14 3/9] fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()

2018-02-14 Thread Michael S. Tsirkin 
On Wed, Feb 14, 2018 at 03:18:44PM +0100, Marc-André Lureau wrote:
> The function is used for both LE & BE target type, use __force casting.
> 
> Fixes:
> $ make C=1 CF=-D__CHECK_ENDIAN__ drivers/firmware/qemu_fw_cfg.o
> 
> drivers/firmware/qemu_fw_cfg.c:55:33: warning: restricted __be16 degrades to 
> integer
> drivers/firmware/qemu_fw_cfg.c:55:52: warning: restricted __le16 degrades to 
> integer
> 
> Signed-off-by: Marc-André Lureau 
> ---
>  drivers/firmware/qemu_fw_cfg.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index 90f467232777..85e693287d87 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -52,7 +52,9 @@ static DEFINE_MUTEX(fw_cfg_dev_lock);
>  /* pick appropriate endianness for selector key */
>  static inline u16 fw_cfg_sel_endianness(u16 key)
>  {
> - return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
> + return fw_cfg_is_mmio ?
> + (u16 __force)cpu_to_be16(key) :
> + (u16 __force)cpu_to_le16(key);
>  }
>  
>  /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */

Well the caller does cpu_to_le16 on the result ...
All this makes my head spin.

IMHO what you want is a wrapper that does iowrite and iowritebe
rather than __force.


> -- 
> 2.16.1.73.g5832b7e9f2

Re: [PATCH v14 3/9] fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()

2018-02-14 Thread Michael S. Tsirkin 
On Wed, Feb 14, 2018 at 03:18:44PM +0100, Marc-André Lureau wrote:
> The function is used for both LE & BE target type, use __force casting.
> 
> Fixes:
> $ make C=1 CF=-D__CHECK_ENDIAN__ drivers/firmware/qemu_fw_cfg.o
> 
> drivers/firmware/qemu_fw_cfg.c:55:33: warning: restricted __be16 degrades to 
> integer
> drivers/firmware/qemu_fw_cfg.c:55:52: warning: restricted __le16 degrades to 
> integer
> 
> Signed-off-by: Marc-André Lureau 
> ---
>  drivers/firmware/qemu_fw_cfg.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index 90f467232777..85e693287d87 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -52,7 +52,9 @@ static DEFINE_MUTEX(fw_cfg_dev_lock);
>  /* pick appropriate endianness for selector key */
>  static inline u16 fw_cfg_sel_endianness(u16 key)
>  {
> - return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
> + return fw_cfg_is_mmio ?
> + (u16 __force)cpu_to_be16(key) :
> + (u16 __force)cpu_to_le16(key);
>  }
>  
>  /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */

Well the caller does cpu_to_le16 on the result ...
All this makes my head spin.

IMHO what you want is a wrapper that does iowrite and iowritebe
rather than __force.


> -- 
> 2.16.1.73.g5832b7e9f2

[PATCH v14 3/9] fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()

2018-02-14 Thread Marc-André Lureau 
The function is used for both LE & BE target type, use __force casting.

Fixes:
$ make C=1 CF=-D__CHECK_ENDIAN__ drivers/firmware/qemu_fw_cfg.o

drivers/firmware/qemu_fw_cfg.c:55:33: warning: restricted __be16 degrades to 
integer
drivers/firmware/qemu_fw_cfg.c:55:52: warning: restricted __le16 degrades to 
integer

Signed-off-by: Marc-André Lureau 
---
 drivers/firmware/qemu_fw_cfg.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index 90f467232777..85e693287d87 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -52,7 +52,9 @@ static DEFINE_MUTEX(fw_cfg_dev_lock);
 /* pick appropriate endianness for selector key */
 static inline u16 fw_cfg_sel_endianness(u16 key)
 {
-   return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
+   return fw_cfg_is_mmio ?
+   (u16 __force)cpu_to_be16(key) :
+   (u16 __force)cpu_to_le16(key);
 }
 
 /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
-- 
2.16.1.73.g5832b7e9f2

[PATCH v14 3/9] fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()

2018-02-14 Thread Marc-André Lureau 
The function is used for both LE & BE target type, use __force casting.

Fixes:
$ make C=1 CF=-D__CHECK_ENDIAN__ drivers/firmware/qemu_fw_cfg.o

drivers/firmware/qemu_fw_cfg.c:55:33: warning: restricted __be16 degrades to 
integer
drivers/firmware/qemu_fw_cfg.c:55:52: warning: restricted __le16 degrades to 
integer

Signed-off-by: Marc-André Lureau 
---
 drivers/firmware/qemu_fw_cfg.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index 90f467232777..85e693287d87 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -52,7 +52,9 @@ static DEFINE_MUTEX(fw_cfg_dev_lock);
 /* pick appropriate endianness for selector key */
 static inline u16 fw_cfg_sel_endianness(u16 key)
 {
-   return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
+   return fw_cfg_is_mmio ?
+   (u16 __force)cpu_to_be16(key) :
+   (u16 __force)cpu_to_le16(key);
 }
 
 /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
-- 
2.16.1.73.g5832b7e9f2