[PATCH 1/2] asm-generic/io.h: suppress endianness warnings for readq() and writeq()

[PATCH 1/2] asm-generic/io.h: suppress endianness warnings for readq() and writeq()

[Vladimir Oltean]

Commit c1d55d50139b ("asm-generic/io.h: Fix sparse warnings on
big-endian architectures") missed fixing the 64-bit accessors.

Arnd explains in the attached link why the casts are necessary, even if
__raw_readq() and __raw_writeq() do not take endian-specific types.

Link: https://lore.kernel.org/lkml/9105d6fc-880b-4734-857d-e3d30b87ccf6@app.fastmail.com/
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 include/asm-generic/io.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 4c44a29b5e8e..d78c3056c98f 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -236,7 +236,7 @@ static inline u64 readq(const volatile void __iomem *addr)
 
 	log_read_mmio(64, addr, _THIS_IP_, _RET_IP_);
 	__io_br();
-	val = __le64_to_cpu(__raw_readq(addr));
+	val = __le64_to_cpu((__le64 __force)__raw_readq(addr));
 	__io_ar(val);
 	log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_);
 	return val;
@@ -287,7 +287,7 @@ static inline void writeq(u64 value, volatile void __iomem *addr)
 {
 	log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
 	__io_bw();
-	__raw_writeq(__cpu_to_le64(value), addr);
+	__raw_writeq((u64 __force)__cpu_to_le64(value), addr);
 	__io_aw();
 	log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
 }
-- 
2.34.1

[PATCH 2/2] asm-generic/io.h: suppress endianness warnings for relaxed accessors

[Vladimir Oltean]

Copy the forced type casts from the normal MMIO accessors to suppress
the sparse warnings that point out __raw_readl() returns a native endian
word (just like readl()).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 include/asm-generic/io.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index d78c3056c98f..587e7e9b9a37 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -319,7 +319,7 @@ static inline u16 readw_relaxed(const volatile void __iomem *addr)
 	u16 val;
 
 	log_read_mmio(16, addr, _THIS_IP_, _RET_IP_);
-	val = __le16_to_cpu(__raw_readw(addr));
+	val = __le16_to_cpu((__le16 __force)__raw_readw(addr));
 	log_post_read_mmio(val, 16, addr, _THIS_IP_, _RET_IP_);
 	return val;
 }
@@ -332,7 +332,7 @@ static inline u32 readl_relaxed(const volatile void __iomem *addr)
 	u32 val;
 
 	log_read_mmio(32, addr, _THIS_IP_, _RET_IP_);
-	val = __le32_to_cpu(__raw_readl(addr));
+	val = __le32_to_cpu((__le32 __force)__raw_readl(addr));
 	log_post_read_mmio(val, 32, addr, _THIS_IP_, _RET_IP_);
 	return val;
 }
@@ -345,7 +345,7 @@ static inline u64 readq_relaxed(const volatile void __iomem *addr)
 	u64 val;
 
 	log_read_mmio(64, addr, _THIS_IP_, _RET_IP_);
-	val = __le64_to_cpu(__raw_readq(addr));
+	val = __le64_to_cpu((__le64 __force)__raw_readq(addr));
 	log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_);
 	return val;
 }
@@ -366,7 +366,7 @@ static inline void writeb_relaxed(u8 value, volatile void __iomem *addr)
 static inline void writew_relaxed(u16 value, volatile void __iomem *addr)
 {
 	log_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_);
-	__raw_writew(cpu_to_le16(value), addr);
+	__raw_writew((u16 __force)cpu_to_le16(value), addr);
 	log_post_write_mmio(value, 16, addr, _THIS_IP_, _RET_IP_);
 }
 #endif
@@ -376,7 +376,7 @@ static inline void writew_relaxed(u16 value, volatile void __iomem *addr)
 static inline void writel_relaxed(u32 value, volatile void __iomem *addr)
 {
 	log_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_);
-	__raw_writel(__cpu_to_le32(value), addr);
+	__raw_writel((u32 __force)__cpu_to_le32(value), addr);
 	log_post_write_mmio(value, 32, addr, _THIS_IP_, _RET_IP_);
 }
 #endif
@@ -386,7 +386,7 @@ static inline void writel_relaxed(u32 value, volatile void __iomem *addr)
 static inline void writeq_relaxed(u64 value, volatile void __iomem *addr)
 {
 	log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
-	__raw_writeq(__cpu_to_le64(value), addr);
+	__raw_writeq((u64 __force)__cpu_to_le64(value), addr);
 	log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
 }
 #endif
-- 
2.34.1

Re: [PATCH 1/2] asm-generic/io.h: suppress endianness warnings for readq() and writeq()

[Vladimir Oltean]

Hi Arnd,

On Mon, Jan 09, 2023 at 03:11:52PM +0200, Vladimir Oltean wrote:
> Commit c1d55d50139b ("asm-generic/io.h: Fix sparse warnings on
> big-endian architectures") missed fixing the 64-bit accessors.
> 
> Arnd explains in the attached link why the casts are necessary, even if
> __raw_readq() and __raw_writeq() do not take endian-specific types.
> 
> Link: https://lore.kernel.org/lkml/9105d6fc-880b-4734-857d-e3d30b87ccf6@app.fastmail.com/
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> ---
>  include/asm-generic/io.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
> index 4c44a29b5e8e..d78c3056c98f 100644
> --- a/include/asm-generic/io.h
> +++ b/include/asm-generic/io.h
> @@ -236,7 +236,7 @@ static inline u64 readq(const volatile void __iomem *addr)
>  
>  	log_read_mmio(64, addr, _THIS_IP_, _RET_IP_);
>  	__io_br();
> -	val = __le64_to_cpu(__raw_readq(addr));
> +	val = __le64_to_cpu((__le64 __force)__raw_readq(addr));
>  	__io_ar(val);
>  	log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_);
>  	return val;
> @@ -287,7 +287,7 @@ static inline void writeq(u64 value, volatile void __iomem *addr)
>  {
>  	log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
>  	__io_bw();
> -	__raw_writeq(__cpu_to_le64(value), addr);
> +	__raw_writeq((u64 __force)__cpu_to_le64(value), addr);
>  	__io_aw();
>  	log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
>  }
> -- 
> 2.34.1
>

Did these patches get lost?

Re: [PATCH 1/2] asm-generic/io.h: suppress endianness warnings for readq() and writeq()

[Jonathan Cameron]

On Mon,  9 Jan 2023 15:11:52 +0200
Vladimir Oltean <vladimir.oltean@nxp.com> wrote:

> Commit c1d55d50139b ("asm-generic/io.h: Fix sparse warnings on
> big-endian architectures") missed fixing the 64-bit accessors.
> 
> Arnd explains in the attached link why the casts are necessary, even if
> __raw_readq() and __raw_writeq() do not take endian-specific types.
> 
> Link: https://lore.kernel.org/lkml/9105d6fc-880b-4734-857d-e3d30b87ccf6@app.fastmail.com/
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Found this when about to send an equivalent patch. Not seeing this in linux-next yet
and would be good to clean the resulting warnings up.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  include/asm-generic/io.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
> index 4c44a29b5e8e..d78c3056c98f 100644
> --- a/include/asm-generic/io.h
> +++ b/include/asm-generic/io.h
> @@ -236,7 +236,7 @@ static inline u64 readq(const volatile void __iomem *addr)
>  
>  	log_read_mmio(64, addr, _THIS_IP_, _RET_IP_);
>  	__io_br();
> -	val = __le64_to_cpu(__raw_readq(addr));
> +	val = __le64_to_cpu((__le64 __force)__raw_readq(addr));
>  	__io_ar(val);
>  	log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_);
>  	return val;
> @@ -287,7 +287,7 @@ static inline void writeq(u64 value, volatile void __iomem *addr)
>  {
>  	log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
>  	__io_bw();
> -	__raw_writeq(__cpu_to_le64(value), addr);
> +	__raw_writeq((u64 __force)__cpu_to_le64(value), addr);
>  	__io_aw();
>  	log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
>  }

Re: [PATCH 1/2] asm-generic/io.h: suppress endianness warnings for readq() and writeq()

[Arnd Bergmann]

On Fri, Mar 10, 2023, at 10:30, Vladimir Oltean wrote:
> Hi Arnd,
>
> On Mon, Jan 09, 2023 at 03:11:52PM +0200, Vladimir Oltean wrote:
>> Commit c1d55d50139b ("asm-generic/io.h: Fix sparse warnings on
>> big-endian architectures") missed fixing the 64-bit accessors.
>> 
>> Arnd explains in the attached link why the casts are necessary, even if
>> __raw_readq() and __raw_writeq() do not take endian-specific types.
>> 
>> Link: https://lore.kernel.org/lkml/9105d6fc-880b-4734-857d-e3d30b87ccf6@app.fastmail.com/
>> Suggested-by: Arnd Bergmann <arnd@arndb.de>
>> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

>>
>
> Did these patches get lost?

Yes, sorry about that. I picked them up for 6.3 now, along with another
one that I just remembered.

     Arnd