[Intel-gfx] [PATCH 2/2] iosys-map: Add per-word write

[Thomas Zimmermann]

Hi Lucas

Am 26.06.22 um 23:01 schrieb Lucas De Marchi:
> On Fri, Jun 17, 2022 at 01:52:04AM -0700, Lucas De Marchi wrote:
>> Like was done for read, provide the equivalent for write. Even if
>> current users are not in the hot path, this should future-proof it.
>>
>> v2:
>>  - Remove default from _Generic() - callers wanting to write more
>>    than u64 should use iosys_map_memcpy_to()
>>  - Add WRITE_ONCE() cases dereferencing the pointer when using system
>>    memory
> 
> Thomas, do you have any additional concern on this patch regarding your
> previous review?

Sorry, your patches simply fell through the cracks. For the patchset:

Reviewed-by: Thomas Zimmermann <tzimmermann at suse.de>

Thanks for the effort you put into this.

Best regards
Thomas

> 
> thanks
> Lucas De Marchi
> 
>>
>> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
>> Reviewed-by: Reviewed-by: Christian König <christian.koenig at amd.com> # v1
>> ---
>> include/linux/iosys-map.h | 42 ++++++++++++++++++++++++++++++---------
>> 1 file changed, 33 insertions(+), 9 deletions(-)
>>
>> diff --git a/include/linux/iosys-map.h b/include/linux/iosys-map.h
>> index f59dd00ed202..580e14cd360c 100644
>> --- a/include/linux/iosys-map.h
>> +++ b/include/linux/iosys-map.h
>> @@ -337,9 +337,13 @@ static inline void iosys_map_memset(struct 
>> iosys_map *dst, size_t offset,
>> #ifdef CONFIG_64BIT
>> #define __iosys_map_rd_io_u64_case(val_, vaddr_iomem_)                \
>>     u64: val_ = readq(vaddr_iomem_)
>> +#define __iosys_map_wr_io_u64_case(val_, vaddr_iomem_)            \
>> +    u64: writeq(val_, vaddr_iomem_)
>> #else
>> #define __iosys_map_rd_io_u64_case(val_, vaddr_iomem_)                \
>>     u64: memcpy_fromio(&(val_), vaddr_iomem__, sizeof(u64))
>> +#define __iosys_map_wr_io_u64_case(val_, vaddr_iomem_)            \
>> +    u64: memcpy_toio(vaddr_iomem_, &(val_), sizeof(u64))
>> #endif
>>
>> #define __iosys_map_rd_io(val__, vaddr_iomem__, type__) 
>> _Generic(val__,        \
>> @@ -354,6 +358,19 @@ static inline void iosys_map_memset(struct 
>> iosys_map *dst, size_t offset,
>>     val__ = READ_ONCE(*((type__ *)vaddr__));                \
>> })
>>
>> +#define __iosys_map_wr_io(val__, vaddr_iomem__, type__) 
>> _Generic(val__,        \
>> +    u8: writeb(val__, vaddr_iomem__),                    \
>> +    u16: writew(val__, vaddr_iomem__),                    \
>> +    u32: writel(val__, vaddr_iomem__),                    \
>> +    __iosys_map_wr_io_u64_case(val__, vaddr_iomem__))
>> +
>> +#define __iosys_map_wr_sys(val__, vaddr__, type__) ({                \
>> +    compiletime_assert(sizeof(type__) <= sizeof(u64),            \
>> +               "Unsupported access size for __iosys_map_wr_sys()"); \
>> +    WRITE_ONCE(*((type__ *)vaddr__), val__);                \
>> +})
>> +
>> +
>> /**
>>  * iosys_map_rd - Read a C-type value from the iosys_map
>>  *
>> @@ -386,12 +403,17 @@ static inline void iosys_map_memset(struct 
>> iosys_map *dst, size_t offset,
>>  * @type__:    Type of the value being written
>>  * @val__:    Value to write
>>  *
>> - * Write a C-type value to the iosys_map, handling possible 
>> un-aligned accesses
>> - * to the mapping.
>> + * Write a C type value (u8, u16, u32 and u64) to the iosys_map. For 
>> other types
>> + * or if pointer may be unaligned (and problematic for the architecture
>> + * supported), use iosys_map_memcpy_to()
>>  */
>> -#define iosys_map_wr(map__, offset__, type__, val__) ({            \
>> -    type__ val = (val__);                        \
>> -    iosys_map_memcpy_to(map__, offset__, &val, sizeof(val));    \
>> +#define iosys_map_wr(map__, offset__, type__, val__) ({                \
>> +    type__ val = (val__);                            \
>> +    if ((map__)->is_iomem) {                        \
>> +        __iosys_map_wr_io(val, (map__)->vaddr_iomem + (offset__), 
>> type__);\
>> +    } else {                                \
>> +        __iosys_map_wr_sys(val, (map__)->vaddr + (offset__), 
>> type__);    \
>> +    }                                    \
>> })
>>
>> /**
>> @@ -472,10 +494,12 @@ static inline void iosys_map_memset(struct 
>> iosys_map *dst, size_t offset,
>>  * @field__:        Member of the struct to read
>>  * @val__:        Value to write
>>  *
>> - * Write a value to the iosys_map considering its layout is described 
>> by a C struct
>> - * starting at @struct_offset__. The field offset and size is 
>> calculated and the
>> - * @val__ is written handling possible un-aligned memory accesses. 
>> Refer to
>> - * iosys_map_rd_field() for expected usage and memory layout.
>> + * Write a value to the iosys_map considering its layout is described 
>> by a C
>> + * struct starting at @struct_offset__. The field offset and size is 
>> calculated
>> + * and the @val__ is written. If the field access would incur in 
>> un-aligned
>> + * access, then either iosys_map_memcpy_to() needs to be used or the
>> + * architecture must support it. Refer to iosys_map_rd_field() for 
>> expected
>> + * usage and memory layout.
>>  */
>> #define iosys_map_wr_field(map__, struct_offset__, struct_type__, 
>> field__, val__) ({    \
>>     struct_type__ *s;                                \
>> -- 
>> 2.36.1
>>

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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